git_repository() is sensitive to GIT_DIR

[rpwoodbu]

Description of the bug:

If GIT_DIR happens to be set, git_repository() may operate on the wrong clone. It is never useful for git_repository() to be influenced by these GIT_ variables.

It is notable that Git sets GIT_DIR and others when calling hooks. This complicates calling Bazel from within a hook (e.g., bazel test). In particular, when using Git worktrees, this can lead to core.bare = true being set, breaking the user's clone.

Which category does this issue belong to?

No response

What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

# MODULE.bazel
git_repository = use_repo_rule("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
git_repository(
    name = "foo",
    commit = "1bbb388780f6016b6981a2f075fb457e999bc3bd",
    remote = "https://github.com/bazelbuild/bazel-skylib.git",
)

# In your terminal:
export GIT_DIR=""
bazel clean --expunge
bazel query @foo//:all

Produces the following error:

Repository rule git_repository defined at:
  /var/tmp/rpwoodbu/.cache/bazel/bc5487f033a0af65dff1ff0bd4000d75/external/bazel_tools/tools/build_defs/repo/git.bzl:189:33: in <toplevel>
ERROR: /var/tmp/rpwoodbu/.cache/bazel/bc5487f033a0af65dff1ff0bd4000d75/external/bazel_tools/tools/build_defs/repo/git_worker.bzl:210:9: An error occurred during the fetch of repository '_main~_repo_rules~foo':
   Traceback (most recent call last):
        File "/var/tmp/rpwoodbu/.cache/bazel/bc5487f033a0af65dff1ff0bd4000d75/external/bazel_tools/tools/build_defs/repo/git.bzl", line 180, column 35, in _git_repository_implementation
                update = _clone_or_update_repo(ctx)
        File "/var/tmp/rpwoodbu/.cache/bazel/bc5487f033a0af65dff1ff0bd4000d75/external/bazel_tools/tools/build_defs/repo/git.bzl", line 43, column 20, in _clone_or_update_repo
                git_ = git_repo(ctx, directory)
        File "/var/tmp/rpwoodbu/.cache/bazel/bc5487f033a0af65dff1ff0bd4000d75/external/bazel_tools/tools/build_defs/repo/git_worker.bzl", line 98, column 12, in git_repo
                _update(ctx, git_repo)
        File "/var/tmp/rpwoodbu/.cache/bazel/bc5487f033a0af65dff1ff0bd4000d75/external/bazel_tools/tools/build_defs/repo/git_worker.bzl", line 114, column 9, in _update
                init(ctx, git_repo)
        File "/var/tmp/rpwoodbu/.cache/bazel/bc5487f033a0af65dff1ff0bd4000d75/external/bazel_tools/tools/build_defs/repo/git_worker.bzl", line 131, column 15, in init
                _error(ctx.name, cl, st.stderr)
        File "/var/tmp/rpwoodbu/.cache/bazel/bc5487f033a0af65dff1ff0bd4000d75/external/bazel_tools/tools/build_defs/repo/git_worker.bzl", line 210, column 9, in _error
                fail("error running '%s' while working with @%s:\n%s" % (command_text, name, stderr))
Error in fail: error running 'git init /var/tmp/rpwoodbu/.cache/bazel/bc5487f033a0af65dff1ff0bd4000d75/external/_main~_repo_rules~foo' while working with @_main~_repo_rules~foo:
fatal: The empty string is not a valid path

Which operating system are you running Bazel on?

Debian Linux

What is the output of bazel info release?

release 7.4.0

If bazel info release returns development version or (@non-git), tell us how you built Bazel.

No response

What's the output of git remote get-url origin; git rev-parse HEAD ?

No response

If this is a regression, please try to identify the Bazel commit where the bug was introduced with bazelisk --bisect.

No response

Have you found anything relevant by searching the web?

No response

Any other information, logs, or outputs that you want to share?

No response

[iancha1992]

A fix for this issue has been included in Bazel 8.0.0 RC3. Please test out the release candidate and report any issues as soon as possible.
If you're using Bazelisk, you can point to the latest RC by setting USE_BAZEL_VERSION=8.0.0rc3. Thanks!