v0.2.2

Built with Go 1.26.10, for a correction to the certificate check of the webhook notification, and with newer versions of the two compression libraries.

• --webhook sends its message over HTTPS. Go 1.26.10 holds a list of intermediate certificates that are no longer to be trusted and refuses a connection whose certificate chain goes through one of them (GO-2026-6809); every earlier version of wslbak was built with a Go that has no such list. The advisory calls the cases it matters for narrow: on most systems the system's own certificate store decides, and the list is for a store that has not been brought up to date. The webhook is the only connection wslbak makes; backups and restores do not touch the network.
• The compression library klauspost/compress is at 1.20.3 (was 1.20.1). Its changes are in parts wslbak does not use (zstd, s2, zip); the code that writes and reads the .tar.gz files is the same.
• klauspost/pgzip, which compresses the backup on several cores, is at 1.3.0 (was 1.2.7). Of its changes, one reaches wslbak: when finishing the file fails (a full destination, for instance), it now also stops its own background work. The compressed data it writes is the same.

v0.2.1

Two corrections to backups of a distro in which files are deleted, renamed or shortened while the backup runs, and corrections to what the npm launcher says inside WSL when Windows programs cannot be started.

• A backup failed with "tar reported an error" when a file was deleted or renamed in the instant after tar had taken it up: tar then cannot look up its access control list and extended attributes by name, and says Warning: Cannot file_has_acl_at: No such file or directory (or acl_get_file_at, or llistxattrat). The file is in the archive all the same; one that was renamed is there under the name it had, without its access control list. wslbak took these lines for errors; a file that disappears an instant earlier was already accepted as normal on a running system, and so are these now. It is rare: of about 150 runs of the tests that create and delete files during a backup, one met it. Every earlier version has the same gap.
• The same for a file that became exactly one byte shorter while it was read: tar then says "File shrank by 1 byte", and only the plural was recognised.
• The launcher's message named [interop] enabled=false in /etc/wsl.conf as the thing to check when Windows programs never worked. That is the cause in a WSL 1 distro only, and the message now says so. In a WSL 2 distro that setting does not lead to this message: the kernel setting the launcher looks at stays in place, and WSL itself prints an error after about ten seconds (tried with WSL 2.7.13). The README describes that case in its own entry.
• The command the message prints puts back a setting that is missing in a WSL 2 distro. It does not help with one that is switched off, and the message now offers it for a missing one only; wsl --shutdown restores it in either case.
• When the kernel setting is in place but the program it names cannot be found, the launcher printed the same message, which is not true of that state. It now says what it found.

Full Changelog: v0.2.0...v0.2.1

v0.2.0

Differential backups: a full backup now and then, and in between only what changed since it. They are off by default; nothing changes for a setup that does not switch them on. Also in this release are safeguards against a run that never ends, which were prepared as 0.1.2 (that version was never published), and a number of corrections that an examination of the whole program before this release turned up.

After updating, run a wslbak command once, for example wslbak status: the scheduled task runs a copy of the program in a fixed place, and that copy is brought up to date when the new version runs a command (--version, --help and --dry-run do not do it).

• wslbak config --mode diff switches a distro to differential backups, --mode full back. --full-every <days> says for how long one full backup is built on (default 30), and wslbak run --full makes a full backup this once. wslbak init mentions the option.
• A differential is <id>.diff.tar.gz: the files whose content or attributes changed since the full backup, and every directory. list has a column for the kind. restore, verify, files and restore --path take a differential like any other backup and put it together with its full backup; a whole distro is still restored with a single wsl --import, and folders brought back with restore --path have their own modification time.
• A differential is only kept when wslbak can account for every file: it is in the differential, or it is unchanged in the full backup, in a directory that is still the same directory. When it cannot, that run makes a full backup instead and says why. This happens after an old folder was renamed, moved or swapped with another, when a folder of the distro is mounted at a second place inside it, when the exclude list or the distro's tar changed, when the clock does not fit the full backup, and on a root file system other than ext4. It also happens when, while the backup runs, a file disappears from a folder the full backup has no record of, or an old folder disappears and a new one appears: a new folder cannot be told from an old one that came from a place the full backup did not cover, nor a rename from a deletion and a creation; the reason given for these is that files or folders came and went while the backup ran. wslbak status shows whether the last backup was a differential and, if not, the reason.
• A full backup is test-restored after every run, as before. A differential is read back and checked after every run, and test-restored together with its full backup for the first differential of each full backup and every seven days; wslbak verify always does the real test restore. With test restores switched off (--verify none, or --no-verify for one run) a differential is not checked at all.
• A full backup is never deleted while a differential that passed its check still needs it. Otherwise retention counts every backup, full or differential, as one.
• Full backups are the same archives as before, and 0.1.x can list, test-restore and restore them. 0.1.x does not show differentials, and deletes nothing in a folder that holds them. It refuses a settings file in which differential backups are switched on ("written by a newer version"), until wslbak config --mode full of this version has switched them off again; the copy of the program in the backup folder needs no settings file to restore. Installing 0.1.x again does not by itself change the program the scheduled task runs (an older version leaves a newer copy in place; wslbak init of the older version replaces it), and 0.1.x deletes old backups again only once the differentials are gone from the folder. When 0.1.x deletes a full backup that was made in differential mode, the small <id>.dirs.gz next to it stays behind, and a --full-every setting is lost the first time 0.1.x writes the settings.
• With differential backups on, a run writes a temporary file inside the distro for each list it makes (one to three, one at a time): tar's list of directories and file names, under /run, or /dev/shm where /run is not kept in memory, so not on the distro's disk; it is removed when it has been read. Without differential backups a backup still writes nothing inside the distro.
• A test restore no longer fails over the distro's host name. WSL writes /etc/hostname every time it starts a distro, and in the temporary copy it writes the PC's name, because the copy does not get the hostname setting of the distro's wsl.conf. On a distro with a host name of its own the file then differed from the backup whenever it was among the files picked for comparison: once in a great while for a full backup, and nearly every time for a differential, which compares all of its files when there are fewer than 512. It is no longer compared, and where it is a symbolic link (NixOS keeps it in /nix/store) a difference in the file behind the link is not counted either. Found on NixOS, whose wsl.conf sets a host name.
• A scheduled run that finds another wslbak still there after 20 hours now fails (exit code 2) and notifies you that it has been running for that many hours. A run started by hand says so too. This catches a wslbak that was started by hand and never ended, a window left at a question included; a run started by the schedule is ended by Windows after 12 hours, without a notification. The time this goes by is written into the lock file while a wslbak runs and removed when it ends, so that a 0.1.x holding the lock later is not taken for a stuck run.
• A backup that receives nothing from the distro at all is given up after ten minutes, like one whose data stops later. Until now the wait for the beginning of the archive had no limit, so a WSL that did not answer when the backup started left wslbak waiting until Windows ended the task.
• When a WSL command can neither finish nor be ended (which can happen when WSL as a whole stops answering), wslbak stops waiting about half a minute after the command's time limit and reports the failure, instead of waiting for ever. This includes the backup itself and the listing of names, where wslbak now gives up reading from a command that will not end.
• An error that tar reports after more than a thousand harmless messages is no longer overlooked. Only the first thousand lines were kept before the run was judged, so a read error behind them did not fail the backup.
• Files whose names are not valid UTF-8 are no longer among the files picked for comparison. Such a name cannot be written into the backup's record unchanged, so a later wslbak verify looked for a file that does not exist, failed, and marked a good backup as failed. Records that already hold such a name are tolerated.
• With test restores switched off and notifications set to always, the notification no longer says that the backup passed its test restore. wslbak status says "test restore or check" when a differential only got the lighter check, and run --dry-run says that the differential would be read back and checked.
• Inside WSL, when Windows programs cannot be started (interop switched off, or its kernel setting removed by another distro that shut down), the npm launcher now says so and how to put it back. On most distros it printed the shell's complaints about the bytes of the executable instead.
• The message about a settings file from a newer version is now in both languages and says what to do, and a scheduled run that cannot load its settings leaves a line in the log.
• The executables in the npm package are marked executable again. In 0.1.1 they were not; inside WSL the launcher then sets the mode itself on every run, which it cannot do when the package was installed with sudo, so it stopped and asked for a chmod by hand.
• The README says where to report a problem, with a link, and how to update; package.json gives the bug tracker in the form that package scanners recognise.
• The Traditional Chinese README is now README-zh-TW.md. With two files named README.*, npm showed one or the other on the package page depending on the machine that published, and the page of 0.1.1 came out in Chinese only. It now shows the English README, which links to the Chinese one.
• The tour at the top of the README was recorded again with this version, and now shows a differential backup as well.
• The README says what was seen with Avast's sandbox (a second, isolated copy of the program that sends a failure notification of its own; WSL no longer starting Windows programs), and what was found about GitHub's test machines that stopped answering with Microsoft Defender switched on.

Full Changelog: v0.1.1...v0.2.0

v0.1.1

Full Changelog: v0.1.0...v0.1.1

v0.1.0

Full Changelog: https://github.com/Boring206/wslbak/commits/v0.1.0