Labeling PRs

Across the Flutter organization, the labeler GitHub action is used per repo.

For repos that already use it, only .github/labeler.yml needs to be edited.

For bringing up new repos, copy both .github/workflows/labeler-trigger.yml and .github/workflows/labeler.yml from an existing repo into the new repo, and update the github.repository == '<org>/<repo>' check in each to match the new repo. The labeler is split into two workflows so that it doesn't need pull_request_target: an unprivileged pull_request workflow records the PR number, and a privileged workflow_run workflow applies the labels. See GitHub Action Workflows for details.

How to add new labels

macos:
  # **/* recursively searches all subdirectories and files
  - shell/platform/darwin/macos/**/*

# For complex label names, it may need to be wrapped in quotes
'a: accessibility':
  - **/accessibility/*

Verifying changes in presubmit

GitHub actions do not test changes in presubmit. To verify, copy your local change into a YAML linter to verify the file is not malformed.

Once landed, you can look at new workflow runs to see if the matches are being used.