# Implementation: harden-parse-verdict

## SCOPE

Closed `add-loop-runner/BUG_REPORT.md` O6 (pass-string coercion bug) plus
the un-noted sibling issue (no score clamping). Pure-function change to
`parse_verdict` in `scripts/loop-runner.py`. No CLI surface change; no
schema change; no new deps (math is stdlib).

## FILES TOUCHED

- `scripts/loop-runner.py`
  - Added `import math`.
  - `parse_verdict(text)`: replaced `verdict["pass"] = bool(data.get("pass"))`
    with explicit string-vs-bool dispatch:
    - bool passed through → `bool(True)` = True; `bool(False)` = False (unchanged).
    - `"true"` (any case, leading/trailing whitespace stripped) → True.
    - `"false"` (any case, leading/trailing whitespace stripped) → False.
    - Any other string → `bool(raw_pass.strip())` (empty → False; non-empty → True).
      Preserves old `bool(...)` truthy semantics for `"yes"` / etc.
  - Replaced `verdict["score"] = float(data.get("score", 0.0))` with:
    - `try: score = float(data.get("score", 0.0))` /
      `except (TypeError, ValueError): score = 0.5`
      (TypeError for non-numeric types like None/list/dict; ValueError for
      non-numeric strings like "great").
    - `if not math.isfinite(score): score = 0.5` (catches NaN, Infinity,
      -Infinity returned by some Hermes-style recursive decoders).
    - `score = max(0.0, min(1.0, score))` (clamp to `[0, 1]`).
  - Updated docstring to spell out the new contract: `pass` accepts
    bool OR `"true"`/`"false"` strings (case-insensitive); `score` is
    clamped to `[0, 1]` with NaN/non-finite → 0.5.

## D-ITEMS Locked

- **D-V1**: `"true"` / `"false"` strings → bool via case-insensitive
  equality. Other strings defer to current `bool(...)` for backwards
  compat (`pass: "yes"` stays truthy).
- **D-V2**: `score` NaN / non-finite → `0.5`.
- **D-V3**: `score` non-numeric string → `0.5`.
- **D-V4**: No opt-out flag for clamping. Strict emitters unaffected.
- **D-V5**: Tests are pure-functional; no subprocess.

## BUG FOUND AND FIXED INLINE

While running `tests/test_parse_verdict.py`, the test
`test_other_truthy_string_pass` failed on the first iteration. The
implementation had:

```python
if isinstance(raw_pass, str):
    verdict_pass = raw_pass.strip().lower() == "true"
```

This treats EVERY non-`"true"` string as False — including `"yes"`,
which used to be True via `bool("yes")`. SPEC R1 explicitly says
non-`true`/`false` strings fall through to `bool(...)` for backwards
compat. Fixed to the three-way branch:

```python
if isinstance(raw_pass, str):
    lower = raw_pass.strip().lower()
    if lower == "true":
        verdict_pass = True
    elif lower == "false":
        verdict_pass = False
    else:
        verdict_pass = bool(raw_pass.strip())
```

This is consistent with SPEC R1 wording. All 22 tests pass after the fix.

## TESTS

New file `tests/test_parse_verdict.py` — 22 tests across 5 classes:

- `TestStrictBaseline` (2): bool `pass` true/false; preserves existing semantics.
- `TestPassStringCoercion` (6): `"true"`/`"false"` strings, case-insensitive,
  surrounding whitespace, empty string, other truthy string.
- `TestScoreClamping` (9): clamped high (1.5→1.0), clamped low (-0.3→0.0),
  edges (0.0, 1.0), NaN → 0.5, Infinity → 0.5, non-numeric string "great"
  → 0.5, numeric string "0.75" → 0.75, missing score → 0.0, None score →
  0.5.
- `TestFenceBlockStillWorks` (2): existing fence-block path with bool pass;
  fence path with string-pass + clamped score.
- `TestOptionalKeysPreserved` (3): reasons+next_hint combination, missing
  reasons → [], non-list reasons coerced to [].

## TEST COUNT

- Baseline: 447 passed (post-`add-state-loop-lock`).
- New: +22 in `tests/test_parse_verdict.py`.
- Final: **469 passed**, 0 regressions.

## PIPELINE TO COMPLETION

research → research:awaiting_approval → research:approved → implement.
Next: → code_review → code_review:awaiting_approval → code_review:approved
→ bug_find → adversarial_bug_find → doc_review → referee → complete.