quak files takes the collection ID as an optional argument (closes #211)

Mandatory arguments are positional, so `quak files` takes the collection ID as an optional argument and the `--collection` option is removed. With a collection ID it lists that collection's files. Without one it lists every file in the account, collection by collection, each file once: the library keeps a record of a file for each collection that holds it, and only the first collection's record is listed, so that collection is its `collectionID` in `--json`. The `--help` text, the README and `TODO.md` say so.

Model: opus-5-5

README.md

@@ -35,8 +35,11 @@ yarn quak login
 # List the user's collections (albums).
 yarn quak collections
 
-# List files in a collection.
-yarn quak files --collection 12345
+# List every file in the account.
+yarn quak files
+
+# List the files in a collection.
+yarn quak files 12345
 
 # Download and decrypt a single file.
 yarn quak get 67890 --out ./photo.jpg
@@ -134,12 +137,12 @@ matters.
 
 ### Exit codes
 
-| Code | Meaning                                                                                                                                                                           |
-| ---- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| `0`  | The backup is complete: every original is at its save path, and no file failed.                                                                                                   |
-| `1`  | The run finished with files in `failures.json` or an album it could not decrypt, or it stopped on another error, printed as one line `quak: <message>`. The next run tries again. |
-| `2`  | Another backup of the same directory is running. This run sent no request and changed nothing.                                                                                    |
-| `3`  | There is no usable session: none is saved, the saved one is corrupt, or the server no longer accepts it. Run `quak login` as the user the cron job runs as.                       |
+| Code | Meaning                                                                                                                                                                                                        |
+| ---- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `0`  | The backup is complete: every original is at its save path, and no file failed.                                                                                                                                |
+| `1`  | The run finished with files in `failures.json` or albums it could not decrypt or write (see "Backup layout"), or it stopped on another error, printed as one line `quak: <message>`. The next run tries again. |
+| `2`  | Another backup of the same directory is running. This run sent no request and changed nothing.                                                                                                                 |
+| `3`  | There is no usable session: none is saved, the saved one is corrupt, or the server no longer accepts it. Run `quak login` as the user the cron job runs as.                                                    |
 
 `<message>` is the error's message, followed by the message of each error that
 caused it. Under Node, as `yarn quak` runs quak, `fetch` reports every failure
@@ -151,16 +154,19 @@ for each, separated by `, `. A file whose download failed that way is in
 `failures.json` with that error, as a transient failure. So is each file with no
 ML data cached when the ML data fetch failed that way, its error starting
 `ML data: `. The `~/bin/quak` that `make install` builds runs under bun, and
-prints bun's own wording for such a failure.
+prints bun's own wording for such a failure, with no reason after it, such as
+`quak: Unable to connect. Is the computer able to access the url?` for a refused
+connection. It records such a failure in `failures.json` as transient too.
 
 After a `1`, the next run fetches each missing original again, fetches the ML
 data that is not cached, and rebuilds the album links. An album quak could not
 decrypt, or a file in `failures.json` because quak could not decrypt it, keeps
 the exit code at `1` until the server sends a copy that decrypts, or deletes it
-(see "Backup layout"). An original that a `--verify` run could not read, or put
-back with bytes that still do not match, stays at its save path. Only a later
-`--verify` run checks it again: a run without `--verify` leaves it as it is and
-takes the file out of `failures.json`, so that run can exit 0.
+(see "Backup layout"). An original that a `--verify` run could not read, or
+could not replace with a download that matches, stays at its save path as it
+was. Only a later `--verify` run checks it again: a run without `--verify`
+leaves it as it is and takes the file out of `failures.json`, so that run can
+exit 0.
 
 ## Examples
 
@@ -494,6 +500,17 @@ request is repeated only when repeating it could produce a different answer:
   declining to retry a transient one costs a single file that the next run picks
   up.
 
+The `~/bin/quak` that `make install` builds runs under bun, whose `fetch`
+rejects with a plain `Error` that has no `cause` and carries a code of bun's
+own. quak retries a refused connection, a name that does not resolve, a reset
+connection and a deadline under bun as it does under Node. Bun reports a refused
+connection, and a TLS handshake that failed, as `ConnectionRefused`. For a name
+that does not resolve it gives `ConnectionRefused` on some requests and
+`FailedToOpenSocket` on others. A connection reset or closed before the response
+ended is `ECONNRESET`, as under Node, and a deadline is the same `TimeoutError`.
+A certificate bun rejects, reported with a code such as
+`DEPTH_ZERO_SELF_SIGNED_CERT`, is not retried.
+
 Backoff is exponential with full jitter: the delay before retry _n_ is
 `random() * min(maxDelayMs, baseDelayMs * 2 ** (n - 1))`. The exponential term
 is the ceiling and the wait is drawn below it, so a client that lost many
@@ -549,9 +566,13 @@ routing errnos `EHOSTUNREACH`, `ENETUNREACH` and `ENETDOWN` are excluded for the
 same reason, despite looking like connect-time failures: on Linux an ICMP
 unreachable arriving mid-flight, or a local interface going down after the
 request was written, delivers them on an already-established socket. They stay
-retryable for the idempotent calls. `putFile` is exempt: a presigned PUT stores
-one whole object at one key in one request, so replaying it has no partial state
-to damage.
+retryable for the idempotent calls. So do bun's `ConnectionRefused` and
+`FailedToOpenSocket`, on which a `POST` or `PUT` is not replayed either. When a
+connection bun kept open from an earlier request closes before any answer, bun
+sends the request again on a new connection, and if that one fails it gives one
+of these codes although the server may already have the request. `putFile` is
+exempt: a presigned PUT stores one whole object at one key in one request, so
+replaying it has no partial state to damage.
 
 A download is retried as a whole — request, stream consumption, and decryption —
 because a socket reset after the response headers have arrived surfaces in the
@@ -629,7 +650,7 @@ quak login                                                interactive or QUAK_EM
 quak whoami                                               print logged-in account as JSON
 quak logout                                               end the session, delete it
 quak collections [--json]                                 list all collections
-quak files --collection <id> [--json]                     list files in a collection
+quak files [collectionID] [--json]                        list files in a collection, or every file
 quak get <fileID> [--out path] [--collection]             download and decrypt a file
 quak get-thumb <fileID> [--out] [--collection]            download and decrypt a thumbnail
 quak backup <dir> [--json] [--verify]                     full incremental backup
@@ -643,45 +664,74 @@ library. The read commands — `collections`, `files`, `get`, `get-thumb`,
 `backup-metadata`, `helper list-missing-thumbnails` and
 `helper fix-missing-thumbnails` — force a fresh server round-trip before they
 answer, so they report current account state rather than whatever the cache last
-held. If that round-trip fails, the command prints the error on one line and
+held. `collections` asks the server for the collection list alone, in one
+request, and neither fetches any collection's files nor changes the cache. The
+others wait for a refresh. With an empty cache, as on a first run, that refresh
+fetches the files of every collection, one collection after another, and stores
+nothing until it has them all, which on a large account takes a while. Meanwhile
+the command prints a line on stderr for each collection whose files it has
+fetched, such as `Fetched the files of 3 of 120 collections`; with `--json`,
+`files` and the two helpers print no such line. stdout holds only the command's
+output. If that round-trip fails, the command prints the error on one line and
 exits 1, or 3 when the server no longer accepts the saved session (see "Session
 handling"). An album or file quak cannot decrypt does not fail it; the command
 answers from what did decrypt (see "Default reads vs. fresh reads").
 `--cache-dir` overrides where the cache lives; without it each account gets its
 own directory under the per-user cache path.
 
-An ID given to `files --collection`, `get`, `get-thumb` or
+`files <collectionID>` lists the files in that collection. `files` with no
+argument lists every file in the account, collection by collection, each file
+once: a file in several collections is listed with the first of them, which is
+its `collectionID` in `--json`.
+
+An ID given to `files`, `get`, `get-thumb` or
 `helper fix-missing-thumbnails --file` is written in decimal digits, no larger
 than 9007199254740991. Anything else, such as `0x10`, `1e3` or `-1`, is refused
 before any request with one line, `Invalid file ID: <arg>` or
 `Invalid collection ID: <arg>`, and exit status 1. One bad `--file` ID refuses
 the whole command, so nothing is fixed.
 
+Without `--out`, `get` writes the file to the working directory under its title,
+and `get-thumb` writes the thumbnail there under `thumb_` followed by the title,
+each with unsafe characters replaced. A name over 255 bytes, which most file
+systems refuse, is cut short between two characters before its extension, so the
+extension is kept whenever it fits. An extension too long to leave room for the
+name's first character is cut short too, so the name never starts with a dot.
+
 `get` and `get-thumb` resolve the file by ID directly, so `--collection` is
 accepted for backward compatibility but ignored. For a live photo, `get` writes
 its image and its video, each named after the title with its own extension, as
-Ente's clients name them (`IMG_0001.heic` and `IMG_0001.mov`). With
-`--out PATH`, the image is written to `PATH` and the video beside it, with
-`PATH`'s name and the video's extension; a `PATH` with the video's extension is
-refused. `backup-metadata --exif` (alias `--all`) additionally fetches each
-file's original through the cache and records, from it or a live photo's image,
-its XMP metadata, its EXIF metadata and, for a JPEG, its dimensions. EXIF is
-read with [exifreader](https://github.com/mattiasw/ExifReader) from any image
-format it reads, JPEG, HEIC/HEIF, AVIF, PNG and WebP among them. The record's
-`exif` field is exifreader's EXIF tag output: each tag by name, with its
-`value`, `description` and `computed` value. An EXIF block exifreader finds but
-reads no tag from is recorded, base64, as `exifRaw`, with the reason in
-`exifError`. `collections`, `files`, `backup`, `helper list-missing-thumbnails`
-and `helper fix-missing-thumbnails` take `--json` for machine-readable output.
+Ente's clients name them (`IMG_0001.heic` and `IMG_0001.mov`), and each name is
+cut short as above once its own extension is in it. With `--out PATH`, the image
+is written to `PATH` and the video beside it, with `PATH`'s name and the video's
+extension; a `PATH` with the video's extension is refused.
+`backup-metadata --exif` (alias `--all`) additionally fetches each file's
+original through the cache and records, from it or a live photo's image, its XMP
+metadata, its EXIF metadata and, for a JPEG, its dimensions. EXIF is read with
+[exifreader](https://github.com/mattiasw/ExifReader) from any image format it
+reads, JPEG, HEIC/HEIF, AVIF, PNG and WebP among them. The record's `exif` field
+is exifreader's EXIF tag output: each tag by name, with its `value`,
+`description` and `computed` value. An EXIF block exifreader finds but reads no
+tag from is recorded, base64, as `exifRaw`, with the reason in `exifError`.
+`collections`, `files`, `backup`, `helper list-missing-thumbnails` and
+`helper fix-missing-thumbnails` take `--json` for machine-readable output.
 
 `backup --verify` also hashes the originals already in the backup and replaces
-any that do not match the content hash Ente records; one it cannot replace goes
-into `failures.json` (see "Backup layout").
+any that do not match the content hash Ente records; one it cannot replace stays
+as it was and goes into `failures.json` (see "Backup layout").
+
+`backup-metadata <dir>` writes `account.json` and, for each collection, a
+directory `collections/<id>-<name>/` holding `_collection.json` and a
+`<fileID>.json` for each of its files. The collection's name has unsafe
+characters replaced and is cut short between two characters so that the
+directory's name fits in 255 bytes; the ID keeps the directories apart.
 
 `backup-metadata` fetches ML data in requests of up to 200 files. When a request
 fails, the error is logged, each of its files is written with the reason in an
-`mlDataError` field instead of `mlData`, and the dump goes on. The exit code is
-non-zero if any ML data request failed.
+`mlDataError` field instead of `mlData`, and the dump goes on. A file whose ML
+data does not decrypt, gunzip or parse is logged and written the same way, with
+why in `mlDataError`. The exit code is non-zero if any file was written with
+`mlDataError`.
 
 `helper fix-missing-thumbnails` regenerates thumbnails for JPEG images only,
 because the bundled decoder (`jpeg-js`) decodes only JPEG. A non-JPEG image
@@ -728,9 +778,10 @@ Each original is saved at its save path, the same path `photo.savePath` gives
 and `photo.download()` writes (see Read surface below). The date is the photo's
 `takenAt` (the date set in Ente if it was edited, else its creation time) in the
 time zone of the machine running quak. The extension is the one in the file's
-name as uploaded, case kept, or `.bin` when it has none or it holds anything but
-letters and digits. When the date or the time zone changes, the next run saves
-the original at its new path and leaves the old copy where it is.
+name as uploaded, case kept, or `.bin` when it has none, it holds anything but
+letters and digits, or it is more than 16 of them long. When the date or the
+time zone changes, the next run saves the original at its new path and leaves
+the old copy where it is.
 
 `account.json` holds the account's `email` and `userID`, as `backup-metadata`
 writes it. A collection's JSON holds its `id`, `name`, `type`, `ownerID`,
@@ -746,8 +797,15 @@ A file's JSON holds Ente's ML data for it (its faces and its CLIP embedding) as
 for has no `mlData`. The backup waits for the library's ML data fetch to finish
 before it writes the JSON files. If that fetch fails, each file whose ML data is
 not in the cache gets the reason in `mlDataError` instead and counts as failed,
-and the next run fetches it again. The JSON files are rewritten on every run, so
-ML data that arrived since the last run appears.
+and the next run fetches it again. The same goes for a file with no ML data in
+the cache whose ML data the server sent but quak could not decrypt, gunzip or
+parse. Its `mlDataError` says why, and `failures.json` records it with an error
+starting `ML data: `. quak keeps that reason in memory only and caches nothing
+for the file, so the next run asks for its ML data again. An ML data fetch that
+fails, such as one the library's refresh starts while the backup writes the JSON
+files, leaves the reasons as the last fetch that succeeded left them. The JSON
+files are rewritten on every run, so ML data that arrived since the last run
+appears.
 
 A file's JSON holds, as `imageMetadata`, what `backup-metadata --exif` records
 from its original, or from a live photo's image: `format`, `width` and `height`
@@ -810,8 +868,24 @@ after the file's title, both with unsafe characters replaced. When two
 collections would get the same name, or two symlinks in one collection the same
 name (ignoring case in both), each of them gets its ID added: two albums named
 `Trip` become `Trip (10)/` and `Trip (11)/`, and two files titled `IMG_0001.JPG`
-become `IMG_0001 (12345).JPG` and `IMG_0001 (12346).JPG`. IDs never change, so a
-name stays the same from run to run until such a clash appears or goes away.
+become `IMG_0001 (12345).JPG` and `IMG_0001 (12346).JPG`. A collection whose
+directory would have the name of another collection's JSON, again ignoring case,
+gets its ID added as well: beside an album `x`, whose JSON is `x.json`, an album
+named `x.json` gets the directory `x.json (12)/`. A name too long for a file
+name, which most file systems limit to 255 bytes, gets its ID added too. A name
+with its ID added is cut short between two characters in the part before the ID,
+just far enough that it fits. When a symlink's extension leaves no room for the
+ID and the first character of the name, the extension is cut short, and the part
+before the ID keeps that character and any bytes the cut leaves over. A
+collection's directory name also leaves room for the `.json` its JSON adds. IDs
+never change, so a name stays the same from run to run until such a clash
+appears or goes away.
+
+A collection whose directory or JSON cannot be written, such as one whose
+directory name is taken by a file you put in `collections/`, does not stop the
+run. A run without `--json` prints `FAILED album <name>: <reason>` for it,
+`--json` and the `BackupResult` list its ID in `failedAlbums`, and the exit code
+is 1. The other collections and `failures.json` are still written.
 
 A live photo, which Ente stores as one ZIP of its image and its video, is stored
 as those two files, which a photo viewer can open: each is
@@ -846,33 +920,41 @@ original already at its save path the way a download is checked (see "On-disk
 cache layout" below): its bytes, read in chunks, or a live photo's image and
 video, joined as `<imageHash>:<videoHash>`. An original that matches the content
 hash its metadata records is left as it is. One that does not is logged on one
-line naming the file, deleted (a live photo's image and video both), and put
-back in the same run like a missing one: downloaded, or copied from the cache if
-the cache holds it. What is put back is hashed too, because a copy from the
-cache is not checked as a download is. If it still does not match, it stays at
-its save path and the file goes into `failures.json`, as it does when the
-download fails. A file whose metadata records no hash is left as it is and
-counted as unchecked. A stored original that cannot be read is left as it is and
-counts as failed. The summary and `--json` add the counts `verified`,
-`mismatched` and `unchecked`, all of originals that were already stored; one
-first downloaded in this run is in none of them. A mismatch that was put back
-with matching bytes does not make the exit code non-zero. Without `--verify`
-nothing is hashed, the summary is unchanged, and the three counts are 0 in
-`--json`.
+line naming the file, and replaced once a matching copy is downloaded, in the
+same run. The copy is downloaded even when the cache holds the original, because
+a copy from the cache is not checked as a download is. It is written to a
+temporary file beside the original, a live photo's image and video each to its
+own, hashed the same way, and renamed over the original only when it matches; a
+live photo's image and video are both hashed before either is renamed. Until
+then the original stays as it was: when the download fails, or what it brings
+does not match either, the temporary files are deleted, the original keeps its
+bytes and its album links, and the file goes into `failures.json`. A run that
+stops between renaming a live photo's new image and its new video leaves the new
+image beside the old video, which a later `--verify` run replaces if the video
+was the part that did not match. A file whose metadata records no hash is left
+as it is and counted as unchecked. A stored original that cannot be read is left
+as it is and counts as failed. The summary and `--json` add the counts
+`verified`, `mismatched` and `unchecked`, all of originals that were already
+stored; one first downloaded in this run is in none of them. A mismatch that was
+replaced with matching bytes does not make the exit code non-zero. Without
+`--verify` nothing is hashed, the summary is unchanged, and the three counts are
+0 in `--json`.
 
 Each original is written to a temporary file in the same directory, synced to
 disk, and renamed into place, so an original is either complete or absent, even
 after a power cut. A downloaded original's temporary file is named
 `.quak-<pid>-<random>.tmp`, one copied from the cache
-`.quak-backup-YYYY-MM-DD.<fileID>.<ext>-<pid>-<random>.tmp`. A run that is
-killed can leave one of these temporary files behind; the next backup deletes
-those whose process is no longer running. The content cache uses the same
-scheme, and opening a library deletes the temporary files in the cache whose
-process is no longer running, so a download another process has in progress in
-the same cache is left alone. The rename replaces whatever was at the
-destination rather than writing through it: a symlink there is replaced, not
-followed, and the new file has the temporary file's permissions, not those of
-the file it replaced.
+`.quak-backup-YYYY-MM-DD.<fileID>.<ext>-<pid>-<random>.tmp`. A copy that
+`--verify` downloads to replace an original is written to such a
+`.quak-<pid>-<random>.tmp` too, a live photo's image and video to
+`.quak-<pid>-<random>.<ext>`, each with its own extension. A run that is killed
+can leave one of these temporary files behind; the next backup deletes those
+whose process is no longer running. The content cache uses the same scheme, and
+opening a library deletes the temporary files in the cache whose process is no
+longer running, so a download another process has in progress in the same cache
+is left alone. The rename replaces whatever was at the destination rather than
+writing through it: a symlink there is replaced, not followed, and the new file
+has the temporary file's permissions, not those of the file it replaced.
 
 ## TODO
 
@@ -911,7 +993,11 @@ loop, and resolves to a `Library`. On an empty cache it awaits the first
 refresh, so it opens onto the account's data whenever the server is reachable;
 if that refresh fails, it opens with no data and records the error in
 `lib.status()`. On an existing cache it returns immediately and refreshes in the
-background, so an unreachable server does not block opening.
+background, so an unreachable server does not block opening. With
+`refreshOnOpen: false` it starts no refresh and returns at once onto what the
+cache holds, empty or not; a refresh then starts only when `fresh()` or
+`lib.backup()` asks, or the background timer fires. The CLI's read commands open
+it so (see "CLI surface").
 
 `LibraryOptions`:
 
@@ -921,6 +1007,7 @@ background, so an unreachable server does not block opening.
 | `cacheDirectory`         | `quak/<userID>` under the per-user cache directory | where `metadata.json` and the content cache live                     |
 | `downloadDirectory`      | `photos` in the working directory                  | root of the save paths; an original stored there counts as cached    |
 | `refreshIntervalSeconds` | `3`                                                | background refresh cadence; `Infinity` for no background timer       |
+| `refreshOnOpen`          | `true`                                             | start a refresh as the library opens                                 |
 | `precacheThumbnails`     | `true`                                             | prefetch every thumbnail, newest first                               |
 | `precacheOriginals`      | `true`                                             | prefetch the favorites album and the latest-window originals         |
 | `precacheOriginalsDays`  | `7`                                                | length in days of that latest window                                 |
@@ -934,6 +1021,14 @@ background, so an unreachable server does not block opening.
 The default `downloadDirectory` is resolved against the working directory once,
 when the library opens; `lib.downloadDirectory` holds the result.
 
+`onProgress` receives a `RefreshEvent` with status `"started"` as a refresh, an
+ML data fetch or a precache sweep starts, and `"done"` or `"failed"` as it ends.
+In between, a refresh sends `"progress"` after each collection whose files it
+fetched, with `fetched`, how many collections it has fetched the files of so
+far, and `total`, how many it will. A refresh fetches the files of each
+collection that is new or changed since the cache's copy, so on an empty cache
+it fetches those of every collection.
+
 Concurrency is set through `pools`: construct
 `new RequestPools({ metadataConcurrency, contentConcurrency, thumbnailConcurrency })`
 and pass it. The three pools default to 10 / 5 / 25 (see Request pools below).
@@ -946,6 +1041,14 @@ resolves once that refresh (including its cache write), the ML data fetch and
 the precache fetches already running have all finished, so the cache directory
 can then be removed.
 
+`lib.status().mlDataErrors` lists, as `{ fileID, error }`, each file whose ML
+data the last ML data fetch that succeeded got but could not decrypt, gunzip or
+parse; the `fetchMLData` event with status `"done"` carries the same list. A
+fetch that is still running leaves the list as it is until it ends, and a fetch
+that fails leaves it as it was. Such ML data is not cached, so the next ML data
+fetch asks for it again. The reasons are kept in memory only, never in the
+cache.
+
 ### Default reads vs. fresh reads
 
 Default reads — `lib.albums`, `lib.photos`, `lib.timeline` — answer
@@ -965,6 +1068,15 @@ rejects the caller (default reads stay silent and keep serving the last good
 copy). The CLI's read commands use fresh reads (issue
 https://git.eeqj.de/sneak/quak/issues/75).
 
+`await lib.freshCollections()` is the fresh read of the collection list alone:
+one collections request, answered with every live collection that decrypts, as
+the `Collection` objects `listCollections()` returns, in the server's order. It
+fetches no collection's files and stores nothing, not even the list: a refresh
+fetches a collection's files only when the collection is new or has changed
+since the stored copy, so a collection stored without its files would never get
+them. `quak collections` uses it (issue
+https://git.eeqj.de/sneak/quak/issues/210).
+
 An album or file in the server's answer that quak cannot decrypt, or whose
 metadata is not JSON, does not fail the refresh. The refresh leaves it out, an
 album with all its files, and drops any older copy the cache held, so reads
@@ -1105,9 +1217,10 @@ photos newest first). `lib.subscribe({ onChange })` delivers a `LibraryChange`
   `downloadDirectory` (falls back to the library's), `includeOriginals` (default
   `true`), `includeThumbnails` (default `false`), `onlyAlbumNames`, `verify`
   (default `false`), `onProgress`, and `lock`. See Backup layout above for the
-  tree it writes. Whether the backup took the lock or its caller did, once the
-  lock is lost the backup rejects with `lost the lock on <dir>: <reason>` before
-  it starts another file.
+  tree it writes, and for the albums `BackupResult` lists in
+  `undecryptableAlbums` and `failedAlbums`. Whether the backup took the lock or
+  its caller did, once the lock is lost the backup rejects with
+  `lost the lock on <dir>: <reason>` before it starts another file.
 
 ### Request pools
 

TODO.md

@@ -17,11 +17,8 @@ pre-1.0
 
 # Next Step
 
-Five bugs are open: https://git.eeqj.de/sneak/quak/issues/197,
-https://git.eeqj.de/sneak/quak/issues/198,
-https://git.eeqj.de/sneak/quak/issues/199,
-https://git.eeqj.de/sneak/quak/issues/205 and
-https://git.eeqj.de/sneak/quak/issues/206. The check of quak against a live Ente
+No bug is open. One change sneak asked for is open:
+https://git.eeqj.de/sneak/quak/issues/212. The check of quak against a live Ente
 account, https://git.eeqj.de/sneak/quak/issues/187, needs an account only sneak
 has, so it waits on him.
 
@@ -30,6 +27,84 @@ declares one.
 
 # Completed Steps
 
+- 2026-10-18: `quak files` takes the collection ID as an optional argument
+  instead of the `--collection` option, which is gone
+  (https://git.eeqj.de/sneak/quak/issues/211). With no argument it lists every
+  file in the account once, collection by collection; a file in several
+  collections is listed with the first of them, which is its `collectionID` in
+  `--json`. The fresh read in `src/cli-read.ts` does this.
+
+- 2026-10-18: Names quak builds from an album name or a title fit in a file name
+  (https://git.eeqj.de/sneak/quak/issues/205). `shortenKeepingExtension` in
+  `src/filename.ts` cuts a name short to a number of bytes, keeping its
+  extension when it fits and always its first character, and can put text right
+  before the extension; the backup's `withID` uses it for an ID.
+  `defaultFileName` there gives the name a file is saved under when the caller
+  gives no path: a prefix such as `thumb_` and the title with unsafe characters
+  replaced, cut short with it to 255 bytes, and, for a live photo's image or
+  video, with that part's own extension before the cut. `quak get`,
+  `quak get-thumb`, `downloadFile` and `downloadThumbnail` use it without
+  `--out` or `outPath`. `backup-metadata` cuts an album's name short so that its
+  folder, `<id>-<name>`, fits in 255 bytes. `safeExtension` gives `.bin` for an
+  extension of more than 16 letters and digits, so a save path's name always
+  fits.
+
+- 2026-10-18: `quak collections` no longer waits for the files of every
+  collection (issue 210). On an empty cache it opened its library with a refresh
+  that fetched and decrypted the files of each collection in turn, printing
+  nothing and storing nothing until all were done, so on a large account it
+  seemed to hang. It now reads the collection list alone through the new
+  `lib.freshCollections()`, one request that stores nothing. The read commands
+  open their library with the new `refreshOnOpen: false`, so each makes only the
+  refresh it asks for. A refresh sends a `"progress"` event after each
+  collection whose files it fetched, and the commands that wait on one print it
+  on stderr, except with `--json`.
+
+- 2026-10-16: ML data the server sends that does not decrypt, gunzip or parse is
+  no longer taken for no ML data (issue 198). `fetchMLDataBatch` returns why for
+  each such file beside the payloads; ML data that parses to something other
+  than a JSON object, such as `null`, is one of them. The library keeps the
+  reasons from its last ML data fetch that succeeded in memory, not in the
+  cache, and gives them in `status().mlDataErrors` and in the `fetchMLData`
+  event with status `"done"`; a fetch still running or one that fails does not
+  change them. `quak backup` writes the reason as `mlDataError` in the file's
+  JSON when no ML data is cached for it, and records the file in `failures.json`
+  with an error starting `ML data: `; `backup-metadata` writes `mlDataError`
+  too. Both exit 1. Tests serve ML data encrypted under a key that is not the
+  file's.
+
+- 2026-10-16: With `--verify`, an original whose hash does not match is no
+  longer removed before its replacement is downloaded (issue 199).
+  `replaceOriginal` in `src/library/content.ts` downloads the replacement to a
+  temporary file beside it, a live photo's image and video each to its own,
+  hashes it and renames it over the original only when it matches. When the
+  download fails or does not match either, the original keeps its bytes and
+  links, and the file goes into `failures.json`. The replacement is always
+  downloaded, through the new `fetchOriginal` of the content cache, never copied
+  from the cache.
+
+- 2026-10-16: The `~/bin/quak` that `make install` builds retries a refused
+  connection and a name that does not resolve, and the backup records either as
+  transient (issue 206). Bun's `fetch` reports them with codes of its own,
+  `ConnectionRefused` and `FailedToOpenSocket`, which `src/retry.ts` now counts
+  as transport failures. A `POST` or `PUT` is not replayed on them, because bun
+  also gives them when it resends a request on a new connection after a
+  connection it kept open closed, and the server may already have the request.
+  Bun already gave `ECONNRESET` for a reset and a `TimeoutError` for a deadline.
+  `classify` in `src/backup.ts` now records any `TimeoutError` as transient, so
+  a stalled download, whose error says only that it stalled, is no longer
+  `unknown`. The shapes were found by running the binary against local
+  listeners.
+
+- 2026-10-15: An album whose folder or JSON `quak backup` cannot write no longer
+  ends the run before the other albums and `failures.json` are written (issue
+  197). The run prints `FAILED album <name>: <reason>`, lists the album's ID in
+  `failedAlbums` in the result and in `--json`, goes on, and exits 1. An album
+  whose folder would have the name of another album's JSON, as `x.json` beside
+  `x` would, gets its ID added. A folder or link name over 255 bytes is cut
+  short between two characters, by `shortenToBytes` in `src/filename.ts`, and
+  gets the ID.
+
 - 2026-10-15: A network failure is printed and recorded with its reason, not as
   just `fetch failed` (issue 196). `describeError` in `src/errors.ts` gives an
   error's message followed by the message of each error on its `cause` chain,

bin/quak.ts

@@ -78,14 +78,15 @@ program
 
 program
     .command("files")
-    .description("List files in a collection")
-    .requiredOption(
-        "--collection <id>",
-        "Collection ID (from `quak collections`)",
+    .description("List the files in a collection, or every file in the account")
+    .argument(
+        "[collectionID]",
+        "Collection ID (from `quak collections`); without it, every file " +
+            "is listed once",
     )
     .option("--json", "Output as JSON array")
-    .action((opts: { collection: string; json?: boolean }) =>
-        run(filesCommand(context(), opts)),
+    .action((collectionID: string | undefined, opts: { json?: boolean }) =>
+        run(filesCommand(context(), collectionID, opts)),
     );
 
 program

src/backup.ts

@@ -41,8 +41,9 @@
 //
 // With `verify`, each original already at its save path is hashed as the
 // download check hashes it, and one that does not match the content hash its
-// metadata records is removed and fetched again in the same run. What is put
-// back is hashed too, and recorded as failed if it still does not match.
+// metadata records is replaced once a matching copy is downloaded, in the same
+// run. Until then it stays as it is: a download that fails, or that does not
+// match either, leaves it in place and is recorded as failed.
 //
 // Resilience (issue #8): no per-file condition aborts the run. A failed
 // download, a failed symlink, or ML data missing because the ML data fetch
@@ -50,7 +51,9 @@
 // running attempt count, and the last-tried time, and the run continues.
 // A file the library could not decrypt is recorded there too, unless a copy of
 // it in another album decrypted; an album it could not decrypt is logged by ID
-// and listed in `result.undecryptableAlbums`, as its name is not known.
+// and listed in `result.undecryptableAlbums`, as its name is not known. An
+// album whose folder or JSON cannot be written is logged by name and
+// listed in `result.failedAlbums`, and the run goes on to the next album.
 // `result.failed` — and thus the CLI's exit code — stays non-zero while any
 // failure remains unresolved and clears once every one succeeds. Each run
 // reconciles the ledger against the files it attempted, so an entry for a file
@@ -59,7 +62,6 @@
 // code.
 
 import {
-    createReadStream,
     lstatSync,
     mkdirSync,
     readdirSync,
@@ -75,20 +77,22 @@ import { readFile } from "node:fs/promises";
 import { dirname, extname, join, relative, resolve } from "node:path";
 import lockfile from "proper-lockfile";
 
-import {
-    chunkHashFinal,
-    chunkHashInit,
-    chunkHashUpdate,
-    init,
-} from "./crypto/index.js";
 import { removeLeftoverTempFiles } from "./download/index.js";
 import { describeError } from "./errors.js";
-import { sanitizeFileName, withExtension } from "./filename.js";
+import {
+    MAX_NAME_BYTES,
+    sanitizeFileName,
+    shortenKeepingExtension,
+    shortenToBytes,
+    withExtension,
+} from "./filename.js";
 import {
     copyAtomic,
     placeOriginal,
+    replaceOriginal,
     savePath,
     storedAtSavePath,
+    storedHash,
 } from "./library/content.js";
 import { representative } from "./library/records.js";
 import type { Undecryptable } from "./library/store.js";
@@ -145,9 +149,9 @@ export interface BackupResult {
     // Originals already at their save path and left untouched.
     skipped: number;
     // With `verify`, the originals already at their save path whose hash
-    // matched, those whose hash did not (each removed and fetched again), and
-    // those whose metadata records no hash (left as they are). All three are
-    // zero without `verify`.
+    // matched, those whose hash did not (each replaced once a matching copy is
+    // downloaded), and those whose metadata records no hash (left as they
+    // are). All three are zero without `verify`.
     verified: number;
     mismatched: number;
     unchecked: number;
@@ -160,6 +164,9 @@ export interface BackupResult {
     // The IDs of the albums the library could not decrypt, whose files it
     // could not list; the CLI exits non-zero while there are any.
     undecryptableAlbums: number[];
+    // The IDs of the albums whose folder or JSON this run could not write;
+    // the CLI exits non-zero while there are any.
+    failedAlbums: number[];
 }
 
 // The slice of the library that backup drives. `Library` implements it; a test
@@ -182,6 +189,15 @@ export interface BackupLibrary {
         fileID: number,
         destination: string,
     ): Promise<{ path: string; videoPath?: string }>;
+    // Fetch an original's bytes to `destination` through the content pool,
+    // a live photo as its image and its video beside it, even when the cache
+    // or the library's save path already holds it, and return where they
+    // landed. With `verify`, an original whose hash does not match is replaced
+    // with what this fetches.
+    fetchOriginal(
+        fileID: number,
+        destination: string,
+    ): Promise<{ path: string; videoPath?: string }>;
     thumbnail(fileID: number): Promise<{ path: string }>;
     // How many originals the backup works on at once: the limit of the
     // library's content pool.
@@ -193,6 +209,11 @@ export interface BackupLibrary {
     // A file's cached ML data, as `lib.mldata.forFile()` returns it, or
     // undefined when none is cached.
     mlData(fileID: number): Promise<MLData | undefined>;
+    // Why the ML data the last ML data fetch that succeeded got for a file did
+    // not decrypt, gunzip or parse, or undefined when it did or the fetch got
+    // none. A fetch still running does not change it. A fetch that fails
+    // leaves it as it was.
+    mlDataError(fileID: number): unknown;
 }
 
 type FailureClass = "transient" | "permanent" | "unknown";
@@ -223,10 +244,13 @@ const isPresent = (path: string): boolean => {
 // are transient; refusals and local filesystem/decrypt errors are permanent;
 // anything else is unknown. The error code and the error as `describeError`
 // gives it are inspected, and so is each errno on the error's cause chain,
-// where Node's `fetch` puts it.
+// where Node's `fetch` puts it. An error named `TimeoutError` is transient
+// whatever its message says, as `isRetryable` retries it: each of quak's
+// deadlines aborts with one, and the download's says only that it stalled.
 const classify = (err: unknown): FailureClass => {
     if (hasTransportCode(err)) return "transient";
     const e = err as NodeJS.ErrnoException;
+    if (e?.name === "TimeoutError") return "transient";
     const text = `${e?.code ?? ""} ${describeError(err)}`.toLowerCase();
     if (
         /timeout|timed out|econnreset|econnrefused|econnaborted|network|socket|eai_again|throttl|temporarily|429|500|502|503|504/.test(
@@ -264,31 +288,46 @@ const rebuildSymlink = (linkPath: string, target: string): void => {
 // The on-disk names for the entries of one directory, in entry order. Each
 // name is used as is unless another entry would get the same name, ignoring
 // case (two names that differ only in case are one entry on a case-insensitive
-// file system); then every entry sharing it gets ` (<id>)`, before the
-// extension when `beforeExtension` is set. A name with an ID added can match
-// another entry's own name (`IMG (6).JPG`), so this repeats until no name is
-// shared. IDs are stable, so the names are too.
+// file system), or it is too long for a file name; then it gets ` (<id>)`,
+// right before the extension when `beforeExtension` is set. To fit, the part
+// before the ID is cut short as far as it must be. When the extension leaves
+// no room for the ID and the first character of the name, the extension is
+// cut short, and the part before the ID keeps that character and any bytes
+// the cut leaves over (see `shortenKeepingExtension`). With `withJSON`, each
+// entry also has the JSON file `<name>.json` beside it, as an album does: a
+// name then leaves room for `.json`, and one that is another entry's JSON name
+// gets its ID added too.
+// Two names with different IDs added never match, but one can match another
+// entry's own name (`IMG (6).JPG`), so this repeats until no name is shared.
+// IDs are stable, so the names are too.
 const uniqueNames = (
     entries: { id: number; name: string }[],
-    beforeExtension: boolean,
+    opts: { beforeExtension?: boolean; withJSON?: boolean },
 ): string[] => {
+    const maxBytes = MAX_NAME_BYTES - (opts.withJSON ? ".json".length : 0);
     const withID = (id: number, name: string): string => {
-        const ext = beforeExtension ? extname(name) : "";
-        const stem = name.slice(0, name.length - ext.length);
-        return `${stem} (${id})${ext}`;
+        const tag = ` (${id})`;
+        return opts.beforeExtension
+            ? shortenKeepingExtension(name, maxBytes, tag)
+            : shortenToBytes(name, maxBytes - Buffer.byteLength(tag)) + tag;
     };
     const names = entries.map((e) => e.name);
     const suffixed = new Set<number>();
     for (;;) {
         const counts = new Map<string, number>();
-        for (const name of names) {
+        const count = (name: string): void => {
             const key = name.toLowerCase();
             counts.set(key, (counts.get(key) ?? 0) + 1);
+        };
+        for (const name of names) {
+            count(name);
+            if (opts.withJSON) count(`${name}.json`);
         }
         let changed = false;
         for (const [i, { id, name }] of entries.entries()) {
             if (suffixed.has(i)) continue;
-            if (counts.get(name.toLowerCase()) === 1) continue;
+            const fits = Buffer.byteLength(name) <= maxBytes;
+            if (fits && counts.get(name.toLowerCase()) === 1) continue;
             names[i] = withID(id, name);
             suffixed.add(i);
             changed = true;
@@ -415,26 +454,6 @@ const saveLedger = (path: string, ledger: Map<number, FailureEntry>): void => {
     );
 };
 
-// The content hash of the original stored at `stored`, computed as the download
-// check computes it: over each file's bytes, read in chunks, and for a live
-// photo `<imageHash>:<videoHash>`.
-const storedHash = async (stored: {
-    path: string;
-    videoPath?: string;
-}): Promise<string> => {
-    await init();
-    const hashFile = async (path: string): Promise<string> => {
-        const state = chunkHashInit();
-        for await (const chunk of createReadStream(path)) {
-            chunkHashUpdate(state, chunk as Buffer);
-        }
-        return chunkHashFinal(state);
-    };
-    const hash = await hashFile(stored.path);
-    if (stored.videoPath === undefined) return hash;
-    return `${hash}:${await hashFile(stored.videoPath)}`;
-};
-
 // A file's EXIF, XMP and dimensions as its JSON holds them: what
 // `extractImageMetadata` found in its original, or why the original could not
 // be read.
@@ -656,11 +675,13 @@ const runLockedBackup = async (
     // through the content cache/pools, as `Photo.download()` does, and fetch
     // the optional thumbnails; a present file is left as is. With `verify`, a
     // present original is hashed first, and one that does not match the hash
-    // its metadata records is removed and fetched like a missing one. One
-    // that cannot be read is recorded as failed and left where it is.
-    // `storeOriginal` does this for one original, and records its failure.
+    // its metadata records is downloaded again and replaced by
+    // `replaceOriginal`, which leaves it as it was when that download fails
+    // or does not match either. One that cannot be read is recorded as failed
+    // and left where it is. `storeOriginal` does this for one original, and
+    // records its failure.
     const storeOriginal = async (file: EnteFile): Promise<void> => {
-        let stored = storedAtSavePath(downloadDirectory, file);
+        const stored = storedAtSavePath(downloadDirectory, file);
         let mismatch = false;
         if (stored !== undefined && verify) {
             try {
@@ -674,11 +695,6 @@ const runLockedBackup = async (
                     );
                     mismatched++;
                     mismatch = true;
-                    rmSync(stored.path);
-                    if (stored.videoPath !== undefined) {
-                        rmSync(stored.videoPath);
-                    }
-                    stored = undefined;
                 }
             } catch (err) {
                 log(
@@ -693,29 +709,25 @@ const runLockedBackup = async (
                 return;
             }
         }
-        if (stored !== undefined) {
+        if (stored !== undefined && !mismatch) {
             skipped++;
             return;
         }
         try {
             log(`Fetching original ${file.metadata.title} (${file.id})...`);
-            // A fetched original is written straight to its save path (a
-            // live photo beside it); only one that was already cached
-            // elsewhere is copied.
-            const placed = await placeOriginal(
-                downloadDirectory,
-                file,
-                (dest) => lib.original(file.id, dest),
-            );
-            storedThisRun.add(file.id);
-            // A copy from the cache is not checked as a download is and can
-            // hold the same bad bytes, so what is put back after a mismatch
-            // is hashed too. A bad copy stays where it is and the file fails.
-            if (mismatch && (await storedHash(placed)) !== file.metadata.hash) {
-                throw new Error(
-                    "the original put back does not match its content hash either",
+            if (mismatch) {
+                await replaceOriginal(downloadDirectory, file, (dest) =>
+                    lib.fetchOriginal(file.id, dest),
+                );
+            } else {
+                // A fetched original is written straight to its save path (a
+                // live photo beside it); only one that was already cached
+                // elsewhere is copied.
+                await placeOriginal(downloadDirectory, file, (dest) =>
+                    lib.original(file.id, dest),
                 );
             }
+            storedThisRun.add(file.id);
             downloaded++;
         } catch (err) {
             log(
@@ -784,19 +796,18 @@ const runLockedBackup = async (
     // Phase 2: rebuild the derived views from the model. Sidecars first, for
     // every present original (this repairs stale ones), each with the file's
     // ML data once an ML data fetch has completed, and its image metadata.
-    // When the fetch fails, a file with no cached ML data gets the reason
-    // instead and is recorded as failed. The next run fetches its ML data
-    // again because none is cached.
+    // When the fetch got a file's ML data but could not decrypt, gunzip or
+    // parse it, or when the fetch failed, a file with no cached ML data gets
+    // the reason instead and is recorded as failed. The next run fetches its
+    // ML data again because none is cached.
     if (includeOriginals) {
         let mlDataFailure: unknown;
-        let mlDataError: string | undefined;
         try {
             log("Fetching ML data...");
             await lib.fetchMLData();
         } catch (err) {
             mlDataFailure = err;
-            mlDataError = describeError(err);
-            log(`FAILED ML data: ${mlDataError}`);
+            log(`FAILED ML data: ${describeError(err)}`);
         }
         for (const file of distinct.values()) {
             if (lock.lost) throw lock.lost;
@@ -813,13 +824,19 @@ const runLockedBackup = async (
                 storedThisRun.has(file.id),
             );
             const mlData = await lib.mlData(file.id);
-            if (mlData === undefined && mlDataError !== undefined) {
-                writeSidecar(path, file, { mlDataError }, image);
+            const failure = lib.mlDataError(file.id) ?? mlDataFailure;
+            if (mlData === undefined && failure !== undefined) {
+                writeSidecar(
+                    path,
+                    file,
+                    { mlDataError: describeError(failure) },
+                    image,
+                );
                 recordFailure(
                     file.id,
                     file.metadata.title,
                     collectionName.get(file.collectionID) ?? "",
-                    new Error("ML data", { cause: mlDataFailure }),
+                    new Error("ML data", { cause: failure }),
                 );
             } else {
                 writeSidecar(path, file, { mlData }, image);
@@ -838,7 +855,7 @@ const runLockedBackup = async (
             id: c.id,
             name: sanitizeFileName(c.name, `collection-${c.id}`),
         })),
-        false,
+        { withJSON: true },
     );
     const albumDirNames = new Map(
         allCollections.map((c, i) => [c.id, dirNames[i]!]),
@@ -854,60 +871,69 @@ const runLockedBackup = async (
         log(`FAILED removing old album directories: ${describeError(err)}`);
     }
 
+    // An album whose folder or JSON cannot be written, such as one whose
+    // folder name is taken by a file the user put there, is logged and listed
+    // in the result, and the run goes on to the next album.
+    const failedAlbums: number[] = [];
     for (const c of collections) {
         if (lock.lost) throw lock.lost;
-        const colDirName = albumDirNames.get(c.id)!;
-        const colDir = join(collectionsDir, colDirName);
-        mkdirSync(colDir, { recursive: true });
-
-        // Every album links the one original, saved from the file's entry in
-        // `distinct`.
-        const files = filesByCollection.get(c.id) ?? [];
-        const links = files.flatMap((f) =>
-            linksFor(
-                f,
-                storedAtSavePath(downloadDirectory, distinct.get(f.id)!),
-            ),
-        );
-        const linkNames = uniqueNames(links, true);
         try {
-            removeStaleLinks(colDir, new Set(linkNames), downloadDirectory);
-        } catch (err) {
-            log(
-                `FAILED removing old links in ${c.name}: ${describeError(err)}`,
-            );
-        }
+            const colDirName = albumDirNames.get(c.id)!;
+            const colDir = join(collectionsDir, colDirName);
+            mkdirSync(colDir, { recursive: true });
 
-        const metaFiles = files.map((f) => ({
-            id: f.id,
-            metadata: f.metadata,
-        }));
-        for (const [i, link] of links.entries()) {
-            if (!includeOriginals || link.target === undefined) continue;
-            const linkName = linkNames[i]!;
+            // Every album links the one original, saved from the file's entry
+            // in `distinct`.
+            const files = filesByCollection.get(c.id) ?? [];
+            const links = files.flatMap((f) =>
+                linksFor(
+                    f,
+                    storedAtSavePath(downloadDirectory, distinct.get(f.id)!),
+                ),
+            );
+            const linkNames = uniqueNames(links, { beforeExtension: true });
             try {
-                rebuildSymlink(
-                    join(colDir, linkName),
-                    relative(colDir, link.target),
-                );
+                removeStaleLinks(colDir, new Set(linkNames), downloadDirectory);
             } catch (err) {
                 log(
-                    `FAILED symlink ${c.name}/${linkName}: ${describeError(err)}`,
-                );
-                recordFailure(
-                    link.file.id,
-                    link.file.metadata.title,
-                    c.name,
-                    err,
+                    `FAILED removing old links in ${c.name}: ${describeError(err)}`,
                 );
             }
-        }
 
-        writeAlbumJSON(
-            join(collectionsDir, `${colDirName}.json`),
-            c,
-            metaFiles,
-        );
+            const metaFiles = files.map((f) => ({
+                id: f.id,
+                metadata: f.metadata,
+            }));
+            for (const [i, link] of links.entries()) {
+                if (!includeOriginals || link.target === undefined) continue;
+                const linkName = linkNames[i]!;
+                try {
+                    rebuildSymlink(
+                        join(colDir, linkName),
+                        relative(colDir, link.target),
+                    );
+                } catch (err) {
+                    log(
+                        `FAILED symlink ${c.name}/${linkName}: ${describeError(err)}`,
+                    );
+                    recordFailure(
+                        link.file.id,
+                        link.file.metadata.title,
+                        c.name,
+                        err,
+                    );
+                }
+            }
+
+            writeAlbumJSON(
+                join(collectionsDir, `${colDirName}.json`),
+                c,
+                metaFiles,
+            );
+        } catch (err) {
+            log(`FAILED album ${c.name}: ${describeError(err)}`);
+            failedAlbums.push(c.id);
+        }
     }
 
     // Reconcile the ledger against what this run actually attempted: an entry
@@ -933,6 +959,7 @@ const runLockedBackup = async (
         failed: ledger.size,
         errors,
         undecryptableAlbums,
+        failedAlbums,
     };
 };
 

src/cli-commands.ts

@@ -125,15 +125,29 @@ const readLibraryClient = (client: Client): LibraryClient => ({
 
 // Open a library for a single point command: the aggressive background precache
 // (issue #48) is off — a one-shot `collections` or `get` must not start
-// downloading the whole account — and the refresh interval is long so no second
-// refresh fires mid-command.
-const openReadLibrary = (ctx: CliContext, client: Client): Promise<Library> =>
+// downloading the whole account — and no refresh starts as it opens or on a
+// timer: each command asks for the one it needs, and `collections` needs none
+// (issue #210). While a refresh runs, each collection whose files it has
+// fetched is counted on stderr, unless `json` is set, so a large account shows
+// progress rather than nothing.
+const openReadLibrary = (
+    ctx: CliContext,
+    client: Client,
+    opts: { json?: boolean } = {},
+): Promise<Library> =>
     Library.open({
         client: readLibraryClient(client),
         cacheDirectory: ctx.cacheDir,
-        refreshIntervalSeconds: 3600,
+        refreshOnOpen: false,
+        refreshIntervalSeconds: Infinity,
         precacheThumbnails: false,
         precacheOriginals: false,
+        onProgress: (event) => {
+            if (opts.json || event.status !== "progress") return;
+            ctx.stderr.write(
+                `Fetched the files of ${event.fetched} of ${event.total} collections\n`,
+            );
+        },
     });
 
 export const loginCommand = async (ctx: CliContext): Promise<number> => {
@@ -221,9 +235,10 @@ export const collectionsCommand = async (
     if (!client) return 3;
     const lib = await openReadLibrary(ctx, client);
     try {
-        // Force a server round-trip and list in enumeration order (issue #36
-        // amendment, issue #52): the pre-library CLI printed current state in
-        // this order, not the albums projection's newest-first order.
+        // Ask the server for the collection list alone and list it in its
+        // order (issue #36 amendment, issues #52 and #210): the pre-library
+        // CLI printed current state in this order, not the albums
+        // projection's newest-first order.
         const collections = await freshCollections(lib);
 
         if (opts.json) {
@@ -254,17 +269,23 @@ export const collectionsCommand = async (
     }
 };
 
+// Lists the files of the collection `collectionIDStr` names, or without it every
+// file in the account, each once (issue #211).
 export const filesCommand = async (
     ctx: CliContext,
-    opts: { collection: string; json?: boolean },
+    collectionIDStr: string | undefined,
+    opts: { json?: boolean },
 ): Promise<number> => {
     await init();
     const client = requireSession(ctx);
     if (!client) return 3;
-    const collectionID = parseID(ctx, "collection", opts.collection);
-    if (collectionID === undefined) return 1;
+    const collectionID =
+        collectionIDStr === undefined
+            ? undefined
+            : parseID(ctx, "collection", collectionIDStr);
+    if (collectionIDStr !== undefined && collectionID === undefined) return 1;
 
-    const lib = await openReadLibrary(ctx, client);
+    const lib = await openReadLibrary(ctx, client, opts);
     try {
         // Force a server round-trip and list in enumeration order (issue #36
         // amendment, issue #52). Each file prints from its own decrypted
@@ -317,8 +338,8 @@ export const getCommand = async (
         const result = await photo.original();
         // Default name is the file's own title, as the pre-library CLI used
         // (not the editedName-preferring projection title) (issue #52).
-        const outPath = opts.out ?? originalName(file);
         if (result.videoPath === undefined) {
+            const outPath = opts.out ?? originalName(file);
             copyFileSync(result.path, outPath);
             ctx.stderr.write(`${result.bytes} bytes -> ${outPath}\n`);
             return 0;
@@ -326,9 +347,13 @@ export const getCommand = async (
         // A live photo is written as its image and its video, each named after
         // the title with its own extension, as Ente's clients name them. With
         // --out, the image goes there and the video beside it.
-        const imageOut =
-            opts.out ?? withExtension(outPath, extname(result.path));
-        const videoOut = withExtension(outPath, extname(result.videoPath));
+        const imageExt = extname(result.path);
+        const videoExt = extname(result.videoPath);
+        const imageOut = opts.out ?? originalName(file, imageExt);
+        const videoOut =
+            opts.out === undefined
+                ? originalName(file, videoExt)
+                : withExtension(opts.out, videoExt);
         if (imageOut.toLowerCase() === videoOut.toLowerCase()) {
             ctx.stderr.write(
                 `File ${fileID} is a live photo, and its video would also be written to ${imageOut}\n`,
@@ -394,11 +419,11 @@ export const backupMetadataCommand = async (
         // Refresh first so the dump holds current account state, not what the
         // cache last held; a failed refresh throws.
         await lib.fresh();
-        const { failedMLBatches } = await runMetadataBackup(lib, client, dir, {
+        const result = await runMetadataBackup(lib, client, dir, {
             exif: opts.exif || opts.all,
             onProgress: (msg) => ctx.stderr.write(msg + "\n"),
         });
-        return failedMLBatches > 0 ? 1 : 0;
+        return result.filesWithMLDataError > 0 ? 1 : 0;
     } finally {
         await lib.close();
     }
@@ -470,7 +495,9 @@ export const backupCommand = async (
                 }
             }
 
-            return result.failed > 0 || result.undecryptableAlbums.length > 0
+            return result.failed > 0 ||
+                result.undecryptableAlbums.length > 0 ||
+                result.failedAlbums.length > 0
                 ? 1
                 : 0;
         } finally {
@@ -488,7 +515,7 @@ export const listMissingThumbnailsCommand = async (
     await init();
     const client = requireSession(ctx);
     if (!client) return 3;
-    const lib = await openReadLibrary(ctx, client);
+    const lib = await openReadLibrary(ctx, client, opts);
     try {
         // Refresh first so files added since the cache was written are
         // checked; a failed refresh throws.
@@ -533,7 +560,7 @@ export const fixMissingThumbnailsCommand = async (
         if (fileID === undefined) return 1;
         fileIDs.push(fileID);
     }
-    const lib = await openReadLibrary(ctx, client);
+    const lib = await openReadLibrary(ctx, client, opts);
     try {
         // Refresh first so files added since the cache was written are found;
         // a failed refresh throws.

src/cli-output.ts

@@ -9,7 +9,7 @@
 // `metadata.title`, and issue #52 requires that output stay byte-identical, so
 // the commands shape their output from the raw `EnteFile` through here.
 
-import { sanitizeFileName } from "./filename.js";
+import { defaultFileName } from "./filename.js";
 import type { EnteFile, FileType, Microseconds } from "./model/types.js";
 
 // One row of `quak files --json`.
@@ -33,11 +33,13 @@ export const fileListRow = (file: EnteFile): FileListRow => ({
 export const fileListLine = (file: EnteFile): string =>
     `${file.id}\t${file.metadata.fileType}\t${file.metadata.title}`;
 
-// Default output path for `quak get` when `--out` is not given. The title comes
-// from the server, so it is sanitized; `--out` is the user's and is used as is.
-export const originalName = (file: EnteFile): string =>
-    sanitizeFileName(file.metadata.title, `file-${file.id}`);
+// Default output path for `quak get` when `--out` is not given, made from the
+// title (see `defaultFileName`), with `ext` in place of its extension for a
+// live photo's image or video; `--out` is the user's and is used as is.
+export const originalName = (file: EnteFile, ext?: string): string =>
+    defaultFileName(file.metadata.title, file.id, { ext });
 
-// Default output path for `quak get-thumb` when `--out` is not given.
+// Default output path for `quak get-thumb` when `--out` is not given: `thumb_`
+// and the title.
 export const thumbnailName = (file: EnteFile): string =>
-    `thumb_${originalName(file)}`;
+    defaultFileName(file.metadata.title, file.id, { prefix: "thumb_" });

src/cli-read.ts

@@ -1,50 +1,72 @@
 // How the CLI's read commands obtain current data.
 //
-// `collections`, `files --collection`, `get`, and `get-thumb` must answer for
+// `collections`, `files`, `get`, and `get-thumb` must answer for
 // the account's state at the moment the command runs, not for whatever the
-// local cache last happened to hold (owner amendment, issue #36). Each helper
-// therefore forces a server round-trip through `Library.fresh()` and only then
-// reads — so a collection, file, or metadata change made elsewhere is visible.
+// local cache last happened to hold (owner amendment, issue #36). `files`,
+// `get` and `get-thumb` therefore force a server round-trip through
+// `Library.fresh()` and only then read — so a collection, file, or metadata
+// change made elsewhere is visible. `collections` asks the library for the
+// collection list alone through `Library.freshCollections()` (issue #210): a
+// refresh would also fetch the files of every collection, which on a large
+// account takes long and which `collections` does not print.
 //
-// `collections` and `files` also list in the library's own enumeration order —
-// `listCollections()`/`listFiles()`, the order the pre-library CLI printed —
+// `collections` lists in the server's order and `files` in the library's own
+// enumeration order (`listFiles()`), the orders the pre-library CLI printed,
 // rather than the `albums`/`photos` projection's newest-first order, which
 // re-sorts the rows. The field values still come from each record's raw
-// metadata via `cli-output.ts`.
+// metadata via `cli-output.ts`. `files` without a collection ID lists every
+// file in the account once (issue #211): the library keeps a record of a file
+// for each collection that holds it, and only the first collection's record is
+// listed.
 
 import type { Collection, EnteFile } from "./model/types.js";
 import type { Photo, PhotosAPI } from "./library/index.js";
 
 // The slice of `Library` these helpers read. `Library` satisfies it
 // structurally; a test can drive them with a stand-in that records the
-// `fresh()` call and serves records in a known enumeration order.
+// `fresh()` and `freshCollections()` calls and serves records in a known
+// enumeration order.
 export interface FreshReadLibrary {
     fresh(): Promise<unknown>;
-    listCollections(): Collection[];
+    freshCollections(): Promise<Collection[]>;
     getCollection(id: number): Collection | undefined;
+    listCollections(): Collection[];
     listFiles(collectionID: number): EnteFile[];
     getFileByID(fileID: number): EnteFile | undefined;
     photos: Pick<PhotosAPI, "byID">;
 }
 
-// Every live collection, current as of a forced refresh, in enumeration order.
-export const freshCollections = async (
+// Every live collection, current as of one collections request, in the
+// server's order.
+export const freshCollections = (
     lib: FreshReadLibrary,
-): Promise<Collection[]> => {
-    await lib.fresh();
-    return lib.listCollections();
-};
+): Promise<Collection[]> => lib.freshCollections();
 
 // The files of one collection, current as of a forced refresh, in enumeration
 // order. `undefined` (not an empty list) when the collection does not exist, so
-// the caller can tell "no such collection" from "an empty collection".
+// the caller can tell "no such collection" from "an empty collection". Without
+// a collection ID, every file in the account, each once, as held by the first
+// collection that holds it.
 export const freshFiles = async (
     lib: FreshReadLibrary,
-    collectionID: number,
+    collectionID?: number,
 ): Promise<EnteFile[] | undefined> => {
     await lib.fresh();
-    if (!lib.getCollection(collectionID)) return undefined;
-    return lib.listFiles(collectionID);
+    if (collectionID !== undefined) {
+        return lib.getCollection(collectionID)
+            ? lib.listFiles(collectionID)
+            : undefined;
+    }
+    const listed = new Set<number>();
+    const files: EnteFile[] = [];
+    for (const collection of lib.listCollections()) {
+        for (const file of lib.listFiles(collection.id)) {
+            if (listed.has(file.id)) continue;
+            listed.add(file.id);
+            files.push(file);
+        }
+    }
+    return files;
 };
 
 // One file, current as of a forced refresh, resolved to both its content

src/client.ts

@@ -373,13 +373,17 @@ export class Client {
     }
 
     // Fetch machine-learning data (face detections + CLIP embeddings) for up
-    // to a batch of files, each decrypted with its own key. One request; the
-    // library batches at `MLDATA_BATCH_SIZE` and schedules each batch through
-    // its metadata request pool.
+    // to a batch of files, each decrypted with its own key, and for each file
+    // whose ML data did not decrypt, gunzip or parse, why not. One request;
+    // the library batches at `MLDATA_BATCH_SIZE` and schedules each batch
+    // through its metadata request pool.
     async fetchMLData(args: {
         fileIDs: number[];
         fileKeys: Map<number, Uint8Array>;
-    }): Promise<Map<number, MLData>> {
+    }): Promise<{
+        payloads: Map<number, MLData>;
+        errors: Map<number, unknown>;
+    }> {
         this.assertLoggedIn();
         return fetchMLDataBatch(this.api, args.fileIDs, args.fileKeys);
     }

src/download/index.ts

@@ -16,7 +16,7 @@ import {
     streamTagFinal,
 } from "../crypto/index.js";
 import { TruncatedStreamError } from "../errors.js";
-import { safeExtension, sanitizeFileName, withExtension } from "../filename.js";
+import { defaultFileName, safeExtension, withExtension } from "../filename.js";
 import { withRetry } from "../retry.js";
 import type { ApiClient } from "../api/client.js";
 import type { EnteFile } from "../model/types.js";
@@ -199,11 +199,13 @@ const isRunning = (pid: number): boolean => {
 };
 
 // Delete the temp files a killed process left in `dir`: the writer's
-// `.quak-<pid>-<random>.tmp` and the backup copy's
-// `.quak-backup-<name>-<pid>-<random>.tmp`. Only files whose process is no
-// longer running are removed, so another process writing into the same
-// directory keeps its own. A reused process ID can only keep a leftover a while
-// longer, never remove a live one.
+// `.quak-<pid>-<random>.tmp`, the backup copy's
+// `.quak-backup-<name>-<pid>-<random>.tmp`, and the image and video of a live
+// photo downloaded to replace a stored one, `.quak-<pid>-<random>.<ext>` (see
+// `replaceOriginal`). Only files whose process is no longer running are
+// removed, so another process writing into the same directory keeps its own. A
+// reused process ID can only keep a leftover a while longer, never remove a
+// live one.
 export const removeLeftoverTempFiles = (dir: string): void => {
     let names: string[];
     try {
@@ -212,7 +214,9 @@ export const removeLeftoverTempFiles = (dir: string): void => {
         return;
     }
     for (const name of names) {
-        const match = /^\.quak-(?:.*-)?(\d+)-[0-9a-z]*\.tmp$/.exec(name);
+        const match = /^\.quak-(?:.*-)?(\d+)-[0-9a-z]*\.[0-9A-Za-z]+$/.exec(
+            name,
+        );
         if (match && !isRunning(Number(match[1]))) {
             rmSync(join(dir, name), { force: true });
         }
@@ -361,10 +365,14 @@ const openPart = async (
 // name starts with `image` as the image and the one whose name starts with
 // `video` as the video, and refuses a ZIP holding a second of either. It is
 // written unpacked: each part is named `destination` with the extension
-// replaced by its own entry's, and the two must differ ignoring case. When the
-// file records a hash, `<imageHash>:<videoHash>` must match it, each over that
-// part's own bytes. Only then are the image, then the video, renamed into
-// place; on any failure neither is stored.
+// replaced by its own entry's, and the two must differ ignoring case. When
+// `defaultName` is set, `destination` is the name `defaultFileName` made from
+// the title rather than a path the caller gave, and each part is named as
+// `defaultFileName` names it with its own extension, so that the name is cut
+// short to fit with that extension. When the file records a hash,
+// `<imageHash>:<videoHash>` must match it, each over that part's own bytes.
+// Only then are the image, then the video, renamed into place; on any failure
+// neither is stored.
 //
 // The ZIP is chosen by its uploader and may expand enormously, so each part is
 // written as it decompresses and never held, and the ZIP is refused once the
@@ -384,6 +392,7 @@ const decryptLivePhoto = async (
     key: Uint8Array,
     onProgress: ProgressCallback | undefined,
     file: EnteFile,
+    defaultName: boolean,
 ): Promise<DownloadResult> => {
     const sliceSize = 4096;
     const dir = dirname(destination);
@@ -482,8 +491,12 @@ const decryptLivePhoto = async (
                 `live photo's image and video have the same extension, ${video.ext}`,
             );
         }
-        const path = withExtension(destination, image.ext);
-        const videoPath = withExtension(destination, video.ext);
+        const partPath = (ext: string): string =>
+            defaultName
+                ? defaultFileName(file.metadata.title, file.id, { ext })
+                : withExtension(destination, ext);
+        const path = partPath(image.ext);
+        const videoPath = partPath(video.ext);
         for (const part of parts) {
             await part.handle.sync();
             await part.handle.close();
@@ -527,6 +540,9 @@ const decryptLivePhoto = async (
 // and then removes its own temp file, and only the attempt that reaches
 // TAG_FINAL renames one into place, so a download that needed three tries still
 // performs exactly one rename over the destination.
+//
+// `defaultName` says `destination` is the name `defaultFileName` made, not a
+// path the caller gave (see `decryptLivePhoto`).
 const fetchAndDecrypt = async (
     api: ApiClient,
     openStream: () => Promise<ReadableStream<Uint8Array>>,
@@ -535,6 +551,7 @@ const fetchAndDecrypt = async (
     destination: string,
     onProgress?: ProgressCallback,
     original?: EnteFile,
+    defaultName = false,
 ): Promise<DownloadResult> =>
     withRetry(async () => {
         const stream = await openStream();
@@ -547,6 +564,7 @@ const fetchAndDecrypt = async (
                     key,
                     onProgress,
                     original,
+                    defaultName,
                 );
             }
             const bytesWritten = await decryptToTemp(
@@ -578,10 +596,11 @@ export const downloadFile = async (
     outPath?: string,
     onProgress?: ProgressCallback,
 ): Promise<DownloadResult> => {
-    // `outPath` is the caller's and is used as is; the title is the server's
-    // and is sanitized so it can only name a file in the current directory.
+    // `outPath` is the caller's and is used as is. Without it, the file is
+    // written in the current directory under the name `defaultFileName` makes
+    // from the title, which is the server's.
     const resolvedPath =
-        outPath ?? sanitizeFileName(file.metadata.title, `file-${file.id}`);
+        outPath ?? defaultFileName(file.metadata.title, file.id);
     const header = fromBase64(file.file.decryptionHeader);
     return fetchAndDecrypt(
         api,
@@ -591,6 +610,7 @@ export const downloadFile = async (
         resolvedPath,
         onProgress,
         file,
+        outPath === undefined,
     );
 };
 
@@ -600,9 +620,10 @@ export const downloadThumbnail = async (
     outPath?: string,
     onProgress?: ProgressCallback,
 ): Promise<DownloadResult> => {
+    // As in `downloadFile`, with `thumb_` before the title.
     const resolvedPath =
         outPath ??
-        `thumb_${sanitizeFileName(file.metadata.title, `file-${file.id}`)}`;
+        defaultFileName(file.metadata.title, file.id, { prefix: "thumb_" });
     const header = fromBase64(file.thumbnail.decryptionHeader);
     return fetchAndDecrypt(
         api,

src/filename.ts

@@ -4,7 +4,10 @@
 // hands us, and quak does not trust the server. Any name taken from them and
 // used on disk goes through here, so it can only ever name one file inside the
 // directory the caller chose: never a path, never `..`, never hidden, never a
-// Windows device name.
+// Windows device name. Such a name can still be too long for a file name, and
+// `shortenToBytes` or `shortenKeepingExtension` cuts one short.
+// `defaultFileName` does both for the name a file is saved under when the
+// caller gives no path.
 //
 // A path the user typed (`--out`, `outPath`) is not passed through here: the
 // caller is trusted, the server is not.
@@ -29,13 +32,80 @@ export const sanitizeFileName = (name: string, fallback: string): string => {
     return RESERVED_DEVICE_NAME.test(cleaned) ? `_${cleaned}` : cleaned;
 };
 
-// The extension of `title` (".jpg"), or ".bin" when it has none or it holds
-// anything but letters and digits.
+// The extension of `title` (".jpg"), or ".bin" when it has none, it holds
+// anything but letters and digits, or it is more than 16 of them long.
 export const safeExtension = (title: string): string => {
     const ext = extname(title);
-    return /^\.[A-Za-z0-9]+$/.test(ext) ? ext : ".bin";
+    return /^\.[A-Za-z0-9]{1,16}$/.test(ext) ? ext : ".bin";
 };
 
 // `name` with its extension, if it has one, replaced by `ext` (".mov").
 export const withExtension = (name: string, ext: string): string =>
     name.slice(0, name.length - extname(name).length) + ext;
+
+// The longest file name, in bytes, that ext4 and most other file systems allow.
+export const MAX_NAME_BYTES = 255;
+
+// `name` cut short to at most `maxBytes` bytes of UTF-8, the encoding a file
+// name is written to disk in, between two characters, never inside one. A name
+// that fits comes back unchanged.
+export const shortenToBytes = (name: string, maxBytes: number): string => {
+    let bytes = 0;
+    let end = 0;
+    for (const character of name) {
+        bytes += Buffer.byteLength(character);
+        if (bytes > maxBytes) break;
+        end += character.length;
+    }
+    return name.slice(0, end);
+};
+
+// `name` cut short to fit in `maxBytes` bytes with `insert` put right before
+// its extension (`IMG_0001 (12).jpg`), each cut made as `shortenToBytes`
+// makes it. The part before the extension is cut first, so the extension is
+// kept whenever it fits, but that part always keeps its first character:
+// when the extension leaves no room for `insert` and that character, the
+// extension is cut short too, and the part before it keeps the bytes that cut
+// leaves over. So a name that does not start with a dot never comes back
+// starting with one, which would hide it. `insert` is never cut. With no
+// `insert`, a name that fits comes back unchanged.
+export const shortenKeepingExtension = (
+    name: string,
+    maxBytes: number,
+    insert = "",
+): string => {
+    const fullExt = extname(name);
+    const stem = name.slice(0, name.length - fullExt.length);
+    const first = Array.from(stem)[0] ?? "";
+    const ext = shortenToBytes(
+        fullExt,
+        maxBytes - Buffer.byteLength(insert + first),
+    );
+    const room = maxBytes - Buffer.byteLength(insert + ext);
+    return shortenToBytes(stem, room) + insert + ext;
+};
+
+// The name a file is saved under in the working directory when the caller
+// gives no path (`quak get` without `--out`, `downloadFile` without
+// `outPath`): `prefix` (`thumb_` for a thumbnail), then the file's title with
+// unsafe characters replaced, or `file-<id>` when the title is empty, cut
+// short so that the whole fits in a file name, keeping the title's extension
+// whenever it fits. `ext` (".mov"), when given, takes the place of the
+// title's extension before the name is cut short; a live photo's image and
+// video are each named with their own. The cut can leave a device name
+// (`CONSOLE.<long extension>` becomes `CON.<long extension>`); that name gets
+// a leading `_`, as `sanitizeFileName` gives one, and is cut a byte shorter to
+// leave room for it.
+export const defaultFileName = (
+    title: string,
+    fileID: number,
+    opts: { prefix?: string; ext?: string } = {},
+): string => {
+    const { prefix = "", ext } = opts;
+    const safe = sanitizeFileName(title, `file-${fileID}`);
+    const name = ext === undefined ? safe : withExtension(safe, ext);
+    const room = MAX_NAME_BYTES - Buffer.byteLength(prefix);
+    const cut = prefix + shortenKeepingExtension(name, room);
+    if (!RESERVED_DEVICE_NAME.test(cut)) return cut;
+    return `_${prefix}${shortenKeepingExtension(name, room - 1)}`;
+};

src/library/content.ts

@@ -13,6 +13,8 @@
 // originals, the thumbnail pool for thumbnails. The pool limits concurrency,
 // orders on-demand work ahead of background, and dedups by key so a fileID
 // requested twice while the first is still in flight downloads once.
+// `fetchOriginal` passes no key, so it is not shared with a fetch of the same
+// file already in flight.
 //
 // Integrity. The reused streaming decrypt is the enforced guarantee: every
 // chunk is authenticated and the writer renames the file into place only once
@@ -27,9 +29,10 @@
 // It also names each original's save path under the download directory
 // (`savePath`), where `Photo.download()` and `lib.backup()` put it. A copy in
 // the cache does not count as saved there, but is copied there rather than
-// fetched again.
+// fetched again. An original stored there whose bytes do not match its content
+// hash is replaced only by a download that does (`replaceOriginal`).
 
-import { existsSync, readFileSync, statSync } from "node:fs";
+import { createReadStream, existsSync, readFileSync, statSync } from "node:fs";
 import {
     chmod,
     copyFile,
@@ -44,6 +47,12 @@ import {
 import { basename, dirname, extname, join } from "node:path";
 
 import type { ApiClient } from "../api/client.js";
+import {
+    chunkHashFinal,
+    chunkHashInit,
+    chunkHashUpdate,
+    init,
+} from "../crypto/index.js";
 import {
     downloadFile,
     downloadThumbnail,
@@ -349,6 +358,26 @@ export const storedAtSavePath = (
     return storedOriginal(dirname(path), basename(path, extname(path)), file);
 };
 
+// The content hash of the original stored at `stored`, computed as the download
+// check computes it: over each file's bytes, read in chunks, and for a live
+// photo `<imageHash>:<videoHash>`.
+export const storedHash = async (stored: {
+    path: string;
+    videoPath?: string;
+}): Promise<string> => {
+    await init();
+    const hashFile = async (path: string): Promise<string> => {
+        const state = chunkHashInit();
+        for await (const chunk of createReadStream(path)) {
+            chunkHashUpdate(state, chunk as Buffer);
+        }
+        return chunkHashFinal(state);
+    };
+    const hash = await hashFile(stored.path);
+    if (stored.videoPath === undefined) return hash;
+    return `${hash}:${await hashFile(stored.videoPath)}`;
+};
+
 // Copy bytes into `dest` via a temp file in the same directory plus rename, so
 // `dest` appears only once it is whole ("present means complete"). As in the
 // download writer, the temp file is fsynced before the rename and the directory
@@ -405,6 +434,62 @@ export const placeOriginal = async (
     return { path, videoPath };
 };
 
+// Replace the original of `file` stored at its save path under `root` with a
+// new copy, keeping the stored one until the copy is complete and its hash,
+// computed as `storedHash` computes it, is the content hash the file's metadata
+// records. `get` is given a temporary file beside the save path and writes the
+// copy there, a live photo as its image and its video beside that file, each
+// with its own extension. Only a copy that matches is renamed over the stored
+// one, and a live photo's image and video are both hashed before either is
+// renamed. The image is renamed first: should the run stop, or the video's
+// rename fail, before the video is renamed, the new image is left beside the
+// old video, and a later backup with `verify` replaces the video if the video
+// was the part that did not match. When `get` fails or the copy does not match,
+// the temporary files are removed and the stored original stays as it was.
+export const replaceOriginal = async (
+    root: string,
+    file: EnteFile,
+    get: (dest: string) => Promise<{ path: string; videoPath?: string }>,
+): Promise<{ path: string; videoPath?: string }> => {
+    const dest = savePath(root, file);
+    const dir = dirname(dest);
+    // Named as the download writer names its temporary files; a live photo's
+    // image and video get this name with their own extensions. The next
+    // backup removes any that a killed run leaves (`removeLeftoverTempFiles`).
+    const tmp = join(
+        dir,
+        `.quak-${process.pid}-${Math.random().toString(36).slice(2)}.tmp`,
+    );
+    let got: { path: string; videoPath?: string } | undefined;
+    try {
+        got = await get(tmp);
+        if ((await storedHash(got)) !== file.metadata.hash) {
+            throw new Error(
+                "the downloaded original does not match its content hash either",
+            );
+        }
+        if (got.videoPath === undefined) {
+            await rename(got.path, dest);
+            await fsyncPath(dir);
+            return { path: dest };
+        }
+        const path = withExtension(dest, extname(got.path));
+        const videoPath = withExtension(dest, extname(got.videoPath));
+        await rename(got.path, path);
+        await rename(got.videoPath, videoPath);
+        const name = basename(dest, extname(dest));
+        await writeLivePhotoJSON(dir, name, { path, videoPath });
+        return { path, videoPath };
+    } finally {
+        // Whatever was not renamed into place. A failure to remove it must
+        // not replace the error that explains what went wrong.
+        for (const path of [tmp, got?.path, got?.videoPath]) {
+            if (path === undefined) continue;
+            await rm(path, { force: true }).catch(() => undefined);
+        }
+    }
+};
+
 export class ContentCache implements PhotoContent, ThumbnailsAPI {
     private readonly pools: RequestPools;
     private readonly source: ContentSource;
@@ -543,6 +628,35 @@ export class ContentCache implements PhotoContent, ThumbnailsAPI {
         };
     }
 
+    // Fetch an original through the content pool to `destination`, a live
+    // photo as its image and its video beside it, and return where it landed.
+    // Unlike `backupOriginal`, it fetches even when the cache or the save path
+    // already holds the original, and it records nothing: what it writes is
+    // the caller's. It is not shared with a fetch of the same file already
+    // under way, which writes somewhere else.
+    async fetchOriginal(
+        fileID: number,
+        destination: string,
+    ): Promise<{ path: string; videoPath?: string }> {
+        const file = this.getFile(fileID);
+        if (!file) throw new Error(`content cache: unknown file ${fileID}`);
+        return this.pools.content.run(
+            async () => {
+                const fetched = await this.fetchInto(
+                    file,
+                    destination,
+                    "original",
+                    undefined,
+                );
+                for (const path of [fetched.path, fetched.videoPath]) {
+                    if (path !== undefined) await chmod(path, FILE_MODE);
+                }
+                return fetched;
+            },
+            { priority: "on-demand" },
+        );
+    }
+
     async ensure(args: EnsureOptions): Promise<EnsureResult[]> {
         return this.ensureThumbnails(args);
     }

src/library/index.ts

@@ -18,6 +18,16 @@
 // the caller (the default reads stay silent and serve the last good copy). The
 // default methods and the background loop are unchanged.
 //
+// `freshCollections()` is the fresh read of the collection list alone (issue
+// #210): one collections request, no collection's files, and nothing stored,
+// for a caller such as `quak collections` that needs no more. A caller that
+// asks for each refresh it needs can also open the library with
+// `refreshOnOpen: false`, so that `open()` starts none.
+//
+// A refresh reports through `onProgress` each collection whose files it has
+// fetched, so a large account, whose first refresh fetches the files of every
+// collection, shows progress.
+//
 // A refresh stages all of its network work first and only mutates the store
 // once every fetch has succeeded. A refresh that fails partway therefore never
 // becomes visible to reads: the last good snapshot stays in place, and the
@@ -89,6 +99,7 @@ export {
 } from "./content.js";
 export { type MLDataAPI, type SimilarResult } from "./mlsearch.js";
 import type { CollectionsPage, FilesPage } from "../client.js";
+import { describeError } from "../errors.js";
 import { MLDATA_BATCH_SIZE, type MLData } from "../mldata-fetch.js";
 import type { Collection, EnteFile } from "../model/types.js";
 import { runBackup, type BackupOptions, type BackupResult } from "../backup.js";
@@ -138,12 +149,16 @@ export interface LibraryClient {
         sinceTime: number;
     }): Promise<FilesPage>;
     // Fetch ML data (face detections + CLIP embeddings) for up to a batch of
-    // files. Optional: a client without it simply disables ML fetching, leaving
-    // the metadata refresh untouched.
+    // files, and for each file whose ML data did not decrypt, gunzip or parse,
+    // why not. Optional: a client without it simply disables ML fetching,
+    // leaving the metadata refresh untouched.
     fetchMLData?(args: {
         fileIDs: number[];
         fileKeys: Map<number, Uint8Array>;
-    }): Promise<Map<number, MLData>>;
+    }): Promise<{
+        payloads: Map<number, MLData>;
+        errors: Map<number, unknown>;
+    }>;
     // The byte source for the on-disk content cache. Optional so a mock client
     // that only serves metadata still satisfies the interface; when absent (and
     // no explicit `contentSource` is passed to `open`) the content cache is
@@ -154,7 +169,11 @@ export interface LibraryClient {
 // A progress event for one unit of background work. A metadata "refresh" or an
 // ML "fetchMLData" pass each fire "started" before their network work and then
 // exactly one of "done" or "failed"; "failed" carries the error message and
-// an ML "done" reports how many payloads it stored. The precache fills
+// an ML "done" reports how many payloads it stored and, in `mlDataErrors`,
+// each file whose ML data did not decrypt, gunzip or parse, with the reason.
+// In between, a refresh fires "progress" after each collection whose files it
+// fetched: `fetched` is how many collections it has fetched the files of so
+// far, `total` how many it will. The precache fills
 // ("precacheThumbnails"/"precacheOriginals", #48) fire "started"/"done" around
 // each sweep that has work, "done" reporting the count newly cached.
 export interface RefreshEvent {
@@ -163,9 +182,11 @@ export interface RefreshEvent {
         | "fetchMLData"
         | "precacheThumbnails"
         | "precacheOriginals";
-    status: "started" | "done" | "failed";
+    status: "started" | "progress" | "done" | "failed";
     error?: string;
     fetched?: number;
+    total?: number;
+    mlDataErrors?: { fileID: number; error: string }[];
 }
 
 export type RefreshProgressCallback = (event: RefreshEvent) => void;
@@ -184,6 +205,10 @@ export interface LibraryOptions {
     // `Infinity` starts none: the library then refreshes only as it opens and
     // when `fresh()` or `backup()` asks.
     refreshIntervalSeconds?: number;
+    // Whether `open()` starts a refresh. Defaults to true. With false, `open()`
+    // returns at once onto what the cache holds, empty or not, and a refresh
+    // starts only when `fresh()` or `backup()` asks or the timer fires.
+    refreshOnOpen?: boolean;
     onProgress?: RefreshProgressCallback;
     // The bounded request pools (issue #45), shared by the ML-data fetch (the
     // metadata pool) and the content cache. Defaults to a fresh set at the
@@ -225,6 +250,11 @@ export interface LibraryStatus {
     lastMLFetchAt?: number;
     // The most recent ML fetch pass's error, set only while it failed.
     lastMLError?: string;
+    // Each file whose ML data the last ML fetch pass that succeeded got but
+    // could not decrypt, gunzip or parse, with the reason. A pass still
+    // running leaves it as it is. A pass that fails leaves it as it was. Such
+    // ML data is not cached, so the next pass asks for it again.
+    mlDataErrors: { fileID: number; error: string }[];
     // ML payloads stored on disk and CLIP embeddings in the index; undefined
     // when ML fetching is disabled.
     mlStored?: number;
@@ -292,6 +322,12 @@ export class Library {
     private lastError?: string;
     private lastMLFetchAt?: number;
     private lastMLError?: string;
+    // For each file whose ML data the last ML fetch pass that succeeded got
+    // but could not decrypt, gunzip or parse, why not, by fileID. A pass
+    // gathers its own and puts them here when it ends without failing, so
+    // `status()` and `backup()` never see the list of a pass that is still
+    // running or that failed. Kept in RAM only, never in the cache.
+    private mlDataErrors = new Map<number, unknown>();
     // The plain-record projection as of the last refresh, and the GUI change
     // subscribers. A refresh that alters the projection notifies each with the
     // delta; `lastRecords` is kept current every refresh so a subscriber that
@@ -363,7 +399,8 @@ export class Library {
     // then opens empty with the failure recorded in `status()`. With an
     // existing cache the first refresh runs in the background and `open()`
     // returns as soon as the cached data is ready — an unreachable server does
-    // not block opening.
+    // not block opening. With `refreshOnOpen: false` there is no first
+    // refresh: `open()` returns onto the cache as it is.
     static async open(opts: LibraryOptions): Promise<Library> {
         const { userID } = opts.client.whoami();
         const cacheDirectory =
@@ -466,7 +503,10 @@ export class Library {
         // refresh.
         precache?.start();
 
-        if (store.loadedFromDisk) {
+        if (opts.refreshOnOpen === false) {
+            // The caller asks for each refresh it needs.
+            lib.scheduleNext();
+        } else if (store.loadedFromDisk) {
             // An existing copy already answers reads; refresh in the background
             // and start the interval once that first cycle settles.
             void lib.runRefresh().then(() => lib.scheduleNext());
@@ -542,6 +582,7 @@ export class Library {
             lastError: this.lastError,
             lastMLFetchAt: this.lastMLFetchAt,
             lastMLError: this.lastMLError,
+            mlDataErrors: this.describeMLDataErrors(),
             mlStored: ml?.stored,
             mlIndexed: ml?.indexed,
             originalsUsedBytes: originals?.usedBytes,
@@ -569,6 +610,21 @@ export class Library {
         };
     }
 
+    // The fresh read of the collection list alone (issue #210): every live
+    // collection that decrypts, in the server's order, from one collections
+    // request. Unlike a refresh, it fetches no collection's files, which on a
+    // large account take long. Nothing is stored: a refresh fetches a
+    // collection's files only when the collection is new or has changed since
+    // the stored copy, so a collection stored here without its files would
+    // never have them fetched.
+    async freshCollections(): Promise<Collection[]> {
+        if (this.closed) throw new Error("the library is closed");
+        const { collections } = await this.client.collectionsSince({
+            sinceTime: 0,
+        });
+        return collections;
+    }
+
     // Back up every in-scope file to `opts.downloadDirectory`, or else the
     // library's, each original at its save path, with a durable failure
     // ledger (issue #51). Takes the lock in that directory first, unless the
@@ -606,10 +662,13 @@ export class Library {
                 undecryptable: () => this.store.listUndecryptable(),
                 original: (fileID, destination) =>
                     cache!.backupOriginal(fileID, destination),
+                fetchOriginal: (fileID, destination) =>
+                    cache!.fetchOriginal(fileID, destination),
                 thumbnail: (fileID) => cache!.thumbnail(fileID),
                 contentConcurrency: this.pools.content.concurrency,
                 fetchMLData: () => this.fetchMLDataNow(),
                 mlData: (fileID) => this.mldata.forFile({ fileID }),
+                mlDataError: (fileID) => this.mlDataErrors.get(fileID),
             },
             { ...opts, downloadDirectory },
         );
@@ -719,18 +778,28 @@ export class Library {
         // Stage per-collection file diffs. A collection's files are
         // re-enumerated only when its updationTime has advanced past the cached
         // copy; an unchanged album's file list cannot have changed. New
-        // collections enumerate from the beginning of time.
+        // collections enumerate from the beginning of time. Each collection
+        // whose files are fetched is reported, with how many there are to
+        // fetch.
+        const changedCollections = page.collections.filter((collection) => {
+            const known = this.store.getCollection(collection.id);
+            return !known || collection.updationTime > known.updationTime;
+        });
         const filePages: { collectionID: number; page: FilesPage }[] = [];
-        for (const collection of page.collections) {
+        for (const collection of changedCollections) {
             const known = this.store.getCollection(collection.id);
-            if (known && collection.updationTime <= known.updationTime)
-                continue;
             const filePage = await this.client.filesSince({
                 collectionID: collection.id,
                 collectionKey: collection.key,
                 sinceTime: known ? known.updationTime : 0,
             });
             filePages.push({ collectionID: collection.id, page: filePage });
+            this.emit({
+                operation: "refresh",
+                status: "progress",
+                fetched: filePages.length,
+                total: changedCollections.length,
+            });
         }
 
         // Network work done; commit to the store and persist only if something
@@ -836,8 +905,11 @@ export class Library {
 
     // One ML fetch pass: fetch, decrypt and store the ML data for every file
     // the store knows about that is not cached (or whose `updationTime` has
-    // advanced), through the metadata pool, and update the CLIP index. A
-    // failure is reported through `status()` and `onProgress`, then thrown.
+    // advanced), through the metadata pool, and update the CLIP index. For a
+    // file whose ML data does not decrypt, gunzip or parse, it gathers the
+    // reason instead, and puts the reasons it gathered in `mlDataErrors` when
+    // it ends without failing. A failure leaves `mlDataErrors` as it was and
+    // is reported through `status()` and `onProgress`, then thrown.
     private async runMLFetch(): Promise<void> {
         const mldata = this.mlStore;
         // Bind so the call keeps the client as its receiver when invoked
@@ -847,7 +919,14 @@ export class Library {
 
         const files = this.uniqueFiles();
         const needed = mldata.neededFor(files);
-        if (needed.length === 0) return;
+        // This pass's reasons, put in `this.mlDataErrors` when it ends without
+        // failing. A file whose ML data did not decode in the pass before is
+        // still among `needed`, so this pass gives its reason anew.
+        const mlDataErrors = new Map<number, unknown>();
+        if (needed.length === 0) {
+            this.mlDataErrors = mlDataErrors;
+            return;
+        }
 
         this.emit({ operation: "fetchMLData", status: "started" });
         try {
@@ -862,20 +941,25 @@ export class Library {
             for (let i = 0; i < needed.length; i += MLDATA_BATCH_SIZE) {
                 if (this.closed) break;
                 const batch = needed.slice(i, i + MLDATA_BATCH_SIZE);
-                const payloads = await this.pools.metadata.run(
+                const { payloads, errors } = await this.pools.metadata.run(
                     () => fetchMLData({ fileIDs: batch, fileKeys }),
                     { priority: "background" },
                 );
+                for (const [id, error] of errors) {
+                    mlDataErrors.set(id, error);
+                }
                 stored += (await mldata.storeFetched(payloads, updation))
                     .stored;
             }
 
+            this.mlDataErrors = mlDataErrors;
             this.lastMLFetchAt = Date.now();
             this.lastMLError = undefined;
             this.emit({
                 operation: "fetchMLData",
                 status: "done",
                 fetched: stored,
+                mlDataErrors: this.describeMLDataErrors(),
             });
         } catch (err) {
             const error = err instanceof Error ? err.message : String(err);
@@ -885,6 +969,14 @@ export class Library {
         }
     }
 
+    // `mlDataErrors` as `status()` and the ML "done" event give it.
+    private describeMLDataErrors(): { fileID: number; error: string }[] {
+        return [...this.mlDataErrors].map(([fileID, err]) => ({
+            fileID,
+            error: describeError(err),
+        }));
+    }
+
     // The distinct files the store holds, one entry per fileID (a file in
     // several collections shares its ML data), each carrying the key and the
     // newest `updationTime` seen across its memberships.

src/metadata-backup.ts

@@ -2,9 +2,14 @@ import { mkdirSync, readFileSync, writeFileSync } from "node:fs";
 import { join } from "node:path";
 import * as jpeg from "jpeg-js";
 import type { Client } from "./client.js";
+import { describeError } from "./errors.js";
 import { readExifTags } from "./exif.js";
 import type { Library, Photo } from "./library/index.js";
-import { sanitizeFileName } from "./filename.js";
+import {
+    MAX_NAME_BYTES,
+    sanitizeFileName,
+    shortenToBytes,
+} from "./filename.js";
 import {
     fetchMLDataBatch,
     MLDATA_BATCH_SIZE,
@@ -91,14 +96,15 @@ const extractExif = async (
 // of plain JSON: account, per-collection, and per-file records including the
 // private and public magic metadata and (by default) the ML data. Collections
 // and files are enumerated from the library's cache, which the caller refreshes
-// first. Returns how many ML data requests failed; their files are still
+// first. Returns how many files have no ML data because their ML data request
+// failed or their ML data did not decrypt, gunzip or parse; they are still
 // written, with `mlDataError` in place of `mlData`.
 export const runMetadataBackup = async (
     lib: Library,
     client: Client,
     outDir: string,
     opts?: MetadataBackupOptions,
-): Promise<{ failedMLBatches: number }> => {
+): Promise<{ filesWithMLDataError: number }> => {
     const log = opts?.onProgress ?? (() => {});
     const wantExif = opts?.exif ?? false;
 
@@ -125,7 +131,15 @@ export const runMetadataBackup = async (
         const col = lib.getCollection(album.collectionID);
         if (!col) continue;
 
-        const dirName = `${col.id}-${sanitizeFileName(col.name, "unnamed")}`;
+        // The album's ID keeps the folders apart, so the name after it can be
+        // cut short to fit in a file name.
+        const prefix = `${col.id}-`;
+        const dirName =
+            prefix +
+            shortenToBytes(
+                sanitizeFileName(col.name, "unnamed"),
+                MAX_NAME_BYTES - prefix.length,
+            );
         const colDir = join(outDir, "collections", dirName);
         mkdirSync(colDir, { recursive: true });
 
@@ -164,24 +178,28 @@ export const runMetadataBackup = async (
     }
 
     // One failed request (retries exhausted) must not end the dump: its files
-    // get the reason in `mlDataError` and the other batches go on.
+    // get the reason in `mlDataError` and the other batches go on. So does a
+    // file whose ML data does not decrypt, gunzip or parse.
     log("Fetching ML data (face detections, CLIP embeddings)...");
     const mlDataMap = new Map<number, MLData>();
     const mlDataErrors = new Map<number, string>();
-    let failedMLBatches = 0;
     const fileIDs = [...fileKeys.keys()];
     for (let i = 0; i < fileIDs.length; i += MLDATA_BATCH_SIZE) {
         const batch = fileIDs.slice(i, i + MLDATA_BATCH_SIZE);
         try {
-            const result = await fetchMLDataBatch(
+            const { payloads, errors } = await fetchMLDataBatch(
                 client.getApiClient(),
                 batch,
                 fileKeys,
             );
-            for (const [id, payload] of result) mlDataMap.set(id, payload);
+            for (const [id, payload] of payloads) mlDataMap.set(id, payload);
+            for (const [id, err] of errors) {
+                const reason = describeError(err);
+                log(`ML data of file ${id} could not be read: ${reason}`);
+                mlDataErrors.set(id, reason);
+            }
         } catch (err) {
             const reason = err instanceof Error ? err.message : String(err);
-            failedMLBatches++;
             log(
                 `ML data request for ${batch.length} file(s) failed: ${reason}`,
             );
@@ -229,5 +247,5 @@ export const runMetadataBackup = async (
     }
 
     log("Metadata backup complete.");
-    return { failedMLBatches };
+    return { filesWithMLDataError: mlDataErrors.size };
 };

src/mldata-fetch.ts

@@ -28,43 +28,52 @@ interface RawRemoteFileData {
     updatedAt?: number;
 }
 
-// Decrypt one entry with its file key and gunzip the JSON payload. Returns
-// undefined when the key is unknown or the entry does not decrypt/parse, so one
-// corrupt file never fails a whole batch.
-const decodeEntry = (
-    entry: RawRemoteFileData,
-    key: Uint8Array | undefined,
-): MLData | undefined => {
-    if (!key) return undefined;
-    try {
-        const decrypted = decryptBlob(
-            fromBase64(entry.encryptedData),
-            fromBase64(entry.decryptionHeader),
-            key,
-        );
-        const json = gunzipSync(Buffer.from(decrypted)).toString("utf-8");
-        return JSON.parse(json) as MLData;
-    } catch {
-        return undefined;
+// Decrypt one entry with its file key and gunzip the JSON payload. Throws why
+// when the entry does not decrypt, gunzip or parse, or parses to something
+// other than a JSON object, such as `null`, a number or an array.
+const decodeEntry = (entry: RawRemoteFileData, key: Uint8Array): MLData => {
+    const decrypted = decryptBlob(
+        fromBase64(entry.encryptedData),
+        fromBase64(entry.decryptionHeader),
+        key,
+    );
+    const json = gunzipSync(Buffer.from(decrypted)).toString("utf-8");
+    const payload: unknown = JSON.parse(json);
+    if (
+        typeof payload !== "object" ||
+        payload === null ||
+        Array.isArray(payload)
+    ) {
+        throw new Error("not a JSON object");
     }
+    return payload as MLData;
 };
 
 // Fetch ML data for up to `MLDATA_BATCH_SIZE` ids in a single request. This is
 // the unit the request pools schedule; callers with more ids split them into
-// batches and submit each batch to the pool.
+// batches and submit each batch to the pool. Returns the payload of each file
+// whose entry decodes and, in `errors`, why not for each file whose entry does
+// not, so one corrupt file never fails a whole batch. An entry for a file
+// whose key is not known, which quak did not ask for, is skipped.
 export const fetchMLDataBatch = async (
     api: ApiClient,
     fileIDs: number[],
     fileKeys: Map<number, Uint8Array>,
-): Promise<Map<number, MLData>> => {
+): Promise<{ payloads: Map<number, MLData>; errors: Map<number, unknown> }> => {
     const { data } = await api.postJSON<{ data: RawRemoteFileData[] }>(
         "/files/data/fetch",
         { type: "mldata", fileIDs },
     );
-    const result = new Map<number, MLData>();
+    const payloads = new Map<number, MLData>();
+    const errors = new Map<number, unknown>();
     for (const entry of data ?? []) {
-        const payload = decodeEntry(entry, fileKeys.get(entry.fileID));
-        if (payload) result.set(entry.fileID, payload);
+        const key = fileKeys.get(entry.fileID);
+        if (!key) continue;
+        try {
+            payloads.set(entry.fileID, decodeEntry(entry, key));
+        } catch (err) {
+            errors.set(entry.fileID, err);
+        }
     }
-    return result;
+    return { payloads, errors };
 };

src/retry.ts

@@ -58,6 +58,14 @@ export const resolveRetryOptions = (
 });
 
 // Transport failures: the request did not complete, for reasons below HTTP.
+//
+// The errnos are Node's. The binary `make install` builds runs under bun,
+// whose `fetch` rejects with a plain `Error` that has no `cause` and a `code`
+// of bun's own. Bun gives `ConnectionRefused` for a refused connection and for
+// a TLS handshake that failed, and `ConnectionRefused` or `FailedToOpenSocket`
+// for a name that does not resolve. For a connection reset or closed before
+// the response ended, it gives Node's `ECONNRESET`. These were found by
+// running that binary, built with bun 1.3.13, against listeners on 127.0.0.1.
 const TRANSPORT_CODES = new Set([
     "ECONNRESET",
     "ECONNABORTED",
@@ -70,6 +78,9 @@ const TRANSPORT_CODES = new Set([
     "ENETUNREACH",
     "ENETRESET",
     "ENETDOWN",
+    // Bun's.
+    "ConnectionRefused",
+    "FailedToOpenSocket",
 ]);
 
 // The subset of the above that can only be reported before a TCP connection
@@ -87,6 +98,12 @@ const TRANSPORT_CODES = new Set([
 // ambiguity this set exists to exclude. They stay in `TRANSPORT_CODES`, so
 // they remain retryable for idempotent calls; only replay eligibility is
 // narrowed. See `isSafeToReplay`.
+//
+// Bun's `ConnectionRefused` and `FailedToOpenSocket` are absent too, so a
+// `POST` or `PUT` is not replayed on them. When a connection bun kept open from
+// an earlier request closes before any answer, bun sends the request again on
+// a new connection, and if that one fails it gives one of these codes although
+// the server may already have the request.
 const CONNECT_CODES = new Set(["ENOTFOUND", "EAI_AGAIN", "ECONNREFUSED"]);
 
 // Collect every `code` in an error's cause chain. undici does not put the
@@ -105,7 +122,7 @@ const causeCodes = (err: unknown): { codes: string[]; complete: boolean } => {
     return { codes, complete };
 };
 
-// Does the error's cause chain hold the errno of a transport failure, one of
+// Does the error's cause chain hold the code of a transport failure, one of
 // `TRANSPORT_CODES`? `isRetryable` retries such an error, and `classify` in
 // `src/backup.ts` calls it transient.
 export const hasTransportCode = (err: unknown): boolean =>
@@ -152,7 +169,8 @@ export const isRetryable = (err: unknown): boolean => {
     // deliberately literal. Demanding a recognised `cause` instead would
     // classify real network failures as permanent and fail backups that should
     // have succeeded; the cost of the imprecision is bounded by the attempt
-    // count.
+    // count. Bun's fetch rejects with a plain `Error` instead, which is
+    // recognised by its code (see `TRANSPORT_CODES`).
     if (err instanceof TypeError) return true;
     return hasTransportCode(err);
 };
@@ -170,11 +188,13 @@ export const isRetryable = (err: unknown): boolean => {
 //
 // Everything else is ambiguous. A 5xx proves the server did process the
 // request. A reset or a broken pipe can arrive after it was fully sent and
-// acted on. A routing errno can be delivered on an established socket. A
-// deadline says nothing at all about the server's state. So every errno in the
-// cause chain must be a connect errno: one other errno anywhere in the chain
-// is doubt, and doubt is not replayed. A chain longer than the walk is doubt
-// too: the links below the limit were never read.
+// acted on. A routing errno can be delivered on an established socket. Bun's
+// `ConnectionRefused` and `FailedToOpenSocket` can come from a new connection
+// bun opened to resend a request that already went out on a connection it kept
+// open. A deadline says nothing at all about the server's state. So every code in the
+// cause chain must be one of `CONNECT_CODES`: one other code anywhere in the
+// chain is doubt, and doubt is not replayed. A chain longer than the walk is
+// doubt too: the links below the limit were never read.
 export const isSafeToReplay = (err: unknown): boolean => {
     const { codes, complete } = causeCodes(err);
     return (

test/cli/backup-end-to-end.test.ts

@@ -9,7 +9,7 @@
  * data this file encrypts with libsodium, as Ente's clients encrypt it. So
  * quak's own code fetches each original, decrypts it, checks it against the
  * hash its uploader recorded and unpacks a live photo, and quak's own retries
- * repeat a failed request. Two tests run `lib.backup()` instead, as a program
+ * repeat a failed request. Three tests run `lib.backup()` instead, as a program
  * using quak as a library does.
  *
  * The account, user 42, has three albums:
@@ -274,15 +274,17 @@ afterAll(() => {
 
 // Run `quak backup <dir>` as `bin/quak.ts` runs it, sending its requests
 // through `fetch`, and return its exit code and everything it printed on
-// stderr. Its requests are retried as those of `quak backup` are, except that
-// a retry does not wait. Its cache is beside `dir`, so each run of one
-// directory finds the cache the run before it left, as cron's runs find the
-// user's.
+// stderr and on stdout. Its requests are retried as those of `quak backup`
+// are, except that a retry does not wait. A download is given up after
+// `downloadTimeoutMs` with no bytes received, 60 seconds unless given. Its
+// cache is beside `dir`, so each run of one directory finds the cache the run
+// before it left, as cron's runs find the user's.
 const backup = async (
     dir: string,
-    opts: { verify?: boolean } = {},
+    opts: { verify?: boolean; json?: boolean } = {},
     fetch = server,
-): Promise<{ code: number; stderr: string }> => {
+    downloadTimeoutMs?: number,
+): Promise<{ code: number; stderr: string; stdout: string }> => {
     let printed = "";
     const stderr = new Writable({
         write(chunk: Buffer, _encoding, done) {
@@ -290,8 +292,10 @@ const backup = async (
             done();
         },
     });
+    let output = "";
     const stdout = new Writable({
-        write(_chunk, _encoding, done) {
+        write(chunk: Buffer, _encoding, done) {
+            output += chunk.toString();
             done();
         },
     });
@@ -308,6 +312,7 @@ const backup = async (
             loadSession(path, {
                 fetch,
                 retry: { ...UNATTENDED_RETRY_OPTIONS, sleep: async () => {} },
+                downloadTimeoutMs,
             }),
         login: prompted,
         prompt: prompted,
@@ -316,7 +321,7 @@ const backup = async (
     const code = await new Promise<number>((resolve) => {
         void run(backupCommand(ctx, dir, opts), stdout, stderr, resolve);
     });
-    return { code, stderr: printed };
+    return { code, stderr: printed, stdout: output };
 };
 
 // The ID of the file whose original a request downloads, or undefined for any
@@ -627,6 +632,40 @@ describe("quak backup", () => {
         ).toEqual([]);
     });
 
+    // The user has put a file in collections/ with the name of the Trips
+    // folder, so quak cannot make that folder. It says so on one line, writes
+    // the two albums after it, and exits 1, and --json lists the album's ID
+    // in `failedAlbums`. No file failed, so there is no failures.json.
+    it("exits 1 when an album's folder cannot be made, writes the other albums, and lists it in --json", async () => {
+        const dir = mkdtempSync(join(root, "backup-"));
+        mkdirSync(join(dir, "collections"));
+        writeFileSync(join(dir, "collections", "Trips"), "mine");
+
+        const first = await backup(dir);
+        const { code, stdout } = await backup(dir, { json: true });
+
+        expect(first.code).toBe(1);
+        expect(first.stderr).toMatch(/^FAILED album Trips: EEXIST: /m);
+        expect(code).toBe(1);
+        expect(JSON.parse(stdout)).toMatchObject({
+            failed: 0,
+            undecryptableAlbums: [],
+            failedAlbums: [10],
+        });
+        const collections = join(dir, "collections");
+        expect(readJSON(join(collections, "Family.json")).id).toBe(20);
+        expect(readdirSync(join(collections, "Family")).sort()).toEqual([
+            "IMG_0002.heic",
+            "IMG_0002.mov",
+            "beach.jpg",
+        ]);
+        expect(readJSON(join(collections, "Friend's Wedding.json")).id).toBe(
+            30,
+        );
+        expect(existsSync(join(collections, "Trips.json"))).toBe(false);
+        expect(existsSync(join(dir, "failures.json"))).toBe(false);
+    });
+
     // The server no longer accepts the saved session's token, as after
     // `quak logout` elsewhere, and answers every request with 401. The run
     // stops at the refresh it starts with, says to log in again, and exits 3.
@@ -724,6 +763,81 @@ describe("quak backup", () => {
         },
     );
 
+    // The download of toast.mp4 fails as bun's `fetch` reports a failure, in
+    // the binary `make install` builds: a plain `Error` with bun's own code
+    // and message, and no cause. These are what bun gave for a refused
+    // connection, a name that did not resolve and a reset connection. The
+    // file is tried as often as under Node, and goes into `failures.json`
+    // with that message, as a transient failure.
+    it.each([
+        [
+            "ConnectionRefused",
+            "Unable to connect. Is the computer able to access the url?",
+        ],
+        ["FailedToOpenSocket", "Was there a typo in the url or port?"],
+        [
+            "ECONNRESET",
+            "The socket connection was closed unexpectedly. For more information, pass `verbose: true` in the second argument to fetch()",
+        ],
+    ])(
+        "records a download that failed with bun's %s in failures.json, as transient",
+        async (bunCode, message) => {
+            let attempts = 0;
+            const fetch: typeof globalThis.fetch = async (input, init) => {
+                if (downloadOf(input) === 200) {
+                    attempts++;
+                    throw Object.assign(new Error(message), {
+                        code: bunCode,
+                        errno: 0,
+                    });
+                }
+                return server(input, init);
+            };
+            const dir = mkdtempSync(join(root, "backup-"));
+
+            const { code } = await backup(dir, {}, fetch);
+
+            expect(code).toBe(1);
+            expect(attempts).toBe(UNATTENDED_RETRY_OPTIONS.attempts);
+            const failures = readJSON(join(dir, "failures.json"));
+            expect(failures.files["200"]).toMatchObject({
+                classification: "transient",
+                error: message,
+            });
+        },
+    );
+
+    // The download of toast.mp4 stalls: the server sends the headers and then
+    // never a byte of the body. Each attempt is given up after 50 ms, quak's
+    // own deadline for this run, with a `TimeoutError` whose message says
+    // only that the download stalled. The file goes into `failures.json` as a
+    // transient failure, as a request that ran out of time is retried.
+    it("records a stalled download in failures.json, as transient", async () => {
+        let attempts = 0;
+        const fetch: typeof globalThis.fetch = async (input, init) => {
+            if (downloadOf(input) === 200) {
+                attempts++;
+                return new Response(
+                    new ReadableStream<Uint8Array>({
+                        pull: () => new Promise<void>(() => {}),
+                    }),
+                );
+            }
+            return server(input, init);
+        };
+        const dir = mkdtempSync(join(root, "backup-"));
+
+        const { code } = await backup(dir, {}, fetch, 50);
+
+        expect(code).toBe(1);
+        expect(attempts).toBe(UNATTENDED_RETRY_OPTIONS.attempts);
+        const failures = readJSON(join(dir, "failures.json"));
+        expect(failures.files["200"]).toMatchObject({
+            classification: "transient",
+            error: "download stalled: no bytes received for 50 ms",
+        });
+    });
+
     // The name of Ente's API server does not resolve when quak fetches the ML
     // data, after every original has been backed up. No file has ML data
     // cached yet, so each goes into `failures.json` with the reason, as a
@@ -763,6 +877,133 @@ describe("quak backup", () => {
         ]);
     });
 
+    // The server sends beach.jpg's ML data encrypted under a key that is not
+    // the file's, so quak cannot decrypt it. The file's JSON has the reason
+    // in place of the ML data, and the file goes into `failures.json` with
+    // it, so the exit code is 1. The other two files have no ML data, which
+    // is no failure.
+    it("records a file whose ML data does not decrypt in its JSON and in failures.json, and exits 1", async () => {
+        const otherKey = sodium.crypto_secretstream_xchacha20poly1305_keygen();
+        const mlData = encryptStreamBlob(
+            gzipSync(JSON.stringify(ML_DATA)),
+            otherKey,
+        );
+        const fetch: typeof globalThis.fetch = async (input, init) => {
+            if (new URL(String(input)).pathname !== "/files/data/fetch") {
+                return server(input, init);
+            }
+            const data = [
+                {
+                    fileID: BEACH.id,
+                    encryptedData: toBase64(mlData.ciphertext),
+                    decryptionHeader: toBase64(mlData.header),
+                },
+            ];
+            return new Response(JSON.stringify({ data }), {
+                headers: { "content-type": "application/json" },
+            });
+        };
+        const dir = mkdtempSync(join(root, "backup-"));
+
+        const { code, stderr } = await backup(dir, {}, fetch);
+
+        expect(code).toBe(1);
+        const reason = "secretstream chunk authentication failed";
+        const beachJSON = readJSON(join(dir, DAY, "2024-03-01.100.json"));
+        expect(beachJSON).not.toHaveProperty("mlData");
+        expect(beachJSON.mlDataError).toBe(reason);
+        const failures = readJSON(join(dir, "failures.json"));
+        expect(Object.keys(failures.files)).toEqual(["100"]);
+        expect(failures.files["100"]).toMatchObject({
+            fileID: 100,
+            title: "beach.jpg",
+            error: `ML data: ${reason}`,
+        });
+        expect(stderr).toContain(`beach.jpg (id 100): ML data: ${reason}\n`);
+        for (const fileID of [200, 300]) {
+            const json = readJSON(join(dir, DAY, `2024-03-01.${fileID}.json`));
+            expect(json).not.toHaveProperty("mlData");
+            expect(json).not.toHaveProperty("mlDataError");
+        }
+    });
+
+    // A program using quak as a library backs the account up, and another ML
+    // data fetch, as one the library's refresh starts, fails while the backup
+    // writes the JSON files. The backup's own fetch got beach.jpg's ML data
+    // under a key that is not the file's; the fetch that fails leaves that
+    // reason in place, so beach.jpg's JSON and `failures.json` still give it.
+    it("keeps the reason in beach.jpg's JSON and in failures.json when an ML data fetch fails while lib.backup() writes the JSON files", async () => {
+        const otherKey = sodium.crypto_secretstream_xchacha20poly1305_keygen();
+        const mlData = encryptStreamBlob(
+            gzipSync(JSON.stringify(ML_DATA)),
+            otherKey,
+        );
+        let mlDataFetchFails = false;
+        const fetch: typeof globalThis.fetch = async (input, init) => {
+            if (new URL(String(input)).pathname !== "/files/data/fetch") {
+                return server(input, init);
+            }
+            if (mlDataFetchFails) throw new Error("the connection was reset");
+            const data = [
+                {
+                    fileID: BEACH.id,
+                    encryptedData: toBase64(mlData.ciphertext),
+                    decryptionHeader: toBase64(mlData.header),
+                },
+            ];
+            return new Response(JSON.stringify({ data }), {
+                headers: { "content-type": "application/json" },
+            });
+        };
+        const dir = mkdtempSync(join(root, "backup-"));
+        const lib = await Library.open({
+            client: loadSession(join(sessionDir, "session.json"), {
+                fetch,
+                retry: { ...UNATTENDED_RETRY_OPTIONS, sleep: async () => {} },
+            })!,
+            cacheDirectory: `${dir}-cache`,
+            downloadDirectory: dir,
+            refreshIntervalSeconds: Infinity,
+            precacheThumbnails: false,
+            precacheOriginals: false,
+        });
+        try {
+            // The backup reads a file's cached ML data just before it writes
+            // that file's JSON. The first time, a refresh starts an ML data
+            // fetch whose request fails, and the backup goes on once that
+            // fetch has failed.
+            const forFile = lib.mldata.forFile.bind(lib.mldata);
+            vi.spyOn(lib.mldata, "forFile").mockImplementationOnce(
+                async (args) => {
+                    mlDataFetchFails = true;
+                    await lib.fresh();
+                    await vi.waitFor(
+                        () => expect(lib.status().lastMLError).toBeDefined(),
+                        { timeout: 2000, interval: 5 },
+                    );
+                    return forFile(args);
+                },
+            );
+
+            const result = await lib.backup();
+
+            expect(result.failed).toBe(1);
+            const reason = "secretstream chunk authentication failed";
+            const beachJSON = readJSON(join(dir, DAY, "2024-03-01.100.json"));
+            expect(beachJSON).not.toHaveProperty("mlData");
+            expect(beachJSON.mlDataError).toBe(reason);
+            const failures = readJSON(join(dir, "failures.json"));
+            expect(Object.keys(failures.files)).toEqual(["100"]);
+            expect(failures.files["100"]).toMatchObject({
+                fileID: 100,
+                title: "beach.jpg",
+                error: `ML data: ${reason}`,
+            });
+        } finally {
+            await lib.close();
+        }
+    });
+
     // Something changed beach.jpg on disk after it was backed up. A run with
     // --verify hashes every stored original, finds that one no longer matches
     // the hash Ente recorded, says so, and downloads it again; it put back the

test/cli/backup-undecryptable.test.ts

@@ -548,7 +548,7 @@ describe("the read commands with records quak cannot decrypt", () => {
         expect(await collectionsCommand(context(ente), {})).toBe(0);
         expect(stdout.text).toBe("1\talbum\tTrip\n");
 
-        expect(await filesCommand(context(ente), { collection: "1" })).toBe(0);
+        expect(await filesCommand(context(ente), "1", {})).toBe(0);
         expect(stdout.text).toBe("10\timage\tphoto-10.jpg\n");
     });
 });

test/cli/backup.test.ts

@@ -191,9 +191,12 @@ class HostileClient extends MockClient {
 }
 
 // A content source that writes byte buffers of the expected length and can be
-// told to fail one fileID's original, to exercise per-file resilience.
+// told to fail one fileID's original, as a server error or as a 404, or to
+// write other bytes for it, to exercise per-file resilience.
 interface StubSource extends ContentSource {
     failID?: number;
+    notFoundID?: number;
+    otherBytesID?: number;
     failThumbID?: number;
     originalCalls: number;
 }
@@ -204,8 +207,10 @@ const stubSource = (): StubSource => {
         original: async ({ file: f, destination }) => {
             s.originalCalls++;
             if (s.failID === f.id) throw new Error("HTTP 500 from server");
+            if (s.notFoundID === f.id) throw new Error("HTTP 404 from server");
             const size = SIZE_BY_ID[f.id] ?? 10;
-            writeFileSync(destination, Buffer.alloc(size));
+            const fill = s.otherBytesID === f.id ? 2 : 0;
+            writeFileSync(destination, Buffer.alloc(size, fill));
             return { bytesWritten: size };
         },
         thumbnail: async ({ file: f, destination }) => {
@@ -696,17 +701,26 @@ describe("lib.backup", () => {
         // A child that has already exited: its process ID is not running.
         const exitedPID = spawnSync(process.execPath, ["-e", ""]).pid;
         const leftover = `.quak-backup-2026-03-01.100.jpg-${exitedPID}-abc123.tmp`;
+        // A live photo's image and video downloaded to replace a stored one,
+        // before they were renamed into place.
+        const replacement = [
+            `.quak-${exitedPID}-abc789.heic`,
+            `.quak-${exitedPID}-abc789.mov`,
+        ];
         // This test's own process stands in for a backup running at the same
         // time.
         const inProgress = `.quak-backup-2026-03-01.101.jpg-${process.pid}-def456.tmp`;
-        writeFileSync(join(day, leftover), "partial");
-        writeFileSync(join(day, inProgress), "partial");
+        for (const name of [leftover, ...replacement, inProgress]) {
+            writeFileSync(join(day, name), "partial");
+        }
         const lib = await openLibrary(stubSource());
 
         await lib.backup({ downloadDirectory: outDir });
 
         const names = readdirSync(day);
         expect(names).not.toContain(leftover);
+        expect(names).not.toContain(replacement[0]);
+        expect(names).not.toContain(replacement[1]);
         expect(names).toContain(inProgress);
         lib.close();
     });
@@ -938,13 +952,14 @@ const ML_PAYLOAD = { face: { faces: [] }, clip: { embedding: [0.5, 0.25] } };
 
 class MLClient extends MockClient {
     mlError?: string;
-    async fetchMLData(args: {
-        fileIDs: number[];
-    }): Promise<Map<number, MLData>> {
+    async fetchMLData(args: { fileIDs: number[] }): Promise<{
+        payloads: Map<number, MLData>;
+        errors: Map<number, unknown>;
+    }> {
         if (this.mlError) throw new Error(this.mlError);
-        const result = new Map<number, MLData>();
-        if (args.fileIDs.includes(100)) result.set(100, ML_PAYLOAD);
-        return result;
+        const payloads = new Map<number, MLData>();
+        if (args.fileIDs.includes(100)) payloads.set(100, ML_PAYLOAD);
+        return { payloads, errors: new Map() };
     }
 }
 
@@ -1294,7 +1309,8 @@ describe("image metadata in each file's JSON", () => {
 });
 
 // With `verify`, each original already stored is hashed, and one that does not
-// match the content hash its metadata records is downloaded again.
+// match the content hash its metadata records is downloaded again, and replaced
+// only by a download that matches.
 describe("backup with verify", () => {
     // MockClient's files, each recording the hash of what `stubSource` writes
     // for it, except diagram.png (200), which records none.
@@ -1337,6 +1353,12 @@ describe("backup with verify", () => {
     const good = Buffer.alloc(SIZE_BY_ID[100]!);
     const corrupt = Buffer.alloc(SIZE_BY_ID[100]!, 1);
 
+    // The temporary files left in the date folder of the backup in `outDir`.
+    const tempFiles = (outDir: string): string[] =>
+        readdirSync(join(outDir, DAY)).filter((name) =>
+            name.startsWith(".quak-"),
+        );
+
     it("leaves an original that matches its hash, and one with no hash, as they are", async () => {
         const { lib, source, outDir } = await backedUp();
         const calls = source.originalCalls;
@@ -1381,13 +1403,16 @@ describe("backup with verify", () => {
         expect(log.filter((msg) => msg.startsWith("MISMATCH"))).toEqual([
             "MISMATCH original beach.jpg (100): its bytes do not match its content hash",
         ]);
+        expect(tempFiles(outDir)).toEqual([]);
         await lib.close();
     });
 
-    it("records a failed download in failures.json, with the original removed", async () => {
+    // A copy whose hash does not match is still mostly the photo, so the
+    // backup keeps it until it holds a better one.
+    it("keeps an original that does not match its hash when its download answers 404", async () => {
         const { lib, source, outDir } = await backedUp();
         writeFileSync(saved(outDir, "100.jpg"), corrupt);
-        source.failID = 100;
+        source.notFoundID = 100;
 
         const result = await lib.backup({
             downloadDirectory: outDir,
@@ -1400,18 +1425,18 @@ describe("backup with verify", () => {
             failed: 1,
         });
         expect(Object.keys(readLedger(outDir).files)).toEqual(["100"]);
-        expect(existsSync(saved(outDir, "100.jpg"))).toBe(false);
+        expect(readFileSync(saved(outDir, "100.jpg"))).toEqual(corrupt);
+        expect(
+            readlinkSync(join(outDir, "collections", "Vacation", "beach.jpg")),
+        ).toBe(linkTo("100.jpg"));
+        expect(tempFiles(outDir)).toEqual([]);
         await lib.close();
     });
 
-    it("records in failures.json an original the cache puts back with the same bad bytes", async () => {
-        const lib = await openLibrary(stubSource(), new HashedClient());
-        const outDir = join(root, "backup");
-        // The cache holds a bad copy, and a backup copies an original the
-        // cache holds to its save path.
-        const cached = await lib.photos.byID({ fileID: 100 })!.original();
-        writeFileSync(cached.path, corrupt);
-        await lib.backup({ downloadDirectory: outDir });
+    it("keeps an original that does not match its hash when its download does not match either", async () => {
+        const { lib, source, outDir } = await backedUp();
+        writeFileSync(saved(outDir, "100.jpg"), corrupt);
+        source.otherBytesID = 100;
 
         const result = await lib.backup({
             downloadDirectory: outDir,
@@ -1424,10 +1449,39 @@ describe("backup with verify", () => {
             failed: 1,
         });
         expect(result.errors.map((e) => e.error)).toEqual([
-            "the original put back does not match its content hash either",
+            "the downloaded original does not match its content hash either",
         ]);
         expect(Object.keys(readLedger(outDir).files)).toEqual(["100"]);
         expect(readFileSync(saved(outDir, "100.jpg"))).toEqual(corrupt);
+        expect(tempFiles(outDir)).toEqual([]);
+        await lib.close();
+    });
+
+    // The cache can hold the same bad bytes, as a copy from it is not checked
+    // as a download is, so the replacement is always downloaded.
+    it("downloads the replacement even when the cache holds the original", async () => {
+        const source = stubSource();
+        const lib = await openLibrary(source, new HashedClient());
+        const outDir = join(root, "backup");
+        // The cache holds a bad copy, and a backup copies an original the
+        // cache holds to its save path.
+        const cached = await lib.photos.byID({ fileID: 100 })!.original();
+        writeFileSync(cached.path, corrupt);
+        await lib.backup({ downloadDirectory: outDir });
+        const calls = source.originalCalls;
+
+        const result = await lib.backup({
+            downloadDirectory: outDir,
+            verify: true,
+        });
+
+        expect(result).toMatchObject({
+            downloaded: 1,
+            mismatched: 1,
+            failed: 0,
+        });
+        expect(source.originalCalls).toBe(calls + 1);
+        expect(readFileSync(saved(outDir, "100.jpg"))).toEqual(good);
         await lib.close();
     });
 
@@ -1498,23 +1552,29 @@ describe("backup album folders", () => {
         files: EnteFile[];
     }
 
-    const libraryOf = (albums: Album[]): BackupLibrary => ({
+    // The original of the file `notFound`, if given, always fails to download.
+    const libraryOf = (albums: Album[], notFound?: number): BackupLibrary => ({
         refresh: async () => {},
         listCollections: () => albums.map((a) => a.collection),
         listFiles: (id) =>
             albums.find((a) => a.collection.id === id)?.files ?? [],
         undecryptable: () => [],
         original: async (fileID) => {
+            if (fileID === notFound) throw new Error("HTTP 404");
             const path = join(root, `source-${fileID}`);
             writeFileSync(path, `original ${fileID}`);
             return { path };
         },
+        fetchOriginal: async () => {
+            throw new Error("no verify in this stand-in");
+        },
         thumbnail: async () => {
             throw new Error("no thumbnails in this stand-in");
         },
         contentConcurrency: 5,
         fetchMLData: async () => {},
         mlData: async () => undefined,
+        mlDataError: () => undefined,
         whoami: () => ({ email: "backup@example.com", userID: USER_ID }),
     });
 
@@ -1600,6 +1660,251 @@ describe("backup album folders", () => {
         expect(albumID(outDir, "Trip (11) (12).json")).toBe(12);
     });
 
+    // The next three tests end with the album "ok" (14), whose one file
+    // always fails to download, so each run has a failure to record in
+    // failures.json after the album folders are written.
+    const ok: Album = {
+        collection: collection(14, "ok"),
+        files: [file(5, 14, "e.jpg")],
+    };
+
+    // The folder of an album named "x.json" would be the JSON file of the
+    // album "x", and once ended every run there. Two runs, as on two nights,
+    // write the same tree, and the failed file's attempt count goes up.
+    it("adds the ID to an album whose folder would have another album's JSON name", async () => {
+        const outDir = join(root, "backup");
+        const lib = libraryOf(
+            [
+                {
+                    collection: collection(10, "x"),
+                    files: [file(1, 10, "a.jpg")],
+                },
+                {
+                    collection: collection(11, "x.json"),
+                    files: [file(2, 11, "b.jpg")],
+                },
+                {
+                    collection: collection(12, "Trip"),
+                    files: [file(3, 12, "c.jpg")],
+                },
+                {
+                    collection: collection(13, "TRIP.json"),
+                    files: [file(4, 13, "d.jpg")],
+                },
+                ok,
+            ],
+            5,
+        );
+
+        await runBackup(lib, { downloadDirectory: outDir });
+        const result = await runBackup(lib, { downloadDirectory: outDir });
+
+        expect(result.failedAlbums).toEqual([]);
+        expect(tree(outDir)).toEqual([
+            "TRIP.json (13)/",
+            `TRIP.json (13)/d.jpg -> ${linkTo("4.jpg")}`,
+            "TRIP.json (13).json",
+            "Trip/",
+            `Trip/c.jpg -> ${linkTo("3.jpg")}`,
+            "Trip.json",
+            "ok/",
+            "ok.json",
+            "x/",
+            `x/a.jpg -> ${linkTo("1.jpg")}`,
+            "x.json",
+            "x.json (11)/",
+            `x.json (11)/b.jpg -> ${linkTo("2.jpg")}`,
+            "x.json (11).json",
+        ]);
+        expect(albumID(outDir, "x.json")).toBe(10);
+        expect(albumID(outDir, "x.json (11).json")).toBe(11);
+        expect(albumID(outDir, "TRIP.json (13).json")).toBe(13);
+        expect(albumID(outDir, "ok.json")).toBe(14);
+        expect(result.failed).toBe(1);
+        expect(readLedger(outDir).files["5"]).toMatchObject({ attempts: 2 });
+    });
+
+    // A name over 255 bytes is refused as a file name, and an album folder's
+    // name leaves room for `.json` in its JSON's. "é" takes two bytes, and a
+    // name is cut between two characters.
+    it("cuts an album name and a title too long for a file name short and adds the ID", async () => {
+        const outDir = join(root, "backup");
+        const lib = libraryOf(
+            [
+                {
+                    collection: collection(10, "L".repeat(300)),
+                    files: [file(1, 10, `${"é".repeat(150)}.jpg`)],
+                },
+                ok,
+            ],
+            5,
+        );
+
+        await runBackup(lib, { downloadDirectory: outDir });
+        const result = await runBackup(lib, { downloadDirectory: outDir });
+
+        const folder = `${"L".repeat(245)} (10)`;
+        const link = `${"é".repeat(123)} (1).jpg`;
+        expect(Buffer.byteLength(`${folder}.json`)).toBe(255);
+        expect(Buffer.byteLength(link)).toBe(254);
+        expect(result.failedAlbums).toEqual([]);
+        expect(tree(outDir)).toEqual([
+            `${folder}/`,
+            `${folder}/${link} -> ${linkTo("1.jpg")}`,
+            `${folder}.json`,
+            "ok/",
+            "ok.json",
+        ]);
+        expect(albumID(outDir, `${folder}.json`)).toBe(10);
+        expect(albumID(outDir, "ok.json")).toBe(14);
+        expect(result.failed).toBe(1);
+        expect(readLedger(outDir).files["5"]).toMatchObject({ attempts: 2 });
+    });
+
+    // The user has put a file in collections/ with the name of the album
+    // Trip's folder, so the folder cannot be made.
+    it("goes on to the next album when an album's folder cannot be made, and lists it as failed", async () => {
+        const outDir = join(root, "backup");
+        const lib = libraryOf(
+            [
+                {
+                    collection: collection(10, "Trip"),
+                    files: [file(1, 10, "a.jpg")],
+                },
+                ok,
+            ],
+            5,
+        );
+        mkdirSync(join(outDir, "collections"), { recursive: true });
+        writeFileSync(join(outDir, "collections", "Trip"), "mine");
+        const logged: string[] = [];
+
+        const result = await runBackup(lib, {
+            downloadDirectory: outDir,
+            onProgress: (message) => logged.push(message),
+        });
+
+        expect(result.failedAlbums).toEqual([10]);
+        expect(logged).toContainEqual(
+            expect.stringMatching(/^FAILED album Trip: EEXIST: /),
+        );
+        expect(tree(outDir)).toEqual(["Trip", "ok/", "ok.json"]);
+        expect(albumID(outDir, "ok.json")).toBe(14);
+        expect(existsSync(saved(outDir, "1.jpg"))).toBe(true);
+        expect(result.failed).toBe(1);
+        expect(readLedger(outDir).files["5"]).toMatchObject({ attempts: 1 });
+    });
+
+    // The extensions of these titles leave no room for the ID and the "a"
+    // before them, so each is cut short to 250 bytes, which leaves one, for
+    // the "a". File 1's extension is 303 bytes and file 2's 271. Neither
+    // extension is only letters and digits, so both originals are saved with
+    // `.bin`, a name that fits.
+    it("cuts the extension of a title short when it leaves no room for the ID", async () => {
+        const outDir = join(root, "backup");
+        const lib = libraryOf([
+            {
+                collection: collection(10, "Trip"),
+                files: [
+                    file(1, 10, `a.${"L".repeat(300)}-x`),
+                    file(2, 10, `a.${"€".repeat(90)}`),
+                ],
+            },
+        ]);
+
+        const result = await runBackup(lib, { downloadDirectory: outDir });
+
+        const link = `a (1).${"L".repeat(249)}`;
+        const link2 = `a (2).${"€".repeat(83)}`;
+        expect(Buffer.byteLength(link)).toBe(255);
+        expect(Buffer.byteLength(link2)).toBe(255);
+        expect(result.failed).toBe(0);
+        expect(tree(outDir)).toEqual([
+            "Trip/",
+            `Trip/${link} -> ${linkTo("1.bin")}`,
+            `Trip/${link2} -> ${linkTo("2.bin")}`,
+            "Trip.json",
+        ]);
+    });
+
+    // Files 1 and 3 share a title, so each gets its ID before the
+    // extension. File 2's title is too long, and its extension leaves no
+    // room for the ID and the "x" before it. Were the ID put at the end of
+    // file 2's title cut short, its link would have file 1's name, and the
+    // link made second would replace the first.
+    it("keeps names unique when a title's extension leaves no room for the ID", async () => {
+        const outDir = join(root, "backup");
+        const shared = `x.${"Q".repeat(245)} (2)`;
+        const lib = libraryOf([
+            {
+                collection: collection(10, "Trip"),
+                files: [
+                    file(1, 10, shared),
+                    file(2, 10, `x (1).${"Q".repeat(250)}-`),
+                    file(3, 10, shared),
+                ],
+            },
+        ]);
+
+        const result = await runBackup(lib, { downloadDirectory: outDir });
+
+        expect(result.failed).toBe(0);
+        expect(tree(outDir)).toEqual([
+            "Trip/",
+            `Trip/x (1).${"Q".repeat(245)} (2) -> ${linkTo("1.bin")}`,
+            `Trip/x (2).${"Q".repeat(249)} -> ${linkTo("2.bin")}`,
+            `Trip/x (3).${"Q".repeat(245)} (2) -> ${linkTo("3.bin")}`,
+            "Trip.json",
+        ]);
+    });
+
+    // A title of 255 bytes is the longest file name allowed, and an album
+    // name of 250 bytes the longest whose JSON name fits; both are kept as
+    // they are. A name one byte longer gets the ID and is cut short. "é"
+    // takes two bytes, and in both names the room left ends inside one, so
+    // the cut falls before it, one byte short of the room.
+    it("keeps a name at the byte limit and adds the ID to one a byte over it", async () => {
+        const outDir = join(root, "backup");
+        const album = "A".repeat(250);
+        const title = `${"t".repeat(251)}.jpg`;
+        const longAlbum = `${"é".repeat(125)}B`;
+        const longTitle = `${"é".repeat(126)}.jpg`;
+        const lib = libraryOf([
+            {
+                collection: collection(10, album),
+                files: [file(1, 10, title), file(2, 10, longTitle)],
+            },
+            {
+                collection: collection(11, longAlbum),
+                files: [file(3, 11, "c.jpg")],
+            },
+        ]);
+
+        const result = await runBackup(lib, { downloadDirectory: outDir });
+
+        const folder = `${"é".repeat(122)} (11)`;
+        const link = `${"é".repeat(123)} (2).jpg`;
+        expect(Buffer.byteLength(`${album}.json`)).toBe(255);
+        expect(Buffer.byteLength(title)).toBe(255);
+        expect(Buffer.byteLength(longAlbum)).toBe(251);
+        expect(Buffer.byteLength(longTitle)).toBe(256);
+        expect(Buffer.byteLength(`${folder}.json`)).toBe(254);
+        expect(Buffer.byteLength(link)).toBe(254);
+        expect(result.failed).toBe(0);
+        expect(result.failedAlbums).toEqual([]);
+        expect(tree(outDir)).toEqual([
+            `${album}/`,
+            `${album}/${title} -> ${linkTo("1.jpg")}`,
+            `${album}/${link} -> ${linkTo("2.jpg")}`,
+            `${album}.json`,
+            `${folder}/`,
+            `${folder}/c.jpg -> ${linkTo("3.jpg")}`,
+            `${folder}.json`,
+        ]);
+        expect(albumID(outDir, `${album}.json`)).toBe(10);
+        expect(albumID(outDir, `${folder}.json`)).toBe(11);
+    });
+
     it("changes nothing on a second run over an unchanged account", async () => {
         const outDir = join(root, "backup");
         const lib = libraryOf([
@@ -1996,11 +2301,12 @@ describe("backup of live photos", () => {
             Buffer.from(IMAGE),
         );
         expect(readFileSync(video)).toEqual(Buffer.from(VIDEO));
+        expect(readdirSync(join(outDir, DAY)).sort()).toEqual(stored);
         expect(tree(outDir)).toEqual(linked);
         await lib.close();
     });
 
-    it("removes both files of a live photo that does not match its hash when downloading it again fails", async () => {
+    it("keeps both files of a live photo that does not match its hash when downloading it again fails", async () => {
         const { file: live, body } = await asLivePhoto(
             file(500, 10, "IMG_0500.HEIC"),
         );
@@ -2018,8 +2324,14 @@ describe("backup of live photos", () => {
 
         expect(result).toMatchObject({ mismatched: 1, failed: 1 });
         expect(Object.keys(readLedger(outDir).files)).toEqual(["500"]);
-        expect(existsSync(saved(outDir, "500.heic"))).toBe(false);
-        expect(existsSync(saved(outDir, "500.mov"))).toBe(false);
+        expect(readFileSync(saved(outDir, "500.heic"))).toEqual(
+            Buffer.from(IMAGE),
+        );
+        expect(readFileSync(saved(outDir, "500.mov"), "utf-8")).toBe(
+            "another few seconds of video",
+        );
+        expect(readdirSync(join(outDir, DAY)).sort()).toEqual(stored);
+        expect(tree(outDir)).toEqual(linked);
         await lib.close();
     });
 

test/cli/bin.test.ts

@@ -1,6 +1,7 @@
 /**
- * Tests for the retry options `bin/quak.ts` loads the saved session with:
- * `quak backup` gets the unattended ones, every other command the default.
+ * Tests for the retry options `bin/quak.ts` loads the saved session with
+ * (`quak backup` gets the unattended ones, every other command the default),
+ * and for `quak files` taking its collection ID as an optional argument.
  *
  * Each test runs `bin/quak.ts`, as the smoke test does, with its session loader
  * replaced by one that records the options it is given and reports no session,
@@ -26,14 +27,19 @@ vi.mock("../../src/cli-session.js", () => ({
 const argv = process.argv;
 const dir = mkdtempSync(join(tmpdir(), "quak-bin-test-"));
 
-// Run `quak <args>` to completion. The "Not logged in" message and the exit
-// are swallowed.
-const quak = async (...args: string[]): Promise<void> => {
-    vi.spyOn(process.stderr, "write").mockImplementation(() => true);
+// Run `quak <args>` to completion and return what it wrote on stderr, which is
+// kept off the terminal. The exit is swallowed.
+const quak = async (...args: string[]): Promise<string> => {
+    let written = "";
+    vi.spyOn(process.stderr, "write").mockImplementation((text) => {
+        written += String(text);
+        return true;
+    });
     vi.spyOn(process, "exit").mockImplementation(() => undefined as never);
     process.argv = ["node", "quak", ...args];
     vi.resetModules();
     await import("../../bin/quak.js");
+    return written;
 };
 
 afterEach(() => {
@@ -69,3 +75,15 @@ describe("bin/quak.ts session loading", () => {
         expect(loaded).toEqual([undefined]);
     });
 });
+
+// The command line takes `files` with or without a collection ID, and the
+// command runs as far as its session check either way (issue #211).
+describe("bin/quak.ts files", () => {
+    it("runs without a collection ID", async () => {
+        expect(await quak("files")).toMatch(/^Not logged in/);
+    });
+
+    it("runs with a collection ID", async () => {
+        expect(await quak("files", "7")).toMatch(/^Not logged in/);
+    });
+});

test/cli/commands.test.ts

@@ -21,7 +21,7 @@ import {
     utimesSync,
     writeFileSync,
 } from "node:fs";
-import { join } from "node:path";
+import { basename, join } from "node:path";
 import { tmpdir } from "node:os";
 import { PassThrough } from "node:stream";
 import * as jpegJs from "jpeg-js";
@@ -53,11 +53,21 @@ import {
 } from "../../src/cli-commands.js";
 import { run } from "../../src/cli-run.js";
 import { loadSession } from "../../src/cli-session.js";
-import type { Client, ClientSnapshot, LoginOptions } from "../../src/client.js";
+import {
+    Client,
+    type ClientSnapshot,
+    type LoginOptions,
+} from "../../src/client.js";
 import { savePath, type ContentSource } from "../../src/library/content.js";
 import type { Collection, EnteFile } from "../../src/model/types.js";
 import { encryptBlob, init, toBase64 } from "../../src/crypto/index.js";
 import { defaultCacheDirectory } from "../../src/library/index.js";
+import {
+    buildAccount,
+    buildMetaFetch,
+    encryptSecretbox,
+    encryptStreamBlob,
+} from "../ente-server.js";
 import { HEIC_WITH_EXIF } from "../exif-heic.js";
 import {
     asLivePhoto,
@@ -111,25 +121,31 @@ const FILES: Record<number, EnteFile[]> = {
 // An original is 7 bytes and a thumbnail 3. `failID` makes that file's
 // original fail; `emptyThumbID` makes the server report that file's
 // thumbnail as empty. `withNewFile` adds new.jpg (102) to Vacation, advancing
-// the collection's updationTime as the server does, and `refreshError` makes
-// listing collections fail with that message.
+// the collection's updationTime as the server does. `beachInWork` adds
+// beach.jpg (100) to Work as well, so that one file is in both albums.
+// `refreshError` makes listing collections fail with that message.
 const fakeClient = (
     opts: {
         failID?: number;
         emptyThumbID?: number;
         withNewFile?: boolean;
+        beachInWork?: boolean;
         refreshError?: string;
     } = {},
 ) => {
     const collections = opts.withNewFile
         ? [{ ...COLLECTIONS[0], updationTime: 2 }, COLLECTIONS[1]]
         : COLLECTIONS;
-    const files = opts.withNewFile
-        ? {
-              ...FILES,
-              1: [...FILES[1], { ...file(102, 1, "new.jpg"), updationTime: 2 }],
-          }
-        : FILES;
+    let files = FILES;
+    if (opts.withNewFile) {
+        files = {
+            ...files,
+            1: [...files[1], { ...file(102, 1, "new.jpg"), updationTime: 2 }],
+        };
+    }
+    if (opts.beachInWork) {
+        files = { ...files, 2: [...files[2], file(100, 2, "beach.jpg")] };
+    }
     const source: ContentSource = {
         original: async ({ file: f, destination }) => {
             if (f.id === opts.failID) throw new Error("HTTP 500 from server");
@@ -171,6 +187,15 @@ const fakeClient = (
     return fake as unknown as Client;
 };
 
+// What a read command prints on stderr while the refresh it waits for fetches
+// the files of each of the fake's two albums, on an empty cache.
+const FETCHED_BOTH_ALBUMS =
+    "Fetched the files of 1 of 2 collections\n" +
+    "Fetched the files of 2 of 2 collections\n";
+
+// The same for an account with one album.
+const FETCHED_ONE_ALBUM = "Fetched the files of 1 of 1 collections\n";
+
 // Collects everything written to it.
 class Output {
     text = "";
@@ -238,7 +263,7 @@ describe("session file", () => {
         const dir = join(root, "backup");
         expect(await whoamiCommand(ctx)).toBe(3);
         expect(await collectionsCommand(ctx, {})).toBe(3);
-        expect(await filesCommand(ctx, { collection: "1" })).toBe(3);
+        expect(await filesCommand(ctx, "1", {})).toBe(3);
         expect(await getCommand(ctx, "100", {})).toBe(3);
         expect(await getThumbCommand(ctx, "100", {})).toBe(3);
         expect(await backupMetadataCommand(ctx, dir, {})).toBe(3);
@@ -485,17 +510,14 @@ describe("collections", () => {
 
 describe("files", () => {
     it("prints one tab-separated line per file", async () => {
-        expect(await filesCommand(context(), { collection: "1" })).toBe(0);
+        expect(await filesCommand(context(), "1", {})).toBe(0);
         expect(stdout.text).toBe(
             "100\timage\tbeach.jpg\n" + "101\timage\tsunset.jpg\n",
         );
     });
 
     it("prints a JSON array with --json", async () => {
-        const code = await filesCommand(context(), {
-            collection: "2",
-            json: true,
-        });
+        const code = await filesCommand(context(), "2", { json: true });
         expect(code).toBe(0);
         expect(JSON.parse(stdout.text)).toEqual([
             {
@@ -509,8 +531,42 @@ describe("files", () => {
     });
 
     it("exits 1 for an unknown collection", async () => {
-        expect(await filesCommand(context(), { collection: "9" })).toBe(1);
-        expect(stderr.text).toBe("Collection 9 not found\n");
+        expect(await filesCommand(context(), "9", {})).toBe(1);
+        expect(stderr.text).toBe(
+            FETCHED_BOTH_ALBUMS + "Collection 9 not found\n",
+        );
+    });
+
+    // Without a collection ID it lists every file in the account once (issue
+    // #211). beach.jpg is in Vacation and Work, and Vacation comes first, so it
+    // is listed once, as Vacation's.
+    it("without a collection ID prints every file once", async () => {
+        const ctx = context(fakeClient({ beachInWork: true }));
+        expect(await filesCommand(ctx, undefined, {})).toBe(0);
+        expect(stdout.text).toBe(
+            "100\timage\tbeach.jpg\n" +
+                "101\timage\tsunset.jpg\n" +
+                "200\timage\tdiagram.png\n",
+        );
+        expect(stderr.text).toBe(FETCHED_BOTH_ALBUMS);
+    });
+
+    it("without a collection ID gives each file the first album holding it with --json", async () => {
+        const ctx = context(fakeClient({ beachInWork: true }));
+        expect(await filesCommand(ctx, undefined, { json: true })).toBe(0);
+        expect(
+            JSON.parse(stdout.text).map(
+                (row: { id: number; collectionID: number }) => [
+                    row.id,
+                    row.collectionID,
+                ],
+            ),
+        ).toEqual([
+            [100, 1],
+            [101, 1],
+            [200, 2],
+        ]);
+        expect(stderr.text).toBe("");
     });
 });
 
@@ -519,39 +575,134 @@ describe("get and get-thumb", () => {
         const out = join(root, "diagram.png");
         expect(await getCommand(context(), "200", { out })).toBe(0);
         expect(readFileSync(out)).toEqual(Buffer.alloc(7, 200));
-        expect(stderr.text).toBe(`7 bytes -> ${out}\n`);
+        expect(stderr.text).toBe(FETCHED_BOTH_ALBUMS + `7 bytes -> ${out}\n`);
     });
 
     it("get-thumb finds a file in any album without --collection", async () => {
         const out = join(root, "thumb.jpg");
         expect(await getThumbCommand(context(), "200", { out })).toBe(0);
         expect(readFileSync(out)).toEqual(Buffer.alloc(3, 200));
-        expect(stderr.text).toBe(`3 bytes -> ${out}\n`);
+        expect(stderr.text).toBe(FETCHED_BOTH_ALBUMS + `3 bytes -> ${out}\n`);
     });
 
     it("get exits 1 when no album has the file", async () => {
         const out = join(root, "x");
         expect(await getCommand(context(), "999", { out })).toBe(1);
-        expect(stderr.text).toBe("File 999 not found\n");
+        expect(stderr.text).toBe(FETCHED_BOTH_ALBUMS + "File 999 not found\n");
         expect(existsSync(out)).toBe(false);
     });
 
     it("get-thumb exits 1 when no album has the file", async () => {
         const out = join(root, "x");
         expect(await getThumbCommand(context(), "999", { out })).toBe(1);
-        expect(stderr.text).toBe("File 999 not found\n");
+        expect(stderr.text).toBe(FETCHED_BOTH_ALBUMS + "File 999 not found\n");
         expect(existsSync(out)).toBe(false);
     });
 });
 
+// A file system refuses a file name over 255 bytes. The account here is one
+// album, whose name is 300 bytes, holding one file, 700, with the title given.
+describe("names from an album name or a title over 255 bytes", () => {
+    const longNames = (title: string): Client =>
+        ({
+            ...fakeClient(),
+            collectionsSince: async () => ({
+                collections: [collection(7, "A".repeat(300))],
+                deleted: [],
+                cursor: 1,
+            }),
+            filesSince: async () => ({
+                files: [file(700, 7, title)],
+                deleted: [],
+                cursor: 1,
+            }),
+        }) as unknown as Client;
+    const longTitle = `${"t".repeat(296)}.jpg`;
+
+    // Run `command` in a new directory, where `get` and `get-thumb` without
+    // `--out` write, and return its exit code and the directory.
+    const inNewDirectory = async (
+        command: () => Promise<number>,
+    ): Promise<{ code: number; dir: string }> => {
+        const dir = mkdtempSync(join(root, "cwd-"));
+        const previous = process.cwd();
+        process.chdir(dir);
+        try {
+            return { code: await command(), dir };
+        } finally {
+            process.chdir(previous);
+        }
+    };
+
+    it("get cuts the title short to 255 bytes, keeping its extension, and exits 0", async () => {
+        const { code, dir } = await inNewDirectory(() =>
+            getCommand(context(longNames(longTitle)), "700", {}),
+        );
+
+        const name = `${"t".repeat(251)}.jpg`;
+        expect(Buffer.byteLength(name)).toBe(255);
+        expect(code).toBe(0);
+        expect(readdirSync(dir)).toEqual([name]);
+        expect(stderr.text).toBe(FETCHED_ONE_ALBUM + `7 bytes -> ${name}\n`);
+    });
+
+    it("get-thumb cuts the title short so that thumb_ and it fit in 255 bytes, and exits 0", async () => {
+        const { code, dir } = await inNewDirectory(() =>
+            getThumbCommand(context(longNames(longTitle)), "700", {}),
+        );
+
+        const name = `thumb_${"t".repeat(245)}.jpg`;
+        expect(Buffer.byteLength(name)).toBe(255);
+        expect(code).toBe(0);
+        expect(readdirSync(dir)).toEqual([name]);
+        expect(stderr.text).toBe(FETCHED_ONE_ALBUM + `3 bytes -> ${name}\n`);
+    });
+
+    it("backup-metadata cuts the album name short so that its folder's name fits in 255 bytes, and exits 0", async () => {
+        const dir = join(root, "dump");
+
+        const code = await backupMetadataCommand(
+            context(longNames("beach.jpg")),
+            dir,
+            {},
+        );
+
+        const folder = `7-${"A".repeat(253)}`;
+        expect(Buffer.byteLength(folder)).toBe(255);
+        expect(code).toBe(0);
+        expect(readdirSync(join(dir, "collections"))).toEqual([folder]);
+        expect(readdirSync(join(dir, "collections", folder)).sort()).toEqual([
+            "700.json",
+            "_collection.json",
+        ]);
+    });
+
+    // The title's extension is 300 letters, too long for the save path's
+    // name, so the original is saved with `.bin`.
+    it("backup saves a title with a 300-letter extension as .bin, and exits 0", async () => {
+        const dir = join(root, "backup");
+        const title = `b.${"e".repeat(300)}`;
+
+        const code = await backupCommand(context(longNames(title)), dir, {});
+
+        const path = savePath(dir, file(700, 7, title));
+        expect(code).toBe(0);
+        expect(basename(path)).toMatch(/^\d{4}-\d{2}-\d{2}\.700\.bin$/);
+        expect(readFileSync(path)).toEqual(Buffer.alloc(7, 700 & 0xff));
+    });
+});
+
 // A live photo, which Ente stores as one ZIP, is written as its image and its
 // video, which a photo viewer can open. The account here is Vacation holding
 // one live photo, 300, downloaded through the real download layer
 // (test/live-photo.ts).
 describe("a live photo", () => {
-    const livePhotoClient = async (image = IMAGE): Promise<Client> => {
+    const livePhotoClient = async (
+        image = IMAGE,
+        title = "IMG_0300.HEIC",
+    ): Promise<Client> => {
         const { file: live, body } = await asLivePhoto(
-            file(300, 1, "IMG_0300.HEIC"),
+            file(300, 1, title),
             livePhotoZip({ "image.heic": image, "video.mov": VIDEO }),
             livePhotoHash(image, VIDEO),
         );
@@ -593,11 +744,50 @@ describe("a live photo", () => {
             Buffer.from(VIDEO),
         );
         expect(stderr.text).toBe(
-            `${IMAGE.length} bytes -> IMG_0300.heic\n` +
+            FETCHED_ONE_ALBUM +
+                `${IMAGE.length} bytes -> IMG_0300.heic\n` +
                 `${VIDEO.length} bytes -> IMG_0300.mov\n`,
         );
     });
 
+    // Run `get` without `--out` in a new directory for a live photo titled
+    // `title`, and return its exit code and the names it wrote.
+    const getInNewDirectory = async (
+        title: string,
+    ): Promise<{ code: number; names: string[] }> => {
+        const ctx = context(await livePhotoClient(IMAGE, title));
+        const dir = mkdtempSync(join(root, "cwd-"));
+        const previous = process.cwd();
+        process.chdir(dir);
+        try {
+            const code = await getCommand(ctx, "300", {});
+            return { code, names: readdirSync(dir).sort() };
+        } finally {
+            process.chdir(previous);
+        }
+    };
+    const imageName = `${"t".repeat(250)}.heic`;
+    const videoName = `${"t".repeat(251)}.mov`;
+
+    // The title fits, but ".heic" is one byte longer than ".jpg", so the
+    // image's name is cut short once its extension is in it.
+    it("get cuts its image's name short for a 255-byte title ending in .jpg, and exits 0", async () => {
+        const title = `${"t".repeat(251)}.jpg`;
+
+        const result = await getInNewDirectory(title);
+
+        expect(Buffer.byteLength(title)).toBe(255);
+        expect(Buffer.byteLength(imageName)).toBe(255);
+        expect(Buffer.byteLength(videoName)).toBe(255);
+        expect(result).toEqual({ code: 0, names: [imageName, videoName] });
+    });
+
+    it("get cuts the names of its image and video short for a 300-byte title with no extension, and exits 0", async () => {
+        const result = await getInNewDirectory("t".repeat(300));
+
+        expect(result).toEqual({ code: 0, names: [imageName, videoName] });
+    });
+
     it("get --out writes the image there and the video beside it", async () => {
         const out = join(root, "photo.jpg");
         const video = join(root, "photo.mov");
@@ -609,7 +799,8 @@ describe("a live photo", () => {
         expect(readFileSync(out)).toEqual(Buffer.from(IMAGE));
         expect(readFileSync(video)).toEqual(Buffer.from(VIDEO));
         expect(stderr.text).toBe(
-            `${IMAGE.length} bytes -> ${out}\n${VIDEO.length} bytes -> ${video}\n`,
+            FETCHED_ONE_ALBUM +
+                `${IMAGE.length} bytes -> ${out}\n${VIDEO.length} bytes -> ${video}\n`,
         );
     });
 
@@ -623,7 +814,8 @@ describe("a live photo", () => {
         expect(existsSync(out)).toBe(false);
         expect(existsSync(join(root, "photo.mov"))).toBe(false);
         expect(stderr.text).toBe(
-            `File 300 is a live photo, and its video would also be written to ${out}\n`,
+            FETCHED_ONE_ALBUM +
+                `File 300 is a live photo, and its video would also be written to ${out}\n`,
         );
     });
 
@@ -1103,11 +1295,12 @@ describe("backup-metadata --exif", () => {
     });
 });
 
-// Each test first runs `collections` so the cache holds the account as it was,
-// then changes the server under it.
+// Each test first runs `files` so the cache holds the account as it was, then
+// changes the server under it. (`collections` would not do: it reads the
+// collection list alone and stores nothing.)
 describe("backup-metadata and the thumbnail helpers refresh first", () => {
     beforeEach(async () => {
-        expect(await collectionsCommand(context(), {})).toBe(0);
+        expect(await filesCommand(context(), "1", {})).toBe(0);
         stdout.text = "";
         stderr.text = "";
     });
@@ -1166,10 +1359,10 @@ describe("backup-metadata and the thumbnail helpers refresh first", () => {
     });
 });
 
-// `files --collection`, `get`, `get-thumb` and `helper fix-missing-thumbnails
-// --file` take an ID only when it is written in decimal digits and is a safe
-// integer. `Number()` alone reads `0x10` as 16, `1e3` as 1000 and an empty
-// string as 0, so the command would act on a file the user never named.
+// `files`, `get`, `get-thumb` and `helper fix-missing-thumbnails --file` take
+// an ID only when it is written in decimal digits and is a safe integer.
+// `Number()` alone reads `0x10` as 16, `1e3` as 1000 and an empty string as 0,
+// so the command would act on a file the user never named.
 // Anything else is refused with one line naming it, and exit 1, before any
 // request.
 //
@@ -1223,21 +1416,18 @@ describe("an ID given on the command line", () => {
 
     it("files looks up a decimal collection ID", async () => {
         const ctx = emptyAccount();
-        expect(await filesCommand(ctx, { collection: "1" })).toBe(1);
+        expect(await filesCommand(ctx, "1", {})).toBe(1);
         expect(stderr.text).toBe("Collection 1 not found\n");
         expect(requests).not.toHaveLength(0);
     });
 
-    it.each(NOT_IDS)(
-        "files refuses --collection %j before any request",
-        async (arg) => {
-            const ctx = emptyAccount();
-            expect(await filesCommand(ctx, { collection: arg })).toBe(1);
-            expect(stderr.text).toBe(`Invalid collection ID: ${arg}\n`);
-            expect(stdout.text).toBe("");
-            expect(requests).toHaveLength(0);
-        },
-    );
+    it.each(NOT_IDS)("files refuses %j before any request", async (arg) => {
+        const ctx = emptyAccount();
+        expect(await filesCommand(ctx, arg, {})).toBe(1);
+        expect(stderr.text).toBe(`Invalid collection ID: ${arg}\n`);
+        expect(stdout.text).toBe("");
+        expect(requests).toHaveLength(0);
+    });
 
     it("get looks up a decimal file ID", async () => {
         expect(await getCommand(emptyAccount(), "100", {})).toBe(1);
@@ -1292,3 +1482,164 @@ describe("an ID given on the command line", () => {
         },
     );
 });
+
+// An account with many albums (issue #210). On an empty cache `collections`
+// used to wait for a refresh that fetched and decrypted the files of every
+// album, one album after another, before it printed anything, so on such an
+// account it seemed to hang. The account here has 40 albums of one photo each,
+// encrypted as Ente's clients encrypt them, on the fake Ente server of
+// `test/ente-server.ts`, which also records the path of each request quak
+// sends. The session is the one logging in to that server saves.
+describe("an account with many albums", () => {
+    const ALBUMS = 40;
+    const PASSWORD = "many-albums";
+    const paths: string[] = [];
+    let server: typeof globalThis.fetch;
+    let snapshot: ClientSnapshot;
+
+    // Album n is named `Album n` and holds one photo, n * 100, titled
+    // `photo-n.jpg`.
+    beforeAll(async () => {
+        await sodium.ready;
+        const account = await buildAccount(PASSWORD);
+        const collections: Record<string, unknown>[] = [];
+        const filesByCollection: Record<number, Record<string, unknown>[]> = {};
+        for (let id = 1; id <= ALBUMS; id++) {
+            const albumKey = sodium.crypto_secretbox_keygen();
+            const albumKeyBox = encryptSecretbox(albumKey, account.masterKey);
+            const name = encryptSecretbox(
+                new TextEncoder().encode(`Album ${id}`),
+                albumKey,
+            );
+            collections.push({
+                id,
+                owner: { id: USER_ID },
+                encryptedKey: toBase64(albumKeyBox.ciphertext),
+                keyDecryptionNonce: toBase64(albumKeyBox.nonce),
+                encryptedName: toBase64(name.ciphertext),
+                nameDecryptionNonce: toBase64(name.nonce),
+                type: "album",
+                updationTime: 1,
+            });
+            const photoKey =
+                sodium.crypto_secretstream_xchacha20poly1305_keygen();
+            const photoKeyBox = encryptSecretbox(photoKey, albumKey);
+            const metadata = encryptStreamBlob(
+                new TextEncoder().encode(
+                    JSON.stringify({
+                        title: `photo-${id}.jpg`,
+                        fileType: 0,
+                        creationTime: 1000,
+                        modificationTime: 1000,
+                    }),
+                ),
+                photoKey,
+            );
+            filesByCollection[id] = [
+                {
+                    id: id * 100,
+                    collectionID: id,
+                    ownerID: USER_ID,
+                    encryptedKey: toBase64(photoKeyBox.ciphertext),
+                    keyDecryptionNonce: toBase64(photoKeyBox.nonce),
+                    metadata: {
+                        encryptedData: toBase64(metadata.ciphertext),
+                        decryptionHeader: toBase64(metadata.header),
+                    },
+                    // These tests fetch no original and no thumbnail.
+                    file: { decryptionHeader: "" },
+                    thumbnail: { decryptionHeader: "" },
+                    updationTime: 1,
+                },
+            ];
+        }
+        const ente = buildMetaFetch({
+            verifier: account.verifier,
+            srpAttributes: account.srpAttributes,
+            keyAttributes: account.keyAttributes,
+            encryptedToken: account.encryptedToken,
+            collections,
+            filesByCollection,
+            encryptedMLData: {},
+            fileCiphertexts: {},
+        });
+        server = (async (input: RequestInfo | URL, init?: RequestInit) => {
+            const url =
+                typeof input === "string"
+                    ? input
+                    : input instanceof URL
+                      ? input.href
+                      : input.url;
+            paths.push(new URL(url).pathname);
+            return ente(input, init);
+        }) as typeof globalThis.fetch;
+        const client = await Client.login({
+            email: "many@example.com",
+            password: PASSWORD,
+            apiOptions: { fetch: server },
+        });
+        snapshot = client.toJSON();
+    });
+
+    beforeEach(() => {
+        paths.length = 0;
+    });
+
+    // A context whose saved session sends its requests to the fake server.
+    const accountContext = (): CliContext => {
+        const ctx = context();
+        saveSession(ctx.sessionDir, snapshot);
+        return {
+            ...ctx,
+            loadSession: (path) => loadSession(path, { fetch: server }),
+        };
+    };
+
+    it("collections lists every album from one request, fetching no album's files", async () => {
+        const ctx = accountContext();
+        expect(await collectionsCommand(ctx, {})).toBe(0);
+
+        let albums = "";
+        for (let id = 1; id <= ALBUMS; id++)
+            albums += `${id}\talbum\tAlbum ${id}\n`;
+        expect(stdout.text).toBe(albums);
+        expect(stderr.text).toBe("");
+        expect(paths).toEqual(["/collections/v2"]);
+
+        // It stored nothing that would make a refresh skip an album's files:
+        // `files` after it still finds the album's photo.
+        stdout.text = "";
+        expect(await filesCommand(ctx, "7", {})).toBe(0);
+        expect(stdout.text).toBe("700\timage\tphoto-7.jpg\n");
+    });
+
+    it("files counts on stderr each album whose files its refresh fetched", async () => {
+        expect(await filesCommand(accountContext(), "7", {})).toBe(0);
+
+        expect(stdout.text).toBe("700\timage\tphoto-7.jpg\n");
+        let progress = "";
+        for (let n = 1; n <= ALBUMS; n++) {
+            progress += `Fetched the files of ${n} of ${ALBUMS} collections\n`;
+        }
+        expect(stderr.text).toBe(progress);
+    });
+
+    // With `--json` the refresh's progress is not printed, as `backup` and
+    // the thumbnail helpers print none of theirs.
+    it("files --json prints no progress", async () => {
+        expect(await filesCommand(accountContext(), "7", { json: true })).toBe(
+            0,
+        );
+
+        expect(JSON.parse(stdout.text)).toEqual([
+            {
+                id: 700,
+                title: "photo-7.jpg",
+                fileType: "image",
+                creationTime: 1000,
+                collectionID: 7,
+            },
+        ]);
+        expect(stderr.text).toBe("");
+    });
+});

test/cli/metadata-backup.test.ts

@@ -489,15 +489,15 @@ describe("quak backup-metadata", () => {
     });
 });
 
-describe("quak backup-metadata when an ML data request fails", () => {
-    // Run the CLI command against the mock and return its exit code, stderr
-    // and output directory.
-    const runCommand = async (failMLDataFor?: number) => {
+describe("quak backup-metadata when a file's ML data cannot be read", () => {
+    // Run the CLI command against `fetch`, the mock unless given, and return
+    // its exit code, stderr and output directory.
+    const runCommand = async (fetch = buildMetaFetch(mock)) => {
         const client = await Client.login({
             email: TEST_EMAIL,
             password: TEST_PASSWORD,
             apiOptions: {
-                fetch: buildMetaFetch(mock, failMLDataFor),
+                fetch,
                 retry: { sleep: async () => {} },
             },
         });
@@ -518,7 +518,9 @@ describe("quak backup-metadata when an ML data request fails", () => {
     };
 
     it("writes every file, marks the failed batch's files, and exits 1", async () => {
-        const { code, stderr, outDir } = await runCommand(200);
+        const { code, stderr, outDir } = await runCommand(
+            buildMetaFetch(mock, 200),
+        );
 
         expect(code).toBe(1);
         expect(stderr).toContain("ML data request for 1 file(s) failed");
@@ -543,6 +545,49 @@ describe("quak backup-metadata when an ML data request fails", () => {
         expect(failed.mlDataError).toContain("500");
     });
 
+    // The server sends ML data for diagram.png encrypted under a key that is
+    // not the file's, so quak cannot decrypt it.
+    it("writes the reason for ML data that does not decrypt, and exits 1", async () => {
+        const otherKey = sodium.crypto_secretstream_xchacha20poly1305_keygen();
+        const { header, ciphertext } = encryptBlob(
+            new Uint8Array(gzipSync(Buffer.from("{}"))),
+            otherKey,
+        );
+        const { code, stderr, outDir } = await runCommand(
+            buildMetaFetch({
+                ...mock,
+                encryptedMLData: {
+                    ...mock.encryptedMLData,
+                    200: {
+                        encryptedData: toBase64(ciphertext),
+                        decryptionHeader: toBase64(header),
+                    },
+                },
+            }),
+        );
+
+        expect(code).toBe(1);
+        const reason = "secretstream chunk authentication failed";
+        expect(stderr).toContain(
+            `ML data of file 200 could not be read: ${reason}\n`,
+        );
+        const failed = JSON.parse(
+            readFileSync(
+                join(outDir, "collections", "20-__Work", "200.json"),
+                "utf-8",
+            ),
+        );
+        expect(failed.mlData).toBeUndefined();
+        expect(failed.mlDataError).toBe(reason);
+        const ok = JSON.parse(
+            readFileSync(
+                join(outDir, "collections", "10-Vacation", "100.json"),
+                "utf-8",
+            ),
+        );
+        expect(ok.mlData.clip.embedding).toEqual([0.5, 0.6, 0.7]);
+    });
+
     it("exits 0 when every ML data request succeeds", async () => {
         const { code } = await runCommand();
         expect(code).toBe(0);

test/cli/read.test.ts

@@ -3,10 +3,13 @@
  * issue #36, issue #52).
  *
  * The `collections`, `files`, `get`, and `get-thumb` commands must answer for
- * current server state, not the local cache, so each helper forces a
- * `Library.fresh()` round-trip before it reads. The stand-in library below
- * serves nothing until `fresh()` has been awaited, so a helper that read
- * without refreshing would come back empty and fail here.
+ * current server state, not the local cache. `files`, `get` and `get-thumb`
+ * force a `Library.fresh()` round-trip before they read; the stand-in library
+ * below serves nothing until `fresh()` has been awaited, so a helper that read
+ * without refreshing would come back empty and fail here. `collections` asks
+ * the library for the collection list alone (`freshCollections()`, issue
+ * #210), and must not wait for a refresh, which would fetch the files of every
+ * collection.
  *
  * `collections` and `files` also list in the library's enumeration order
  * (`listCollections`/`listFiles`) — the order the pre-library CLI printed — not
@@ -60,10 +63,13 @@ const file = (
 });
 
 // A library that reveals its records only after `fresh()` has been awaited, and
-// serves them in the enumeration order it was given. `photos.byID` returns a
-// stand-in `Photo` carrying just the fileID the helper passes through.
+// serves them in the enumeration order it was given. `freshCollections()`
+// answers the collection list in that order without a refresh. `photos.byID`
+// returns a stand-in `Photo` carrying just the fileID the helper passes
+// through.
 class FakeLibrary implements FreshReadLibrary {
     freshCalls = 0;
+    freshCollectionsCalls = 0;
     private refreshed = false;
 
     constructor(
@@ -77,12 +83,18 @@ class FakeLibrary implements FreshReadLibrary {
         return {};
     }
 
-    listCollections(): Collection[] {
-        return this.refreshed ? this.collections : [];
+    async freshCollections(): Promise<Collection[]> {
+        this.freshCollectionsCalls++;
+        return this.collections;
     }
 
     getCollection(id: number): Collection | undefined {
-        return this.listCollections().find((c) => c.id === id);
+        if (!this.refreshed) return undefined;
+        return this.collections.find((c) => c.id === id);
+    }
+
+    listCollections(): Collection[] {
+        return this.refreshed ? this.collections : [];
     }
 
     listFiles(collectionID: number): EnteFile[] {
@@ -106,7 +118,7 @@ class FakeLibrary implements FreshReadLibrary {
 }
 
 describe("CLI read helpers (issue #36 amendment, issue #52)", () => {
-    it("freshCollections refreshes first, then lists in enumeration order", async () => {
+    it("freshCollections reads the collection list alone, in enumeration order", async () => {
         // Enumeration order 2, 1, 3; a newest-first sort would be 3, 2, 1.
         const lib = new FakeLibrary(
             [collection(2, 200), collection(1, 300), collection(3, 100)],
@@ -114,7 +126,8 @@ describe("CLI read helpers (issue #36 amendment, issue #52)", () => {
         );
         const rows = await freshCollections(lib);
 
-        expect(lib.freshCalls).toBe(1);
+        expect(lib.freshCollectionsCalls).toBe(1);
+        expect(lib.freshCalls).toBe(0);
         expect(rows.map((c) => c.id)).toEqual([2, 1, 3]);
         // The projection's newest-first order is a different sequence, so this
         // is not accidentally that order.
@@ -166,6 +179,30 @@ describe("CLI read helpers (issue #36 amendment, issue #52)", () => {
         ]);
     });
 
+    // Without a collection ID, `files` lists every file in the account once
+    // (issue #211). File 11 is in collections 1 and 2; collection 2 is
+    // enumerated first, so 11 is listed once, with collection 2's record.
+    it("freshFiles without a collection ID lists every file once, from the first collection holding it", async () => {
+        const files = [
+            file(10, 1, 1_700_000_000_000_000),
+            file(11, 1, 1_700_000_000_000_001),
+            file(20, 2, 1_700_000_000_000_002),
+            file(11, 2, 1_700_000_000_000_001),
+        ];
+        const lib = new FakeLibrary(
+            [collection(2, 100), collection(1, 200)],
+            files,
+        );
+
+        const rows = await freshFiles(lib);
+        expect(lib.freshCalls).toBe(1);
+        expect(rows?.map((f) => [f.id, f.collectionID])).toEqual([
+            [20, 2],
+            [11, 2],
+            [10, 1],
+        ]);
+    });
+
     it("freshFiles returns undefined for an unknown collection", async () => {
         const lib = new FakeLibrary([collection(1, 100)], []);
         const rows = await freshFiles(lib, 999);

test/download/download.test.ts

@@ -658,6 +658,26 @@ describe("downloadFile", () => {
         expect(readdirSync(parent)).toEqual(["cwd"]);
     });
 
+    // A file system refuses a file name over 255 bytes.
+    it("cuts a title too long for a file name short, keeping its extension", async () => {
+        const plaintext = new Uint8Array([1, 2, 3]);
+        const key = sodium.crypto_secretstream_xchacha20poly1305_keygen();
+        const { header, ciphertext } = encryptFileBody(plaintext, key);
+        const thumbPush =
+            sodium.crypto_secretstream_xchacha20poly1305_init_push(key);
+        const file = buildMockEnteFile(key, header, thumbPush.header);
+        file.metadata.title = `${"t".repeat(296)}.jpg`;
+        const dir = mkdtempSync(join(testDir, "long-title-"));
+
+        const api = new ApiClient({ fetch: mockFetchForBody(ciphertext) });
+        const result = await inDirectory(dir, () => downloadFile(api, file));
+
+        const name = `${"t".repeat(251)}.jpg`;
+        expect(Buffer.byteLength(name)).toBe(255);
+        expect(result.path).toBe(name);
+        expect(readdirSync(dir)).toEqual([name]);
+    });
+
     it("uses an explicit outPath verbatim, even one with ..", async () => {
         // The caller is trusted: its path is not sanitized.
         const { api, file } = fixtureFor(
@@ -751,6 +771,28 @@ describe("downloadThumbnail", () => {
         expect(result.path).toBe("thumb__etc_passwd");
         expect(readdirSync(dir)).toEqual(["thumb__etc_passwd"]);
     });
+
+    it("leaves room for thumb_ when it cuts a title too long for a file name short", async () => {
+        const plaintext = new Uint8Array([0xff, 0xd8, 0xff, 0xe0]);
+        const key = sodium.crypto_secretstream_xchacha20poly1305_keygen();
+        const filePush =
+            sodium.crypto_secretstream_xchacha20poly1305_init_push(key);
+        const { header: thumbHeader, ciphertext: thumbCipher } =
+            encryptFileBody(plaintext, key);
+        const file = buildMockEnteFile(key, filePush.header, thumbHeader);
+        file.metadata.title = `${"t".repeat(296)}.jpg`;
+        const dir = mkdtempSync(join(testDir, "long-thumb-title-"));
+
+        const api = new ApiClient({ fetch: mockFetchForBody(thumbCipher) });
+        const result = await inDirectory(dir, () =>
+            downloadThumbnail(api, file),
+        );
+
+        const name = `thumb_${"t".repeat(245)}.jpg`;
+        expect(Buffer.byteLength(name)).toBe(255);
+        expect(result.path).toBe(name);
+        expect(readdirSync(dir)).toEqual([name]);
+    });
 });
 
 // ---------------------------------------------------------------------------
@@ -1881,6 +1923,53 @@ describe("downloadFile live photos", () => {
         ]);
     });
 
+    // A file system refuses a file name over 255 bytes. Each name is cut
+    // short once its own extension is in it.
+    const imageName = `${"t".repeat(250)}.heic`;
+    const videoName = `${"t".repeat(251)}.mov`;
+
+    // The title fits, but ".heic" is one byte longer than ".jpg".
+    it("cuts the image's name short for a 255-byte title ending in .jpg when no outPath is given", async () => {
+        const title = `${"t".repeat(251)}.jpg`;
+        const t = setup(livePhotoZip(), { ...livePhoto, title });
+
+        const result = await inDirectory(t.dir, () =>
+            downloadFile(t.api, t.file),
+        );
+
+        expect(Buffer.byteLength(title)).toBe(255);
+        expect(Buffer.byteLength(imageName)).toBe(255);
+        expect(Buffer.byteLength(videoName)).toBe(255);
+        expect(result.path).toBe(imageName);
+        expect(result.videoPath).toBe(videoName);
+        expect(readdirSync(t.dir).sort()).toEqual([imageName, videoName]);
+    });
+
+    it("cuts the names of the image and the video short for a 300-byte title with no extension when no outPath is given", async () => {
+        const t = setup(livePhotoZip(), {
+            ...livePhoto,
+            title: "t".repeat(300),
+        });
+
+        const result = await inDirectory(t.dir, () =>
+            downloadFile(t.api, t.file),
+        );
+
+        expect(result.path).toBe(imageName);
+        expect(result.videoPath).toBe(videoName);
+        expect(readdirSync(t.dir).sort()).toEqual([imageName, videoName]);
+    });
+
+    // The caller's path is used as is; only the extension is each part's own.
+    it("keeps an outPath too long for a file name as given", async () => {
+        const t = setup(livePhotoZip(), livePhoto);
+        const outPath = join(t.dir, `${"t".repeat(251)}.jpg`);
+
+        await expect(downloadFile(t.api, t.file, outPath)).rejects.toThrow(
+            /ENAMETOOLONG/,
+        );
+    });
+
     it("gives each part its own extension from the ZIP, letters and digits only", async () => {
         const zip = livePhotoZip({ "image.JPG": IMAGE, "video.m-4v": VIDEO });
         const t = setup(zip, livePhoto);

test/filename/filename.test.ts

@@ -14,7 +14,13 @@
 
 import { describe, expect, it } from "vitest";
 
-import { safeExtension, sanitizeFileName } from "../../src/filename.js";
+import {
+    defaultFileName,
+    safeExtension,
+    sanitizeFileName,
+    shortenKeepingExtension,
+    shortenToBytes,
+} from "../../src/filename.js";
 
 const FALLBACK = "file-42";
 
@@ -90,4 +96,133 @@ describe("safeExtension", () => {
         expect(safeExtension("x.jp g")).toBe(".bin");
         expect(safeExtension("x.jpg\0")).toBe(".bin");
     });
+
+    it("keeps an extension of 16 letters and digits, and uses .bin for a longer one", () => {
+        expect(safeExtension(`x.${"e".repeat(16)}`)).toBe(`.${"e".repeat(16)}`);
+        expect(safeExtension(`x.${"e".repeat(17)}`)).toBe(".bin");
+        expect(safeExtension(`b.${"e".repeat(300)}`)).toBe(".bin");
+    });
+});
+
+describe("shortenToBytes", () => {
+    it("returns a name that fits unchanged", () => {
+        expect(shortenToBytes("beach", 5)).toBe("beach");
+        expect(shortenToBytes("café", 5)).toBe("café");
+        expect(shortenToBytes("", 0)).toBe("");
+    });
+
+    it("cuts a name to the number of bytes given", () => {
+        expect(shortenToBytes("L".repeat(300), 255)).toBe("L".repeat(255));
+    });
+
+    // In UTF-8 "é" takes two bytes and an emoji four, which a JavaScript
+    // string holds as two halves.
+    it("cuts between two characters, never inside one", () => {
+        expect(shortenToBytes("ééé", 5)).toBe("éé");
+        expect(shortenToBytes("a\u{1F600}b", 4)).toBe("a");
+        expect(shortenToBytes("a\u{1F600}b", 5)).toBe("a\u{1F600}");
+        expect(Buffer.byteLength(shortenToBytes("é".repeat(200), 255))).toBe(
+            254,
+        );
+    });
+});
+
+describe("shortenKeepingExtension", () => {
+    it("returns a name that fits unchanged", () => {
+        expect(shortenKeepingExtension("beach.jpg", 9)).toBe("beach.jpg");
+        expect(shortenKeepingExtension("beach", 5)).toBe("beach");
+    });
+
+    it("cuts the part before the extension short and keeps the extension", () => {
+        expect(shortenKeepingExtension(`${"t".repeat(296)}.jpg`, 255)).toBe(
+            `${"t".repeat(251)}.jpg`,
+        );
+        expect(shortenKeepingExtension("é".repeat(150), 255)).toBe(
+            "é".repeat(127),
+        );
+    });
+
+    // A name cut down to its extension would start with a dot, and so be
+    // hidden.
+    it("keeps the first character before the extension, cutting the extension short to leave room for it", () => {
+        expect(shortenKeepingExtension(`b.${"e".repeat(300)}`, 255)).toBe(
+            `b.${"e".repeat(253)}`,
+        );
+        expect(shortenKeepingExtension(`ab.${"e".repeat(300)}`, 255)).toBe(
+            `a.${"e".repeat(253)}`,
+        );
+        expect(shortenKeepingExtension(`é.${"e".repeat(300)}`, 255)).toBe(
+            `é.${"e".repeat(252)}`,
+        );
+        // "€" takes three bytes, so the extension is cut to 253 and the
+        // part before it keeps the two bytes left over, for the "a".
+        expect(shortenKeepingExtension(`a.${"€".repeat(90)}`, 255)).toBe(
+            `a.${"€".repeat(84)}`,
+        );
+    });
+
+    it("puts `insert` right before the extension and leaves room for it", () => {
+        expect(shortenKeepingExtension("beach.jpg", 255, " (7)")).toBe(
+            "beach (7).jpg",
+        );
+        expect(
+            shortenKeepingExtension(`${"t".repeat(296)}.jpg`, 255, " (7)"),
+        ).toBe(`${"t".repeat(247)} (7).jpg`);
+        expect(
+            shortenKeepingExtension(`b.${"e".repeat(300)}`, 255, " (7)"),
+        ).toBe(`b (7).${"e".repeat(249)}`);
+    });
+});
+
+describe("defaultFileName", () => {
+    it("is the title when it is safe and fits", () => {
+        expect(defaultFileName("IMG_0001.HEIC", 42)).toBe("IMG_0001.HEIC");
+    });
+
+    it("replaces unsafe characters, and is file-<id> for an empty title", () => {
+        expect(defaultFileName("../x.jpg", 42)).toBe("__x.jpg");
+        expect(defaultFileName("", 42)).toBe("file-42");
+    });
+
+    it("cuts a title over 255 bytes short, keeping its extension", () => {
+        expect(defaultFileName(`${"t".repeat(296)}.jpg`, 42)).toBe(
+            `${"t".repeat(251)}.jpg`,
+        );
+        expect(defaultFileName(`b.${"e".repeat(300)}`, 42)).toBe(
+            `b.${"e".repeat(253)}`,
+        );
+    });
+
+    it("puts `prefix` before the title and leaves room for it", () => {
+        expect(defaultFileName("beach.jpg", 42, { prefix: "thumb_" })).toBe(
+            "thumb_beach.jpg",
+        );
+        expect(
+            defaultFileName(`${"t".repeat(296)}.jpg`, 42, { prefix: "thumb_" }),
+        ).toBe(`thumb_${"t".repeat(245)}.jpg`);
+    });
+
+    // A live photo's image and video are each named with their own
+    // extension, and the name is cut short once that extension is in it.
+    it("puts `ext` in place of the title's extension before cutting the name short", () => {
+        expect(defaultFileName("IMG_0001.HEIC", 42, { ext: ".mov" })).toBe(
+            "IMG_0001.mov",
+        );
+        expect(defaultFileName("", 42, { ext: ".mov" })).toBe("file-42.mov");
+        expect(
+            defaultFileName(`${"t".repeat(251)}.jpg`, 42, { ext: ".heic" }),
+        ).toBe(`${"t".repeat(250)}.heic`);
+        expect(defaultFileName("t".repeat(300), 42, { ext: ".heic" })).toBe(
+            `${"t".repeat(250)}.heic`,
+        );
+    });
+
+    // Cutting `CONSOLE` or `NULL` short before a long extension leaves `CON`
+    // or `NUL`, so the name gets the `_` `sanitizeFileName` gives a device
+    // name, and the part before the extension gives up a byte for it.
+    it("never returns a Windows device name, even once cut short", () => {
+        const ext = `.${"e".repeat(251)}`;
+        expect(defaultFileName(`CONSOLE${ext}`, 42)).toBe(`_CO${ext}`);
+        expect(defaultFileName(`NULL${ext}`, 42)).toBe(`_NU${ext}`);
+    });
 });

test/library/fresh.test.ts

@@ -14,6 +14,9 @@
  *     three.
  *  3. A refresh that fails rejects the fresh read (currency was unavailable),
  *     while the default reads stay silent and keep serving the last good copy.
+ *  4. `freshCollections()` reads the collection list alone, with one request
+ *     and no collection's files, and stores nothing, so the next refresh still
+ *     fetches the files of every collection (issue #210).
  *
  * The client is the same metadata-only mock the background-refresh tests use:
  * no crypto, no network, scripted pages, and a record of each call. A long
@@ -270,3 +273,70 @@ describe("Library.fresh", () => {
         }
     });
 });
+
+describe("Library.freshCollections", () => {
+    let dir: string;
+    let cacheDirectory: string;
+
+    beforeEach(() => {
+        dir = mkdtempSync(join(tmpdir(), "quak-fresh-collections-"));
+        cacheDirectory = join(dir, "cache");
+    });
+
+    afterEach(() => {
+        rmSync(dir, { recursive: true, force: true });
+    });
+
+    // A refresh fetches a collection's files only when the collection is new
+    // or its updationTime has advanced past the stored copy's. Had the
+    // collection list been stored, the next refresh would take every
+    // collection for one it already holds the files of, and fetch none.
+    it("asks for the collection list alone and stores nothing", async () => {
+        const client = new MockClient();
+        const page = {
+            collections: [collection(2, 100), collection(1, 110)],
+            deleted: [],
+            cursor: 110,
+        };
+        client.collectionsQueue.push(page, page);
+        client.filesFor(1, {
+            files: [file(1001, 1, 90)],
+            deleted: [],
+            cursor: 90,
+        });
+        client.filesFor(2, {
+            files: [file(2001, 2, 95)],
+            deleted: [],
+            cursor: 95,
+        });
+
+        const lib = await Library.open({
+            client,
+            cacheDirectory,
+            refreshOnOpen: false,
+            refreshIntervalSeconds: SLOW_INTERVAL,
+        });
+        try {
+            // One request, the whole list in the server's order, and no
+            // collection's files.
+            const collections = await lib.freshCollections();
+            expect(collections.map((c) => c.id)).toEqual([2, 1]);
+            expect(collections.map((c) => c.name)).toEqual([
+                "album-2",
+                "album-1",
+            ]);
+            expect(client.collectionsSinceTimes).toEqual([0]);
+            expect(client.filesCalls).toEqual([]);
+            expect(lib.listCollections()).toEqual([]);
+
+            // The next refresh still asks from the beginning and fetches the
+            // files of both collections.
+            const reads = await lib.fresh();
+            expect(client.collectionsSinceTimes).toEqual([0, 0]);
+            expect(reads.photos.byID({ fileID: 1001 })?.fileID).toBe(1001);
+            expect(reads.photos.byID({ fileID: 2001 })?.fileID).toBe(2001);
+        } finally {
+            await lib.close();
+        }
+    });
+});

test/library/library.test.ts

@@ -26,6 +26,9 @@
  *    opening.
  * 8. A save failure that leaves RAM ahead of disk keeps `status().lastError`
  *    set and keeps retrying the write; a later empty refresh does not clear it.
+ * 9. With `refreshOnOpen: false`, `open()` starts no refresh at all, and a
+ *    refresh reports through `onProgress` each collection whose files it
+ *    fetched.
  *
  * The client is a mock: no crypto, no network. It serves scripted pages and
  * records the `sinceTime` each call carried so cursor threading is provable.
@@ -581,6 +584,107 @@ describe("Library.open and background refresh", () => {
         }
     });
 
+    // A caller that asks for each refresh it needs, as the CLI's read commands
+    // do, opens without one: on an empty cache the refresh `open()` would
+    // await fetches the files of every collection, which `quak collections`
+    // never needs (issue #210).
+    it("starts no refresh as it opens when refreshOnOpen is false", async () => {
+        const client = new MockClient();
+        client.collectionsQueue.push({
+            collections: [collection(1, 100)],
+            deleted: [],
+            cursor: 100,
+        });
+
+        const lib = await Library.open({
+            client,
+            cacheDirectory,
+            refreshOnOpen: false,
+            refreshIntervalSeconds: Infinity,
+        });
+        try {
+            expect(client.collectionsSinceTimes).toEqual([]);
+            expect(lib.listCollections()).toEqual([]);
+            expect(lib.status().lastRefreshAt).toBeUndefined();
+
+            // The refresh comes when the caller asks for it.
+            await lib.fresh();
+            expect(client.collectionsSinceTimes).toEqual([0]);
+            expect(lib.listCollections().map((c) => c.id)).toEqual([1]);
+        } finally {
+            await lib.close();
+        }
+    });
+
+    // A refresh fetches the files of each collection that changed, one
+    // collection after another, and stores nothing until it has them all. On
+    // a large account that takes a while, so it reports each collection whose
+    // files it has fetched, and how many it will fetch in all (issue #210).
+    it("reports each collection whose files a refresh fetched", async () => {
+        const events: RefreshEvent[] = [];
+        const client = new MockClient();
+        client.collectionsQueue.push({
+            collections: [
+                collection(1, 100),
+                collection(2, 100),
+                collection(3, 100),
+            ],
+            deleted: [],
+            cursor: 100,
+        });
+
+        const lib = await Library.open({
+            client,
+            cacheDirectory,
+            refreshIntervalSeconds: Infinity,
+            onProgress: (e) => events.push(e),
+        });
+        try {
+            expect(events).toEqual([
+                { operation: "refresh", status: "started" },
+                {
+                    operation: "refresh",
+                    status: "progress",
+                    fetched: 1,
+                    total: 3,
+                },
+                {
+                    operation: "refresh",
+                    status: "progress",
+                    fetched: 2,
+                    total: 3,
+                },
+                {
+                    operation: "refresh",
+                    status: "progress",
+                    fetched: 3,
+                    total: 3,
+                },
+                { operation: "refresh", status: "done" },
+            ]);
+
+            // Only collection 2 changed since, so the next refresh fetches
+            // its files alone and counts one.
+            events.length = 0;
+            client.collectionsQueue.push({
+                collections: [collection(2, 200)],
+                deleted: [],
+                cursor: 200,
+            });
+            await lib.fresh();
+            expect(events.filter((e) => e.status === "progress")).toEqual([
+                {
+                    operation: "refresh",
+                    status: "progress",
+                    fetched: 1,
+                    total: 1,
+                },
+            ]);
+        } finally {
+            await lib.close();
+        }
+    });
+
     it("keeps a save failure visible until a save actually succeeds", async () => {
         const saveSpy = vi
             .spyOn(MetadataStore.prototype, "save")

test/library/mldata.test.ts

@@ -12,9 +12,11 @@
  *
  *   2. `Library` wiring: after each refresh the library fetches ML data through
  *      the metadata pool for every known file not yet cached, is incremental on
- *      later refreshes, and refetches a file whose `updationTime` advanced.
- *      Opening a cache directory written by another account starts empty,
- *      its ML data included (issue #104).
+ *      later refreshes, and refetches a file whose `updationTime` advanced. A
+ *      file whose ML data did not decode is reported with the reason, which
+ *      stays listed until the next pass ends, and asked for again. Opening a
+ *      cache directory written by another account starts empty, its ML data
+ *      included (issue #104).
  *
  * Embedding values are chosen to be exactly representable as float32 so the
  * round-trip through `clip.f32` compares equal.
@@ -26,7 +28,7 @@ import { tmpdir } from "node:os";
 import { join } from "node:path";
 
 import { MLDataStore } from "../../src/library/mldata.js";
-import { Library } from "../../src/library/index.js";
+import { Library, type RefreshEvent } from "../../src/library/index.js";
 import type { CollectionsPage, FilesPage } from "../../src/client.js";
 import type { MLData } from "../../src/mldata-fetch.js";
 import type { Collection, EnteFile } from "../../src/model/types.js";
@@ -256,12 +258,14 @@ const file = (
 
 // A mock client that serves scripted collection/file pages and per-file ML
 // payloads, recording every ML fetch request so incremental behaviour is
-// provable.
+// provable. A file in `mlErrorByFile` has ML data that did not decode, for
+// the reason given there.
 class MLMockClient {
     userID = USER_ID;
     collectionsQueue: CollectionsPage[] = [];
     filesByCollection = new Map<number, FilesPage[]>();
     mlByFile = new Map<number, MLData>();
+    mlErrorByFile = new Map<number, Error>();
     mlFetchCalls: number[][] = [];
 
     whoami(): { email: string; userID: number } {
@@ -298,14 +302,20 @@ class MLMockClient {
     async fetchMLData(args: {
         fileIDs: number[];
         fileKeys: Map<number, Uint8Array>;
-    }): Promise<Map<number, MLData>> {
+    }): Promise<{
+        payloads: Map<number, MLData>;
+        errors: Map<number, unknown>;
+    }> {
         this.mlFetchCalls.push([...args.fileIDs]);
-        const result = new Map<number, MLData>();
+        const payloads = new Map<number, MLData>();
+        const errors = new Map<number, unknown>();
         for (const id of args.fileIDs) {
             const p = this.mlByFile.get(id);
-            if (p) result.set(id, p);
+            if (p) payloads.set(id, p);
+            const error = this.mlErrorByFile.get(id);
+            if (error) errors.set(id, error);
         }
-        return result;
+        return { payloads, errors };
     }
 
     filesFor(collectionID: number, ...pages: FilesPage[]): void {
@@ -449,6 +459,137 @@ describe("Library ML-data fetch on refresh", () => {
         }
     });
 
+    it("reports a file whose ML data did not decode through status() and onProgress, and asks for it again", async () => {
+        const client = new MLMockClient();
+        client.collectionsQueue.push({
+            collections: [collection(1, 100)],
+            deleted: [],
+            cursor: 100,
+        });
+        client.filesFor(1, {
+            files: [file(1001, 1, 90), file(1002, 1, 95)],
+            deleted: [],
+            cursor: 95,
+        });
+        client.mlByFile.set(1001, payload([0.5, 0.25, 0.75]));
+        client.mlErrorByFile.set(
+            1002,
+            new Error("secretstream chunk authentication failed"),
+        );
+        const events: RefreshEvent[] = [];
+
+        const lib = await Library.open({
+            client,
+            cacheDirectory,
+            refreshIntervalSeconds: Infinity,
+            onProgress: (event) => events.push(event),
+        });
+        try {
+            await vi.waitFor(
+                () => expect(lib.status().lastMLFetchAt).toBeGreaterThan(0),
+                { timeout: 2000, interval: 5 },
+            );
+            const reasons = [
+                {
+                    fileID: 1002,
+                    error: "secretstream chunk authentication failed",
+                },
+            ];
+            expect(lib.status().mlDataErrors).toEqual(reasons);
+            expect(lib.status().mlStored).toBe(1);
+            expect(events.filter((e) => e.operation === "fetchMLData")).toEqual(
+                [
+                    { operation: "fetchMLData", status: "started" },
+                    {
+                        operation: "fetchMLData",
+                        status: "done",
+                        fetched: 1,
+                        mlDataErrors: reasons,
+                    },
+                ],
+            );
+
+            // Nothing was cached for 1002, so the pass a refresh starts asks
+            // for it again, and once its ML data decodes the reason is gone.
+            client.mlErrorByFile.clear();
+            client.mlByFile.set(1002, payload([1, -2, 0.5]));
+            await lib.fresh();
+            await vi.waitFor(
+                () => {
+                    expect(lib.status().mlStored).toBe(2);
+                    expect(lib.status().mlDataErrors).toEqual([]);
+                },
+                { timeout: 2000, interval: 5 },
+            );
+            expect(client.mlFetchCalls.at(-1)).toEqual([1002]);
+        } finally {
+            await lib.close();
+        }
+    });
+
+    it("still lists the last pass's reasons while the next pass runs", async () => {
+        const client = new MLMockClient();
+        client.collectionsQueue.push({
+            collections: [collection(1, 100)],
+            deleted: [],
+            cursor: 100,
+        });
+        client.filesFor(1, {
+            files: [file(1002, 1, 95)],
+            deleted: [],
+            cursor: 95,
+        });
+        client.mlErrorByFile.set(
+            1002,
+            new Error("secretstream chunk authentication failed"),
+        );
+        const reasons = [
+            { fileID: 1002, error: "secretstream chunk authentication failed" },
+        ];
+        let release!: () => void;
+        const held = new Promise<void>((r) => (release = r));
+
+        const lib = await Library.open({
+            client,
+            cacheDirectory,
+            refreshIntervalSeconds: Infinity,
+        });
+        try {
+            await vi.waitFor(
+                () => expect(lib.status().lastMLFetchAt).toBeGreaterThan(0),
+                { timeout: 2000, interval: 5 },
+            );
+            expect(lib.status().mlDataErrors).toEqual(reasons);
+
+            // Hold the next ML data fetch open until the test releases it.
+            let fetchStarted!: () => void;
+            const started = new Promise<void>((r) => (fetchStarted = r));
+            const realFetch = client.fetchMLData.bind(client);
+            client.fetchMLData = async (args) => {
+                fetchStarted();
+                await held;
+                return realFetch(args);
+            };
+            client.mlErrorByFile.clear();
+            client.mlByFile.set(1002, payload([1, -2, 0.5]));
+
+            // The pass a refresh starts asks for 1002 again. While it is
+            // held, the reason from the pass before is still listed; once it
+            // ends, its own empty list takes the place of that one.
+            await lib.fresh();
+            await started;
+            expect(lib.status().mlDataErrors).toEqual(reasons);
+            release();
+            await vi.waitFor(
+                () => expect(lib.status().mlDataErrors).toEqual([]),
+                { timeout: 2000, interval: 5 },
+            );
+        } finally {
+            release();
+            await lib.close();
+        }
+    });
+
     it("close() resolves only after a running ML data fetch has stored its payloads", async () => {
         const client = new MLMockClient();
         client.collectionsQueue.push({

test/mldata-fetch/mldata-fetch.test.ts

@@ -0,0 +1,54 @@
+// `fetchMLDataBatch`, against a server that sends one file's ML data.
+//
+// ML data that decrypts and gunzips but is not a JSON object is reported with
+// the reason, as ML data that does not parse is, and is never returned as a
+// payload: the library would fail to store it.
+
+import { gzipSync } from "node:zlib";
+import sodium from "libsodium-wrappers-sumo";
+import { beforeAll, describe, expect, it } from "vitest";
+
+import { ApiClient } from "../../src/api/client.js";
+import { encryptBlob, init, toBase64 } from "../../src/crypto/index.js";
+import { fetchMLDataBatch } from "../../src/mldata-fetch.js";
+
+beforeAll(async () => {
+    await init();
+    await sodium.ready;
+});
+
+// Fetch the ML data of file 1 from a server that sends `json`, gzipped and
+// encrypted with the file's key.
+const fetchServing = async (json: string) => {
+    const key = sodium.crypto_secretstream_xchacha20poly1305_keygen();
+    const { header, ciphertext } = encryptBlob(
+        new Uint8Array(gzipSync(json)),
+        key,
+    );
+    const data = [
+        {
+            fileID: 1,
+            encryptedData: toBase64(ciphertext),
+            decryptionHeader: toBase64(header),
+        },
+    ];
+    const api = new ApiClient({
+        fetch: async () =>
+            new Response(JSON.stringify({ data }), {
+                headers: { "content-type": "application/json" },
+            }),
+    });
+    return fetchMLDataBatch(api, [1], new Map([[1, key]]));
+};
+
+describe("fetchMLDataBatch", () => {
+    it.each(["null", "5", "[]"])(
+        "gives a reason for ML data that is %s",
+        async (json) => {
+            const { payloads, errors } = await fetchServing(json);
+
+            expect(payloads.size).toBe(0);
+            expect(errors.get(1)).toEqual(new Error("not a JSON object"));
+        },
+    );
+});

test/retry/retry.test.ts

@@ -77,6 +77,14 @@ const recordingSleep = (): {
 const errnoError = (code: string, message = code): Error =>
     Object.assign(new Error(message), { code });
 
+/**
+ * An error shaped like what bun's `fetch` rejects with for a failure below
+ * HTTP: a plain `Error` with bun's own message, a `code`, an `errno` of 0, and
+ * no `cause`.
+ */
+const bunError = (code: string, message: string): Error =>
+    Object.assign(new Error(message), { code, errno: 0 });
+
 // ---------------------------------------------------------------------------
 // Classification
 // ---------------------------------------------------------------------------
@@ -244,6 +252,82 @@ describe("isRetryable: transport failures", () => {
     });
 });
 
+describe("isRetryable and isSafeToReplay: bun's fetch errors", () => {
+    // The binary `make install` builds runs quak under bun, whose `fetch`
+    // does not reject as Node's does. Each shape here was found by running
+    // that binary, built with bun 1.3.13, against listeners on 127.0.0.1 and
+    // a name under `.invalid`.
+
+    it("retries a refused connection, and does not replay it", () => {
+        // Bun gives the same error when the TLS handshake fails, and when a
+        // new connection it opened to resend a request is refused. That
+        // request may already have reached the server on a connection bun
+        // kept open from an earlier request.
+        const refused = bunError(
+            "ConnectionRefused",
+            "Unable to connect. Is the computer able to access the url?",
+        );
+        expect(isRetryable(refused)).toBe(true);
+        expect(isSafeToReplay(refused)).toBe(false);
+    });
+
+    it("retries a name that does not resolve, with either code bun gives, and does not replay it", () => {
+        // For the same name bun gave `ConnectionRefused` on some requests and
+        // `FailedToOpenSocket` on others. Either can also come from a new
+        // connection bun opened to resend a request, as above.
+        for (const unresolved of [
+            bunError(
+                "ConnectionRefused",
+                "Unable to connect. Is the computer able to access the url?",
+            ),
+            bunError(
+                "FailedToOpenSocket",
+                "Was there a typo in the url or port?",
+            ),
+        ]) {
+            expect(isRetryable(unresolved)).toBe(true);
+            expect(isSafeToReplay(unresolved)).toBe(false);
+        }
+    });
+
+    it("retries a connection closed before the response ended, and does not replay it", () => {
+        // Bun gives Node's errno, `ECONNRESET`, for a reset and for a close,
+        // before the response or part-way through the body. The request may
+        // already have reached the server.
+        const reset = bunError(
+            "ECONNRESET",
+            "The socket connection was closed unexpectedly. For more information, pass `verbose: true` in the second argument to fetch()",
+        );
+        expect(isRetryable(reset)).toBe(true);
+        expect(isSafeToReplay(reset)).toBe(false);
+    });
+
+    it("retries a request that ran out of time, and does not replay it", () => {
+        // What bun's fetch rejects with when `AbortSignal.timeout()`, which
+        // bounds each JSON request, fires.
+        const timedOut = new DOMException(
+            "The operation timed out.",
+            "TimeoutError",
+        );
+        expect(isRetryable(timedOut)).toBe(true);
+        expect(isSafeToReplay(timedOut)).toBe(false);
+    });
+
+    it("does not retry a certificate bun rejects", () => {
+        // A certificate that fails verification fails the same way however
+        // often it is asked. Under Node it is retried only because every
+        // `TypeError` is.
+        expect(
+            isRetryable(
+                bunError(
+                    "DEPTH_ZERO_SELF_SIGNED_CERT",
+                    "self signed certificate",
+                ),
+            ),
+        ).toBe(false);
+    });
+});
+
 describe("isRetryable: stream truncation versus corruption", () => {
     it("retries a truncated stream", () => {
         // Truncation is a transfer that stopped early. The bytes that did