Baseline Key Derivation

Rigor::Analysis::Baseline filters a live diagnostic stream against a recorded .rigor-baseline.yml so a project can adopt Rigor without fixing every pre-existing finding at once (ADR-22). This page pins the bucket-key derivation — how a diagnostic maps to a stored row — which is the durable contract a baseline file’s format depends on. The operational guide (generating, refreshing, editing the file) is in the User Manual § “Baseline”; the design rationale (rule-id vs message granularity) is in ADR-22 WD1.

Baseline filtering is the last suppression layer, applied after inline # rigor:disable markers and after severity resolution (diagnostic-policy.md).

Bucket key

A baseline row (Baseline::Bucket) is keyed by a tuple:

[ file, rule, message_regex ]

• file — the diagnostic’s path relative to the project root (the working directory when rigor runs). Storing relative paths keeps the generated file portable across machines and checkout locations; a live diagnostic’s absolute path is normalised to relative before the lookup.
• rule — the diagnostic’s qualified_rule (diagnostic-shape.md). A diagnostic whose qualified_rule is nil (an unsuppressible parse / internal error) or whose path is nil is never baselined.
• message_regex — nil in rule mode; a Regexp in message mode (below).

Each bucket also carries a count — the PHPStan-compatible number of occurrences recorded for that key, so a baseline tolerates exactly the recorded multiplicity and surfaces a regression when the count grows.

Match modes

The match_mode selects the key granularity:

• :rule — the key’s message_regex is nil, so every diagnostic for a (file, qualified_rule) pair contributes to one bucket regardless of message. The coarser, more churn-tolerant mode.
• :message — the key carries a message_regex derived from the diagnostic’s message, so each distinct message gets its own bucket. The generator writes Regexp.escape(message) so the YAML round-trip matches the literal message; a user hand-editing the row MAY replace the escaped form with a looser pattern. The tighter mode — it distinguishes undefined method 'foo' from undefined method 'bar' under the same rule.

The stored file format version is Baseline::CURRENT_VERSION (1).