Three review fixes:
1. Security: validate lane/split/version against ^[a-z0-9_]+$ before
building the runner module name. The runner_args list is passed to
subprocess.run without shell=True (no shell injection possible),
but defense-in-depth blocks arbitrary token characters from
reaching Python's -m module loader. Bad input now errors at the
CLI boundary with a clear message.
2. Bug-risk: _classify_refusal docstring referenced a
no_admissible_candidate bucket that the implementation never
emitted. Aligned docstring with actual buckets
(no_admissible_question / no_admissible_statement). Also made all
matching consistently case-insensitive (was mixed — some checks
used raw reason, one used .lower()).
3. Bug-risk: fetch_committed_baseline wrote to
.git/coverage_baseline_tmp.json. Replaced with tempfile.mkstemp in
the system temp dir — avoids (a) failures in non-git worktrees
where .git is a file pointer, (b) concurrent-access collisions
between simultaneous operators.
Tests (+3 new):
- test_classify_refusal_is_case_insensitive
- test_classify_docstring_matches_implementation_buckets
- test_fetch_committed_baseline_uses_system_temp
All 16 coverage tests green. Verified the validation:
core teaching coverage --lane 'evil; rm -rf /'
→ ERROR: lane='evil; rm -rf /' must match ^[a-z0-9_]+$
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