Summary

This PR introduces xfail_if_raises, a context manager that approximates @pytest.mark.xfail(..., raises=...) behavior inside a test body rather than as a decorator.

Problem

@pytest.mark.xfail evaluates its condition argument during test collection (module import time). In test_index_mutation, this condition includes Git().config("core.symlinks") == "true", which:

1. Spawns an external git config process even when the test is not being run
2. Can fail or behave unexpectedly during collection if git configuration is unavailable
3. Relies on in-repo code during test discovery, which may not be appropriate in all contexts

Solution

xfail_if_raises moves the xfail logic into the test body. The side-effectful condition is only evaluated if the test actually raises the specified exception(s). This keeps test collection lightweight and avoids relying on in-repo code as part of module import/test discovery.

This change is applied to test_index_mutation in test/test_index.py.

AI disclosure

This PR description was prepared with assistance from an agent. All code was written by hand.