Using the precompiled git-annex distribution, I have encountered a problem which looks like this:

git -c foo.bar=baz annex sync
error: bogus format in GIT_CONFIG_PARAMETERS
fatal: unable to parse command-line config
git-annex: user error (git ["config","--null","--list"] exited 128)

I believe I understand what is causing this, and it's not a bug with git-annex. But I thought it would be worth reporting here in case anyone else encounters similar issues in the future.

On my system I have three different git installations:

• The one in /usr/bin/git etc. provided by the distribution package (version 2.28.0)
• One I've compiled myself in my home directory from a recent upstream master, accessible via ~/bin/git (version 2.30.1.490.ge54fde04c8.dirty)
• The one embedded in the git-annex bundle obtained from the above link, which I've put under ~/software/scm/git-annex.static/ (~/software/scm/git-annex.static/shimmed/git/git --version reports version 2.30.1)

Normally ~/bin is near the front of my $PATH, so my hand-compiled git is used whenever I run git some-command. If I place the following executable script at ~/bin/git-show-config-params:

#!/bin/sh
echo "$GIT_CONFIG_PARAMETERS"

then it can be seen there's a difference between the versions in how GIT_CONFIG_PARAMETERS is constructed:

% ~/bin/git -c foo.bar=baz show-config-params
'foo.bar'='baz'
% /usr/bin/git -c foo.bar=baz show-config-params
'foo.bar=baz'
% ~/software/scm/git-annex.static/shimmed/git/git -c foo.bar=baz show-config-params
'foo.bar=baz'

This appears to be due to commit 294e949fa from 2021-01-25 which first appeared in the tag v2.31.0-rc0.

This commit is also required in order to successfully parse the new format:

% GIT_CONFIG_PARAMETERS="'foo.bar'='baz'" ~/software/scm/git-annex.static/shimmed/git/git branch
error: bogus format in GIT_CONFIG_PARAMETERS
fatal: unable to parse command-line config
% GIT_CONFIG_PARAMETERS="'foo.bar'='baz'" /usr/bin/git branch
error: bogus format in GIT_CONFIG_PARAMETERS
fatal: unable to parse command-line config
% GIT_CONFIG_PARAMETERS="'foo.bar'='baz'" ~/bin/git branch
  git-annex
* master
  synced/git-annex
  synced/master

So now we can fully understand the cause: when I run

git -c foo.bar=baz annex sync

it first invokes the newer hand-compiled git with this patch, resulting in GIT_CONFIG_PARAMETERS being set to 'foo.bar'='baz'. That environment variable is then passed through various wrappers to ~/software/scm/git-annex.static/shimmed/git/git, which does not know how to parse the new format, hence the bogus format error.

The solution is to avoid using the newer development version of git as the "outer" git, since it's not backwards compatible in this respect. If the two versions were switched around, i.e. the older one setting GIT_CONFIG_PARAMETERS and the newer parsing it, that would have worked fine, but of course that's not how the git annex wrapper system works.