I perform most of my Debian development work in unprivileged Incus
containers with ZFS for their underlying storage. In such setups,
several of desync's tests fail in a similar way:

  I'm unsure if the desync binary is also similarly broken when run in
an environment using ZFS storage. Performing the build in an identical
setup with ext4-backed storage works, so I'm not reporting this as an
RC bug.

Mathias

Hi Mathias,

... snip ...

I wonder how I could reproduce this ? I guess I could setup a virtual machine
with ZFS-backed storage. I've never played with ZFS, so not entirely sure what
I am talking about here really.

For completeness, can you confirm the version of ZFS you are using ? I assume it'll
be the latest zfs-dkms (2.4.2-2) ?

In any case, I've forwarded the bug upstream to see if they have any bright
ideas.

I guess one quick thing you could do is to try to run the latest upstream test
suite on ZFS and see if you get the same issue. That could rule out any upstream
fixes.

You could do that with the Go libraries the project specifies, that could rule out
any difference in library version as well.


Cheers!

Chris

Hello again,

I managed to setup a Debian Forky VM with a separate 20G qcow disk and format/mount it as ZFS. Wasn't too
much trouble.

But the test suite (built the package with gbp buildpackage on the VM directly) on both ext4 and ZFS
built and the tests ran fine.

I wonder if my ZFS setup isn't as "complicated" as yours ? Perhaps the VM adds some perfection into the mix ?


I created the filesystem with:

 $ zpool create tank /dev/vdb
 $ zfs set compression=zstd tank
 $ zfs create tank/build



Cheers!

Chris

Hello again,

It turns out upstream has found the root-cause, described it very well in the GitHub issue and fixed the issue
in https://github.com/folbricht/desync/pull/356

Once upstream releases a new version I will attempt to get it into Debian fairly quickly, or would you like it
sooner and for me to backport the patch ?


Thanks!

Chris

Hello,

So for completeness I managed to reproduce the issue with the same ZFS settings as upstream:

  echo 1 | sudo tee /sys/module/zfs/parameters/zfs_bclone_enabled
  sudo zfs set recordsize=128K tank/build


And I made double sure the build was done on that drive too:

  export TMPDIR=/tank/build/tmp
  mkdir -p "$TMPDIR"
  dpkg-buildpackage -us -uc -b

Upstream has released a new version with this fix; and it no longer FTBFS on ZFS for me ! I will upload it into the
archive soon.


Cheers!

Chris

We believe that the bug you reported is fixed in the latest version of
desync, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1137623@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Christopher Obbard <obbardc@debian.org> (supplier of updated desync package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Thu, 11 Jun 2026 09:26:26 +0100
Source: desync
Architecture: source
Version: 1.0.2-1
Distribution: unstable
Urgency: medium
Maintainer: Debian Go Packaging Team <team+pkg-go@tracker.debian.org>
Changed-By: Christopher Obbard <obbardc@debian.org>
Closes: 1137623
Changes:
 desync (1.0.2-1) unstable; urgency=medium
 .
   * New upstream version 1.0.2
     - Fixes broken behaviour on ZFS filesystems. (Closes: #1137623)
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 f183970e2dcbe91208829781bcaba59008a4e33b 3480 desync_1.0.2-1.debian.tar.xz
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Files:
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