Reverse-check alone can theoretically succeed via git-apply fuzz when the file carries the postimage at another location, so treating it as sufficient risked silently dropping a task patch whose intended hunk still needed to run.
Required both `--reverse --check` to succeed AND forward `--check` to fail before declaring a no-op. When both check directions succeed (ambiguous), the merge falls through to a forward apply instead of skipping — mirroring the pre-idempotence behavior. Both checks are read-only, so no worktree writes on ambiguity.
Added a spy-based regression that forces the ambiguous case and asserts the merge applies forward instead of silently dropping the change.
roboomp
cd692bcb02