Fix nine review findings in the documents and help text

- snapshot verify and snapshot restore also list the destination for a
  snapshot ID that is not in the local index: README, REPOSTRUCTURE,
  ARCHITECTURE, DATAMODEL and the two commands' help.
- prune on a separate machine deletes only unused data and does not
  remove old snapshots.
- The --quiet usage string names everything the flag leaves out.
- A warning written as a log record stays on stderr.
- config set on a config that does not load refuses three things.
- No test is held back by a build tag.
- A plain docker build . adds no -dirty.
- The backup's order of work records directories.
- TODO.md says what parallel downloads would speed up and names
  restorePlan and restoreSweeper.

Model: fable-5-1

README.md

@@ -308,8 +308,11 @@ is `vaultik config set compression_level 99`. The file is then left unchanged.
 
 A config that does not load yet is checked less strictly. An example is the file
 `config init` writes, which has no `storage_url`. There the command refuses only
-two things: an unknown key, and a value of the wrong type, such as a word where
-a number belongs.
+three things:
+
+- an unknown key
+- a value of the wrong type, such as a word where a number belongs
+- a `${ENV:NAME}` value whose variable is unset or empty
 
 ### `snapshot create`
 
@@ -477,7 +480,8 @@ Without `--deep`, it checks two things:
 - The snapshot's encrypted database is present.
 
 This reads no blob contents and needs no private key. It needs permission to
-read at the destination, and to list it when you give a remote key.
+read at the destination, and to list it when you give a remote key, or a
+snapshot ID that is not in the local index.
 
 Flags:
 
@@ -583,7 +587,7 @@ It needs:
 - The age private key, as for `snapshot verify --deep`. See
   [The private key](#the-private-key).
 - Permission to read at the destination, and to list it when you give a remote
-  key.
+  key, or a snapshot ID that is not in the local index.
 - Write access to `<target-dir>`. The command creates the directory when it does
   not exist.
 - Free temporary space for the decrypted blobs. See
@@ -1066,12 +1070,14 @@ An rclone remote that can move objects also needs permission to read and delete.
 An upload there looks up the object it replaces and deletes it. It stops when
 the look-up is refused.
 
-`snapshot verify` and `snapshot restore` list only when you give a remote key.
-`snapshot remove --local-only` does not reach the destination.
-`snapshot remove --dry-run` deletes nothing.
+`snapshot verify` and `snapshot restore` list only when you give a remote key,
+or a snapshot ID that is not in the local index. `snapshot remove --local-only`
+does not reach the destination. `snapshot remove --dry-run` deletes nothing.
 
 A machine that runs `snapshot create --prune` can delete its own backups. To
 keep it to write-only credentials, run `prune` from a separate, trusted machine.
+`prune` there deletes only data that no snapshot uses. It does not remove old
+snapshots.
 
 A backup tries to look up the marker file and each blob before it writes. On S3
 it goes on when the destination refuses those look-ups.
@@ -1095,7 +1101,8 @@ not exist, commands treat the destination as not present:
     - `prune`
     - `snapshot purge`
     - `remote nuke`
-    - `snapshot verify` and `snapshot restore`, when given a remote key
+    - `snapshot verify` and `snapshot restore`, when given a remote key, or a
+      snapshot ID that is not in the local index
 - `snapshot list` shows the local index alone.
 - `snapshot remove` deletes nothing at the destination.
 
@@ -1210,8 +1217,10 @@ stderr carries the rest:
 - log records, including those from `--verbose` and `--debug`
 - the error that a failed command ends with
 
-So `vaultik snapshot list > out.txt` captures the list and any warnings. The
-banner, log records and a final error stay on your terminal.
+So `vaultik snapshot list > out.txt` captures the list and the warnings printed
+below it. The banner, log records and a final error stay on your terminal. A
+warning written as a log record, such as the one about a config file others can
+read, stays there too.
 
 Log records are colored lines when stderr is a terminal. They are JSON, one
 object per line, when stderr is redirected.
@@ -1409,8 +1418,8 @@ call them.
 Every `docker build` in these scripts uses `--no-cache`. A cached layer would
 skip the tests or the linter and still report success.
 
-The test suite has no separate integration target. Every test runs every time.
-Each test binary is stopped after 90 seconds.
+The test suite has no separate integration target. No test is held back by a
+build tag. Each test binary is stopped after 90 seconds.
 
 To change the Go version, change these together:
 
@@ -1474,6 +1483,9 @@ The version a binary reports comes from git. It is the output of
 `script/version` gives this value to the `Makefile`. `script/docker` and
 `script/cibuild` compute it themselves.
 
+A plain `docker build .` adds no `-dirty`. The `Dockerfile` runs `git describe`
+without `--dirty`.
+
 `make` outside a git checkout, and `docker build .` without `.git`, stamp `dev`.
 An image built by `script/docker` or `script/cibuild` outside a git checkout
 reports `unknown`.

docs/ARCHITECTURE.md

@@ -291,10 +291,11 @@ therefore marks a backup that did not finish.
 - With `--verify`, `verifyRestoredFiles` reads each restored regular file and
   checks its chunk hashes.
 
-Given a snapshot ID, the restore does not read the local index. Given a remote
-key, it reads the local index only to check the destination marker. It does not
-read the manifest. It finds each file's chunks and blobs through the downloaded
-database.
+Given a snapshot ID, the restore looks it up in the local index. When it is not
+there, the restore checks the destination marker and lists the snapshot's
+directory. Given a remote key, it reads the local index only to check the
+destination marker. It does not read the manifest. It finds each file's chunks
+and blobs through the downloaded database.
 
 ### Checks on the downloaded database
 

docs/DATAMODEL.md

@@ -299,6 +299,7 @@ A backup works on the tables in this order:
 - It walks each path. It compares each regular file and symlink with its row in
   `files`.
 - It links each unchanged file to the snapshot in `snapshot_files`.
+- It writes a `files` row and a `snapshot_files` row for each directory.
 - It records each mount point in `snapshot_mount_points`.
 - It reads each changed regular file and stores it. See below. A changed symlink
   is recorded without being read.
@@ -362,9 +363,9 @@ still be in the `-wal` file beside it.
 
 ### Restore
 
-A restore reads no file, chunk or blob rows from the local index. Given a remote
-key, it reads `snapshots` and `local_meta` there to check the destination
-marker.
+A restore reads no file, chunk or blob rows from the local index. It reads
+`snapshots` and `local_meta` there, to look up a snapshot ID and to check the
+destination marker.
 
 - It downloads and decrypts `db.zst.age` into a temporary directory.
 - It opens that file read-only. It applies no migration to it.

docs/REPOSTRUCTURE.md

@@ -59,7 +59,8 @@ not exist, commands treat the destination as not present:
     - `prune`
     - `snapshot purge`
     - `remote nuke`
-    - `snapshot verify` and `snapshot restore`, when given a remote key
+    - `snapshot verify` and `snapshot restore`, when given a remote key, or a
+      snapshot ID that is not in the local index
 - `snapshot list` shows the local index alone.
 - `snapshot remove` deletes nothing at the destination.
 
@@ -334,12 +335,14 @@ An upload there looks up the object it replaces and deletes it. It stops when
 the look-up is refused.
 
 `snapshot verify` and `snapshot restore` list only when they are given a remote
-key. `snapshot remove --local-only` does not reach the destination.
+key, or a snapshot ID that is not in the local index.
+`snapshot remove --local-only` does not reach the destination.
 `snapshot remove --dry-run` deletes nothing.
 
 `snapshot create --prune` runs a prune on the backed-up machine. That machine
 then holds credentials that can delete its own backups. To keep it to write-only
-credentials, run `prune` from a separate, trusted machine.
+credentials, run `prune` from a separate, trusted machine. `prune` there deletes
+only data that no snapshot uses. It does not remove old snapshots.
 
 ### New recipients cannot read old data
 

docs/TODO.md

@@ -41,10 +41,11 @@ Work planned after 1.0, loosely ordered by priority.
 
 - **Parallel blob downloads during restore.** A restore downloads one blob at a
   time now. With a fast S3 endpoint and a multi-core machine, restore speed is
-  bound by the fetch, decryption and decompression of each blob. Running several
-  of those in parallel against the disk cache would close most of the remaining
-  gap. This needs to interact correctly with the locality planner and the
-  sweeper.
+  bound by the fetch, decryption and decompression of each blob. Fetching,
+  decrypting and decompressing several blobs at once would make such a restore
+  faster. The change must work with `restorePlan`, which orders the files, and
+  with `restoreSweeper`, which deletes a cached blob once no remaining file
+  needs it.
 - **Bandwidth limiting (`--bwlimit`).** For both upload and download. It is
   useful for backing up over a shared link. It is tricky to make work correctly
   with parallel downloads.

internal/cli/root.go

@@ -58,8 +58,9 @@ an rclone remote. The backed-up machine needs no private key: only
 	cmd.PersistentFlags().BoolVar(&rootFlags.Debug, "debug", false,
 		"Enable debug output")
 	cmd.PersistentFlags().BoolVarP(&rootFlags.Quiet, "quiet", "q", false,
-		"Suppress status output (warnings, errors, JSON documents, "+
-			"'config get' values and confirmation prompts are still printed)")
+		"Leave out the banner, status lines, tables and reports (warnings, "+
+			"errors, JSON documents, 'config get' values and confirmation "+
+			"prompts are still printed)")
 	cmd.PersistentFlags().BoolVar(&rootFlags.SkipErrors, "skip-errors", false,
 		"Skip files that cannot be read when creating a snapshot, or "+
 			"that cannot be restored when restoring, instead of aborting "+

internal/cli/snapshot.go

@@ -252,7 +252,8 @@ snapshot's encrypted database is present. It does not read blob
 contents and does not need the age private key.
 
 Needs permission to read the backup destination store, and to list it
-when a remote key is given.
+when given a remote key, or a snapshot ID that is not in the local
+index.
 
 Use --deep to download, decrypt, and re-hash every blob to detect
 corruption -- integrity, not who wrote it.

internal/cli/snapshot_restore.go

@@ -49,8 +49,9 @@ typing it, so that it does not land in your shell history:
   export VAULTIK_AGE_SECRET_KEY="$(cat vaultik_backup_private_key.txt)"
 
 Also needs permission to read the backup destination store (and to list
-it when a remote key is given), and free space in the temporary directory
-for the decrypted blobs.
+it when given a remote key, or a snapshot ID that is not in the local
+index), and free space in the temporary directory for the decrypted
+blobs.
 
 Examples:
   # Restore entire snapshot