--suggest-ignores

plumb lint --suggest-ignores appends a suggested .plumbignore block after the normal lint output. The block lists one entry per (rule_id, selector_path) tuple that would suppress every current violation, sorted by (rule_id, selector_path) for byte-identical output across runs.

The flag is opt-in. Default behavior is unchanged.

Why

Plumb is most useful on a brownfield codebase, but a 200-violation first run is too noisy to action. --suggest-ignores produces a ready-made starter ignore file: paste it into .plumbignore, fix the violations as a follow-up, and remove entries one by one.

Pretty format

$ plumb lint plumb-fake://hello --suggest-ignores
desktop
  spacing/grid-conformance
    html > body
      warning: `html > body` has off-grid padding-top 13px; expected a multiple of 4px.
      ...

stats
  ...

Suggested .plumbignore (would suppress 1 violation):
# Format: <rule_id> <selector_path>
spacing/grid-conformance html > body

The footer prints after the existing stats block, separated by a blank line.

JSON format

--format json --suggest-ignores adds a suggested_ignores array to the existing envelope:

{
  "plumb_version": "0.0.x",
  "run_id": "sha256:…",
  "stats": { … },
  "suggested_ignores": [
    { "rule_id": "color/palette-conformance", "selector": "#cta" },
    { "rule_id": "spacing/grid-conformance", "selector": "html > body" }
  ],
  "summary": { … },
  "violations": [ … ]
}

Entries are sorted by (rule_id, selector). The run_id and violations fields are unchanged — toggling --suggest-ignores MUST NOT shift the run digest.

SARIF

The SARIF formatter ignores --suggest-ignores. SARIF 2.1.0 has no canonical slot for ignore suggestions, and consumers (GitHub Code Scanning, IDE plugins) parse the schema strictly. Use the JSON output for tooling that wants the suggestions.

File format

The suggested footer follows a deliberately minimal grammar:

# Format: <rule_id> <selector_path>
spacing/grid-conformance .header
spacing/grid-conformance .footer .copyright
color/palette-conformance #cta-button

One entry per line, two whitespace-separated fields:

• <rule_id> — slash-separated rule identifier (e.g. spacing/grid-conformance).
• <selector_path> — the CSS selector path Plumb attached to the violation.

Lines beginning with # are comments. Trailing whitespace is insignificant.