| """Reject analysis caches whose inputs or implementation have changed.""" |
| import hashlib |
| import json |
| from pathlib import Path |
|
|
|
|
| def digest(path): |
| result = hashlib.sha256() |
| with Path(path).open('rb') as stream: |
| for block in iter(lambda: stream.read(1024 * 1024), b''): |
| result.update(block) |
| return result.hexdigest() |
|
|
|
|
| def provenance(inputs): |
| paths = [Path(path).resolve() for path in inputs] |
| paths.append(Path(__file__).resolve()) |
| return {str(path): digest(path) for path in sorted(set(paths))} |
|
|
|
|
| def verified_cache(path, inputs): |
| """An unverified legacy cache must be rebuilt in a new analysis directory. |
| |
| Fail closed rather than silently mixing a new recording with archived |
| arrays, split identities or reports. Never delete archived evidence here. |
| """ |
| path = Path(path) |
| if not path.exists(): |
| return False |
| manifest = Path(str(path) + '.provenance.json') |
| if manifest.exists(): |
| saved = json.loads(manifest.read_text()) |
| if (saved.get('inputs') == provenance(inputs) |
| and saved.get('cache_sha256') == digest(path)): |
| return True |
| raise ValueError( |
| f'Unverified or stale analysis cache: {path}. ' |
| 'Use a new analysis output directory and rebuild upstream stages; ' |
| 'retain the archived directory for reproducing previous reports.') |
|
|
|
|
| def record_cache(path, inputs): |
| path = Path(path) |
| manifest = Path(str(path) + '.provenance.json') |
| manifest.write_text(json.dumps( |
| {'inputs': provenance(inputs), 'cache_sha256': digest(path)}, |
| indent=2) + '\n') |
|
|
