Label

The label action allows Mergify to automatically add or remove labels from a pull request based on the conditions specified in your rules.

A label named in add or toggle that does not exist in the repository yet is created with a randomly picked color. Create it yourself first if you want to choose its color and description. Mergify only adds labels the pull request does not already carry, and only removes ones it does, so a rule whose conditions keep matching does not keep calling GitHub.

pull_request_rules:
  - name: add "WIP" label when the title contains "WIP"
    conditions:
      - title ~= WIP
    actions:
      label:
        toggle:
          - WIP

In this example, Mergify will automatically add the “WIP” label to any pull request whose title contains “WIP”. If the pull request does not match the rule anymore, the label will be removed.

When browsing the list of pull requests, GitHub does not give any indication on which pull requests might be in conflict. Mergify lets you do this by adding a label.

pull_request_rules:
  - name: warn on conflicts
    conditions:
      - conflict
    actions:
      comment:
        message: "@{{author}} this pull request is now in conflict 😩"
      label:
        toggle:
          - conflict

Then, your pull request list will look like this on conflict:

This rule toggles a label based on the failure status of a CI system.

pull_request_rules:
  - name: toggle labels based on CI state
    conditions:
      - check-failure = CI
    actions:
      label:
        toggle:
          - "CI:fail"

This rule adds a static label to pull requests targeting a given branch.

pull_request_rules:
  - name: label pull requests targeting the release branch
    conditions:
      - base = release
    actions:
      label:
        add:
          - "release"