typos-format/ruff-format: opt-in config grep misses TOML inline-table form for [tool.X]

[kyle-sexton]

Summary

Both typos-format's pyproject.toml/Cargo.toml opt-in check and ruff-format's pyproject.toml opt-in check use a line-anchored grep for a [tool.X] section header:

grep -qE '^[[:space:]]*\[tool\.typos(\]|[.])' "$dir/pyproject.toml"
grep -qE '^[[:space:]]*\[tool\.ruff(\]|[.])'  "$dir/pyproject.toml"

TOML allows the equivalent configuration as an inline table under a [tool] header instead:

[tool]
typos = { default = { extend-words = { ... } } }

Both tools (verified empirically for typos-cli 1.44.0) honor this form when actually run. Neither hook's grep recognizes it, so a repo using this style is treated as "no config" and the hook silently skips — a false-negative on the opt-in gate, not an incorrect correction.

Impact

Low. Inline-table syntax for an entire [tool.X] section is unusual in practice — TOML style strongly favors the [tool.X] header form for anything beyond a single scalar value. Surfaced by Codex review on #872 (typos-format), applies identically to the already-shipped ruff-format.

Why not fixed inline

A robust fix needs real TOML parsing (inline tables can span multiple lines, nest arbitrarily, and the typos/ruff key can appear in any order within [tool]). A multi-pass grep heuristic ("has [tool]" + "has a typos = or ruff = line somewhere after it") risks false positives from an unrelated typos = \"...\"/ruff = \"...\" key in a different table, or from commented-out lines. Out of scope for a fast, dependency-free, cross-platform bash hook.

Related

• Surfaced during feat(typos-format): add per-file typos autofix hook plugin #872 (epic Epic: lint/static-analysis gap closure #830, docs/topics/lint-static-analysis-gaps/PLAN.md).

[kyle-sexton]

This was generated by AI during triage.

Triage → status: ready (decision-defaulted). Verified-by-report false-negative: both typos-format and ruff-format opt-in checks use a line-anchored grep -qE '^[[:space:]]*\[tool\.X(\]|[.])' that misses the TOML inline-table form ([tool] + typos = { ... }), which both tools honor when run — so a repo using that style is treated as no-config and the hook silently skips. Fails SAFE (skip, never mis-correct); impact LOW (inline-table for a whole [tool.X] section is unusual — TOML style favors the header form).

Decision defaulted: document the inline-table form as a known limitation in BOTH hooks (typos-format + ruff-format) rather than add a fragile heuristic or a TOML-parser dependency — veto before merge. The reporter's own analysis shows a robust fix needs real TOML parsing (inline tables span lines / nest / any key order), which is out of scope for a fast, dependency-free, cross-platform bash hook; a multi-pass grep heuristic risks false positives from an unrelated typos =/ruff = key or commented lines. The fail-safe skip means the cost of the gap is a missed opt-in for a rare config style, not a wrong edit. Maintainer may veto to implement a heuristic or an opt-in TOML-parse path (e.g. python -c tomllib where available) if the rare form matters.

Applies identically to both hooks (2 surfaces). Priority medium (ruff-format/typos-format outside the priority set; impact low). Type Bug (documents/bounds a real false-negative).

[kyle-sexton]