Add missing git feature dep to preserve_executable_bit test

[mgorny]

Summary

Without the git feature, it fails with:

error: Failed to initialize Git repository at `/home/mgorny/.local/share/uv/tests/.tmp01wGGK/temp/preserve_executable_bit`
stdout:
stderr: error: `git` operations are not allowed — are you missing a cfg for the `git` feature?

Test Plan

cargo test --features python --profile=fast-build --no-default-features

[charliermarsh]

@konstin -- Do you know why this test uses Git? I think uv init is meant to be robust to a missing git.

[konstin]

We first check if we are in a git repository in uv init. If that fails, we fall back to assuming VCS defaults (init a git repo). We don't check the error condition, so both fatal: not a git repository (or any of the parent directories): .git and our git blocking shim cause this path. We then try to init a git repo, but in that case we only ignore a missing git installation, but fail at the git blocking shim.

Can we rely on errors such as not a git repository being stable? If so, we could differentiate between the two cases.

[charliermarsh]

But doesn't "init a Git repo" return VersionControlError::GitNotInstalled, which we explicitly handle?

[konstin]

Our shims put a git in PATH so we're falling in a gap where git is installed (which git find the git-not-allowed shim), but invoking git errors with the error seen above:

First we take the None-branch, since detecting an existing git repo errors (through the shim):

uv/crates/uv-configuration/src/vcs.rs

Line 97 in 0c801f8

None

But that was a check for an existing git repo, so we ignore it:

uv/crates/uv/src/commands/project/init.rs

Line 1203 in 42dcea0

(None, None) => VersionControlSystem::default(),

When we finally initialize the repo, we can run the git shim, but it errors on execution:

uv/crates/uv-configuration/src/vcs.rs

Line 52 in 0c801f8

if !output.status.success() {

If we want to handle this better, we should find a way to better tell apart "there is no git repo" (this is fine) from "git errored" (don't use git at all) in the first check.

[konstin]

I tried to make this more resilient: #12895