Use os.path.abspath for the cwd in commid_id.py os.path.realpath will resolve subst drives to the underlying path, which is inappropriate when the CWD is actually in the subst path. This causes os.path.relpath to fail due to a mismatched drive letter. Example mapping: D: -> S:\src\D E: -> S:\src\E Fixed: chromium:417529141 Change-Id: I70de53d511672dedf9cf2f77006526977b736526 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6546083 Auto-Submit: Robert Liao <robliao@chromium.org> Reviewed-by: Yuxin Hu <yuxinhu@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Yuxin Hu <yuxinhu@google.com>