Test failure for git 2.30.1 and 2.34.1 due to GIT_EXEC_PATH

[typesanitizer]

When running tests locally from master using PATH_TO_GIT="$(which git)" cargo test, I'm seeing a failure for command::test_undo::test_git_bisect_produces_empty_event where bisect is not found.

A minimal reproducer for this is:

GIT_EXEC_PATH=/usr/bin git bisect -h

This fails with

git: 'bisect' is not a git command. See 'git --help'

It only fails for bisect, not other subcommands, so it seems like a Git bug, not a git-branchless bug.

With git 2.25.1, the test doesn't call bisect, so the test passes. With git 2.30.1 (AppleGit-130) on macOS, or 2.34.1 on Linux from, the test fails. Which makes sense, because that test only calls bisect for 2.29 or newer.

I see that the CI has recent Git versions in the build matrix here:

git-branchless/.github/workflows/linux.yml

Line 21 in b343a84

git-version: ["v2.24.3", "v2.29.2", "v2.31.1", "v2.33.1"]

It's unclear to me how this test is passing in CI but failing locally. I'm wondering if there is a difference between even-numbered versions (stable?) vs odd numbers (unstable?).

I'll try to investigate this further, but just putting it up here, in case anyone else hits the same issue.

[typesanitizer]

I built git 2.33.1 from source on Linux and it has this same issue when running GIT_EXEC_PATH=/usr/bin git bisect -h (and the tests). So it seems to be some other configuration difference between the CI and my local machines. 🤔

[arxanas]

If you built Git from source, you might want to set GIT_EXEC_PATH to the same directory the git executable lives in; I think there'll be a git bisect in there.

[typesanitizer]

I installed the locally built git to /usr/bin with make install, hence the same GIT_EXEC_PATH=/usr/bin.

[typesanitizer]

If I run GIT_EXEC_PATH=. git bisect -h (or ./git bisect -h) in the build directory, that works. Similarly, after installation, /usr/bin/git bisect -h works.

[arxanas]

GIT_EXEC_PATH generally won't be a path like /usr/bin. For example, this is the path on my system:

$ /usr/bin/git --exec-path
/Library/Developer/CommandLineTools/usr/libexec/git-core

My guess is that make install installs the Git helper tools somewhere other than /usr/bin.

If you run GIT_EXEC_PATH=. in the build directory, then it works because the helper tools happen to have been built in that directory.