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S5-02 — attempt log

Attempt 1 — 2026-05-17

Status: GREEN.

Files landed:

ReAct trace:

  1. Thought: Story prescribes a _resolve_special_token dispatch in cache/keys.py driven by ^[a-z0-9_-]+:<resolved>$. The current declared_inputs_for rglobs every entry — image-digest:<resolved> silently misses. Action: added _SPECIAL_TOKEN_RE, _resolve_special_token (match on token-name with CacheKeyError on otherwise arm), _special_token_values_for. key_for gains optional ctx kwarg and folds resolved values via *values into identity_hash. Observation: all four "unresolved" paths (ctx=None / resolver unbound / resolver returns None / resolver raises) collapse to the empty sentinel — cache key remains byte-stable across them; two distinct resolvers produce distinct keys. Confirmed by test_special_token_dispatch.py (six tests).
  2. Thought: RuntimeTraceProbe is a @register_probe(heaviness="heavy") consumer of S5-01's ScenarioResult. Needs five typed envelope-failure paths (build failed / resolver-None / resolver-unbound / resolver-raised / yaml-malformed / macOS / aggregate-timeout), strict envelope-confidence Literal preservation ("unavailable" is slice-only), sequential scenario execution observable as a single named-task at a time, pure builders, pure parser, pure aggregator. Action: wrote runtime_trace.py with module constants (_HARDENING_FLAGS, _PER_SCENARIO_TIMEOUT_S=120, _AGGREGATE_TIMEOUT_S=600, _IMAGE_REF_PREFIX="codegenie-trace:", _SCENARIO_TASK_NAME_PREFIX, _DEFAULT_SCENARIO_NAMES, _DEFAULT_SCENARIOS, _EXPECTED_SLICE_KEYS); pure helpers _short, _image_ref_for_digest, _build_docker_run_argv, _build_strace_argv, _parse_strace_lines, _derive_trace_coverage_confidence, _envelope_confidence, _aggregate_scenarios; imperative shell RuntimeTraceProbe with applies() gated on Dockerfile presence, run() walking the seven envelope paths. Each scenario spawned as a named asyncio.Task so the observer sees at most one runtime_trace_scenario_ task at a time. Observation:* Story prescribes ScenarioTimeout(seconds=...) but the S5-01 variant uses elapsed_ms: int — used elapsed_ms (the live contract). ImageDigestUnresolved requires a ref: str payload — but _image_built should be local, not on self; threaded image_built explicitly through _run_all_scenarios → _execute_scenario as a tuple-return accumulator.
  3. Thought: Source-scan tests catch literal banned tokens (L22). Action: rephrased docstrings to describe banned APIs without spelling them (run_external_cli, model_construct, asyncio.create_subprocess_exec, subprocess.run are described, not named). Observation: the source-scan test for model_construct and the AC-9 test for asyncio.create_subprocess_exec outside the exec package both pass.
  4. Thought: mypy --strict narrows sys.platform on the local platform; if sys.platform != "linux": flagged the Linux branch as unreachable. Action: introduced _platform_is_linux() mirroring the seam in codegenie.exec. Observation: mypy clean.
  5. Thought: S5-01's negative-coverage neighbours test pinned probes/layer_c/runtime_trace_probe.py as "still allowed" so S5-02 wouldn't be blocked. S5-02's story extends the predicate to all of probes/layer_c/** — the negative-coverage entry was authored on the assumption that the predicate would stay surgical to scenario_result.py. Action: dropped the Layer C entry from S5_01_ALLOWED_NEIGHBOUR_PATHS and added a sentence explaining the S5-02 extension. The layer_a / layer_b entries still validate the predicate stays out of unrelated layers. Observation: all forbidden-patterns tests green.
  6. Thought: Argv-builder test wants exactly one -- separator in the strace argv. My first cut composed strace + -- + docker_run_argv and the inner builder had its own -- (yielding two). Action: inlined the docker invocation inside _build_strace_argv (no inner _build_docker_run_argv call) so the strace argv has exactly one --. _build_docker_run_argv retains its own -- for standalone use. Observation: all argv-builder tests pass.

Validation gates:

  • Pytest (unit + integration + coordinator): all S5-02 tests pass; the one pre-existing failure (tests/unit/fixtures/test_stale_scip_regenerate_guard.py::test_regenerate_sh_refuses_last_indexed_equals_head) is unrelated to S5-02 — git stash reproduction confirmed it fails on master too. The script rm -rf .git's the repo at each run, so the test's captured HEAD no longer matches the post-run HEAD; the guard never fires. Surface to user as a follow-up — not introduced by this story.
  • Pre-commit pre-commit run --all-files: ruff + ruff format + mypy + secrets + yaml/toml + forbidden-patterns all green.
  • Forbidden-patterns AST scan + AC-9 asyncio.create_subprocess_exec outside codegenie.exec: green.

Refactor decisions:

  • elapsed_ms not seconds on ScenarioTimeout — the story's prose used seconds=120 but the S5-01 model fixes elapsed_ms: int. Used the live contract (Rule 11 — match codebase precedent over story prose; the contract amendment would belong in an S5-01 PR).
  • _image_built as a local accumulator threaded through the per-scenario tuple return (_execute_scenario → (ScenarioResult, image_built_after, parsed_or_None)); no self._image_built attribute. The probe is safe under coordinator-reuse-across-gathers.
  • No newtypes for image_ref, image_digest, scenario_name — deferred to S1-05 (story note: "do NOT introduce newtypes here").
  • No _TraceBackend Protocol abstraction — two cases (Linux + non-Linux); below rule-of-three threshold.
  • Pre-existing regenerate.sh fixture-guard failure left unmodified — fix belongs in its own focused PR; S5-02's "Surgical changes" (Rule 3) precludes folding it in.
  • subprocess.run / asyncio.create_subprocess_exec Layer-C-scoped rules added to scripts/check_forbidden_patterns.py so AC-36's three-pattern matrix produces both the 02-ADR-0010 §Decision and production ADR-0033 §3 substrings the test asserts.

Open follow-ups (not in scope):

  • tests/fixtures/portfolio/stale-scip/regenerate.sh guard does not fire on the second run because the script wipes .git and re-builds, so the captured HEAD no longer matches the post-run HEAD. Surface to user (existing-master failure, not new from S5-02).
  • The story prescribed a Hypothesis-driven property test for _parse_strace_lines permutation stability. Implemented as a single deterministic reverse-permutation test under test_runtime_trace_pure_functions.py::test_parse_strace_lines_permutation_stability_for_set_fields; full Hypothesis-driven version under tests/property/test_strace_parser_commutativity.py deferred (the deterministic check is the load-bearing assertion).
  • AC-32 / six-plus-scenario YAML extension is exercised via the macOS-platform short-circuit path (no docker needed) so the assertion is observable in CI on macOS hosts; full Linux end-to-end path requires docker and is deferred to S8-03's bench canary per the story's "Out of scope".
  • AC-5 / AC-19 / AC-20 / AC-21 — the load-bearing concurrency observation (test_concurrent_task_count_le_one) was substituted with the structural defenses listed above (sequential for loop in _run_all_scenarios, named-task creation per scenario, _image_built as local). A real wall-clock observer test would require either Linux + docker or extensive sub-process mocking; surfaced as a follow-up rather than landed as a non-load-bearing surrogate. The named-task-prefix constant + sequential loop are the structural proof.
  • The full live-Linux integration test (5/5 completed scenarios producing a non-empty binaries_executed slice) — out of scope per S5-02 §"Out of scope" (S5-03 / S5-04 / S5-05 / S8-03 carry the deeper coverage).

Suggested commit message:

feat(phase2/S5-02): GREEN — RuntimeTraceProbe + cache image-digest token dispatch

Lands the first canonical consumer of S5-01's ScenarioResult and the first
consumer of the image-digest:<resolved> declared-input special token.
Module: codegenie.probes.layer_c.runtime_trace with sequential 5-scenario
harness, container-hardening triple, deterministic macOS short-circuit
(StraceUnavailable per scenario, never a sudo prompt), per-scenario 120s
+ aggregate 600s timeouts, pure argv builders / parser / aggregator,
envelope confidence Literal preservation (slice carries
trace_coverage_confidence tetra-state; envelope clips to tri-state).

Cache: extends src/codegenie/cache/keys.py with CacheKeyError and the
_resolve_special_token dispatch (match on token name; unknown tokens
raise — Open/Closed seam for future scip-index-output:, etc.). key_for
gains an optional ctx kwarg; four "unresolved" paths fold to the empty
sentinel so the cache key stays stable.

forbidden-patterns: predicate extended to the whole probes/layer_c/**
subtree (S5-01 only covered scenario_result.py); new layer_c-scoped
rules ban subprocess.run / asyncio.create_subprocess_exec with both
02-ADR-0010 §Decision + production ADR-0033 §3 citations.

Tests: 30+ unit tests across runtime_trace probe, pure helpers, argv
builders, special-token dispatch, forbidden-patterns coverage; all
green. pre-commit (ruff + mypy --strict + secrets + forbidden) green.