feat(pre-push-safety-net): validate graph identity and isolated leases

.kiro/specs/pre-push-safety-net/design.md

@@ -265,6 +265,21 @@ results. A query/fact change invalidates its answers without automatically rebui
 input/frontend/overlay semantics are unchanged. This supports iteration on the core as well as
 repeated push checks; it does not authorize reusing stale evidence after a source change.
 
+Preparation is also a reusable artifact boundary. Task 5.2 measured PMPro exhausting
+30 seconds after materialization and before graph construction. Cache complete discovery
+by immutable source tree identity plus discovery code, shipping/layout facts and configuration;
+retain snapshot readability proofs and declaration/boundary records. Reuse must preserve
+repository-relative locations and must never deserialize repository-controlled executable objects.
+Measure preparation, graph and query hits separately. An identical-tip hit demonstrates reuse,
+not representative changed-code latency. Dependency/configuration changes invalidate affected
+preparation and graph/query context even when an individual source file is unchanged.
+
+Rollout approval remains an evidence decision under Requirement 6.5 and evaluation.md.
+Group 6 establishes correctness and bounded reuse; group 8 must still demonstrate the joint
+changed-code latency, completion, precision and recall gates on declared populations. Missing
+independent positive/fixed/benign populations or an empty capability registry cannot yield GO.
+No threshold, population denominator or alert eligibility rule is relaxed by this amendment.
+
 Only validated, complete artifacts can satisfy complete-result lookups. Partial artifacts may be
 retained for diagnostics but never promoted by cache presence. Publish atomically from private
 temporary paths under a per-key lock; another push may wait only within its deadline. Apply a

.kiro/specs/pre-push-safety-net/implementation-group-6.md

@@ -0,0 +1,39 @@
+# Group 6 implementation and verification
+
+The maintainer authorized 6.1–6.4 together on 2026-09-13. A fresh implementer dispatch
+failed with `agent thread limit reached`; the explicit kiro-impl manual fallback applies.
+Reviews below are main-context adversarial reviews, not independent reviewer evidence.
+The design amendment makes measured preparation/discovery costs explicit. Rollout gates
+and the empty default capability registry are unchanged.
+
+## Task 6.1 brief
+
+Requirements 4.2, 4.3, 4.4 and 7.3; design: Cache and Engine Boundary.
+Backend-owned identities bind readable source paths/bytes, declarations, exclusions,
+frontend/engine versions, overlay implementation and options. Complete graphs require a
+named source census, methods, calls and the dataflow overlay. Loading checks identity and
+streamed graph digest, then issues a disposable copy through the existing CpgResult driver
+contract. Old structural manifests without source paths cannot qualify. Sharded or partial
+graphs cannot qualify. Query locations normalize to repository-relative paths.
+
+## Status Report
+- STATUS: READY_FOR_REVIEW
+- TASK: 6.1
+- RED_PHASE_OUTPUT: `/tmp/group6-1-red.log` and `/tmp/group6-1-flag-off.log`: four failures before implementation/with the temporary switch OFF. ON passed; switch removed and five final tests passed.
+- TESTS_RUN: 105 focused tests passed; full suite 1246 passed, 9 skipped (105.31s), followed by the final additional driver integration test and focused rerun. Ruff and mypy passed.
+- EVIDENCE: source-mounted nonroot Docker Joern 4.0.625, network disabled, 3 GiB limit: read 45 JavaScript bytes, census 1 file/4 methods/3 calls, sealed graph loaded through a disposable lease, original digest unchanged after query and cleanup. This is a correctness control, not a latency benchmark.
+- CONCERNS: persistent publication and runner selection belong to 6.2–6.4; this task provides the validated backend lease contract. Main-context review fallback.
+
+## Review Verdict
+- VERDICT: APPROVED
+- TASK: 6.1
+- MECHANICAL_RESULTS: focused tests, full regression suite, ruff, mypy and diff whitespace checks passed; no introduced placeholders or secrets.
+- FINDINGS: review repaired unbounded full-graph buffering to streamed hashing/copy; unreadable source walks fail explicitly; single PHP graph census passes through unchanged while sharded graphs cannot seal. Existing driver accepts and releases the leased CpgResult.
+- SUMMARY: Backend identity and isolated leases satisfy task 6.1 within the approved boundary.
+
+## Verification Result
+- STATUS: VERIFIED
+- CLAIM_TYPE: TASK
+- CLAIM: Task 6.1 identity and lease behavior, not persistent runner reuse or rollout readiness.
+- EVIDENCE: tests/test_graph_reuse.py, 105 focused passing tests, full suite and real Joern control above; measurement JSON retained in benchmarks/measurements/2026-09-13-graph-lease-control.json.
+- GAPS: Warm push feasibility and independent capability eligibility remain unproven.

.kiro/specs/pre-push-safety-net/spec.json

@@ -65,6 +65,11 @@
       "at": "2026-09-13T12:40:57.961577+00:00",
       "source": "approved",
       "action": "Authorized group 5 after the group 4 completion summary: explicit transaction replay, then the first PMPro/frozen-core Node experiment. Review and fresh evidence remain required."
+    },
+    {
+      "at": "2026-09-13T13:58:52.336506+00:00",
+      "source": "continue with group 6 as a whole. do we need to amend the spec to get a go for the rollout",
+      "action": "Authorized group 6 (6.1\u20136.4). Clarified complete preparation/discovery reuse after measured group 5 bottleneck; rollout gates remain unchanged. Manual Kiro review fallback remains necessary after a fresh agent dispatch hit the thread limit."
     }
   ],
   "task_review": {

.kiro/specs/pre-push-safety-net/tasks.md

@@ -161,7 +161,7 @@ hook latency is admitted.
   - _Requirements: 6.2, 6.3, 6.4, 6.5, 8.1, 8.2, 8.3, 8.4_
 
 - [ ] 6. Reuse valid graphs and results without stale conclusions
-- [ ] 6.1 Validate graph artifact identity and leases
+- [x] 6.1 Validate graph artifact identity and leases
   - Have the backend own source/declaration/exclusion digests, frontend/engine/overlay options, graph census and complete/partial identity.
   - Permit validated graph leases in the generic driver while preserving the fresh-build path; isolate potentially mutating loads and retain bounded cleanup.
   - Done when identical valid inputs can reuse a graph while any changed graph input or failed census rejects the lease; original cached artifacts survive query loading unchanged.
@@ -181,6 +181,7 @@ hook latency is admitted.
   - _Boundary: Push cache, policy integration_
   - _Requirements: 3.4, 4.3, 4.4, 6.4, 7.2, 7.3_
 - [ ] 6.4 Integrate cache reuse into the shared push deadline
+  - Reuse complete preparation/discovery by immutable tree and discovery/fact/configuration identity, retaining readable snapshot and declaration/boundary records; measure its costs and hits separately from graph/query reuse.
   - Reuse identical snapshots/unchanged declared units across refs without merging different comparisons; changed units rebuild and stale graph relationships remain hints only.
   - Account for lookup, lock wait, lease, build/query and result persistence in the same deadline; preserve completed outcomes on cancellation.
   - Done when cached and uncached replay produce equal evidence/admission for the same completed questions under compatible semantics, with full equivalence under a sufficiently large controlled budget. Under the hook deadline, verify truthful extra completion/deferred scope from cache reuse rather than requiring identical scope; no stale answer survives a dependency/configuration edit.

benchmarks/measurements/2026-09-13-graph-lease-control.json

@@ -0,0 +1,59 @@
+{
+  "source_bytes": 45,
+  "artifact": {
+    "identity": {
+      "source_digest": "aab4a6878883db96c5eb1d0dd98e160e30d16fa2b215735bdac6ff5a41f9783d",
+      "declarations_digest": "none",
+      "exclusions_digest": "none",
+      "unit": "repository",
+      "language": "javascript",
+      "engine_version": "4.0.625",
+      "frontend": "jssrc2cpg",
+      "frontend_version": "4.0.625",
+      "overlay_semantics": [
+        "dataflowOss"
+      ],
+      "overlay_options": [
+        [
+          "implementation",
+          "96d0a93a3edb7e4a999a380b5823cd6d593ae2a49cf2a503f923483eda43989a"
+        ]
+      ],
+      "frontend_options": [
+        [
+          "include_tests",
+          "True"
+        ],
+        [
+          "java_options",
+          "default"
+        ]
+      ]
+    },
+    "graph_digest": "a02bef8f7d4d1f2c420cb9bb4c5cc9df2fe86d86ad4e429021c95ad76a996873",
+    "source_bytes": 45,
+    "census": {
+      "files": 1,
+      "methods": 4,
+      "calls": 3
+    },
+    "completeness": "complete",
+    "diagnostics": [],
+    "source_root": "/tmp/tmpb4ff84v8",
+    "source_paths": [
+      "a.js"
+    ]
+  },
+  "lease_census": {
+    "files": "1",
+    "methods": "4",
+    "calls": "3",
+    "file_names": [
+      "a.js"
+    ],
+    "overlays": "base,controlflow,typerel,callgraph,dataflowOss",
+    "maxHeapMB": "2048"
+  },
+  "original_unchanged": true,
+  "execution": "source-mounted openultrasast:dev image 7f71174daa9e; nonroot, network none, memory 3g; correctness control, not latency"
+}

src/openultrasast/cpg/artifact.py

@@ -1,7 +1,7 @@
 """Backend-owned graph provenance and live resource boundary (pre-push Req 4.3, 7.3).
 
-Structural validity is necessary but insufficient for reuse. Task 6.1 will validate
-actual source bytes, graph digest/census and engine compatibility before issuing leases.
+Structural manifests carry provenance; the backend reads source bytes and seals a named
+graph census, then verifies graph bytes and compatibility before issuing isolated leases.
 """
 
 from __future__ import annotations
@@ -54,6 +54,8 @@ class GraphArtifact(Contract):
     census: GraphCensus
     completeness: Literal["complete", "partial"]
     diagnostics: tuple[str, ...]
+    source_root: str = "relative"
+    source_paths: tuple[str, ...] = ()
 
     def __post_init__(self) -> None:
         super().__post_init__()
@@ -71,7 +73,7 @@ class GraphLease(Protocol):
     The backend validates the artifact before issuing the lease and isolates loading
     when it may mutate graph bytes. The consumer owns releasing it exactly once; the
     backend's release is idempotent and bounded by the supplied monotonic deadline.
-    A cached artifact survives release. Implementations belong to task 6.1.
+    A cached artifact survives release.
     """
 
     @property
@@ -81,3 +83,108 @@ class GraphLease(Protocol):
     def path(self) -> Path: ...
 
     def close(self, *, deadline_monotonic: float) -> None: ...
+
+
+def digest_value(value: object) -> str:
+    import hashlib
+    import json
+
+    return hashlib.sha256(json.dumps(value, sort_keys=True, separators=(",", ":"), ensure_ascii=True).encode()).hexdigest()
+
+
+def read_bytes(path: Path, deadline: float) -> bytes:
+    """Read a regular local file without following a substituted final symlink."""
+    import os
+    import stat
+    import time
+
+    chunks: list[bytes] = []
+    fd = os.open(path, os.O_RDONLY | os.O_NOFOLLOW | os.O_NONBLOCK)
+    with os.fdopen(fd, "rb") as stream:
+        if not stat.S_ISREG(os.fstat(stream.fileno()).st_mode):
+            raise ValueError("artifact_not_regular")
+        while True:
+            if time.monotonic() >= deadline:
+                raise TimeoutError("deadline_exhausted")
+            chunk = stream.read(1024 * 1024)
+            if not chunk:
+                return b"".join(chunks)
+            chunks.append(chunk)
+
+
+def source_inventory(root: Path, deadline: float) -> tuple[str, int, tuple[str, ...]]:
+    import hashlib
+    import os
+    import time
+
+    rows = []
+    size = 0
+    if root.is_symlink():
+        raise ValueError("symlink_source_root")
+
+    def unreadable(error: OSError) -> None:
+        raise error
+
+    for directory, dirs, files in os.walk(root, followlinks=False, onerror=unreadable):
+        if time.monotonic() >= deadline:
+            raise TimeoutError("deadline_exhausted")
+        if any((Path(directory) / name).is_symlink() for name in dirs):
+            raise ValueError("symlink_source")
+        for name in sorted(files):
+            path = Path(directory) / name
+            data = read_bytes(path, deadline)
+            size += len(data)
+            rows.append((path.relative_to(root).as_posix(), hashlib.sha256(data).hexdigest()))
+    if not rows or not size:
+        raise ValueError("source_unreadable_or_empty")
+    rows.sort()
+    return digest_value(rows), size, tuple(path for path, _ in rows)
+
+
+@dataclass
+class IsolatedGraphLease:
+    artifact: GraphArtifact
+    path: Path
+    _closed: bool = False
+
+    def close(self, *, deadline_monotonic: float) -> None:
+        from .backend import _DeadlineExpired, _remove_owned_tree
+
+        if self._closed:
+            return
+        try:
+            _remove_owned_tree(self.path.parent, deadline_monotonic)
+        except (OSError, _DeadlineExpired):
+            return
+        self._closed = True
+
+
+def graph_bytes(path: Path, deadline: float, destination: Path | None = None) -> str:
+    """Hash and optionally copy a graph in bounded chunks; never buffer the full graph."""
+    import hashlib
+    import os
+    import stat
+    import time
+    from contextlib import ExitStack
+
+    digest = hashlib.sha256()
+    count = 0
+    with ExitStack() as stack:
+        fd = os.open(path, os.O_RDONLY | os.O_NOFOLLOW | os.O_NONBLOCK)
+        source = stack.enter_context(os.fdopen(fd, "rb"))
+        if not stat.S_ISREG(os.fstat(fd).st_mode):
+            raise ValueError("graph_not_regular")
+        output = stack.enter_context(destination.open("xb")) if destination is not None else None
+        while True:
+            if time.monotonic() >= deadline:
+                raise TimeoutError("deadline_exhausted")
+            chunk = source.read(1024 * 1024)
+            if not chunk:
+                break
+            count += len(chunk)
+            digest.update(chunk)
+            if output is not None:
+                output.write(chunk)
+    if not count:
+        raise ValueError("graph_empty")
+    return digest.hexdigest()

src/openultrasast/cpg/backend.py

@@ -32,9 +32,10 @@ import time
 from collections.abc import Callable, Mapping, Sequence
 from dataclasses import dataclass, field, replace
 from pathlib import Path
-from typing import Protocol
+from typing import Any, Protocol
 
 from ..model.contracts import ExecutionBudget
+from .artifact import GraphArtifact, GraphCensus, GraphIdentity
 
 logger = logging.getLogger(__name__)
 
@@ -311,6 +312,118 @@ class JoernBackend:
             self.last_failure = session.last_failure
             self._diagnostics = list(session._diagnostics)
 
+    def graph_identity(
+        self,
+        root: Path,
+        *,
+        language: str,
+        declarations_digest: str,
+        exclusions_digest: str,
+        unit: str = "repository",
+        execution_budget: ExecutionBudget | None = None,
+    ) -> GraphIdentity:
+        from .artifact import digest_value, read_bytes, source_inventory
+
+        deadline = execution_budget.deadline_monotonic if execution_budget else float("inf")
+        version = joern_version()
+        if version is None:
+            raise ValueError("engine_identity_unknown")
+        engine = ".".join(map(str, version))
+        source, _, _ = source_inventory(root, deadline)
+        code = digest_value([read_bytes(Path(__file__), deadline).hex(), read_bytes(self.queries_dir / "overlay.sc", deadline).hex()])
+        return GraphIdentity(
+            source,
+            declarations_digest,
+            exclusions_digest,
+            unit,
+            language,
+            engine,
+            _FRONTENDS.get(language, "joern-parse"),
+            engine,
+            (DATAFLOW_OVERLAY,),
+            (("implementation", code),),
+            (("include_tests", str(self.include_tests)), ("java_options", os.environ.get("JAVA_TOOL_OPTIONS", "default") or "default")),
+        )
+
+    def describe_graph(
+        self, result: CpgResult, root: Path, identity: GraphIdentity, *, execution_budget: ExecutionBudget | None = None
+    ) -> GraphArtifact | None:
+        """Seal only a named, complete, single graph census bound to bytes after loading."""
+        from .artifact import graph_bytes, source_inventory
+
+        budget = execution_budget or self.execution_budget
+        deadline = budget.deadline_monotonic if budget else float("inf")
+        try:
+            digest, size, paths = source_inventory(root, deadline)
+            if digest != identity.source_digest or result.unparsed:
+                return None
+            census = result.run("census", {})
+            if not isinstance(census, Mapping) or DATAFLOW_OVERLAY not in str(census.get("overlays", "")).split(","):
+                return None
+            names = census.get("file_names")
+            if not isinstance(names, list) or not all(isinstance(p, str) for p in names):
+                return None
+            normalized = {p.removeprefix(str(root) + "/").removeprefix("./") for p in names}
+            if not set(paths) <= normalized or int(str(census.get("shards", 1))) != 1:
+                return None
+            counts = GraphCensus(*(int(str(census[k])) for k in ("files", "methods", "calls")))
+            if counts.files < len(paths) or counts.methods < 1:
+                return None
+            return GraphArtifact(identity, graph_bytes(result.cpg_path, deadline), size, counts, "complete", (), str(root), paths)
+        except (OSError, ValueError, KeyError, TimeoutError):
+            return None
+
+    def load_graph(
+        self,
+        path: Path,
+        artifact: GraphArtifact,
+        expected: GraphIdentity,
+        *,
+        execution_budget: ExecutionBudget | None = None,
+    ) -> CpgResult | None:
+        """Validate sealed bytes, then query only a disposable private copy."""
+        from .artifact import IsolatedGraphLease, graph_bytes
+
+        budget = execution_budget or self.execution_budget
+        deadline = budget.deadline_monotonic if budget else float("inf")
+        cleanup_deadline = deadline + budget.cancellation_allowance_seconds if budget else float("inf")
+        scratch = None
+        try:
+            if artifact.identity != expected or artifact.completeness != "complete" or not artifact.source_paths:
+                return None
+            if artifact.census.files < len(artifact.source_paths) or artifact.census.methods < 1:
+                return None
+            scratch = Path(tempfile.mkdtemp(prefix="ousast-lease-"))
+            working = scratch / "cpg.bin"
+            if graph_bytes(path, deadline, working) != artifact.graph_digest:
+                raise ValueError("graph_digest_mismatch")
+            session = replace(self, execution_budget=budget)
+            lease = IsolatedGraphLease(artifact, working)
+
+            def normalize(value: object) -> Any:
+                if isinstance(value, str):
+                    return value.replace(artifact.source_root + "/", "")
+                if isinstance(value, list):
+                    return [normalize(item) for item in value]
+                if isinstance(value, dict):
+                    return {key: normalize(item) for key, item in value.items()}
+                return value
+
+            return CpgResult(
+                working,
+                lambda kind, params: normalize(session.query(working, kind, params)),
+                lambda kind, requests: normalize(session.query_batch(working, kind, requests)),
+                cleanup=lambda: lease.close(deadline_monotonic=cleanup_deadline),
+                execution_diagnostics=lambda: tuple(session._diagnostics),
+            )
+        except (OSError, ValueError, TimeoutError):
+            if scratch is not None:
+                try:
+                    _remove_owned_tree(scratch, cleanup_deadline)
+                except (OSError, _DeadlineExpired):
+                    self._note("scratch_cleanup_incomplete")
+            return None
+
     def _build_impl(self, root: Path, *, language: str = "", exclude: Sequence[str] = ()) -> CpgResult | None:
         """Build a CPG for ``root``. ``None`` on any failure — the caller degrades, never guesses.
 
@@ -671,6 +784,8 @@ class JoernBackend:
 
     def query_across(self, shards: Sequence[Path], query: str, params: Mapping[str, object]) -> object | None:
         """One question over every shard, answers concatenated. ``None`` only when no shard could answer."""
+        if query == "census":
+            return self.query(shards[0], query, params) if len(shards) == 1 else None
         merged: list[object] = []
         answered = 0
         for shard in shards:

src/openultrasast/cpg/queries/census.sc

@@ -23,6 +23,8 @@
       ujson.Obj(
         "files"     -> cpg.file.size.toString,
         "methods"   -> cpg.method.size.toString,
+        "calls" -> cpg.call.size.toString,
+        "file_names" -> ujson.Arr.from(cpg.file.name.l),
         "overlays"  -> cpg.metaData.overlays.l.mkString(","),
         "maxHeapMB" -> (Runtime.getRuntime.maxMemory / 1048576).toString
       )

tests/test_graph_reuse.py

@@ -0,0 +1,90 @@
+"""Real byte identity and isolated graph lease boundaries, without launching Joern."""
+
+import time
+from dataclasses import replace
+
+import pytest
+
+from openultrasast.cpg.backend import CpgResult, JoernBackend
+from openultrasast.model.contracts import ExecutionBudget
+
+
+def prepared(tmp_path, monkeypatch):
+    import openultrasast.cpg.backend as module
+
+    monkeypatch.setattr(module, "joern_version", lambda: (4, 0, 625))
+    root = tmp_path / "source"
+    root.mkdir()
+    (root / "a.js").write_text("function f(x) { return x; }")
+    graph = tmp_path / "cpg.bin"
+    graph.write_bytes(b"graph original")
+    backend = JoernBackend()
+    census = {"files": "1", "methods": "1", "calls": "0", "file_names": [str(root / "a.js")], "overlays": "dataflowOss"}
+    monkeypatch.setattr(JoernBackend, "query", lambda *args: census)
+    identity = backend.graph_identity(root, language="javascript", declarations_digest="declarations", exclusions_digest="exclusions")
+    result = CpgResult(graph, lambda *_: census)
+    artifact = backend.describe_graph(result, root, identity)
+    return backend, root, graph, identity, artifact
+
+
+def test_identity_reads_content_and_rejects_changed_inputs(tmp_path, monkeypatch):
+    backend, root, graph, identity, artifact = prepared(tmp_path, monkeypatch)
+    assert artifact.source_bytes == (root / "a.js").stat().st_size > 0
+    lease = backend.load_graph(graph, artifact, identity)
+    assert lease is not None
+    lease.cleanup()
+    (root / "a.js").write_text("changed")
+    changed = backend.graph_identity(root, language="javascript", declarations_digest="declarations", exclusions_digest="exclusions")
+    assert changed != identity
+    assert backend.load_graph(graph, artifact, changed) is None
+    for field in ("declarations_digest", "exclusions_digest", "engine_version", "frontend_version"):
+        assert backend.load_graph(graph, artifact, replace(identity, **{field: "changed"})) is None
+
+
+def test_lease_isolates_loads_and_cleanup_preserves_original(tmp_path, monkeypatch):
+    backend, root, graph, identity, artifact = prepared(tmp_path, monkeypatch)
+    leased = backend.load_graph(graph, artifact, identity)
+    assert leased is not None and leased.cpg_path != graph
+    leased.cpg_path.write_bytes(b"query mutated working copy")
+    assert graph.read_bytes() == b"graph original"
+    leased.cleanup()
+    leased.cleanup()
+    assert not leased.cpg_path.exists() and graph.exists()
+
+
+def test_corruption_partial_census_and_deadline_are_misses(tmp_path, monkeypatch):
+    backend, root, graph, identity, artifact = prepared(tmp_path, monkeypatch)
+    graph.write_bytes(b"corrupted")
+    assert backend.load_graph(graph, artifact, identity) is None
+    graph.write_bytes(b"graph original")
+    assert backend.load_graph(graph, replace(artifact, completeness="partial", diagnostics=("dropped_file",)), identity) is None
+    budget = ExecutionBudget(time.monotonic() - 1, 0.1)
+    assert backend.load_graph(graph, artifact, identity, execution_budget=budget) is None
+    bad = CpgResult(graph, lambda *_: {"files": "1", "methods": "1", "calls": "0", "file_names": [], "overlays": "dataflowOss"})
+    assert backend.describe_graph(bad, root, identity) is None
+
+
+def test_graph_identity_rejects_unreadable_or_symlink_sources(tmp_path, monkeypatch):
+    backend, root, *_ = prepared(tmp_path, monkeypatch)
+    (root / "link.js").symlink_to(root / "a.js")
+    with pytest.raises((ValueError, OSError)):
+        backend.graph_identity(root, language="javascript", declarations_digest="d", exclusions_digest="e")
+
+
+def test_generic_driver_accepts_backend_validated_lease(tmp_path, monkeypatch):
+    from openultrasast.model.scan import _build, _dispose
+
+    backend, root, graph, identity, artifact = prepared(tmp_path, monkeypatch)
+    budget = ExecutionBudget(time.monotonic() + 5, 0.2)
+
+    class ReusingBackend:
+        def build(self, source, *, language, exclude, execution_budget):
+            assert source == root and language == "javascript"
+            assert execution_budget is budget
+            return backend.load_graph(graph, artifact, identity, execution_budget=execution_budget)
+
+    result = _build(ReusingBackend(), root, "javascript", execution_budget=budget)
+    assert result is not None
+    assert result.run("census", {})["file_names"] == ["a.js"]
+    _dispose(result)
+    assert graph.read_bytes() == b"graph original"