git.stella-ops.org/tests/supply-chain/02-schema-fuzz/run_mutations.py

#!/usr/bin/env python3
"""Schema-aware deterministic mutation lane for supply-chain fixtures."""

from __future__ import annotations

import argparse
import json
import pathlib
import random
import sys
import time
import unicodedata
from typing import Callable

TOOLS_DIR = pathlib.Path(__file__).resolve().parents[1] / "tools"
sys.path.insert(0, str(TOOLS_DIR))

from canonicalize_json import DuplicateKeyError, canonicalize_text, parse_json_strict  # noqa: E402
from emit_artifacts import TestCaseResult, record_failure, write_junit  # noqa: E402

MutationFn = Callable[[str], str]


def _truncate_payload(text: str) -> str:
    return text[:-1] if text else text


def _append_garbage(text: str) -> str:
    return text + " !!!"


def _inject_duplicate_key(text: str) -> str:
    if text.lstrip().startswith("{"):
        return text.replace("{", '{"bomFormat":"CycloneDX","bomFormat":"CycloneDX",', 1)
    return text


def _unicode_normalization_toggle(text: str) -> str:
    return unicodedata.normalize("NFD", text)


def _reorder_known_keys(text: str) -> str:
    parsed = parse_json_strict(text)
    if isinstance(parsed, dict):
        reordered = {k: parsed[k] for k in sorted(parsed.keys(), reverse=True)}
        return json.dumps(reordered, ensure_ascii=False, indent=2)
    return text


MUTATORS: list[tuple[str, MutationFn]] = [
    ("truncate", _truncate_payload),
    ("append_garbage", _append_garbage),
    ("duplicate_key", _inject_duplicate_key),
    ("unicode_nfd", _unicode_normalization_toggle),
    ("reorder_keys", _reorder_known_keys),
]


def _load_inputs() -> list[tuple[str, str]]:
    root = pathlib.Path(__file__).resolve().parents[1] / "05-corpus" / "fixtures"
    files = sorted(path for path in root.rglob("*.json") if "malformed" not in path.parts)
    return [(path.name, path.read_text(encoding="utf-8")) for path in files]


def main() -> int:
    parser = argparse.ArgumentParser(description="Run deterministic schema mutation lane.")
    parser.add_argument("--seed", type=int, default=20260226)
    parser.add_argument("--limit", type=int, default=1000)
    parser.add_argument("--time-seconds", type=int, default=60)
    parser.add_argument(
        "--output",
        type=pathlib.Path,
        default=pathlib.Path("out/supply-chain/02-schema-fuzz"),
    )
    args = parser.parse_args()

    rng = random.Random(args.seed)
    output = args.output.resolve()
    output.mkdir(parents=True, exist_ok=True)
    mutated_dir = output / "corpus" / "mutated"
    mutated_dir.mkdir(parents=True, exist_ok=True)

    fixture_inputs = _load_inputs()
    if not fixture_inputs:
        raise SystemExit("No mutation inputs found")

    start = time.perf_counter()
    counts = {
        "accepted": 0,
        "rejected_invalid_json": 0,
        "rejected_duplicate_keys": 0,
        "crash": 0,
    }

    lane_case_results: list[TestCaseResult] = []
    mutation_records: list[dict[str, str | int]] = []

    executed = 0
    while executed < args.limit and (time.perf_counter() - start) < args.time_seconds:
        fixture_name, payload = fixture_inputs[executed % len(fixture_inputs)]
        mutator_name, mutator = MUTATORS[rng.randrange(0, len(MUTATORS))]
        case_id = f"{executed:05d}-{fixture_name}-{mutator_name}"
        case_start = time.perf_counter()

        try:
            mutated = mutator(payload)
            canonicalize_text(mutated)
            counts["accepted"] += 1
            lane_case_results.append(
                TestCaseResult(
                    suite="02-schema-fuzz",
                    name=case_id,
                    passed=True,
                    duration_seconds=time.perf_counter() - case_start,
                )
            )
        except DuplicateKeyError as exc:
            mutated = mutator(payload)
            counts["rejected_duplicate_keys"] += 1
            lane_case_results.append(
                TestCaseResult(
                    suite="02-schema-fuzz",
                    name=case_id,
                    passed=True,
                    duration_seconds=time.perf_counter() - case_start,
                )
            )
            mutation_records.append(
                {"caseId": case_id, "result": "rejected_duplicate_keys", "reason": str(exc)}
            )
        except json.JSONDecodeError as exc:
            mutated = mutator(payload)
            counts["rejected_invalid_json"] += 1
            lane_case_results.append(
                TestCaseResult(
                    suite="02-schema-fuzz",
                    name=case_id,
                    passed=True,
                    duration_seconds=time.perf_counter() - case_start,
                )
            )
            mutation_records.append(
                {"caseId": case_id, "result": "rejected_invalid_json", "reason": str(exc)}
            )
        except Exception as exc:  # noqa: BLE001
            mutated = mutator(payload)
            counts["crash"] += 1
            record_failure(
                lane_output_dir=output,
                case_id=case_id,
                seed=args.seed,
                payload_text=mutated,
                error_class="mutation_lane_crash",
                message=str(exc),
                details={
                    "fixture": fixture_name,
                    "mutator": mutator_name,
                },
                canonical_diff_patch=None,
            )
            lane_case_results.append(
                TestCaseResult(
                    suite="02-schema-fuzz",
                    name=case_id,
                    passed=False,
                    duration_seconds=time.perf_counter() - case_start,
                    failure_message=str(exc),
                )
            )

        if executed < 50:
            mutated_path = mutated_dir / f"{executed:05d}-{mutator_name}.json"
            mutated_path.write_text(mutated, encoding="utf-8", newline="\n")
        executed += 1

    report = {
        "seed": args.seed,
        "executed": executed,
        "limit": args.limit,
        "timeBudgetSeconds": args.time_seconds,
        "durationSeconds": round(time.perf_counter() - start, 4),
        "counts": counts,
        "machineReadableErrorClasses": sorted(
            {
                "invalid_json",
                "duplicate_key",
                "mutation_lane_crash",
            }
        ),
        "records": mutation_records,
    }
    (output / "report.json").write_text(json.dumps(report, sort_keys=True, indent=2) + "\n", encoding="utf-8")
    write_junit(output / "junit.xml", lane_case_results)

    repro = (
        "# Repro Playbook\n\n"
        f"- Seed: `{args.seed}`\n"
        f"- Executed mutations: `{executed}`\n"
        "- Replay command:\n"
        f"  - `python tests/supply-chain/02-schema-fuzz/run_mutations.py --seed {args.seed} --limit {executed} --time-seconds {args.time_seconds}`\n"
    )
    (output / "repro_playbook.md").write_text(repro, encoding="utf-8", newline="\n")

    return 0 if counts["crash"] == 0 else 1


if __name__ == "__main__":
    raise SystemExit(main())