_diff_system reached complexity 42, and its hash-based rename fallback
is the part that stands alone: a platform is free to call a file
whatever it likes, so a name matching nothing is not yet a gap, and
counting one file as both missing and extra invents a discrepancy.
That step is now its own function at complexity 31, with the tests it
never had: pairing on any of the three digests, case folding, non-string
values, and the case where two files simply have no hashes and so are
not evidence of anything. diff_truth output is unchanged.
Run ruff check --fix: remove unused imports (F401), fix f-strings
without placeholders (F541), remove unused variables (F841), fix
duplicate dict key (F601).
Run isort --profile black: normalize import ordering across all files.
Run ruff format: apply consistent formatting (black-compatible) to
all 58 Python files.
3 intentional E402 remain (imports after require_yaml() must execute
after yaml is available).
Abdessamad Derraz