git_commit_subject_matches

Each commit’s subject line (the first line of its message) must match the matches: regex — the subject-grammar member of the commit family. Enforces a prefix + shape convention like go / Gerrit’s pkg/path: lowercase summary, node’s subsystem: description, or conventional-commit types. The regex is anchored to the subject alone (so ^…$ describes the first line exactly), unlike git_commit_message’s pattern: which matches the whole subject + body; for a subject-length cap use git_commit_message’s subject_max_length:. Shares the commit-validation family’s since: / include_merges: semantics and failure modes (HEAD-only when since: is unset, <since>..HEAD when set; silent outside a git repo; a bad since: ref hard-fails with a shallow-clone hint).

- id: subject-grammar
  kind: git_commit_subject_matches
  matches: '^[a-z0-9_/.-]+: [a-z].{0,70}$'   # `component: lowercase summary`
  since: "{{env.ALINT_BASE_SHA | default('origin/main')}}"
  level: error

Options

Option	Type	Required	Default	Description
include_merges	boolean		false	When validating a range (since: set), include merge commits. Has no effect when since: is unset; combining include_merges: true with no since: is a load-time error.
matches	string	yes		Rust-regex the commit subject (first line of the message) must match.
since	string		null	Git ref to use as the base of the commit range. When set, validates every commit in <since>..HEAD instead of just HEAD. Use the canonical {{env.X}} interpolation to pass a SHA via an env var, e.g. since: "{{env.ALINT_BASE_SHA | default('origin/main')}}".

Plus the common level, id, and when fields. This rule analyses the whole repository, so it takes no paths. This table is generated from the JSON Schema; option types and defaults are authoritative.