Bug#1010173: git: "git pull" fails with "fatal: commit-graph requires overflow generation data but has none"

[Norbert Kiesel]

Package: git
Version: 1:2.36.0-1
Severity: important
X-Debbugs-Cc: n...@iname.com

Dear Maintainer,

after upgrading Git, I cannot pull anymore because I always get the above erro
message.

I run a daily "git show-ref -s | git commit-graph write --stdin-commits
--changed-path --no-progress" in that repo.
For repos where I do not run this command, `git pull` continues to work. I
tried to "shrink" the commit graph using
`git commit-graph write --stdin-commits --changed-path --no-progress <
/dev/null` but while this did not produce any
error, it also did not fix my problem.


-- System Information:
Debian Release: bookworm/sid
APT prefers unstable
APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.17.0-1-amd64 (SMP w/8 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages git depends on:
ii git-man 1:2.36.0-1
ii libc6 2.33-7
ii libcurl3-gnutls 7.82.0-2
ii liberror-perl 0.17029-1
ii libexpat1 2.4.8-1
ii libpcre2-8-0 10.39-4
ii perl 5.34.0-4
ii zlib1g 1:1.2.11.dfsg-4

Versions of packages git recommends:
ii ca-certificates 20211016
ii less 590-1
ii openssh-client [ssh-client] 1:9.0p1-1
ii patch 2.7.6-7

Versions of packages git suggests:
ii gettext-base 0.21-6
pn git-cvs <none>
pn git-daemon-run | git-daemon-sysvinit <none>
pn git-doc <none>
pn git-email <none>
pn git-gui <none>
pn git-mediawiki <none>
pn git-svn <none>
pn gitk <none>
pn gitweb <none>

-- no debconf information

[Norbert Kiesel]

After running `git config core.commitGraph false`, `git pull` works again. Thus, priority for this bug could be reduced.

[Jan Braun]

Hi,
for me, removing the commit graph cache with
rm -r .git/objects/info/commit-graph{,s}
and regenerating with
git commit-graph write
worked as well.
See here
https://lore.kernel.org/git/f50e74f0-9ffa-f4f2...@github.com/
for confirmation that it's indeed just a cache, and upstream noting that
git should be fixed to handle a corrupt cache better than dying.

HTH,
Jan