# Code Review Report — Batch 48

**Batch**: 48 (Cycle 1)
**Tasks**: AZ-508 — ISO-timestamp helper consolidation (2 pt)
**Date**: 2026-05-13
**Verdict**: **PASS**

## Findings

_No findings._

## Phase Summary

### Phase 1 — Context Loading

- Task spec: `_docs/02_tasks/todo/AZ-508_hygiene_iso_timestamps_consolidation.md`
- Cumulative review F2 (batches 31–33) + F3 (batches 28–30) — origin of the
  hygiene PBI.
- Changed source files: 1 new helper + 1 helper package re-export +
  3 c6 import rewires + 2 c7 local-def → import rewires + 1 deleted
  c6 internal shim.
- Changed test files: 1 new (`tests/unit/test_az508_iso_timestamps.py`,
  9 tests covering AC-1..AC-7 + Layer-1 invariant).
- Changed docs: `module-layout.md` (new `shared/helpers/iso_timestamps`
  entry) + task spec (drift note + corrected AC-2 regex).

### Phase 2 — Spec Compliance (AC-by-AC)

| AC | Verdict | Evidence |
|----|---------|----------|
| AC-1 | PASS | `test_ac1_import_and_call_returns_str` |
| AC-2 | PASS | `test_ac2_format_matches_canonical_regex` + `test_ac2_fromisoformat_roundtrip_yields_utc_aware_datetime` |
| AC-3 | PASS | `test_ac3_two_successive_calls_are_non_decreasing` |
| AC-4 | PASS | `test_ac4_no_other_iso_ts_now_definition_exists_in_src` (AST walk over `src/`) + `test_ac4_c6_and_c7_callers_import_from_helpers` |
| AC-5 | PASS | `tests/unit/test_az272_fdr_record_schema.py` runs unmodified, 100% pass |
| AC-6 | PASS | `test_ac6_helper_uses_stdlib_only` (AST whitelist) — `pyproject.toml` unchanged |
| AC-7 | PASS | `tests/unit/test_az270_compose_root.py::test_ac6_only_compose_root_imports_concrete_strategies` passes |

**Spec drift note**: the task spec originally listed 5 call-sites and a
`+00:00` regex. On-disk reality at implementation time: 3 call-sites
(c6 already locally consolidated under `_timestamp.py`; `tensorrt_runtime.py`
had no local copy) and the canonical FDR `ts` format is `Z`-suffix per
the `_TS = "2026-05-11T00:00:00.000000Z"` fixture. Spec + AC-2 regex
updated in this batch; no behavioral drift from the spec's actual intent
("single Layer-1 helper, byte-identical to existing locals, no FDR
schema change"). User explicitly approved the path via Choose A.

### Phase 3 — Code Quality

- **SRP**: pure stateless free function; no class wrapper (per Constraint
  § "no class wrapping").
- **Error handling**: no exception suppression; stdlib `datetime.now`
  cannot raise under normal operation.
- **Naming**: `iso_ts_now` matches the canonical name used by all three
  pre-existing local helpers — no naming churn in call sites
  (`from … import iso_ts_now as _iso_ts_now` alias preserved in the c7
  files).
- **Complexity**: 1 line. n/a.
- **DRY**: net deletion — eliminates duplication (the explicit goal).
- **Test quality**: assertions cover format, parseability, monotonicity,
  absence of stray definitions, import-path enforcement, layer-1
  invariant, and stdlib-only constraint.
- **Dead code**: removed unused `from datetime import datetime, timezone`
  imports from both c7 files after the local `_iso_ts_now` defs were
  removed (adjacent-hygiene, permitted by `coderule.mdc`).

### Phase 4 — Security Quick-Scan

No SQL, no `subprocess`, no `eval` / `exec`, no secrets, no untrusted
input handling. Helper is stdlib-only and side-effect-free. n/a.

### Phase 5 — Performance Scan

`datetime.now(timezone.utc).strftime(...)` is the same call all three
previous local helpers made; zero runtime delta. No new allocations on
the hot path.

### Phase 6 — Cross-Task Consistency

Single task in batch — no inter-task interface concerns. Helper aligns
with the existing 8-helper convention (single-file Layer-1 modules under
`src/gps_denied_onboard/helpers/`, re-exported from `helpers/__init__.py`).

### Phase 7 — Architecture Compliance

- **Layer direction**: helper sits at Layer 1 (Foundation / shared);
  consumers in c6 (Layer 2 Infrastructure) and c7 (Layer 2
  Infrastructure) import strictly downward. ✓
- **Public API respect**: consumers import via
  `gps_denied_onboard.helpers.iso_timestamps` (or the `helpers` package
  facade after the `__init__.py` re-export). Internal modules of c6/c7
  are not imported across components. ✓
- **No new cyclic deps**: the helper imports only stdlib; no possible
  cycle. ✓
- **Duplicate symbols**: eliminated by design — the AC-4 AST walk
  asserts zero other `iso_ts_now` / `_iso_ts_now` definitions remain
  anywhere under `src/`. ✓
- **Cross-cutting concern home**: moved from per-component locals to
  the canonical `helpers/` directory. ✓
- **AZ-507 layering lint**: `test_ac6_only_compose_root_imports_concrete_strategies`
  passes — helper imports are allowed from components. ✓
- **AZ-270 lint**: passes. ✓

## Pre-existing Findings (NOT introduced by this batch)

The following ruff findings remain in
`src/gps_denied_onboard/components/c7_inference/onnx_trt_ep_runtime.py`
but are pre-existing (verified by re-running ruff against `HEAD` before
this batch's edits):

- **B905** at line 547 — `zip()` without `strict=`.
- **RUF022** at lines 88–98 — `__all__` not sorted.
- **RUF023** at lines 127–134 — `__slots__` not sorted.

Per `coderule.mdc` "Pre-existing lint errors should only be fixed if
they're in the modified area" — left untouched. Candidate for a future
c7 hygiene PBI.

## Verdict Justification

- Critical findings: 0
- High findings:     0
- Medium findings:   0
- Low findings:      0

**PASS** — proceed to commit per implement skill Step 11.
