Stop the disk size tests failing at random on ZFS (closes #150 )

One ZFS commit can take a file through several sizes, and unix.Sync can return before the blocks are counted. A test that expected the size on disk to be settled therefore failed at random. The test that needs the size to change now calls unix.Sync in a loop until it does, for at most 30 seconds. It then rescans until the size reads the same before and after a rescan, and compares disk_size exactly, within the same 30 seconds. The other two tests fail only on a disk_size outside their two reads. They call unix.Sync once first, so a wrong 512 usually fails them. Model: opus-5-5
Rewrite TODO.md sentence by sentence (closes #135 )
2026-11-03 02:55:48 +00:00 · 2026-11-02 23:29:22 +01:00 · 2026-11-02 23:12:27 +01:00 · 2026-10-27 19:56:49 +01:00 · 2026-10-27 18:59:37 +01:00 · 2026-10-26 15:15:37 +01:00
14 changed files with 2377 additions and 1361 deletions
@@ -20,7 +20,7 @@

 # Next Step

- Take the next issue from the `1.0.0` milestone:
+- Take the next issue from the `1.0.0` milestone,
  https://git.eeqj.de/sneak/sfdupes/milestone/17. The issues are not restated
  here, because a copy drifts as soon as the tracker moves.

@@ -29,40 +29,72 @@
 Newest first. An entry ends with its date and its issue or branch, where those
 are known.

- `TODO.md` rewritten from scratch by the same rules as `README.md`: short
-  sentences, lists as bullets, nothing a newcomer reads twice. Every completed
-  step is kept, with its date and its issue or branch. The policy-compliance
-  checklist of 2026-07-22 is folded into its step (2026-10-26,
-  https://git.eeqj.de/sneak/sfdupes/issues/135)
+- The three disk size tests in `scan_test.go` no longer fail at random on ZFS.
+  `unix.Sync` can return before ZFS has counted a file's blocks, and one ZFS
+  commit can take a file through several sizes. The test that needs the size to
+  change waits for it, for at most 30 seconds. Each test reads the size before
+  and after its scan. The rewrite test rescans until the two reads match, then
+  compares exactly. The other two fail only on a `disk_size` outside the two
+  reads (2026-11-02, https://git.eeqj.de/sneak/sfdupes/issues/150)
+
+- `TODO.md` rewritten from scratch by the same rules as `README.md`, sentence by
+  sentence. Every completed step is kept, with its date and its issue or branch.
+  The policy-compliance checklist of 2026-07-22 is folded into its step
+  (2026-11-02, https://git.eeqj.de/sneak/sfdupes/issues/135)

 - `README.md` rewritten from scratch, sentence by sentence, as a newcomer reads
  it. It leads with what the program is and how to use it. A reference section
-  covers the settings, the database, the output formats and the exit codes;
-  development and testing come last. Every statement was checked against the
-  code on `next` (2026-10-26, https://git.eeqj.de/sneak/sfdupes/issues/135)
+  covers every setting and every subcommand. Development and testing come last.
+  Every statement was checked against the code on `next`. Five comments in
+  `main_test.go` cite "Settings", where their rules now live. One comment each
+  in `scan_test.go`, `trees_test.go` and `exclude_test.go` cites what the README
+  now says (2026-11-02, https://git.eeqj.de/sneak/sfdupes/issues/135)
+
+- Each record holds `disk_size`, the bytes the file takes on disk. That is its
+  allocated blocks, `st_blocks` × 512, from the `lstat` call the walk already
+  makes. `trees` prints a `disk_size` column after `size`. It is the sum over
+  the `dupe` copy's files. On a compressed or sparse file `disk_size` differs
+  from `size`. A rescan updates the `disk_size` of an unchanged file whose size
+  on disk changed, without reading the file (2026-10-27,
+  https://git.eeqj.de/sneak/sfdupes/issues/147)
+
+- The database keeps the number of records and the sum of their sizes in the one
+  row of a `totals` table. Three triggers on `files` keep that row current.
+  `info` reads that row. So do `scan`'s `load` phase and the `read` phases of
+  `report` and `trees`, for their totals. No count reads every record any more.
+  The triggers make each write to `files` slower. `scan` keeps SQLite's
+  temporary data in memory. That wins back part of that time (2026-10-27,
+  https://git.eeqj.de/sneak/sfdupes/issues/146)
+
+- an operand at or inside a directory named `.zfs` is never scanned, whether
+  given alone or under another operand. `scan` warns about it, counts it as
+  skipped and does not walk it (2026-10-26,
+  https://git.eeqj.de/sneak/sfdupes/issues/142)

 - A file or directory removed while the scan runs is not an error, in the walk
  or in the hash phase. The scan prints no line for it and does not count it as
  skipped. When the first of several hard links to a file is gone, the hash
  phase reads the next one instead. On a terminal every progress display starts
  with the spinner, the hash phase's included. A phase with an exact total ends
-  its line with its percent and a 10-column bar at the terminal's right edge,
-  which no longer moves as the line's length changes. A line too wide for the
+  its line with its percent and a 10-column bar at the terminal's right edge.
+  The bar no longer moves as the line's length changes. A line too wide for the
  terminal now loses its rate before its bar. The time remaining is labelled
  `remain`, not `eta` (2026-10-26, https://git.eeqj.de/sneak/sfdupes/issues/133)

 - The `head`, `tail` and `content` columns are BLOBs, each holding the raw 32
-  bytes of a SHA-256, half the size of the hex text they held. The hashes stay
-  raw from the hash phase through the database to `report` and `trees`. Reading
-  a record whose hash is not 32 bytes is an error (2026-10-26,
+  bytes of a SHA-256. That is half the size of the hex text they held. The
+  hashes stay raw from the hash phase through the database to `report` and
+  `trees`. Reading a record whose hash is not 32 bytes is an error (2026-10-26,
  https://git.eeqj.de/sneak/sfdupes/issues/134)

- Every file the walk records gets three hashes in the hash phase. `head` and
-  `tail` are the SHA-256 of its first and last 64 KiB. `content` is the SHA-256
-  of the whole file under 100 MiB, and of 1 MiB at each gigabyte from 100 MiB
-  up. Gone are:
+- The hash phase gives three hashes to every file that the walk records. `head`
+  and `tail` are the SHA-256 of its first and last 64 KiB. `content` is the
+  SHA-256 of the whole file under 100 MiB, and of 1 MiB at each gigabyte from
+  100 MiB up. Gone are:
    - the 10 MiB and 50 MiB thresholds;
-    - the size census;
+    - the size census, which counted the sizes of every walked file and of every
+      record outside the operands. A file was hashed only when the census showed
+      another file of its size;
    - the records without hashes;
    - the content phase.

@@ -71,72 +103,110 @@ are known.
    with a content hash, since every record has all three (2026-10-25,
    https://git.eeqj.de/sneak/sfdupes/issues/132)

- `REPO_POLICIES.md` and the four scripts that pass `CACHEBUST` re-vendored from
-  `sneak/prompts` `next` at `0653579`. Two steps now come before
-  `ARG CACHEBUST`: the module download in the `lint`, `test` and `builder`
-  stages of the `Dockerfile`, and the package install in `builder`. Docker keeps
-  them until the base image, the install line, `go.mod` or `go.sum` changes.
-  Every step that lints, tests or compiles still comes after it.
-  `golangci-lint run` also keeps the linter's own cache. README says the same
-  (2026-10-18, https://git.eeqj.de/sneak/sfdupes/issues/109)
+- `REPO_POLICIES.md` and the four scripts that pass `CACHEBUST` were copied
+  again from `sneak/prompts` `next` at `0653579`. Two steps now come before
+  `ARG CACHEBUST`:
+    - the module download in the `lint`, `test` and `builder` stages of the
+      `Dockerfile`;
+    - the package install in `builder`.

- Release rule set: until 1.0, each tip of `main` that passes the build gets the
-  next `v0.0.N` tag, so `go install sneak.berlin/go/sfdupes@latest` installs it.
-  `go.mod` retracts `v0.0.1`, the early build without a database. When the
-  linker set no version, `sfdupes --version` prints the version Go recorded in
-  the binary: the tag, or the pseudo-version of a `go install` build. It prints
-  `dev` only when neither is known. README "Install" documented the rule, what
-  `@main` and `v0.0.1` give, and how to check an installed binary (2026-10-17,
-  https://git.eeqj.de/sneak/sfdupes/issues/116)
+    Docker keeps them until one of these changes:
+    - the base image;
+    - the install line;
+    - `go.mod` or `go.sum`.
+
+    Every step that checks or compiles the code still comes after
+    `ARG CACHEBUST`. `golangci-lint run` also keeps the linter's own cache.
+    README says the same (2026-10-18,
+    https://git.eeqj.de/sneak/sfdupes/issues/109)
+
+- The release rule was set. Until 1.0, each tip of `main` that passes the build
+  gets the next `v0.0.N` tag. `go install sneak.berlin/go/sfdupes@latest` then
+  installs it. `go.mod` retracts `v0.0.1`, the early build without a database.
+  When the linker set no version, `sfdupes --version` prints the version Go
+  recorded in the binary. That is the tag, or the pseudo-version of a
+  `go install` build. It prints `dev` only when neither is known. README
+  "Install" documented:
+    - the rule;
+    - what `@main` and `v0.0.1` give;
+    - how to check an installed binary.
+
+    (2026-10-17, https://git.eeqj.de/sneak/sfdupes/issues/116)

 - `scan` creates the database's directory where the database path leads. The
-  directory is the path with its last element cut off as text, never cleaned. A
-  `..` after a symlinked directory therefore goes through the symlink, as it
-  does when the file is opened. With
+  directory is the path with its last element cut off as text, so a `..` in it
+  stays. A `..` after a symlinked directory therefore goes through the symlink,
+  as it does when the file is opened. With
  `SFDUPES_DATABASE=/srv/link/../new/db.sqlite` and `/srv/link` a symlink to
  `/data/x`, it now creates `/data/new` and the database in it. It used to
  create `/srv/new` and then fail (2026-10-17,
  https://git.eeqj.de/sneak/sfdupes/issues/119)

 - `scan` never records its own database. Once the database and its `.lock` file
-  are open, it notes the device and inode of the database file, its `-wal` and
-  `-shm` files and the `.lock` file. The walk passes over a file with one of
-  them wherever it reaches it, through a symlinked directory included, printing
-  no line and counting nothing. A record an earlier scan left for one of them is
-  deleted (2026-10-17, https://git.eeqj.de/sneak/sfdupes/issues/115)
+  are open, it notes the device and inode of each of these:
+    - the database file;
+    - its `-wal` and `-shm` files;
+    - the `.lock` file.

- `scan` never records or reads anything on a filesystem that is not persistent:
-  `tmpfs`, `proc`, `sysfs` and the other kernel or memory-backed types. It
-  matches them by device ID. As the scan starts, it lists the mounted
+    The walk passes over any file with the device and inode of one of them,
+    however it reaches the file. It prints no line for such a file and counts
+    nothing. A record an earlier scan left for one of them is deleted
+    (2026-10-17, https://git.eeqj.de/sneak/sfdupes/issues/115)
+
+- `scan` never records or reads anything on a filesystem that is not persistent,
+  such as `tmpfs` or `proc`. Such a filesystem is one the kernel makes up or
+  keeps in memory. `scan` matches them by device ID, however the walk or the
+  content phase reaches a path. As the scan starts, it lists the mounted
  filesystems of those types, from `/proc/self/mountinfo` on Linux and from the
  mount list on macOS. No flag turns that off. Below an operand, the walk does
-  not enter the default excludes either, so `sfdupes scan /` skips the kernel's
-  view of the running system and the temporary directories. On Linux those are
-  `/proc`, `/sys`, `/dev`, `/run`, `/tmp` and `/var/tmp`. On macOS they are
-  `/dev`, `/private/tmp`, `/private/var/tmp`, `/private/var/vm`,
-  `/System/Volumes/VM` and `/System/Volumes/Data`. A Windows list exists in the
-  code but is not used. An operand at or inside a default exclude is still
-  walked. The scan prints a line for each path it leaves out, without counting
-  it as skipped, and the records there count as outside the scanned operands, as
-  for `-x`. `--no-default-excludes` turns off the default excludes only, and
-  `scan --help` lists them (2026-10-17,
-  https://git.eeqj.de/sneak/sfdupes/issues/124)
+  not enter the default excludes either. So `sfdupes scan /` skips the kernel's
+  view of the running system and the temporary directories. On Linux those are:

- The rate a progress display shows covers the items completed over the last 5
-  seconds, or since the line before when stderr is not a terminal. It falls to 0
-  while nothing completes, and a burst after a wait no longer reads as a steady
-  rate of over 1,000 files a second. The time remaining still comes from the
-  phase's average. Once no item has completed for 10 seconds, the word `stalled`
-  and where the phase waits take the rate's place, as `stalled disk/db`. The
-  places are `disk`, `db`, `out` for stdout and `cpu`, or two of them for a
-  phase that may wait on either. Each phase gives its word where it is defined.
-  A line too wide for the terminal loses its bar first, then its rate or those
-  words, so the phase, progress, elapsed time and ETA stay whole. On an
-  80-column terminal, at counts like those of README's example, the content
-  phase's checks and reads lose those words at most times in minutes. Every
-  other phase keeps them whenever the elapsed time and the ETA are both in
-  minutes. The content phase's last partial batch is written under a display of
-  its own (2026-10-16, https://git.eeqj.de/sneak/sfdupes/issues/125)
+    ```
+    /proc, /sys, /dev, /run, /tmp, /var/tmp
+    ```
+
+    On macOS they are:
+
+    ```
+    /dev, /private/tmp, /private/var/tmp, /private/var/vm
+    /System/Volumes/VM, /System/Volumes/Data
+    ```
+
+    A Windows list exists in the code but is not used. An operand at or inside a
+    default exclude is still walked. The scan prints a line for each path it
+    leaves out, without counting it as skipped. The records there count as
+    outside the scanned operands, as for `-x`. `--no-default-excludes` turns off
+    the default excludes only, and `scan --help` lists them (2026-10-17,
+    https://git.eeqj.de/sneak/sfdupes/issues/124)
+
+- A progress display's rate covers the items completed over the last 5 seconds.
+  When stderr is not a terminal, it covers the items since the line before. It
+  falls to 0 while nothing completes. A burst after a wait no longer reads as a
+  steady rate of over 1,000 files a second. The time remaining still comes from
+  the phase's average. Once no item has completed for 10 seconds, the line shows
+  `stalled` and where the phase waits in place of the rate, as
+  `stalled disk/db`. The places are:
+    - `disk`;
+    - `db`;
+    - `out`, for stdout;
+    - `cpu`.
+
+    A phase that may wait in two places names both. Each phase's word is set in
+    the code that defines the phase. A line too wide for the terminal loses its
+    bar first, then its rate or those words. Four parts stay whole:
+    - the phase;
+    - the progress;
+    - the elapsed time;
+    - the ETA, the time remaining.
+
+    The content phase had one display for its checks and one for its reads. Both
+    lost those words on an 80-column terminal, at counts like those of README's
+    example. That happened for most elapsed times and ETAs in minutes. Every
+    other phase kept them whenever the elapsed time and the ETA were both in
+    minutes. The content phase writes its last partial batch, the records not
+    yet written, under a display of its own (2026-10-16,
+    https://git.eeqj.de/sneak/sfdupes/issues/125)

 - New subcommand `info` prints the database's details on stdout, one per line as
  a name, a tab and the value:
@@ -144,13 +214,15 @@ are known.
    - the sizes of the database file and of its `-wal` file, when there is one;
    - when the database file was last changed;
    - the schema version;
-    - the number of records, how many have `head` and `tail` hashes, and how
-      many have a content hash;
+    - the number of records;
+    - how many records have `head` and `tail` hashes;
+    - how many records have a content hash;
    - the sizes of all records added up.

    It opens the database as `report` does and shows two phases on stderr,
    `[1/2] open` and `[2/2] count`. The schema version and the counts come from
-    one read-only transaction, the counts from one query (2026-10-16,
+    one read-only transaction, a read of the database at one moment. The counts
+    come from one query (2026-10-16,
    https://git.eeqj.de/sneak/sfdupes/issues/117)

 - `report` shows its work on stderr in two phases, `[1/2] open` and
@@ -159,84 +231,96 @@ are known.
  opening the database, also while it waits on a busy one. `read` counts the
  records, then reads them against that count in signature order. SQLite takes
  that order from the `files_signature` index without sorting, so the first
-  record comes at once. `report` forms the duplicate groups itself, holding only
-  those of the size it is reading, and writes them ordered by first path before
-  it reads the next size. stdout and the summary line are unchanged, and SQLite
-  no longer needs a temporary file to sort in (2026-10-16,
+  record comes at once. `report` forms the duplicate groups itself and holds
+  only those of the size it is reading. It writes them ordered by first path
+  before it reads the next size. stdout and the summary line are unchanged, and
+  SQLite no longer needs a temporary file to sort in (2026-10-16,
  https://git.eeqj.de/sneak/sfdupes/issues/114)

- `trees` shows its work on stderr in four phases, `[1/4] open`, `[2/4] read`,
-  `[3/4] group` and `[4/4] write`, each with the progress display `scan` uses.
-  The display runs from the moment `trees` starts until the summary line. `open`
-  says it is opening the database, also while it waits on a busy one. `read`
-  counts the records, then reads them against that count. `group` counts the
-  directories it groups, and `write` the groups it writes. A display's rate
-  names what its phase counts: files, records, directories or groups. stdout and
-  the summary line are unchanged. When stdout and stderr are the same file, as
-  one terminal is, no line of stdout shares a line with the display. When they
-  are not, the display keeps being drawn while stdout waits on a slow reader
-  (2026-10-16, https://git.eeqj.de/sneak/sfdupes/issues/113)
+- `trees` shows its work on stderr in four phases, from `[1/4] open` to
+  `[4/4] write`, each with the progress display `scan` uses. The display runs
+  from the moment `trees` starts until the summary line. `open` says it is
+  opening the database, also while it waits on a busy one. `read` counts the
+  records, then reads them against that count. `group` counts the directories it
+  groups, and `write` the groups it writes. A display's rate names what its
+  phase counts:
+    - files;
+    - records;
+    - directories;
+    - groups.
+
+    stdout and the summary line are unchanged. When stdout and stderr are the
+    same file, as one terminal is, no line of stdout shares a line with the
+    display. When they are not, the display keeps being drawn while stdout waits
+    on a slow reader (2026-10-16, https://git.eeqj.de/sneak/sfdupes/issues/113)

 - Each `scan` phase's progress display names the phase and its place among the
-  five, as `[2/5] walk`. It runs from the moment the phase starts and shows its
-  progress, elapsed time and ETA. `load` counts the records first. The walk's
-  total is estimated from the records under the operands. The content phase
-  counts the records it checks from SQLite's grouping alone, then says it is
-  searching the database until the first one is returned. On a terminal a phase
-  with an exact total draws its line followed by the library's bar. Any other
-  phase draws a spinner followed by the line. Every display is drawn again
-  several times a second. No line reaches the terminal's last column, however
-  narrow, also after the terminal is made narrower during a phase. A line too
-  wide leaves out its rate, then its bar, keeping the phase, progress, elapsed
-  time and ETA whole. It is cut short only when those alone do not fit, as below
-  about 70 columns late in a large scan. In plain mode the line is printed every
-  5 seconds whether or not an item completed (2026-10-16,
-  https://git.eeqj.de/sneak/sfdupes/issues/112)
+  five, as `[2/5] walk`. It runs from the moment that the phase starts. It
+  shows:
+    - the progress;
+    - the elapsed time;
+    - the ETA, the time remaining.
+
+    `load` counts the records first. The walk's total is estimated from the
+    records under the operands. The content phase takes its total from SQLite's
+    grouping alone. Until the first record is returned, it says it is searching
+    the database. On a terminal a phase with an exact total draws its line
+    followed by the bar of the progress-bar library. Any other phase draws a
+    spinner followed by the line. Every display is drawn again several times a
+    second. No line reaches the terminal's last column, however narrow the
+    terminal is, even after it is made narrower during a phase. A line too wide
+    leaves out its rate, then its bar. The rest stays whole. The line is cut
+    short only when the rest alone does not fit, as below about 70 columns late
+    in a large scan. When stderr is not a terminal, the line is printed every 5
+    seconds whether or not an item completed (2026-10-16,
+    https://git.eeqj.de/sneak/sfdupes/issues/112)

 - `scan`, `report` and `trees` first print a line on stderr naming the database
-  they use, as an absolute path, and whether that path is the default or comes
-  from `SFDUPES_DATABASE`. `scan` says when the database is new. README
+  they use, as an absolute path. The line says whether that path is the default
+  or comes from `SFDUPES_DATABASE`. `scan` says when the database is new. README
  "Database" says when `scan` writes each file (2026-10-16,
  https://git.eeqj.de/sneak/sfdupes/issues/111)

- The canonical files and model scripts re-vendored from `sneak/prompts` `next`
-  at `e3f79c4`:
+- The canonical files and model scripts were copied again from `sneak/prompts`
+  `next` at `e3f79c4`:
    - `golangci-lint` v2.14.0;
    - lint and test are phases of the `Dockerfile` that write no image, and
-      `make test` runs the suite under the race detector. `Dockerfile.lint`,
-      `script/verify-lint-image-pin` and `make test-race` are gone;
-    - every `docker build` in `script/` passes a new `CACHEBUST` value, which
-      every stage of the `Dockerfile` declares first, so every `RUN` step runs
-      on every build. The steps that compile keep Go's build cache, and the
-      tests run with `-count=1`;
+      `make test` runs the suite under the race detector. Gone are
+      `Dockerfile.lint`, `script/verify-lint-image-pin` and `make test-race`;
+    - every `docker build` in `script/` passes a new `CACHEBUST` value. Every
+      stage of the `Dockerfile` declares it first, so every `RUN` step runs on
+      every build. The steps that compile keep Go's build cache, and the tests
+      run with `-count=1`;
    - `prettier` runs on the host, from the `node` and `yarn` that
-      `script/bootstrap` installs, so the `prettier` and `markdown` stages are
-      gone and the build stage installs `git` and `make` itself;
+      `script/bootstrap` installs. The `prettier` and `markdown` stages are
+      gone, and the build stage installs `git` and `make` itself;
    - a new push cancels the workflow's older run on the same branch, and a run
      stops after 20 minutes;
-    - `.claude/settings.json` is deleted.
+    - a coding agent's settings file is deleted.

    Since https://git.eeqj.de/sneak/sfdupes/issues/109 two steps come before
-    `ARG CACHEBUST`: the module download in `lint`, `test` and the build stage,
-    and the install of `git` and `make` in the build stage. Docker keeps them
-    between builds, and every step that lints, tests or compiles still runs on
-    every build (2026-10-15, https://git.eeqj.de/sneak/sfdupes/issues/95)
+    `ARG CACHEBUST`:
+    - the module download in `lint`, `test` and the build stage;
+    - the install of `git` and `make` in the build stage.

- With `-x`, an operand under another operand is no longer dropped when the
-  outer operand's walk cannot reach it. That is the case when a directory from
-  the inner operand up to, but not including, the outer one is on a different
+    Docker keeps them between builds. Every step that checks or compiles the
+    code still runs on every build (2026-10-15,
+    https://git.eeqj.de/sneak/sfdupes/issues/95)
+
+- With `-x`, an operand under another operand is no longer dropped when a
+  directory between the two, the inner one included, is on a different
  filesystem than the outer one. The inner operand is then walked on its own.
-  For a regular-file operand the directories checked start at its directory. The
-  records of files gone from below it are deleted (2026-10-14,
+  For a regular-file operand the check starts at its directory. The records of
+  files gone from below it are deleted (2026-10-14,
  https://git.eeqj.de/sneak/sfdupes/issues/106)

 - With `-x`, `scan` keeps the records below a directory on another filesystem
-  under its operand, and counts their sizes in the size census, instead of
-  deleting them (2026-10-14, https://git.eeqj.de/sneak/sfdupes/issues/99)
+  under its operand, instead of deleting them. It counts their sizes in the size
+  census (2026-10-14, https://git.eeqj.de/sneak/sfdupes/issues/99)

 - The hash and content phases open each file without blocking and check that it
-  is still a regular file. A file replaced by a FIFO or device node after it was
-  statted is warned about and skipped instead of hanging the scan (2026-10-14,
+  is still a regular file. A file that is now a FIFO or device node is warned
+  about and skipped instead of hanging the scan (2026-10-14,
  https://git.eeqj.de/sneak/sfdupes/issues/100)

 - The scan lock file is named from the database's path with symlinks resolved,
@@ -262,29 +346,34 @@ are known.
 - `make test-race` ran the test suite under the race detector in a cgo-enabled
  container, outside `make check`. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 `make test` itself runs the suite
-  under the race detector, in the `Dockerfile`'s Debian-based `test` phase, and
+  under the race detector, in the `Dockerfile`'s Debian-based `test` phase.
  `make test-race` is gone (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/18)

 - A bare `docker build .` failed, naming `script/cibuild` and `script/docker`,
-  rather than serve the gates from cache. Since
+  rather than serve the gates, the lint and test steps, from cache. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 a bare build succeeds, as
  `REPO_POLICIES.md` requires, and may serve the gates from cache. The builds in
  `script/` pass a new `CACHEBUST` value, so theirs always run (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/39)

- `make fmt` and `make fmt-check` run `prettier` over all Markdown, and CI
-  checks it. All Markdown was reformatted (2026-10-04,
+- `make fmt` and `make fmt-check` run `prettier` over all Markdown, and the
+  Gitea workflow checks it. All Markdown was reformatted (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/19)

 - `script/lint` writes no image, so a run no longer leaves an untagged one
  behind (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/48)

- Tests cover a missing database, `scan` keeping stdout empty, its skip warning,
-  the `report` and `trees` summary lines, and every subcommand going through
-  `runE` (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/16)
+- Tests cover:
+    - a missing database;
+    - `scan` keeping stdout empty;
+    - its skip warning;
+    - the `report` and `trees` summary lines;
+    - every subcommand going through `runE`.

- `.golangci.yml` replaced with the current canonical copy, which uses
+    (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/16)
+
+- `.golangci.yml` was replaced with the current canonical copy, which uses
  `gomodguard_v2`, so lint no longer prints a deprecation warning (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/26)

@@ -303,8 +392,8 @@ are known.
 - A test checks that `scan` refuses a database with another schema version
  (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/64)

- Four inaccurate comments in `cancel_test.go` corrected, and
-  `walkCancelInFlightDirs` renamed to `walkCancelInFlightFiles` (2026-10-04,
+- Four inaccurate comments in `cancel_test.go` were corrected, and
+  `walkCancelInFlightDirs` was renamed to `walkCancelInFlightFiles` (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/33)

 - The `-x` filesystem-boundary rules in `subdirJob` are tested (2026-10-04,
@@ -314,13 +403,13 @@ are known.
  `files` table is refused with a clear schema-version error (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/11)

- README documents install, Docker, a daily cron scan and how to read and check
-  the reports (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/54)
+- README documents install, Docker, a daily `cron` scan and how to read and
+  check the reports (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/54)

 - The `Dockerfile` build stage kept the Go module cache out of `builder`'s home
  and copied the sources with `--chown`, so no `chown -R` walked them. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 there is no `builder` user and
-  nothing changes owner: the build stage only compiles, as root, and the tests
+  nothing changes owner. The build stage only compiles, as root, and the tests
  run as `nobody` in the `test` phase (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/43)

@@ -335,13 +424,19 @@ are known.
  The schema gains the `files_signature` index (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/14)

- Progress prints at once on a non-terminal, uses a real terminal test, and
-  prints warnings through a spinner instead of racing its redraw (2026-10-03,
+- Progress prints at once on a non-terminal and uses a real terminal test.
+  Warnings print through a spinner instead of racing its redraw (2026-10-03,
  https://git.eeqj.de/sneak/sfdupes/issues/13)

- Symlink, socket, FIFO, device and `.zfs` operands are warned about and
-  skipped, and the records beneath them are kept (2026-10-03,
-  https://git.eeqj.de/sneak/sfdupes/issues/9)
+- These operands are warned about and skipped, and the records beneath them are
+  kept:
+    - symlinks;
+    - sockets;
+    - FIFOs;
+    - device nodes;
+    - `.zfs` directories.
+
+    (2026-10-03, https://git.eeqj.de/sneak/sfdupes/issues/9)

 - `scan` holds a lock on a lock file beside the database for its whole run, so a
  second `scan` fails at once with exit 1 (2026-10-03,
@@ -355,42 +450,47 @@ are known.
  WAL mode, so reading needs only read access (2026-10-03,
  https://git.eeqj.de/sneak/sfdupes/issues/8)

- Tabs, newlines, carriage returns and backslashes are escaped in report, trees
-  and warning paths. The root directory's path is `/` (2026-10-03,
-  https://git.eeqj.de/sneak/sfdupes/issues/7)
+- Four characters are escaped in `report`, `trees` and warning paths:
+    - tab;
+    - newline;
+    - carriage return;
+    - backslash.

- A plain `docker build .` stamps the git tag or short commit instead of `dev`.
-  `.dockerignore` sends `.git` without `.git/config`. The build stage stamps the
-  `VERSION` build argument, else `git describe --tags --always`. It fails if the
-  context carries `.git` and the version is still empty, `dev` or `unknown`. CI
-  checks out the full history (`fetch-depth: 0`), so it stamps the same value as
-  `make build` (2026-10-02, branch `next`,
+    The root directory's path is `/` (2026-10-03,
+    https://git.eeqj.de/sneak/sfdupes/issues/7)
+
+- A plain `docker build .` stamps the `git` tag or short commit instead of
+  `dev`. `.dockerignore` sends `.git` without `.git/config`. The build stage
+  stamps the `VERSION` build argument, else `git describe --tags --always`. It
+  fails if the context carries `.git` and the version is still empty, `dev` or
+  `unknown`. The Gitea workflow checks out the full history (`fetch-depth: 0`),
+  so it stamps the same value as `make build` (2026-10-02, branch `next`,
  https://git.eeqj.de/sneak/sfdupes/issues/67)

 - The 1 KiB end-window sampling was replaced with the hashes chosen by file
  size, and README "Duplicate detection" documented every size threshold. A file
  under 10 MiB was hashed in full, and its `head`, `tail` and `content` all held
  that hash. A larger file got only its 64 KiB `head` and `tail` in the hash
-  phase. The content phase, after the update phase, read it for `content` only
-  when its size, `head` and `tail` matched another record's, from this scan or
-  an earlier one. `content` was the whole file below 50 MiB, and gigabyte-spaced
-  1 MiB samples at or above. A file gone or changed since its record was written
-  was never read. `report` and `trees` left out any record without a `content`
-  hash. The `content` column is part of the version 1 schema. Superseded by
-  https://git.eeqj.de/sneak/sfdupes/issues/132 (2026-09-22, branch `next`,
-  https://git.eeqj.de/sneak/sfdupes/issues/61)
+  phase. The content phase ran after the update phase. It read a file for
+  `content` only when its size, `head` and `tail` matched another record's, from
+  this scan or an earlier one. `content` was the whole file below 50 MiB, and
+  gigabyte-spaced 1 MiB samples at or above. It never read a file gone or
+  changed since its record was written. `report` and `trees` left out any record
+  without a `content` hash. The `content` column is part of the version 1
+  schema. Superseded by https://git.eeqj.de/sneak/sfdupes/issues/132
+  (2026-09-22, branch `next`, https://git.eeqj.de/sneak/sfdupes/issues/61)

- The dead `files.dat` references removed from `Makefile`, `.gitignore` and
+- The dead `files.dat` references were removed from `Makefile`, `.gitignore` and
  `.dockerignore` (2026-09-21, branch `next`,
  https://git.eeqj.de/sneak/sfdupes/issues/22)

 - The lint-image pin comments and `FROM` form in `Dockerfile` and
-  `Dockerfile.lint` fixed. Both pins became the policy
+  `Dockerfile.lint` were fixed. Both pins became the policy
  `# image:vX.Y.Z, YYYY-MM-DD` comment over a bare `FROM image@sha256:...`,
  without the false `(Debian-based)` note or the tag. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 the `Dockerfile`'s `lint` phase
-  holds the only `golangci-lint` pin, in that form. `Dockerfile.lint` and
-  `script/verify-lint-image-pin`, which compared the two pins, are gone
+  holds the only `golangci-lint` pin, in that form. `Dockerfile.lint` is gone,
+  and so is `script/verify-lint-image-pin`, which compared the two pins
  (2026-08-10, branch `next`, https://git.eeqj.de/sneak/sfdupes/issues/25)

 - All linting ran in Docker, via `Dockerfile.lint` and `script/lint`. Per the
@@ -399,8 +499,8 @@ are known.
  `script/bootstrap` stopped installing or pinning the linter, and
  `script/verify-linter-pin` was retired. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 both commands run in the
-  `Dockerfile`'s `lint` phase, which `script/lint` builds alone and the build
-  stage depends on through `COPY --from=lint /src/go.sum /dev/null`.
+  `Dockerfile`'s `lint` phase. `script/lint` builds that phase alone, and the
+  build stage depends on it through `COPY --from=lint /src/go.sum /dev/null`.
  `Dockerfile.lint` and `script/verify-lint-image-pin` are gone. Nothing inside
  an image build may run `docker`, so the phase calls `golangci-lint` directly
  (2026-08-10, branch `next`, https://git.eeqj.de/sneak/sfdupes/issues/46)
@@ -408,106 +508,144 @@ are known.
 - The Docker build stage's prerequisites were installed by running
  `script/bootstrap` instead of `apk add --no-cache make` inline.
  `script/verify-linter-pin` failed the build unless the linter copied from the
-  lint stage was the version `script/bootstrap` pinned. Builds then took up to
-  5m14s cold, mostly in a `chown -R` of the module cache, filed as
-  https://git.eeqj.de/sneak/sfdupes/issues/43. Since
+  lint stage was the version that `script/bootstrap` pinned. Builds then took up
+  to 5m14s from an empty cache, mostly in a `chown -R` of the module cache,
+  filed as https://git.eeqj.de/sneak/sfdupes/issues/43. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 the build stage installs `git` and
-  `make` with `apk add --no-cache` and only compiles; the `lint` and `test`
+  `make` with `apk add --no-cache` and only compiles. The `lint` and `test`
  phases are the gates (2026-08-09, branch `dockerfile-bootstrap`,
  https://git.eeqj.de/sneak/sfdupes/issues/42)

- The Docker layer cache is busted for the gate steps, so `script/cibuild` and
-  `script/docker` cannot report a green they did not earn. The `Dockerfile`
-  copies the tree before its gates, so on an unchanged tree Docker served them
-  from cache and the build exited 0 having run nothing. The fix was a
+- The Docker layer cache is defeated for the gate steps, so `script/cibuild` and
+  `script/docker` cannot report a pass they did not earn. The `Dockerfile`
+  copies the tree before its gates. On an unchanged tree Docker served them from
+  cache, and the build exited 0 without running them. The fix was a
  `CHECK_EPOCH` build argument. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 every `docker build` in `script/`
-  passes a new `CACHEBUST` value instead, which every stage of the `Dockerfile`
-  declares before every step that lints, tests or compiles. Run as root, the
-  tests fail `TestScanHardlinkRunFailsTogether`, because root reads through the
-  `chmod(0)` the test relies on, so the `test` phase runs them as `nobody`
+  passes a new `CACHEBUST` value instead. Every stage of the `Dockerfile`
+  declares it before every step that checks or compiles the code. Run as root,
+  the tests fail `TestScanHardlinkRunFailsTogether`, because root reads through
+  the `chmod(0)` the test relies on. So the `test` phase runs them as `nobody`
  (2026-08-09, branch `cibuild-cache-bust`,
  https://git.eeqj.de/sneak/sfdupes/issues/32)

 - `script/bootstrap` checked the installed `golangci-lint` version instead of
  only its presence. The version lived only in `GOLANGCI_LINT_VERSION`, with the
-  `go install` module ref derived from it. Any installed version that was not
-  the pin was reinstalled: older, newer, absent or unparseable. `go install`
-  writes into `GOBIN` (or `GOPATH/bin`) while `make lint` ran the first
-  `golangci-lint` on `PATH`, so bootstrap re-read the effective version after
-  installing. On a mismatch it printed both paths and both versions and exited
-  non-zero; it did not reorder `PATH` or delete anyone's binary. The `--version`
-  call kept its stderr and was bounded by `timeout(1)` where that exists. `git`,
-  `make` and `go` kept presence-only checks. `make check` and `make lint` were
-  clean at v2.12.2, so v2.10.1 had not been hiding findings on `main`.
-  Superseded by https://git.eeqj.de/sneak/sfdupes/issues/46: the linter is no
-  longer installed on a host (2026-08-09, branch `bootstrap-version-check`,
-  https://git.eeqj.de/sneak/sfdupes/issues/24)
+  `go install` module reference derived from it. Any installed version that was
+  not the pin was reinstalled, whether:
+    - older;
+    - newer;
+    - absent;
+    - unparseable.
+
+    `go install` writes into `GOBIN`, or `GOPATH/bin`, while `make lint` ran the
+    first `golangci-lint` on `PATH`. So bootstrap re-read the effective version
+    after installing. On a mismatch it printed both paths and both versions and
+    exited non-zero. It did not reorder `PATH` or delete anyone's binary. The
+    `--version` call kept its stderr and was bounded by `timeout(1)` where that
+    exists. `git`, `make` and `go` kept presence-only checks. The version check
+    was verified by bootstrapping this host from v2.10.1 to v2.12.2, and again
+    to a no-op. Stub runs of the script under `dash` covered:
+    - a thirteen-input version-parse matrix;
+    - a shadowed install, which must exit non-zero;
+    - an install destination not on `PATH`;
+    - `GOBIN` set;
+    - a wedged binary, which must hit the timeout.
+
+    `make check` and `make lint` were clean at v2.12.2, so v2.10.1 had not been
+    hiding findings on `main`. Superseded by
+    https://git.eeqj.de/sneak/sfdupes/issues/46, since the linter is no longer
+    installed on a host (2026-08-09, branch `bootstrap-version-check`,
+    https://git.eeqj.de/sneak/sfdupes/issues/24)

 - The hash worker pool unwinds on the error path. The pool is an owned,
  context-aware `hashPool`. Every blocking send in the feeder and the workers
  selects on `ctx.Done()`, and `jobs` is closed on every path out. `hashPhase`
  defers `pool.stop()`, which cancels and then drains `results` until the last
-  goroutine has exited; draining is what frees a worker parked on a send. `ctx`
-  is threaded from `cmd.Context()` through `runScan`, `syncScan`, both worker
-  pools and the whole database layer, as the first parameter everywhere. The
-  walk pool gets the same treatment, plus a `ctx.Err()` guard after the walk. A
-  cancelled walk yields a partial size census, and every file it never reached
-  looks vanished to the update phase. That phase's own `BeginTx` also fails on
-  the cancelled context before deleting anything, but the guard is the barrier
-  that still holds once an interrupted scan may commit what it has. Tests drive
-  `run(scan)` against a database whose insert trigger aborts, and assert that
-  the scan fails instead of hanging and that the goroutine count returns to its
-  pre-scan baseline. Other tests cancel a scan part-way through the walk and
-  assert that it stops at the guard with every record intact. Direct tests of
-  `sendEvent`, the walk workers, `dispatchDirs`, `feedHashJobs`, `hashWorker`
-  and `hashPhase` cover the remaining cancellation branches of both pools
-  (2026-08-09, branch `hash-pool-cleanup`,
-  https://git.eeqj.de/sneak/sfdupes/issues/6)
+  goroutine has exited. Draining is what frees a worker parked on a send. `ctx`
+  is passed from `cmd.Context()` as the first parameter, through:
+    - `runScan`;
+    - `syncScan`;
+    - both worker pools;
+    - the whole database layer.
+
+    The walk pool gets the same treatment, plus a `ctx.Err()` guard after the
+    walk. A cancelled walk yields a partial size census, and every file that it
+    never reached looks vanished to the update phase. That phase's own `BeginTx`
+    also fails on the cancelled context before deleting anything. The guard is
+    still the barrier once an interrupted scan may commit what it has. Tests
+    drive `run(scan)` against a database whose insert trigger aborts. They
+    assert that the scan fails instead of hanging, and that the goroutine count
+    returns to its pre-scan baseline. Other tests cancel a scan part-way through
+    the walk, deterministically, by counting the scan's own checks of
+    `ctx.Done()`. They assert that it stops at the guard with every record
+    intact. It then holds a partial size census and a still-populated record
+    index. Direct tests cover the remaining cancellation branches of both pools.
+    They test:
+    - `sendEvent`;
+    - the walk workers;
+    - `dispatchDirs`;
+    - `feedHashJobs`;
+    - `hashWorker`;
+    - `hashPhase`.
+
+    (2026-08-09, branch `hash-pool-cleanup`,
+    https://git.eeqj.de/sneak/sfdupes/issues/6)

 - The database is closed on every fatal exit path. `fatalf` and its `os.Exit(1)`
-  are gone, so the deferred `db.Close()`, and with it the SQLite WAL checkpoint,
-  runs when a subcommand fails. `runScan`, `runReport`, `runTrees`,
-  `loadRecords` and `resolveRoots` return errors instead. The single exit point
-  is `run` in `main.go`. It maps a `fatalError` to exit 1 and cobra's own
-  argument and flag errors to exit 2, so a runtime failure is never reported as
-  a usage error or printed with the usage text. `main_test.go` drives the CLI
-  in-process and asserts the exit codes from README "Error handling" and the
-  stdout/stderr split. That includes a fatal error after the database is open
-  leaving no `-wal` or `-shm` file behind, for `scan`, `report` or `trees`
-  (2026-08-09, branch `db-close-on-fatal`,
-  https://git.eeqj.de/sneak/sfdupes/issues/4)
+  are gone. So the deferred `db.Close()` runs when a subcommand fails, and with
+  it the SQLite WAL checkpoint. These return errors instead:
+    - `runScan`;
+    - `runReport`;
+    - `runTrees`;
+    - `loadRecords`;
+    - `resolveRoots`.

- `golangci-lint` updated to v2.12.2 with the canonical config, merged as
+    The single exit point is `run` in `main.go`. It maps a `fatalError`,
+    anything a subcommand returned, to exit 1, and cobra's own argument and flag
+    errors to exit 2. So a runtime failure is never reported as a usage error,
+    nor printed with the usage text. `main_test.go` drives the CLI in-process
+    and asserts the exit codes from README "Error handling" and the
+    stdout/stderr split. It also checks that a fatal error after the database is
+    open leaves no `-wal` or `-shm` file behind, for `scan`, `report` or `trees`
+    (2026-08-09, branch `db-close-on-fatal`,
+    https://git.eeqj.de/sneak/sfdupes/issues/4)
+
+- `golangci-lint` was updated to v2.12.2 with the canonical config, merged as
  `38a01bd`. The pinned linter in the `Dockerfile` lint stage and
  `script/bootstrap` went from v2.12.1 to v2.12.2, and `.golangci.yml` was
-  replaced with the canonical file. The linter settings (`lll`, `funlen`,
-  `cyclop`, `dupl` thresholds) now live under `linters.settings`, per the v2
-  schema, so they are applied. No new lint findings surfaced (2026-08-09, branch
-  `golangci-v2.12.2`, https://git.eeqj.de/sneak/sfdupes/issues/3)
+  replaced with the canonical file. Four thresholds now live under
+  `linters.settings`, as the v2 schema requires, so they are applied:
+    - `lll`;
+    - `funlen`;
+    - `cyclop`;
+    - `dupl`.

- Makefile targets converted to scripts-to-rule-them-all `script/` entrypoints,
-  like the other managed repos. All 12 entrypoints exist:
+    No new lint findings surfaced (2026-08-09, branch `golangci-v2.12.2`,
+    https://git.eeqj.de/sneak/sfdupes/issues/3)
+
+- `Makefile` targets were converted to scripts-to-rule-them-all `script/`
+  entrypoints, like the other managed repos. All 12 entrypoints exist:
    - `bootstrap`, `setup` and `projectname`;
    - `test`, `lint`, `fmt`, `fmt-check` and `check`;
    - `docker`, `cibuild`, `precommit` and `install-precommit`.

-    Every Makefile target is a thin shim over them (2026-07-26, commit
+    Every `Makefile` target does nothing but call its script (2026-07-26, commit
    `3abeacf`, https://git.eeqj.de/sneak/sfdupes/issues/1)

- The binary is the default Make target: plain `make` builds `sfdupes`, where it
-  used to run `check` plus `build`. `make build` remains as an alias
+- The binary is the default `make` target. Plain `make` builds `sfdupes`, where
+  it used to run `check` plus `build`. `make build` remains as an alias
  (2026-07-24, branch `make-default-target`)

- Scan-wide phases, concurrent operands and batched updates. All operands seed
-  the shared walk pool, and every pass runs once over the whole scan, so totals
-  and ETAs are scan-global. The per-operand walk, hash and update cycles and
-  their stderr announcements are gone. The update pass commits in batched
-  transactions. The filesystem is authoritative and the database an
-  eventually-consistent reflection of it, so scan-level atomicity is not
-  required (2026-07-24, branch `scan-wide-phases`)
+- The phases became scan-wide, with concurrent operands and batched updates. All
+  operands seed the shared walk pool, and every pass runs once over the whole
+  scan. So the totals and ETAs cover the whole scan. The per-operand walk, hash
+  and update cycles and their stderr announcements are gone. The update pass
+  writes in batches, each in its own transaction. The filesystem is
+  authoritative and the database follows it, so one scan's changes need not land
+  all at once (2026-07-24, branch `scan-wide-phases`)

- The stat pass split back out of the walk. Phases are strictly sequential
+- The stat pass was split back out of the walk. Phases are strictly sequential
  again, per operand, with parallelism only inside each phase:
    - walk;
    - stat;
@@ -515,77 +653,92 @@ are known.
    - update.

    The walk enumerates paths with per-directory workers, and the stat pass
-    lstats them with per-file workers, restoring the exact total and ETA of the
-    stat bar (2026-07-24, branch `parallel-phases`)
+    lstats them with per-file workers. That restores the exact total and ETA of
+    the stat bar (2026-07-24, branch `parallel-phases`)

 - Each operand is announced on stderr before its passes. With per-operand walk,
  hash and update cycles, a multi-operand run such as `scan /srv/*` showed pass
  totals that looked like the whole run's (2026-07-24, branch
  `scan-operand-progress`)

- Parallel walk. The walk pass was a single goroutine and took hours at about 20
-  million files on a busy pool: 22 million files in 4 hours on a ZFS server. It
-  is now a per-directory worker-pool traversal that records size and mtime
-  during the walk, folding away the separate stat pass and halving metadata I/O.
-  Each `PATH` operand commits in its own transaction, so an interrupted scan
-  keeps completed operands (2026-07-24, branch `parallel-walk`)
+- The walk became parallel. The walk pass was a single goroutine and took hours
+  at about 20 million files on a busy pool. One ZFS server took 4 hours for 22
+  million files. It is now a walk by a pool of per-directory workers that
+  records size and mtime as it goes. That folds away the separate stat pass and
+  halves the metadata reads. Each `PATH` operand commits in its own transaction,
+  so an interrupted scan keeps completed operands (2026-07-24, branch
+  `parallel-walk`)

- Persistent scan database. `scan` maintains a SQLite database
-  (`modernc.org/sqlite`, pure Go, cgo stays disabled), keyed by absolute path,
-  that survives between runs. A rescan hashes only new or changed files, by
-  mtime and size. It deletes the records of files vanished from under the
-  scanned operands and leaves records outside them untouched, so `scan` can be
-  cronned daily. `report` and `trees` read the database, with no positional
-  arguments, instead of a scan stream. The database is at
-  `/var/lib/sfdupes/db.sqlite`, overridable via `SFDUPES_DATABASE`. WAL
+- `scan` gained a persistent database. It maintains an SQLite database that
+  survives between runs, with the absolute path as each record's key. The driver
+  is `modernc.org/sqlite`, pure Go, so cgo stays disabled. A rescan hashes only
+  new or changed files, by mtime and size. It deletes the records of files
+  vanished from under the scanned operands and leaves records outside them
+  untouched. So `scan` can run daily from `cron`. `report` and `trees` read the
+  database, with no positional arguments, instead of a scan stream. The database
+  is at `/var/lib/sfdupes/db.sqlite`, and `SFDUPES_DATABASE` overrides that. WAL
  journaling plus a single-transaction update keep a report run during a scan
  safe (2026-07-24, branch `persistent-database`)

- The `origin` remote (`git@git.eeqj.de:sneak/sfdupes.git`) added, `v0.0.1`
-  tagged, and `main` plus tags pushed (2026-07-23)
+- The `origin` remote, `git@git.eeqj.de:sneak/sfdupes.git`, was added. `v0.0.1`
+  was tagged, and `main` and the tags were pushed (2026-07-23)

- `scan` CLI rework. Required `PATH...` operands via cobra replace the `/srv`
-  `-root` default. The new `-x`/`--one-file-system` flag (GNU convention) stops
-  at filesystem boundaries, which are crossed by default (2026-07-23, branch
-  `scan-required-paths`)
+- The `scan` command line was reworked. Required `PATH...` operands, parsed by
+  cobra, replace the `/srv` `-root` default. The new `-x`, `--one-file-system`
+  flag follows the GNU convention and stops at filesystem boundaries, which the
+  walk crosses by default (2026-07-23, branch `scan-required-paths`)

 - The repo was brought into compliance with `REPO_POLICIES.md` (the version of
  2026-07-06), the existing repo checklist and the Go styleguide. The audit of
  2026-07-22 found these gaps, and the branch closed them:
-    - `.gitignore`, with OS, editor, Go and secrets patterns; the compiled
-      `sfdupes` binary and `files.dat` had been sitting untracked in the tree;
+    - `.gitignore`, with the standard patterns for secrets and for OS, editor
+      and Go files. The compiled `sfdupes` binary and `files.dat` had been
+      sitting untracked in the tree;
    - `.editorconfig`;
    - `LICENSE` and the README License section. MIT was assumed from house
      convention, for the owner to confirm;
    - `REPO_POLICIES.md` in the repo root;
-    - the canonical `.golangci.yml`, with the 150 findings it raised fixed;
-    - the `Makefile` targets `test`, `lint`, `fmt`, `fmt-check`, `docker` and
-      `hooks`, and a `check` target that no longer depends on `build`;
+    - the canonical `.golangci.yml`, with its 150 findings fixed, so that
+      `make lint` is clean;
+    - the `Makefile` targets the policy requires:
+        - `test` and `lint`;
+        - `fmt` and `fmt-check`;
+        - `docker` and `hooks`.
+
+        `check` depended on `build`, which wrote the binary. `make check` must
+        not modify files, so `check` no longer depends on `build`;
+
    - a test suite, which the policy required with a 30-second timeout and the
-      conditional `-v` rerun. It covers parsing, grouping, digests, suppression,
-      hashing and the scan pipeline, at 64% coverage;
-    - a multistage `Dockerfile` with hash-pinned images, a fail-fast lint stage
-      and a build stage running `make check`, plus `.dockerignore`;
+      conditional `-v` rerun. At 64% coverage, it covers:
+        - parsing and grouping;
+        - digests and suppression;
+        - hashing and the scan pipeline;
+    - a multistage `Dockerfile` and `.dockerignore`. The `Dockerfile` had:
+        - hash-pinned images;
+        - a lint stage that failed fast;
+        - a build stage that ran `make check`;
    - `.gitea/workflows/check.yml`, running `docker build .` on push with the
      checkout action pinned by commit SHA;
-    - the README sections the policy requires: a Description first line with the
-      name, purpose, category, license and author, then Getting Started,
-      Rationale, TODO, License and Author;
+    - the README sections the policy requires. The first is a Description whose
+      first line names the project, its purpose and category, its license and
+      its author. Then come Getting Started and Rationale, and at the end TODO,
+      License and Author;
    - the stale README non-goal "no git repository setup and no CI" removed;
-    - the pre-commit hook installed.
+    - the pre-commit hook, installed with `make hooks` once that target existed.

    The code was already `gofmt`-clean, so no standalone formatting commit was
    needed (2026-07-23, branch `repo-policy-compliance`)

- `git init` with a README-only first commit; the code baseline committed on
-  `main` (2026-07-22)
+- `git init` was run, with a README-only first commit. The code baseline was
+  committed on `main` (2026-07-22)

- `scan`, `report` and `trees` subcommands implemented (pre-git history)
+- The `scan`, `report` and `trees` subcommands were implemented (pre-git
+  history)

 # Future Steps

- Possible later features, out of scope per README: full-content verification of
-  candidates, and helper scripts for removal.
+- Possible later features, out of scope per README, are a byte-for-byte check of
+  candidates and helper scripts for removal.

 # Accepted Divergences

@@ -47,14 +47,15 @@ const dbFilePerm = 0o644
 const lockFilePerm = 0o600

 // createTableSQL is the schema applied to a fresh database. Paths are
-// BLOBs because Unix paths are raw bytes, not guaranteed UTF-8. mtime
-// holds whole Unix seconds and mtime_nsec the nanoseconds within that
-// second. head, tail and content each hold the raw 32 bytes of a
-// SHA-256.
+// BLOBs because Unix paths are raw bytes, not guaranteed UTF-8.
+// disk_size holds the bytes the file takes on disk. mtime holds whole
+// Unix seconds and mtime_nsec the nanoseconds within that second. head,
+// tail and content each hold the raw 32 bytes of a SHA-256.
 const createTableSQL = `
 CREATE TABLE files (
    path       BLOB PRIMARY KEY,
    size       INTEGER NOT NULL,
+    disk_size  INTEGER NOT NULL,
    mtime      INTEGER NOT NULL,
    mtime_nsec INTEGER NOT NULL,
    head       BLOB NOT NULL,
@@ -69,14 +70,59 @@ const createIndexSQL = `
 CREATE INDEX files_signature ON files (size, head, tail, content)
 `

+// createTotalsSQL creates the totals table, which holds one row: the
+// number of records and the sizes of all records added up. Counting
+// them over files would read every record. The three triggers below
+// keep the row current, in the transaction of each change to files.
+const createTotalsSQL = `
+CREATE TABLE totals (
+    records INTEGER NOT NULL,
+    size    INTEGER NOT NULL
+)
+`
+
+// insertTotalsSQL adds the one row of totals, for an empty files table.
+const insertTotalsSQL = `
+INSERT INTO totals (records, size) VALUES (0, 0)
+`
+
+// totalsAfterInsertSQL counts each inserted record into totals.
+const totalsAfterInsertSQL = `
+CREATE TRIGGER totals_after_insert AFTER INSERT ON files BEGIN
+    UPDATE totals SET records = records + 1, size = size + NEW.size;
+END
+`
+
+// totalsAfterDeleteSQL takes each deleted record out of totals.
+const totalsAfterDeleteSQL = `
+CREATE TRIGGER totals_after_delete AFTER DELETE ON files BEGIN
+    UPDATE totals SET records = records - 1, size = size - OLD.size;
+END
+`
+
+// totalsAfterUpdateSQL replaces a record's old size in totals with its
+// new one. scan's upsert of an existing record is such an update.
+const totalsAfterUpdateSQL = `
+CREATE TRIGGER totals_after_update AFTER UPDATE OF size ON files BEGIN
+    UPDATE totals SET size = size + NEW.size - OLD.size;
+END
+`
+
+// recordCountSQL reads the number of records from totals.
+const recordCountSQL = `
+SELECT records FROM totals
+`
+
 // upsertSQL inserts one file record, replacing any existing record for
 // the same path.
 const upsertSQL = `
-INSERT INTO files (path, size, mtime, mtime_nsec, head, tail, content)
-VALUES (?, ?, ?, ?, ?, ?, ?)
+INSERT INTO files (
+    path, size, disk_size, mtime, mtime_nsec, head, tail, content
+)
+VALUES (?, ?, ?, ?, ?, ?, ?, ?)
 ON CONFLICT (path) DO UPDATE SET
-    size = excluded.size, mtime = excluded.mtime,
-    mtime_nsec = excluded.mtime_nsec,
+    size = excluded.size, disk_size = excluded.disk_size,
+    mtime = excluded.mtime, mtime_nsec = excluded.mtime_nsec,
    head = excluded.head, tail = excluded.tail,
    content = excluded.content
 `
@@ -150,9 +196,14 @@ func createDatabaseDirectory(path string) error {
 // scanParams are the connection parameters for scan: read-write, with
 // WAL journaling and a busy timeout, so a report can run while a cron
 // scan is in progress. closeScanDatabase leaves WAL mode again.
+//
+// Each write to files fires a trigger, so SQLite keeps a statement
+// journal for it. temp_store(MEMORY) keeps that journal in memory,
+// which costs far less than a temporary file.
 const scanParams = "_pragma=busy_timeout(10000)" +
 	"&_pragma=journal_mode(WAL)" +
-	"&_pragma=synchronous(NORMAL)"
+	"&_pragma=synchronous(NORMAL)" +
+	"&_pragma=temp_store(MEMORY)"

 // reportParams are the connection parameters for report, trees and
 // info: read-only, with the same busy timeout. They set no journal
@@ -426,14 +477,14 @@ func createSchema(ctx context.Context, db *sql.DB) error {

 	defer func() { _ = tx.Rollback() }()

-	_, err = tx.ExecContext(ctx, createTableSQL)
-	if err != nil {
-		return fmt.Errorf("create schema: %w", err)
-	}
-
-	_, err = tx.ExecContext(ctx, createIndexSQL)
-	if err != nil {
-		return fmt.Errorf("create schema: %w", err)
+	for _, stmt := range []string{
+		createTableSQL, createIndexSQL, createTotalsSQL, insertTotalsSQL,
+		totalsAfterInsertSQL, totalsAfterDeleteSQL, totalsAfterUpdateSQL,
+	} {
+		_, err = tx.ExecContext(ctx, stmt)
+		if err != nil {
+			return fmt.Errorf("create schema: %w", err)
+		}
 	}

 	_, err = tx.ExecContext(ctx,
@@ -480,7 +531,7 @@ func loadFileRows(ctx context.Context, db *sql.DB, total func(n int64),

 	var n int64

-	err = tx.QueryRowContext(ctx, "SELECT COUNT(*) FROM files").Scan(&n)
+	err = tx.QueryRowContext(ctx, recordCountSQL).Scan(&n)
 	if err != nil {
 		return fmt.Errorf("count records: %w", err)
 	}
@@ -488,8 +539,8 @@ func loadFileRows(ctx context.Context, db *sql.DB, total func(n int64),
 	total(n)

 	rows, err := tx.QueryContext(ctx,
-		"SELECT path, size, mtime, mtime_nsec, head, tail, content "+
-			"FROM files ORDER BY path")
+		"SELECT path, size, disk_size, mtime, mtime_nsec, head, tail, "+
+			"content FROM files ORDER BY path")
 	if err != nil {
 		return fmt.Errorf("read records: %w", err)
 	}
@@ -503,7 +554,8 @@ func loadFileRows(ctx context.Context, db *sql.DB, total func(n int64),
 			r                         scanRec
 		)

-		err = rows.Scan(&path, &r.size, &sec, &nsec, &head, &tail, &content)
+		err = rows.Scan(&path, &r.size, &r.diskSize, &sec, &nsec,
+			&head, &tail, &content)
 		if err != nil {
 			return fmt.Errorf("read record: %w", err)
 		}
@@ -538,10 +590,11 @@ ORDER BY size DESC, head DESC, tail DESC, content DESC
 `

 // loadSignatureRows gives total the number of records, then streams
-// every record's signature and path to fn, without its mtime, in the
-// order of signatureRowsSQL. The count and the records are read in one
-// transaction, so they agree while a scan is committing. An error from
-// fn stops the reading and is returned as it is.
+// every record's signature and path to fn, without its mtime or its
+// disk_size, in the order of signatureRowsSQL. The count and the
+// records are read in one transaction, so they agree while a scan is
+// committing. An error from fn stops the reading and is returned as it
+// is.
 func loadSignatureRows(ctx context.Context, db *sql.DB,
 	total func(n int64), fn func(r scanRec) error,
 ) error {
@@ -556,7 +609,7 @@ func loadSignatureRows(ctx context.Context, db *sql.DB,

 	var n int64

-	err = tx.QueryRowContext(ctx, "SELECT COUNT(*) FROM files").Scan(&n)
+	err = tx.QueryRowContext(ctx, recordCountSQL).Scan(&n)
 	if err != nil {
 		return fmt.Errorf("count records: %w", err)
 	}
@@ -622,7 +675,7 @@ func (r *scanRec) setHashes(head, tail, content []byte) error {
 func countRecords(ctx context.Context, db *sql.DB) (int64, error) {
 	var n int64

-	err := db.QueryRowContext(ctx, "SELECT COUNT(*) FROM files").Scan(&n)
+	err := db.QueryRowContext(ctx, recordCountSQL).Scan(&n)
 	if err != nil {
 		return 0, fmt.Errorf("count records: %w", err)
 	}
@@ -630,12 +683,10 @@ func countRecords(ctx context.Context, db *sql.DB) (int64, error) {
 	return n, nil
 }

-// databaseCountsSQL counts the records and adds up their sizes, in one
-// pass over the table. A SUM over no rows is NULL, so on an empty table
-// the SUM falls back to 0.
+// databaseCountsSQL reads the number of records and the sizes of all
+// records added up from totals.
 const databaseCountsSQL = `
-SELECT COUNT(*), COALESCE(SUM(size), 0)
-FROM files
+SELECT records, size FROM totals
 `

 // databaseCounts is what info reads from the database: its schema
@@ -678,15 +729,15 @@ func readDatabaseCounts(ctx context.Context,
 	return c, nil
 }

-// loadFileMeta streams every record's path, size and mtime to fn. Scan
-// change detection needs no hash values, and skipping the hash columns
-// keeps the scan's in-memory index small on multi-million-file
-// databases.
+// loadFileMeta streams every record's path, size, disk_size and mtime
+// to fn. Scan change detection needs no hash values, and skipping the
+// hash columns keeps the scan's in-memory index small on
+// multi-million-file databases.
 func loadFileMeta(ctx context.Context, db *sql.DB,
-	fn func(path string, size int64, mtime time.Time),
+	fn func(path string, m fileMeta),
 ) error {
 	rows, err := db.QueryContext(ctx,
-		"SELECT path, size, mtime, mtime_nsec FROM files")
+		"SELECT path, size, disk_size, mtime, mtime_nsec FROM files")
 	if err != nil {
 		return fmt.Errorf("read records: %w", err)
 	}
@@ -695,16 +746,19 @@ func loadFileMeta(ctx context.Context, db *sql.DB,

 	for rows.Next() {
 		var (
-			path            []byte
-			size, sec, nsec int64
+			path      []byte
+			m         fileMeta
+			sec, nsec int64
 		)

-		err = rows.Scan(&path, &size, &sec, &nsec)
+		err = rows.Scan(&path, &m.size, &m.diskSize, &sec, &nsec)
 		if err != nil {
 			return fmt.Errorf("read record: %w", err)
 		}

-		fn(string(path), size, time.Unix(sec, nsec))
+		m.mtime = time.Unix(sec, nsec)
+
+		fn(string(path), m)
 	}

 	err = rows.Err()
@@ -722,21 +776,21 @@ func loadFileMeta(ctx context.Context, db *sql.DB,
 // WAL small and let concurrent reports observe progress.
 const updateBatchSize = 10000

-// applyChanges writes one scan's database changes — upserts for new and
-// changed files, deletes for vanished ones — in batched transactions.
-// Progress is rendered on prog (one increment per change).
+// applyChanges writes upserts for new and changed files and deletes for
+// vanished ones, in batched transactions. Progress is rendered on prog
+// (one increment per change).
 func applyChanges(ctx context.Context, db *sql.DB, upserts []scanRec,
 	deletes []string, prog *progress,
 ) error {
 	for batch := range slices.Chunk(upserts, updateBatchSize) {
-		err := applyBatch(ctx, db, batch, nil, prog)
+		err := applyBatch(ctx, db, batch, nil, nil, prog)
 		if err != nil {
 			return err
 		}
 	}

 	for batch := range slices.Chunk(deletes, updateBatchSize) {
-		err := applyBatch(ctx, db, nil, batch, prog)
+		err := applyBatch(ctx, db, nil, nil, batch, prog)
 		if err != nil {
 			return err
 		}
@@ -745,10 +799,26 @@ func applyChanges(ctx context.Context, db *sql.DB, upserts []scanRec,
 	return nil
 }

-// applyBatch commits one batch of upserts and deletes in a single
-// transaction.
+// applyDiskSizes writes the disk_size of each of recs into its record,
+// in batched transactions, and leaves the rest of the record alone.
+// Progress is rendered on prog (one increment per record).
+func applyDiskSizes(ctx context.Context, db *sql.DB, recs []fileRec,
+	prog *progress,
+) error {
+	for batch := range slices.Chunk(recs, updateBatchSize) {
+		err := applyBatch(ctx, db, nil, batch, nil, prog)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// applyBatch commits one batch of upserts, disk_size updates and
+// deletes in a single transaction.
 func applyBatch(ctx context.Context, db *sql.DB, upserts []scanRec,
-	deletes []string, prog *progress,
+	diskSizes []fileRec, deletes []string, prog *progress,
 ) error {
 	tx, err := db.BeginTx(ctx, nil)
 	if err != nil {
@@ -762,6 +832,11 @@ func applyBatch(ctx context.Context, db *sql.DB, upserts []scanRec,
 		return err
 	}

+	err = execDiskSizes(ctx, tx, diskSizes, prog)
+	if err != nil {
+		return err
+	}
+
 	err = execDeletes(ctx, tx, deletes, prog)
 	if err != nil {
 		return err
@@ -787,7 +862,7 @@ func execUpserts(ctx context.Context, tx *sql.Tx, upserts []scanRec,
 	defer func() { _ = st.Close() }()

 	for _, r := range upserts {
-		_, err = st.ExecContext(ctx, []byte(r.path), r.size,
+		_, err = st.ExecContext(ctx, []byte(r.path), r.size, r.diskSize,
 			r.mtime.Unix(), r.mtime.Nanosecond(),
 			r.head[:], r.tail[:], r.content[:])
 		if err != nil {
@@ -800,6 +875,31 @@ func execUpserts(ctx context.Context, tx *sql.Tx, upserts []scanRec,
 	return nil
 }

+// execDiskSizes sets the disk_size of the record of each of recs. It
+// does not touch size, so the totals triggers do not fire.
+func execDiskSizes(ctx context.Context, tx *sql.Tx, recs []fileRec,
+	prog *progress,
+) error {
+	st, err := tx.PrepareContext(ctx,
+		"UPDATE files SET disk_size = ? WHERE path = ?")
+	if err != nil {
+		return fmt.Errorf("prepare disk_size update: %w", err)
+	}
+
+	defer func() { _ = st.Close() }()
+
+	for _, r := range recs {
+		_, err = st.ExecContext(ctx, r.diskSize, []byte(r.path))
+		if err != nil {
+			return fmt.Errorf("update disk_size of %s: %w", r.path, err)
+		}
+
+		prog.increment()
+	}
+
+	return nil
+}
+
 // execDeletes removes the records for paths no longer present.
 func execDeletes(ctx context.Context, tx *sql.Tx, deletes []string,
 	prog *progress,
@@ -535,17 +535,12 @@ func TestLoadRowsRefuseWrongSizeHash(t *testing.T) {
 	}
 }

-// TestSignatureRowsNeedNoSort checks that SQLite reads signatureRowsSQL
-// from the files_signature index alone, with nothing to sort: the
-// first record comes at once, so report's read phase counts each
-// record as it comes rather than waiting on SQLite for all of them.
-func TestSignatureRowsNeedNoSort(t *testing.T) {
-	t.Parallel()
+// queryPlan returns the detail of each line of SQLite's EXPLAIN QUERY
+// PLAN for query.
+func queryPlan(t *testing.T, db *sql.DB, query string) []string {
+	t.Helper()

-	db := openTestDB(t)
-
-	rows, err := db.QueryContext(t.Context(),
-		"EXPLAIN QUERY PLAN "+signatureRowsSQL)
+	rows, err := db.QueryContext(t.Context(), "EXPLAIN QUERY PLAN "+query)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -573,12 +568,164 @@ func TestSignatureRowsNeedNoSort(t *testing.T) {
 		t.Fatal(err)
 	}

+	return plan
+}
+
+// TestSignatureRowsNeedNoSort checks that SQLite reads signatureRowsSQL
+// from the files_signature index alone, with nothing to sort: the
+// first record comes at once, so report's read phase counts each
+// record as it comes rather than waiting on SQLite for all of them.
+func TestSignatureRowsNeedNoSort(t *testing.T) {
+	t.Parallel()
+
+	db := openTestDB(t)
+
+	plan := queryPlan(t, db, signatureRowsSQL)
+
 	want := []string{"SCAN files USING COVERING INDEX files_signature"}
 	if !slices.Equal(plan, want) {
 		t.Errorf("query plan = %q, want %q", plan, want)
 	}
 }

+// TestCountsReadOnlyTotals checks that SQLite answers the queries for
+// the number of records and their total size from the one row of
+// totals. A plan that reads files or its index reads every record.
+func TestCountsReadOnlyTotals(t *testing.T) {
+	t.Parallel()
+
+	db := openTestDB(t)
+
+	for _, query := range []string{recordCountSQL, databaseCountsSQL} {
+		plan := queryPlan(t, db, query)
+
+		want := []string{"SCAN totals"}
+		if !slices.Equal(plan, want) {
+			t.Errorf("query plan of %q = %q, want %q", query, plan, want)
+		}
+	}
+}
+
+// TestCountsComeFromTotals sets the row of totals to numbers that files
+// does not hold, then checks that scan's load phase, the read phases of
+// trees and report, and info each report the numbers from totals.
+func TestCountsComeFromTotals(t *testing.T) {
+	t.Parallel()
+
+	// files is empty, so a count over files gives 0 records of 0 bytes.
+	const records, size = 7, 9000
+
+	db := openTestDB(t)
+
+	_, err := db.ExecContext(t.Context(),
+		"UPDATE totals SET records = ?, size = ?", records, size)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	scanTotal, err := countRecords(t.Context(), db)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var treesTotal, reportTotal int64
+
+	err = loadFileRows(t.Context(), db,
+		func(n int64) { treesTotal = n }, func(scanRec) {})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = loadSignatureRows(t.Context(), db,
+		func(n int64) { reportTotal = n },
+		func(scanRec) error { return nil })
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	info, err := readDatabaseCounts(t.Context(), db)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for name, got := range map[string]int64{
+		"scan's load":   scanTotal,
+		"trees' read":   treesTotal,
+		"report's read": reportTotal,
+		"info":          info.records,
+	} {
+		if got != records {
+			t.Errorf("%s: %d records, want %d from totals",
+				name, got, records)
+		}
+	}
+
+	if info.size != size {
+		t.Errorf("info: size %d, want %d from totals", info.size, size)
+	}
+}
+
+// assertTotalsMatchFiles fails unless the row of totals holds the
+// number of records and the sizes of all records added up, as counted
+// over files.
+func assertTotalsMatchFiles(t *testing.T, db *sql.DB) {
+	t.Helper()
+
+	got, err := readDatabaseCounts(t.Context(), db)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var records, size int64
+
+	err = db.QueryRowContext(t.Context(),
+		"SELECT COUNT(*), COALESCE(SUM(size), 0) FROM files").
+		Scan(&records, &size)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if got.records != records || got.size != size {
+		t.Errorf("totals = %d records of %d bytes, files holds %d of %d",
+			got.records, got.size, records, size)
+	}
+}
+
+// TestTotalsMatchFiles scans the smoke tree, rescans it after two files
+// change size, and rescans it after two files are removed. After each
+// scan the row of totals must agree with files.
+func TestTotalsMatchFiles(t *testing.T) {
+	t.Parallel()
+
+	dir := buildSmokeTree(t)
+	db := openTestDB(t)
+
+	syncTree(t, db, dir)
+	assertTotalsMatchFiles(t, db)
+
+	writeFile(t, dir, "a/one.bin", pattern(10, 2500))
+	writeFile(t, dir, "t1/f1", pattern(30, 1000))
+
+	if st := syncTree(t, db, dir); st.updated != 2 {
+		t.Fatalf("rescan stats = %+v, want 2 updated", st)
+	}
+
+	assertTotalsMatchFiles(t, db)
+
+	for _, name := range []string{"a/unique.bin", "t2/sub/f2"} {
+		err := os.Remove(filepath.Join(dir, name))
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	if st := syncTree(t, db, dir); st.removed != 2 {
+		t.Fatalf("rescan stats = %+v, want 2 removed", st)
+	}
+
+	assertTotalsMatchFiles(t, db)
+}
+
 func TestApplyChangesRoundTrip(t *testing.T) {
 	t.Parallel()

@@ -17,7 +17,9 @@ import (
 func TestDefaultExcludes(t *testing.T) {
 	t.Parallel()

-	// README "Rules for the walk": each system's list.
+	// README "Rules for the walk": the Linux and macOS lists, and none
+	// on any other system. The Windows list exists in the code only: the
+	// binary does not build for Windows, so the README leaves it out.
 	cases := map[string][]string{
 		goosLinux: {"/proc", "/sys", "/dev", "/run", "/tmp", "/var/tmp"},
 		goosDarwin: {
@@ -26,11 +26,11 @@ func infoPhase(name string) string {
 // it. Any database problem, including a missing database, is fatal.
 //
 // The work runs in two phases, each under a progress display of its
-// own on stderr: open (open the database) and count (count the records,
-// with one query). Each display ends before the next phase starts, and
-// before an error is returned to be printed. The details are written
-// once the last display has ended, so no display is drawn while they
-// are written.
+// own on stderr: open (open the database) and count (read the number of
+// records and their total size from the totals table). Each display
+// ends before the next phase starts, and before an error is returned
+// to be printed. The details are written once the last display has
+// ended, so no display is drawn while they are written.
 func runInfo(ctx context.Context, stdout io.Writer) error {
 	dbPath, source, err := databasePath()
 	if err != nil {
@@ -56,7 +56,7 @@ func runInfo(ctx context.Context, stdout io.Writer) error {

 	defer func() { _ = db.Close() }()

-	// One query counts everything, so the phase never has a total.
+	// One row holds both counts, so the phase never has a total.
 	prog = newProgress(progressParams{
 		label: infoPhase("count"), total: -1,
 		waitingFor: countingRecords,
@@ -180,9 +180,9 @@ func capture(t *testing.T, std **os.File) func() string {
 }

 // brokenDatabase writes a database that opens cleanly and passes the
-// schema-version check but has no files table, so the first query
-// fails with the database already open: a fatal error on a path that
-// owns an open database. It closes the database the way scan does.
+// schema-version check but has no tables, so the first query fails
+// with the database already open: a fatal error on a path that owns an
+// open database. It closes the database the way scan does.
 func brokenDatabase(t *testing.T) string {
 	t.Helper()

@@ -265,8 +265,9 @@ func TestRunFatalAfterOpenClosesDatabase(t *testing.T) {
 			assertFatalOutput(t, stderr.String(), stdout())

 			// Proof that the failure happened after the open: only a
-			// query against the opened database can report this.
-			if !strings.Contains(stderr.String(), "no such table: files") {
+			// query against the opened database can report this. Each
+			// subcommand's first query reads totals.
+			if !strings.Contains(stderr.String(), "no such table: totals") {
 				t.Errorf("stderr = %q, want the failure to come from a "+
 					"query on the open database", stderr.String())
 			}
@@ -393,7 +394,7 @@ func TestRunNamesRelativeDatabase(t *testing.T) {
 }

 func TestRunUsesDatabaseThroughSymlinkedDirectory(t *testing.T) {
-	// README §Database: the path names the file exactly. With link a
+	// README §Settings: the path names the file exactly. With link a
 	// symlink to the directory real/sub, link/../db.sqlite names
 	// real/db.sqlite, not db.sqlite beside link. Every subcommand must
 	// use that file, relative or absolute, and its first line must name
@@ -648,7 +649,7 @@ func TestRunUsageErrors(t *testing.T) {
 }

 func TestRunScanRejectsWorkersBelowOne(t *testing.T) {
-	// README §scan mode: --workers below 1 is a usage error reported in
+	// README §Settings: --workers below 1 is a usage error reported in
 	// one line on stderr, before the scan opens the database.
 	for _, workers := range []string{"0", "-1"} {
 		t.Run(workers, func(t *testing.T) {
@@ -686,8 +687,8 @@ func TestRunScanRejectsWorkersBelowOne(t *testing.T) {
 func TestRunHelp(t *testing.T) {
 	t.Parallel()

-	// README §Subcommands: help goes to stderr, exits 0, and leaves
-	// stdout empty.
+	// README §Settings: help goes to stderr, exits 0, and leaves stdout
+	// empty.
 	cases := [][]string{{"--help"}, {"-h"}, {cmdScan, "--help"}}

 	for _, args := range cases {
@@ -713,8 +714,8 @@ func TestRunHelp(t *testing.T) {
 func TestRunVersion(t *testing.T) {
 	t.Parallel()

-	// README §Subcommands: the version is one line on stdout, with
-	// nothing on stderr, and exits 0.
+	// README §Settings: the version is one line on stdout, with nothing
+	// on stderr, and exits 0.
 	info, _ := debug.ReadBuildInfo()

 	for _, arg := range []string{"--version", "-v"} {
@@ -773,8 +774,8 @@ func TestBuildVersion(t *testing.T) {
 func TestRunVersionWriteFailureIsFatal(t *testing.T) {
 	t.Parallel()

-	// README §Error handling: a stdout write failure exits 1, reported
-	// in one line on stderr.
+	// README §Error handling: a failed write to stdout is a fatal error,
+	// exit 1, reported on stderr starting with "sfdupes:".
 	var stderr bytes.Buffer

 	code := run([]string{"--version"}, failingWriter{}, &stderr)
@@ -817,6 +818,23 @@ func scanFixture(t *testing.T) []string {
 	return dupes
 }

+// storedDiskSize returns the disk_size of the record for path in the
+// database at dbPath. A test of a trees run compares with this rather
+// than with a new lstat, which on ZFS can differ from the scan's (see
+// diskSizeOf).
+func storedDiskSize(t *testing.T, dbPath, path string) int64 {
+	t.Helper()
+
+	db, err := openReportDatabase(t.Context(), dbPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	defer func() { _ = db.Close() }()
+
+	return recordByPath(t, dbRecords(t, db), path).diskSize
+}
+
 // scanOK runs scan over operands, fails the test unless it exits 0 with
 // nothing on stdout, and returns everything it printed to stderr.
 func scanOK(t *testing.T, operands ...string) string {
@@ -928,24 +946,21 @@ func TestRunScanWalksOperandUnderSymlinkOperand(t *testing.T) {
 }

 func TestRunScanSkipsZFSOperand(t *testing.T) {
-	path := testDBPath(t)
-	t.Setenv(databaseEnv, path)
-
 	zfs := filepath.Join(t.TempDir(), ".zfs")
-	snapshot := filepath.Join(zfs, "snapshot", "hourly")
-	f := writeFile(t, snapshot, "f", pattern(1, 10))
+	f := writeFile(t, zfs, "snapshot/hourly/f", pattern(1, 10))

-	// An operand beneath a .zfs directory is walked, because it is not
-	// itself named .zfs.
-	scanOK(t, snapshot)
+	// No scan records a file inside a .zfs directory, so the record
+	// beneath the operand is written straight into the database.
+	path := seedDatabase(t, []scanRec{{size: 10, path: f}})
+	t.Setenv(databaseEnv, path)

 	assertOperandSkipped(t, path, zfs, ".zfs directory", f)
 }

 // assertOperandSkipped scans operand alone and checks that it is skipped
 // as kind: a warning naming it, one skip in the summary, exit 0, and the
-// record for kept, which an earlier scan stored beneath operand, still
-// in the database at dbPath.
+// record for kept, stored beneath operand before this scan, still in the
+// database at dbPath.
 func assertOperandSkipped(t *testing.T, dbPath, operand, kind,
 	kept string,
 ) {
@@ -974,6 +989,121 @@ func assertOperandSkipped(t *testing.T, dbPath, operand, kind,
 	recordByPath(t, dbRecords(t, db), kept)
 }

+// TestRunScanSkipsOperandInsideZFS scans a directory inside a .zfs
+// directory, first alone and then under another operand. Each time it
+// is warned about and counted as skipped, and nothing in it is walked.
+// The other operand is scanned as usual.
+func TestRunScanSkipsOperandInsideZFS(t *testing.T) {
+	path := testDBPath(t)
+	t.Setenv(databaseEnv, path)
+
+	dir := t.TempDir()
+	hourly := filepath.Join(dir, ".zfs", "snapshot", "hourly")
+	writeFile(t, hourly, "f", pattern(1, 10))
+	f := writeFile(t, dir, "f", pattern(2, 10))
+
+	warning := "walk " + hourly + ": skipping operand inside a .zfs directory\n"
+
+	for _, tc := range []struct {
+		operands []string
+		summary  string
+	}{
+		{
+			[]string{hourly},
+			"scan: 0 files seen (0 added, 0 updated, 0 removed, " +
+				"0 unchanged), 1 skipped\n",
+		},
+		{
+			[]string{dir, hourly},
+			"scan: 1 files seen (1 added, 0 updated, 0 removed, " +
+				"0 unchanged), 1 skipped\n",
+		},
+	} {
+		stderr := scanOK(t, tc.operands...)
+		if !strings.Contains(stderr, warning) ||
+			!strings.Contains(stderr, tc.summary) {
+			t.Errorf("scan %q: stderr = %q, want %q and %q", tc.operands,
+				stderr, warning, tc.summary)
+		}
+	}
+
+	db, err := openDB(path, reportParams)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Cleanup(func() { _ = db.Close() })
+
+	if got := recordPaths(dbRecords(t, db)); !slices.Equal(got, []string{f}) {
+		t.Errorf("records = %q, want %q", got, []string{f})
+	}
+}
+
+// TestRunScanSkipsOperandThroughSymlinkIntoZFS scans snaps/daily, where
+// snaps is a symlink to pool/.zfs/snapshot. The operand is warned about
+// by the path given, counted as skipped, and not walked.
+func TestRunScanSkipsOperandThroughSymlinkIntoZFS(t *testing.T) {
+	t.Setenv(databaseEnv, testDBPath(t))
+
+	dir := t.TempDir()
+	writeFile(t, dir, "pool/.zfs/snapshot/daily/f", pattern(1, 10))
+
+	snaps := filepath.Join(dir, "snaps")
+
+	err := os.Symlink(filepath.Join(dir, "pool", ".zfs", "snapshot"), snaps)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	daily := filepath.Join(snaps, "daily")
+	stderr := scanOK(t, daily)
+
+	warning := "walk " + daily + ": skipping operand inside a .zfs directory\n"
+	summary := "scan: 0 files seen (0 added, 0 updated, 0 removed, " +
+		"0 unchanged), 1 skipped\n"
+
+	if !strings.Contains(stderr, warning) ||
+		!strings.Contains(stderr, summary) {
+		t.Errorf("stderr = %q, want %q and %q", stderr, warning, summary)
+	}
+}
+
+// TestRunScanWalksOperandThroughSymlink scans data/daily, where data is
+// a symlink to a directory outside any .zfs directory. The operand is
+// scanned as usual, and its file is recorded by the path given.
+func TestRunScanWalksOperandThroughSymlink(t *testing.T) {
+	path := testDBPath(t)
+	t.Setenv(databaseEnv, path)
+
+	dir := t.TempDir()
+	writeFile(t, dir, "pool/data/daily/f", pattern(1, 10))
+
+	data := filepath.Join(dir, "data")
+
+	err := os.Symlink(filepath.Join(dir, "pool", "data"), data)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	daily := filepath.Join(data, "daily")
+	stderr := scanOK(t, daily)
+
+	summary := "scan: 1 files seen (1 added, 0 updated, 0 removed, " +
+		"0 unchanged), 0 skipped\n"
+	if !strings.Contains(stderr, summary) {
+		t.Errorf("stderr = %q, want %q", stderr, summary)
+	}
+
+	db, err := openDB(path, reportParams)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Cleanup(func() { _ = db.Close() })
+
+	recordByPath(t, dbRecords(t, db), filepath.Join(daily, "f"))
+}
+
 func TestRunReportSucceeds(t *testing.T) {
 	path := testDBPath(t)
 	t.Setenv(databaseEnv, path)
@@ -1028,8 +1158,9 @@ func TestRunTreesSucceeds(t *testing.T) {

 	// The two directories holding the duplicate pair are duplicate
 	// trees of each other.
-	want := "first\tdupe\tfiles\tsize\n" +
-		filepath.Dir(dupes[0]) + "\t" + filepath.Dir(dupes[1]) + "\t1\t300\n"
+	want := "first\tdupe\tfiles\tsize\tdisk_size\n" +
+		filepath.Dir(dupes[0]) + "\t" + filepath.Dir(dupes[1]) + "\t1\t300\t" +
+		strconv.FormatInt(storedDiskSize(t, path, dupes[1]), 10) + "\n"
 	if got := stdout.String(); got != want {
 		t.Errorf("stdout = %q, want %q", got, want)
 	}
@@ -1063,9 +1194,10 @@ func TestRunReportsNeedOnlyReadAccess(t *testing.T) {
 	cases := map[string]string{
 		cmdReport: "first\tdupe\tsize\n" +
 			dupes[0] + "\t" + dupes[1] + "\t300\n",
-		cmdTrees: "first\tdupe\tfiles\tsize\n" +
+		cmdTrees: "first\tdupe\tfiles\tsize\tdisk_size\n" +
 			filepath.Dir(dupes[0]) + "\t" + filepath.Dir(dupes[1]) +
-			"\t1\t300\n",
+			"\t1\t300\t" +
+			strconv.FormatInt(storedDiskSize(t, path, dupes[1]), 10) + "\n",
 	}

 	for name, want := range cases {
@@ -1100,8 +1232,11 @@ func assertRunsUseDatabase(t *testing.T, dir, name string) {
 		t.Errorf("report stdout = %q, want %q", got, want)
 	}

-	want = "first\tdupe\tfiles\tsize\n" +
-		filepath.Dir(dupes[0]) + "\t" + filepath.Dir(dupes[1]) + "\t1\t300\n"
+	diskSize := storedDiskSize(t, filepath.Join(dir, name), dupes[1])
+
+	want = "first\tdupe\tfiles\tsize\tdisk_size\n" +
+		filepath.Dir(dupes[0]) + "\t" + filepath.Dir(dupes[1]) + "\t1\t300\t" +
+		strconv.FormatInt(diskSize, 10) + "\n"
 	if got := runStdout(t, cmdTrees); got != want {
 		t.Errorf("trees stdout = %q, want %q", got, want)
 	}
@@ -1122,7 +1257,7 @@ func assertRunsUseDatabase(t *testing.T, dir, name string) {
 }

 func TestRunDatabasePathUsedAsGiven(t *testing.T) {
-	// README §Database: the path names the database file exactly. In
+	// README §Settings: the path names the database file exactly. In
 	// SQLite's connection string an unescaped ? or # would end the file
 	// name and % would start an escape, and a path starting with //
 	// could be read as a host name. %25 is a valid escape, so unescaped
@@ -1167,9 +1302,8 @@ func holdScanLock(t *testing.T, path string) {
 }

 func TestRunSecondScanFails(t *testing.T) {
-	// README §Database: while one scan holds the lock, a second scan
-	// fails at once, naming the lock file, without opening the
-	// database.
+	// README §Database: a second scan that finds the lock held fails
+	// at once, naming the lock file, without opening the database.
 	path := testDBPath(t)
 	t.Setenv(databaseEnv, path)

@@ -1228,7 +1362,7 @@ func assertSecondScanFails(t *testing.T, path string) {
 }

 func TestRunSecondScanThroughSymlinkFails(t *testing.T) {
-	// README §Database: every path to one database names the same lock
+	// README §Database: a path through a symlink names the same lock
 	// file, so while a scan holds it through one path, a scan through
 	// another fails, naming the lock file beside the database's real
 	// path.
@@ -1333,8 +1467,8 @@ func TestRunReportsDuringScan(t *testing.T) {
 }

 func TestRunStdoutClosedIsFatal(t *testing.T) {
-	// README §Error handling: a stdout write failure exits 1, reported
-	// in one line on stderr.
+	// README §Error handling: a failed write to stdout is a fatal error,
+	// exit 1, reported on stderr starting with "sfdupes:".
 	for _, name := range []string{cmdReport, cmdTrees, cmdInfo} {
 		t.Run(name, func(t *testing.T) {
 			t.Setenv(databaseEnv, testDBPath(t))
@@ -60,7 +60,7 @@ const fallbackWidth = 80
 const spinnerMargin = 5

 // countingRecords is what the display of a phase that reads the records
-// says while it counts them, before it has its total.
+// says until it has the number of records, its total.
 const countingRecords = "counting the records"

 // openPhase is the name of the phase in which report, trees and info
@@ -21,14 +21,16 @@ const minGroupSize = 2

 // scanRec is one file record from the database. The signature (size,
 // head, tail, content) is the duplicate key; mtime is informational
-// only and used by scan for change detection.
+// only and used by scan for change detection. diskSize is the bytes the
+// file takes on disk, which trees adds up.
 type scanRec struct {
-	size    int64
-	mtime   time.Time
-	head    [sha256.Size]byte
-	tail    [sha256.Size]byte
-	content [sha256.Size]byte
-	path    string
+	size     int64
+	diskSize int64
+	mtime    time.Time
+	head     [sha256.Size]byte
+	tail     [sha256.Size]byte
+	content  [sha256.Size]byte
+	path     string
 }

 // reportPhase names one phase of report with its place among all of
@@ -45,11 +47,11 @@ func reportPhase(name string) string {
 // problem, including a missing database, is fatal.
 //
 // The work runs in two phases, each under a progress display of its
-// own on stderr: open (open the database) and read (count the records,
-// then read them in signature order, writing each size's duplicate
-// groups to stdout once that size is read; see readReport). Each
-// display ends before the next phase starts, and before an error is
-// returned to be printed.
+// own on stderr: open (open the database) and read (read the number of
+// records from the totals table, then read the records in signature
+// order, writing each size's duplicate groups to stdout once that size
+// is read; see readReport). Each display ends before the next phase
+// starts, and before an error is returned to be printed.
 func runReport(ctx context.Context, stdout io.Writer) error {
 	dbPath, source, err := databasePath()
 	if err != nil {
@@ -38,8 +38,8 @@ func awkwardPairRecs() []scanRec {
 	h, tl, c := testHash("h"), testHash("t"), testHash("c")

 	return []scanRec{
-		{size: 5, head: h, tail: tl, content: c, path: "/d/A/f"},
-		{size: 5, head: h, tail: tl, content: c, path: awkwardDir + "/f"},
+		{size: 5, diskSize: 4096, head: h, tail: tl, content: c, path: "/d/A/f"},
+		{size: 5, diskSize: 4096, head: h, tail: tl, content: c, path: awkwardDir + "/f"},
 	}
 }

@@ -52,23 +52,26 @@ const workQueueDepth = 1024
 // has already printed its line, so run prints nothing more.
 var errInterrupted = errors.New("scan interrupted")

-// fileRec carries one statted file between the scan phases. dev and
-// ino identify the underlying inode so hard-linked paths can share
-// one read; both are zero when the platform exposes no inode.
+// fileRec carries one statted file between the scan phases. diskSize is
+// the bytes the file takes on disk. dev and ino identify the underlying
+// inode so hard-linked paths can share one read; both are zero when the
+// platform exposes no inode.
 type fileRec struct {
-	path  string
-	size  int64
-	mtime time.Time
-	dev   uint64
-	ino   uint64
+	path     string
+	size     int64
+	diskSize int64
+	mtime    time.Time
+	dev      uint64
+	ino      uint64
 }

 // fileMeta is the in-memory index entry for one existing database
-// record: just enough for change detection. Hashes stay on disk; at
+// record: what the walk compares the file with. Hashes stay on disk; at
 // tens of millions of records they would dominate the scan's memory.
 type fileMeta struct {
-	size  int64
-	mtime time.Time
+	size     int64
+	diskSize int64
+	mtime    time.Time
 }

 // scanUnit is what every scan phase counts, as its progress display
@@ -339,11 +342,12 @@ type scanStats struct {
 // whatever remains after the walk and hash phases is deleted by the
 // update phase.
 type scanState struct {
-	db       *sql.DB
-	existing map[string]fileMeta
-	toHash   []fileRec // new and changed files: must be read
-	batch    []scanRec
-	st       scanStats
+	db        *sql.DB
+	existing  map[string]fileMeta
+	toHash    []fileRec // new and changed files: must be read
+	diskSizes []fileRec // unchanged files whose disk_size changed
+	batch     []scanRec
+	st        scanStats
 }

 // syncScan synchronizes the database with the filesystem under roots;
@@ -383,7 +387,8 @@ func (s *scanState) runPhases(ctx context.Context, roots []string,
 ) error {
 	// Types and filesystems are checked before pruning so that an
 	// operand under a dropped one is still scanned, not dropped as lying
-	// under it.
+	// under it, and so that an operand inside a .zfs directory gets its
+	// warning even when it lies under another operand.
 	roots = pruneRoots(s.walkableRoots(roots, rules), oneFS, rules,
 		deviceOfPath)

@@ -411,15 +416,15 @@ func (s *scanState) runPhases(ctx context.Context, roots []string,
 }

 // walkableRoots returns the operands the walk can start from: regular
-// files, and directories not named .zfs. Every other operand is warned
-// about, counted as skipped, and dropped. A dropped operand is no
-// longer a root, so the records stored beneath it are treated as if it
-// had not been given: those under no other root count as outside the
-// roots and are not deleted as unverified. An operand on a filesystem
-// in rules that is not persistent is dropped the same way, with a line
-// saying so that is not a warning, and is not counted as skipped. An
-// operand that fails lstat here is kept, and the walk warns about it
-// unless it no longer exists.
+// files, and directories not named .zfs, none of them inside a
+// directory named .zfs. Every other operand is warned about, counted as
+// skipped, and dropped. A dropped operand is no longer a root, so the
+// records stored beneath it are treated as if it had not been given:
+// those under no other root count as outside the roots and are not
+// deleted as unverified. An operand on a filesystem in rules that is not
+// persistent is dropped the same way, with a line saying so that is not
+// a warning, and is not counted as skipped. An operand that fails lstat
+// here is kept, and the walk warns about it unless it no longer exists.
 func (s *scanState) walkableRoots(roots []string, rules walkRules) []string {
 	kept := make([]string, 0, len(roots))

@@ -454,8 +459,8 @@ func (s *scanState) walkableRoots(roots []string, rules walkRules) []string {
 // included, so its display counts against the number of records.
 func (s *scanState) loadIndex(ctx context.Context, roots []string) error {
 	// Indexing tens of millions of records takes real time; without a
-	// display the scan looks hung before the walk begins. Counting them
-	// first gives the display its total.
+	// display the scan looks hung before the walk begins. The number of
+	// records, read first, gives the display its total.
 	prog := newProgress(progressParams{
 		label: scanPhase("load"), unit: scanUnit, total: -1,
 		waitingFor: countingRecords, stalledOn: "db",
@@ -471,24 +476,24 @@ func (s *scanState) loadIndex(ctx context.Context, roots []string) error {

 	s.existing = make(map[string]fileMeta)

-	return loadFileMeta(ctx, s.db,
-		func(path string, size int64, mtime time.Time) {
-			prog.increment()
+	return loadFileMeta(ctx, s.db, func(path string, m fileMeta) {
+		prog.increment()

-			if underAnyRoot(path, roots) {
-				s.existing[path] = fileMeta{size: size, mtime: mtime}
-			}
-		})
+		if underAnyRoot(path, roots) {
+			s.existing[path] = m
+		}
+	})
 }

 // walkPhase drains the walk and queues every new or changed file for
-// the hash phase. An unchanged file needs nothing more, and its record
-// counts as verified. A record at or below a path the walk left out,
-// because -x stopped at it, it is a default exclude, or it is not on a
-// persistent filesystem, counts as outside the roots: it is not
-// deleted. That does not hold below a root at or inside that path,
-// since that root's own walk verifies the records below it; nor is a
-// line printed for such a root.
+// the hash phase. An unchanged file is not read, and its record counts
+// as verified. When its disk_size differs from the record's, it is
+// queued for the update phase, which writes the new disk_size. A record
+// at or below a path the walk left out, because -x stopped at it, it is
+// a default exclude, or it is not on a persistent filesystem, counts as
+// outside the roots: it is not deleted. That does not hold below a root
+// at or inside that path, since that root's own walk verifies the
+// records below it; nor is a line printed for such a root.
 func (s *scanState) walkPhase(events <-chan walkEvent, roots []string) {
 	// The records the last scan left under the roots estimate how many
 	// files the walk will find. A first scan has none, and no estimate.
@@ -546,6 +551,13 @@ func (s *scanState) walkPhase(events <-chan walkEvent, roots []string) {
 		delete(s.existing, ev.rec.path)

 		s.st.unchanged++
+
+		// The space a file takes on disk can change while its size and
+		// mtime stay the same. ZFS, for one, counts a new file's blocks
+		// only seconds after the write.
+		if old.diskSize != ev.rec.diskSize {
+			s.diskSizes = append(s.diskSizes, ev.rec)
+		}
 	}

 	prog.finish()
@@ -694,12 +706,13 @@ func (s *scanState) recordRun(ctx context.Context, r hashResult) error {
 		s.resolve(rec.path)

 		s.batch = append(s.batch, scanRec{
-			size:    rec.size,
-			mtime:   rec.mtime,
-			head:    r.head,
-			tail:    r.tail,
-			content: r.content,
-			path:    rec.path,
+			size:     rec.size,
+			diskSize: rec.diskSize,
+			mtime:    rec.mtime,
+			head:     r.head,
+			tail:     r.tail,
+			content:  r.content,
+			path:     rec.path,
 		})
 	}

@@ -715,7 +728,7 @@ func (s *scanState) commitFullBatch(ctx context.Context) error {
 		return nil
 	}

-	err := applyBatch(ctx, s.db, s.batch, nil, nil)
+	err := applyBatch(ctx, s.db, s.batch, nil, nil, nil)
 	if err != nil {
 		return err
 	}
@@ -726,9 +739,10 @@ func (s *scanState) commitFullBatch(ctx context.Context) error {
 }

 // updatePhase writes the scan's tail under one progress display: the
-// final partial batch of hashed records, and deletions for every record
-// the scan did not verify (vanished files, plus paths that failed to
-// stat or hash).
+// final partial batch of hashed records, the new disk_size of every
+// unchanged file whose disk_size changed, and deletions for every
+// record the scan did not verify (vanished files, plus paths that
+// failed to stat or hash).
 func (s *scanState) updatePhase(ctx context.Context) error {
 	deletes := make([]string, 0, len(s.existing))
 	for path := range s.existing {
@@ -740,7 +754,7 @@ func (s *scanState) updatePhase(ctx context.Context) error {

 	s.st.removed = len(deletes)

-	total := len(s.batch) + len(deletes)
+	total := len(s.batch) + len(s.diskSizes) + len(deletes)
 	prog := newProgress(progressParams{
 		label: scanPhase("update"), unit: scanUnit, total: int64(total),
 		stalledOn: "db",
@@ -755,6 +769,11 @@ func (s *scanState) updatePhase(ctx context.Context) error {

 	s.batch = nil

+	err = applyDiskSizes(ctx, s.db, s.diskSizes, prog)
+	if err != nil {
+		return err
+	}
+
 	return applyChanges(ctx, s.db, nil, deletes, prog)
 }

@@ -874,9 +893,24 @@ func sendEvent(ctx context.Context, events chan<- walkEvent,

 // operandWarning returns the one-line warning for an operand the walk
 // does not start from, naming the path and what it is, or "" for one it
-// does: a regular file, or a directory not named .zfs. Symlinks are
-// never followed, including as operands.
+// does: a regular file, or a directory not named .zfs, that is not
+// inside a directory named .zfs, neither as given nor with its symlinks
+// resolved. Symlinks are never followed, including as operands.
 func operandWarning(root string, fi fs.FileInfo) string {
+	// The walk never enters a .zfs directory, so it starts from nothing
+	// inside one either, not even through a symlink. An operand whose
+	// symlinks cannot be resolved is checked as given.
+	resolved, err := filepath.EvalSymlinks(root)
+	if err != nil {
+		resolved = root
+	}
+
+	if slices.Contains(strings.Split(filepath.Dir(root), "/"), ".zfs") ||
+		slices.Contains(strings.Split(filepath.Dir(resolved), "/"), ".zfs") {
+		return fmt.Sprintf("walk %s: skipping operand inside a .zfs directory",
+			root)
+	}
+
 	var kind string

 	switch mode := fi.Mode(); {
@@ -945,11 +979,12 @@ func seedRoot(ctx context.Context, root string, rules walkRules,

 	dev, ino := inodeOfInfo(fi)
 	rec := fileRec{
-		path:  root,
-		size:  fi.Size(),
-		mtime: fi.ModTime(),
-		dev:   dev,
-		ino:   ino,
+		path:     root,
+		size:     fi.Size(),
+		diskSize: diskSizeOfInfo(fi),
+		mtime:    fi.ModTime(),
+		dev:      dev,
+		ino:      ino,
 	}

 	if !isDatabaseFile(rec, rules) {
@@ -1129,11 +1164,12 @@ func emitFile(ctx context.Context, p string, e fs.DirEntry,

 	dev, ino := inodeOfInfo(info)
 	rec := fileRec{
-		path:  p,
-		size:  info.Size(),
-		mtime: info.ModTime(),
-		dev:   dev,
-		ino:   ino,
+		path:     p,
+		size:     info.Size(),
+		diskSize: diskSizeOfInfo(info),
+		mtime:    info.ModTime(),
+		dev:      dev,
+		ino:      ino,
 	}

 	if !isDatabaseFile(rec, rules) {
@@ -1225,6 +1261,23 @@ func inodeOfInfo(fi fs.FileInfo) (uint64, uint64) {
 	return statDev(st), st.Ino
 }

+// statBlockSize is the unit of st_blocks in an lstat result on Linux and
+// macOS, whatever the filesystem's own block size.
+const statBlockSize = 512
+
+// diskSizeOfInfo returns the bytes a file takes on disk: its allocated
+// blocks, st_blocks × 512. On a compressed or sparse file it is less
+// than the file's size. It is 0 when the platform exposes no block
+// count.
+func diskSizeOfInfo(fi fs.FileInfo) int64 {
+	st, ok := fi.Sys().(*syscall.Stat_t)
+	if !ok {
+		return 0
+	}
+
+	return st.Blocks * statBlockSize
+}
+
 // hashResult carries the hashes computed for one inode run (or the
 // error that prevented computing them) from the pool's workers to the
 // hash phase. Its run leaves out the paths found removed.
@@ -42,6 +42,30 @@ func writeFile(t *testing.T, dir, name string, data []byte) string {
 	return p
 }

+// diskSizeOf returns the bytes the file at path takes on disk, from its
+// own lstat: st_blocks counts 512-byte units. ZFS counts a write's
+// blocks only when it commits the write, up to seconds later, and one
+// commit can take the file through several growing sizes. So this value
+// can change at any moment. Neither fsync nor unix.Sync hastens that,
+// but a unix.Sync call often takes long enough that the blocks are
+// counted when it returns. A test that needs the value to change waits
+// for the change. A test that compares it with a scan's disk_size reads
+// it before and after the scan. The rewrite test rescans until the two
+// reads match, then compares exactly. The other two tests fail only on
+// a disk_size outside the two reads.
+func diskSizeOf(t *testing.T, path string) int64 {
+	t.Helper()
+
+	var st syscall.Stat_t
+
+	err := syscall.Lstat(path, &st)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	return st.Blocks * 512
+}
+
 // pattern returns n bytes of deterministic content seeded by tag.
 func pattern(tag byte, n int) []byte {
 	data := make([]byte, n)
@@ -1064,8 +1088,9 @@ func TestScanOneFilesystemWalksNestedFileOperand(t *testing.T) {
 	}
 }

-// buildSmokeTree recreates the README smoke-test filesystem layout
-// with deterministic content and returns the tree root.
+// buildSmokeTree recreates the tree of the test under README
+// "Definition of done" with deterministic content and returns the tree
+// root.
 func buildSmokeTree(t *testing.T) string {
 	t.Helper()

@@ -1228,9 +1253,9 @@ func TestScanPipeline(t *testing.T) {
 // TestScanProgressNamesEachPhase checks the plain progress lines of a
 // first scan, and of a rescan of one operand holding two of the
 // database's records. Each phase's first line names it with its place
-// among the four: load counts the records before reading them, and the
-// walk estimates its total from the records under its operand, or says
-// its time remaining is unknown when there are none.
+// among the four: load gets the number of records before reading them,
+// and the walk estimates its total from the records under its operand,
+// or says its time remaining is unknown when there are none.
 //
 //nolint:paralleltest // captureStderr replaces the process-wide os.Stderr
 func TestScanProgressNamesEachPhase(t *testing.T) {
@@ -1416,6 +1441,159 @@ func TestScanStoresRawHashes(t *testing.T) {
 	}
 }

+// TestScanStoresDiskSize scans a sparse file, which takes less space on
+// disk than its length, once through its directory and once as the
+// operand itself. Each scan stores the disk_size of the file's lstat.
+func TestScanStoresDiskSize(t *testing.T) {
+	t.Parallel()
+
+	const length = 1024 * 1024
+
+	p := sparseFile(t, t.TempDir(), "sparse", length)
+	pokeAt(t, p, 0, []byte("x"))
+
+	unix.Sync() // see diskSizeOf
+
+	size := diskSizeOf(t, p)
+	if size == 0 || size >= length {
+		t.Fatalf("the file takes %d bytes on disk, want more than none "+
+			"and fewer than its length %d", size, length)
+	}
+
+	for _, operand := range []string{filepath.Dir(p), p} {
+		db := openTestDB(t)
+
+		// ZFS may count the blocks during the scan; see diskSizeOf.
+		before := diskSizeOf(t, p)
+
+		syncTree(t, db, operand)
+
+		after := diskSizeOf(t, p)
+
+		got := recordByPath(t, dbRecords(t, db), p).diskSize
+		if got < before || got > after {
+			t.Errorf("scan of %s: disk_size = %d, want %d to %d",
+				operand, got, before, after)
+		}
+	}
+}
+
+// TestSyncScanRewriteUpdatesDiskSize writes into the hole of a scanned
+// sparse file and moves its mtime on. The rescan hashes the file again
+// and rewrites its record with the new disk_size.
+func TestSyncScanRewriteUpdatesDiskSize(t *testing.T) {
+	t.Parallel()
+
+	dir := t.TempDir()
+	db := openTestDB(t)
+	p := sparseFile(t, dir, "sparse", 1024*1024)
+	pokeAt(t, p, 0, []byte("x"))
+
+	syncTree(t, db, dir)
+
+	recorded := recordByPath(t, dbRecords(t, db), p).diskSize
+
+	pokeAt(t, p, 512*1024, pattern(7, 64*1024))
+
+	// The write may leave the mtime the scan recorded; a later one makes
+	// the rescan read the file again.
+	later := time.Now().Add(time.Hour)
+
+	err := os.Chtimes(p, later, later)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Wait for ZFS to count the write; see diskSizeOf.
+	deadline := time.Now().Add(30 * time.Second)
+	for diskSizeOf(t, p) == recorded {
+		if time.Now().After(deadline) {
+			t.Fatalf("the file still takes %d bytes on disk 30 seconds "+
+				"after the write into its hole", recorded)
+		}
+
+		unix.Sync()
+	}
+
+	// ZFS may still be counting, so the size may change during a rescan.
+	// Only a rescan with the same size on both sides of it can be compared
+	// exactly. A rescan that keeps the old size still fails, because the
+	// wait made before differ from it.
+	for {
+		before := diskSizeOf(t, p)
+
+		st := syncTree(t, db, dir)
+
+		after := diskSizeOf(t, p)
+
+		if st != (scanStats{walked: 1, updated: 1}) {
+			t.Fatalf("rescan stats = %+v, want 1 updated", st)
+		}
+
+		if before == after {
+			got := recordByPath(t, dbRecords(t, db), p).diskSize
+			if got != after {
+				t.Errorf("disk_size = %d, want %d", got, after)
+			}
+
+			return
+		}
+
+		if time.Now().After(deadline) {
+			t.Fatalf("the size on disk was still changing 30 seconds after "+
+				"the write into its hole: %d, then %d", before, after)
+		}
+
+		// A later mtime makes the next rescan read the file again.
+		later = later.Add(time.Second)
+
+		err = os.Chtimes(p, later, later)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
+// TestSyncScanUnchangedUpdatesDiskSize gives a file's record a
+// disk_size the file does not have, as when ZFS had not yet counted the
+// file's blocks at the last scan. The rescan writes the file's own
+// disk_size into the record without reading the file again.
+func TestSyncScanUnchangedUpdatesDiskSize(t *testing.T) {
+	t.Parallel()
+
+	dir := t.TempDir()
+	db := openTestDB(t)
+	p := writeFile(t, dir, "a.bin", pattern(1, 500))
+
+	syncTree(t, db, dir)
+
+	// lstat counts 512-byte units, so no file takes 1 byte on disk.
+	_, err := db.ExecContext(t.Context(),
+		"UPDATE files SET disk_size = 1 WHERE path = ?", []byte(p))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	unix.Sync() // see diskSizeOf
+
+	// ZFS may count the blocks during the rescan; see diskSizeOf.
+	before := diskSizeOf(t, p)
+
+	// A file read again would count as updated.
+	st := syncTree(t, db, dir)
+
+	after := diskSizeOf(t, p)
+
+	if st != (scanStats{walked: 1, unchanged: 1}) {
+		t.Fatalf("rescan stats = %+v, want 1 unchanged", st)
+	}
+
+	got := recordByPath(t, dbRecords(t, db), p).diskSize
+	if got < before || got > after {
+		t.Errorf("disk_size = %d, want %d to %d", got, before, after)
+	}
+}
+
 // TestSyncScanSameSecondRewrite rewrites a file in place at the same
 // size with an mtime later in the same second as the recorded one: the
 // next scan must notice the change and re-hash the file. The operand is
@@ -22,6 +22,10 @@ type treeNode struct {
 	digest    [sha256.Size]byte
 	fileCount int64
 	totalSize int64
+	// diskSize is the bytes the directory's files take on disk. Two
+	// copies of one tree have the same totalSize, but their diskSize
+	// can differ.
+	diskSize int64
 }

 // treesPhase names one phase of trees with its place among all of them,
@@ -40,11 +44,11 @@ func treesPhase(name string) string {
 // database problem, including a missing database, is fatal.
 //
 // The work runs in four phases, each under a progress display of its
-// own on stderr: open (open the database), read (count the records,
-// then read them into the hierarchy), group (group the directories by
-// digest) and write (write the groups to stdout). Each display ends
-// before the next phase starts, and before an error is returned to be
-// printed.
+// own on stderr: open (open the database), read (read the number of
+// records from the totals table, then read the records into the
+// hierarchy), group (group the directories by digest) and write (write
+// the groups to stdout). Each display ends before the next phase
+// starts, and before an error is returned to be printed.
 func runTrees(ctx context.Context, stdout io.Writer) error {
 	dbPath, source, err := databasePath()
 	if err != nil {
@@ -139,15 +143,16 @@ func readTree(ctx context.Context, db *sql.DB,

 // writeTreeGroups writes dupes to stdout as TSV, a header line and then
 // a row for every member of each group but its first, counting each
-// group on prog once its rows are written. stdout may be the terminal
-// prog is drawn on, so the lines go through prog's writer. It returns
-// the number of rows (dupe trees) and the bytes they could reclaim.
+// group on prog once its rows are written. The disk_size column is the
+// dupe's own. stdout may be the terminal prog is drawn on, so the lines
+// go through prog's writer. It returns the number of rows (dupe trees)
+// and the bytes they could reclaim.
 func writeTreeGroups(stdout io.Writer, dupes [][]*treeNode,
 	prog *progress,
 ) (int, int64, error) {
 	out := prog.writer(stdout)

-	_, err := fmt.Fprintln(out, "first\tdupe\tfiles\tsize")
+	_, err := fmt.Fprintln(out, "first\tdupe\tfiles\tsize\tdisk_size")
 	if err != nil {
 		return 0, 0, fmt.Errorf("write stdout: %w", err)
 	}
@@ -159,9 +164,9 @@ func writeTreeGroups(stdout io.Writer, dupes [][]*treeNode,
 	for _, g := range dupes {
 		first := g[0]
 		for _, n := range g[1:] {
-			_, err = fmt.Fprintf(out, "%s\t%s\t%d\t%d\n",
+			_, err = fmt.Fprintf(out, "%s\t%s\t%d\t%d\t%d\n",
 				escapePath(first.path), escapePath(n.path),
-				first.fileCount, first.totalSize)
+				first.fileCount, first.totalSize, n.diskSize)
 			if err != nil {
 				return 0, 0, fmt.Errorf("write stdout: %w", err)
 			}
@@ -232,6 +237,7 @@ func (b *treeBuilder) add(r scanRec) {
 	dir.entries = append(dir.entries, fileEntry(name, r))
 	dir.fileCount++
 	dir.totalSize += r.size
+	dir.diskSize += r.diskSize
 }

 // openDir starts the directory called name inside the innermost open
@@ -270,6 +276,7 @@ func (b *treeBuilder) closeTo(n int) {
 			"d\x00"+name+"\x00"+string(dir.digest[:]))
 		dir.parent.fileCount += dir.fileCount
 		dir.parent.totalSize += dir.totalSize
+		dir.parent.diskSize += dir.diskSize
 		b.dirs = append(b.dirs, dir)
 	}
 }
@@ -15,20 +15,26 @@ import (
 const treesOpenLine = "[1/4] open: opening the database, elapsed 0s, " +
 	"remain unknown"

-// smokeTreeRecs mirrors the README smoke-test tree layout: /d/t1 and
-// /d/t2 are identical, /d/t3 differs from them only by one filename.
+// smokeTreeRecs mirrors the tree of the test under README "Definition
+// of done": /d/t1 and /d/t2 are identical, /d/t3 differs from them only
+// by one filename. Each file takes one 4 KiB block on disk.
 func smokeTreeRecs() []scanRec {
 	f1Head, f1Tail, f1Content := testHash("f1h"), testHash("f1t"), testHash("f1c")
 	f2Head, f2Tail, f2Content := testHash("f2h"), testHash("f2t"), testHash("f2c")

 	return []scanRec{
-		{size: 3000, head: f1Head, tail: f1Tail, content: f1Content, path: "/d/t1/f1"},
-		{size: 100, head: f2Head, tail: f2Tail, content: f2Content, path: "/d/t1/sub/f2"},
-		{size: 3000, head: f1Head, tail: f1Tail, content: f1Content, path: "/d/t2/f1"},
-		{size: 100, head: f2Head, tail: f2Tail, content: f2Content, path: "/d/t2/sub/f2"},
-		{size: 3000, head: f1Head, tail: f1Tail, content: f1Content, path: "/d/t3/f1"},
-		{size: 100, head: f2Head, tail: f2Tail, content: f2Content,
-			path: "/d/t3/sub/f2renamed"},
+		{size: 3000, diskSize: 4096, head: f1Head, tail: f1Tail,
+			content: f1Content, path: "/d/t1/f1"},
+		{size: 100, diskSize: 4096, head: f2Head, tail: f2Tail,
+			content: f2Content, path: "/d/t1/sub/f2"},
+		{size: 3000, diskSize: 4096, head: f1Head, tail: f1Tail,
+			content: f1Content, path: "/d/t2/f1"},
+		{size: 100, diskSize: 4096, head: f2Head, tail: f2Tail,
+			content: f2Content, path: "/d/t2/sub/f2"},
+		{size: 3000, diskSize: 4096, head: f1Head, tail: f1Tail,
+			content: f1Content, path: "/d/t3/f1"},
+		{size: 100, diskSize: 4096, head: f2Head, tail: f2Tail,
+			content: f2Content, path: "/d/t3/sub/f2renamed"},
 	}
 }

@@ -198,13 +204,33 @@ func TestRunTreesEscapesPaths(t *testing.T) {
 			code, exitOK, stderr.String())
 	}

-	want := "first\tdupe\tfiles\tsize\n" +
-		`/d/\tone\ntwo\rthree\\four` + "\t/d/A\t1\t5\n"
+	want := "first\tdupe\tfiles\tsize\tdisk_size\n" +
+		`/d/\tone\ntwo\rthree\\four` + "\t/d/A\t1\t5\t4096\n"
 	if got := stdout.String(); got != want {
 		t.Errorf("stdout = %q, want %q", got, want)
 	}
 }

+// TestRunTreesDiskSize runs trees on two copies of a tree whose files
+// take different space on disk. The row's disk_size is the sum over the
+// dupe copy's files, those in its subdirectory included.
+func TestRunTreesDiskSize(t *testing.T) {
+	f, g := testHash("f"), testHash("g")
+	recs := []scanRec{
+		{size: 10, diskSize: 4096, head: f, tail: f, content: f, path: "/a/f"},
+		{size: 20, diskSize: 4096, head: g, tail: g, content: g, path: "/a/sub/g"},
+		{size: 10, diskSize: 512, head: f, tail: f, content: f, path: "/b/f"},
+		{size: 20, diskSize: 1024, head: g, tail: g, content: g, path: "/b/sub/g"},
+	}
+
+	t.Setenv(databaseEnv, seedDatabase(t, recs))
+
+	want := "first\tdupe\tfiles\tsize\tdisk_size\n/a\t/b\t2\t30\t1536\n"
+	if got := runStdout(t, cmdTrees); got != want {
+		t.Errorf("stdout = %q, want %q", got, want)
+	}
+}
+
 // TestRunTreesProgressNamesEachPhase runs trees on the smoke-test
 // records with stderr not a terminal, and checks every line it prints
 // there. After the line naming the database, each phase prints a line
@@ -226,7 +252,8 @@ func TestRunTreesProgressNamesEachPhase(t *testing.T) {
 			code, exitOK, stderr())
 	}

-	report := "first\tdupe\tfiles\tsize\n/d/t1\t/d/t2\t2\t3100\n"
+	report := "first\tdupe\tfiles\tsize\tdisk_size\n" +
+		"/d/t1\t/d/t2\t2\t3100\t8192\n"
 	if got := stdout.String(); got != report {
 		t.Errorf("stdout = %q, want %q", got, report)
 	}
@@ -291,7 +318,9 @@ func TestWriteTreeGroupsOnTerminal(t *testing.T) {
 		shown = append(shown, line[strings.LastIndex(line, "\r")+1:])
 	}

-	want := []string{"first\tdupe\tfiles\tsize", "/d/t1\t/d/t2\t2\t3100"}
+	want := []string{
+		"first\tdupe\tfiles\tsize\tdisk_size", "/d/t1\t/d/t2\t2\t3100\t8192",
+	}
 	if len(shown) < len(want) || !slices.Equal(shown[:len(want)], want) {
 		t.Errorf("terminal shows lines %q, want %q first", shown, want)
 	}
Author	SHA1	Message	Date
sneak	5f51a4da78	Stop the disk size tests failing at random on ZFS (closes #150 ) check / check (push) Waiting to run Details One ZFS commit can take a file through several sizes, and unix.Sync can return before the blocks are counted. A test that expected the size on disk to be settled therefore failed at random. The test that needs the size to change now calls unix.Sync in a loop until it does, for at most 30 seconds. It then rescans until the size reads the same before and after a rescan, and compares disk_size exactly, within the same 30 seconds. The other two tests fail only on a disk_size outside their two reads. They call unix.Sync once first, so a wrong 512 usually fails them. Model: opus-5-5	2026-11-03 02:55:48 +00:00
clawbot	4ecf8dc484	Rewrite TODO.md sentence by sentence (closes #135 ) check / check (push) Canceled after 0s Details Rewrites `TODO.md` from scratch for #135, by the rules applied to `README.md`. Every completed step keeps its date, its issue or branch and its facts, in short sentences, with lists as bullets. An entry superseded later says so. Entries record history, so they were not corrected against the code. Known stale: the 2026-10-17 release-rule entry. Changed: one product name in the 2026-10-15 entry is replaced by a description. Model: fable-5-1 (rewrite); opus-5-5 (review, landing message)	2026-11-02 23:29:22 +01:00
clawbot	2322f8bb02	Rewrite README.md sentence by sentence for a newcomer check / check (push) Canceled after 0s Details Rewrites `README.md` from scratch for #135, so that a newcomer can follow each sentence on one reading. It leads with what the program is and how to use it, then the reference, then development. Where the old text and the code disagreed, it states what the code does; #140 lists each point. Test comments that cited moved text cite the new headings. Review scope: full reviews through the 16th, then only text changed since. Dropped: the permission to add `github.com/spf13/viper`. Model: fable-5-1 (rewrite); opus-5-5 (review, landing message)	2026-11-02 23:12:27 +01:00
clawbot	4ed2e370b1	Record each file's size on disk and print it in trees (closes #147 ) check / check (push) Canceled after 0s Details The files table gets a disk_size column: the file's allocated blocks, st_blocks × 512, from the lstat the walk already does. scan writes it with every record it writes. When a rescan finds a file with its size and mtime unchanged but a different disk_size, it updates disk_size alone, without reading the file. trees adds disk_size up per directory and prints it as a column after size. On a compressed or sparse file it is less than size, so two copies of one tree can differ. Judgement calls: each row's disk_size is the dupe copy's, not the first's. A file whose record gets only a new disk_size counts as unchanged. Model: opus-5-5	2026-10-27 19:56:49 +01:00
clawbot	98193b2896	Keep the record count and total size in a totals table (closes #146 ) check / check (push) Canceled after 0s Details info counted the records and added up their sizes with a query that reads every record, which takes minutes on a large database. The schema now has a totals table of one row, kept current by three triggers on files, in the transaction of each insert, delete and size update. info, scan's load phase and the read phases of report and trees read that row instead of counting over files. scan writes files with the same statements as before. Each of those writes now fires a trigger and is slower, so scan keeps SQLite's temporary data in memory, which wins back part of that time. Model: opus-5-5	2026-10-27 18:59:37 +01:00
clawbot	ee09cda355	Never scan an operand inside a .zfs directory (closes #142 ) check / check (push) Canceled after 0s Details An operand inside a directory named .zfs was walked, because the operand check looked only at the operand's own name. The check now also looks at every directory above the operand, both as given and with its symlinks resolved. Such an operand gets a warning, counts as skipped and is not walked, whether given alone or under another operand. The check runs before overlapping operands are pruned, so an operand under another one still gets its warning. The test for an operand named .zfs now writes its record beneath .zfs straight into the database, since no scan stores one there any more. Judgement call: a path component named .zfs counts whatever it is, a symlink included. Model: opus-5-5	2026-10-26 15:15:37 +01:00