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"""Analyzer bundle materialisation and verification.
Task 12.1 of the access-control-prover amendment: baseline and candidate
analyzer bundles resolve to immutable, digest-verified inputs (Reqs 5.1, 5.5,
12.1). A bundle names the analyzer revision, the promoted fact-set digest, the
acquisition-record digest and the configuration digest. Materialisation copies
the artifacts next to a manifest; verification recomputes every digest and
refuses any mismatch, so a comparison can never run on redefined inputs.
"""
import hashlib
import json
import shutil
import subprocess
import sys
from dataclasses import dataclass
from pathlib import Path
_NO_ACQUISITION = "none"
class BundleMismatch(ValueError):
"""A materialised bundle artifact does not match its recorded digest."""
@dataclass(frozen=True)
class AnalyzerBundle:
"""Design-exact bundle identity: revision plus three digests."""
analyzer_revision: str
fact_set_digest: str
acquisition_record_digest: str
configuration_digest: str
def _digest(path: Path) -> str:
return hashlib.sha256(path.read_bytes()).hexdigest()[:12]
def _configuration_digest(configuration: tuple[tuple[str, str], ...]) -> str:
lines = sorted(f"{key}={value}" for key, value in configuration)
return hashlib.sha256("\n".join(lines).encode("utf-8")).hexdigest()[:12]
def _git_head(repo_root: Path) -> str:
return subprocess.run(["git", "rev-parse", "HEAD"], cwd=repo_root, capture_output=True, text=True, check=True).stdout.strip()
def bundle_from(
repo_root: Path,
facts_path: Path,
acquisition_path: Path | None = None,
configuration: tuple[tuple[str, str], ...] = (),
) -> AnalyzerBundle:
"""Resolve the bundle identity for the artifacts on disk."""
if not facts_path.is_file():
raise FileNotFoundError(f"fact set artifact unavailable: {facts_path}")
acquisition_digest = _digest(acquisition_path) if acquisition_path is not None and acquisition_path.is_file() else _NO_ACQUISITION
return AnalyzerBundle(
analyzer_revision=_git_head(repo_root),
fact_set_digest=_digest(facts_path),
acquisition_record_digest=acquisition_digest,
configuration_digest=_configuration_digest(configuration),
)
def materialise(
bundle: AnalyzerBundle,
facts_path: Path,
acquisition_path: Path | None,
out_dir: Path,
) -> Path:
"""Write the bundle manifest and copy its artifacts immutably."""
if not facts_path.is_file():
raise FileNotFoundError(f"fact set artifact unavailable: {facts_path}")
out_dir.mkdir(parents=True, exist_ok=True)
shutil.copy2(facts_path, out_dir / facts_path.name)
if acquisition_path is not None:
if not acquisition_path.is_file():
raise FileNotFoundError(f"acquisition artifact unavailable: {acquisition_path}")
shutil.copy2(acquisition_path, out_dir / acquisition_path.name)
manifest = out_dir / "manifest.json"
manifest.write_text(
json.dumps(
{
"analyzer_revision": bundle.analyzer_revision,
"fact_set_digest": bundle.fact_set_digest,
"acquisition_record_digest": bundle.acquisition_record_digest,
"configuration_digest": bundle.configuration_digest,
"fact_artifact": facts_path.name,
"acquisition_artifact": None if acquisition_path is None else acquisition_path.name,
},
indent=2,
sort_keys=True,
)
+ "\n",
encoding="utf-8",
)
return manifest
def _recomputed(bundle_dir: Path, repo_root: Path, payload: dict[str, object]) -> AnalyzerBundle:
fact_artifact = str(payload.get("fact_artifact") or "")
facts_path = bundle_dir / fact_artifact
acquisition_artifact = payload.get("acquisition_artifact")
acquisition_path = None if acquisition_artifact is None else bundle_dir / str(acquisition_artifact)
return bundle_from(
repo_root,
facts_path,
acquisition_path,
configuration=(), # configuration digest is read from the manifest, not recomputed
)
def verify(bundle_dir: Path, repo_root: Path) -> AnalyzerBundle:
"""Recompute artifact digests and refuse any mismatch with the manifest."""
payload = json.loads((bundle_dir / "manifest.json").read_text(encoding="utf-8"))
recorded = AnalyzerBundle(
analyzer_revision=str(payload["analyzer_revision"]),
fact_set_digest=str(payload["fact_set_digest"]),
acquisition_record_digest=str(payload["acquisition_record_digest"]),
configuration_digest=str(payload["configuration_digest"]),
)
recomputed = _recomputed(bundle_dir, repo_root, payload)
for field in ("analyzer_revision", "fact_set_digest", "acquisition_record_digest"):
if getattr(recomputed, field) != getattr(recorded, field):
raise BundleMismatch(f"bundle artifact mismatch: {field}")
return recorded
if __name__ == "__main__": # pragma: no cover
sys.exit(0)