Build/Test Tools: Introduce Props Bot workflow.

Props Bot is a new GitHub Action that will compile a list of contributors for a given pull request. The bot will leave a comment with a list of contributors formatted for use in both Trac SVN and GitHub.

Props dharm1025, desrosj, jorbin, jeffpaul, dd32, pento, gziolo, swissspidy, talldanwp, noisysocks, youknowriad, peterwilsoncc, joemcgill, chrisdavidmiles, wpscholar, annezazu, chanthaboune, desrosjbot.
See #60417.

git-svn-id: https://develop.svn.wordpress.org/trunk@57517 602fd350-edb4-49c9-b593-d223f7449a82

.github/workflows/props-bot.yml

@@ -0,0 +1,86 @@
+name: Props Bot
+
+on:
+  # This event runs anytime a PR is (re)opened, updated, or labeled.
+  # GitHub does not allow filtering the `labeled` event by a specific label.
+  # However, the logic below will short-circuit the workflow when the `props-bot` label is not the one being added.
+  # Note: The pull_request_target event is uesed instead of pull_request because this workflow needs permission to comment
+  # on the pull request. Because this event grants extra permissions to `GITHUB_TOKEN`, any code changes within the PR
+  # should be considered untrusted. See https://securitylab.github.com/research/github-actions-preventing-pwn-requests/.
+  pull_request_target:
+    types:
+      - opened
+      - synchronize
+      - reopened
+      - labeled
+  # This event runs anytime a comment is added or deleted.
+  # You cannot filter this event for PR comments only.
+  # However, the logic below does short-circuit the workflow for issues.
+  issue_comment:
+    type:
+      - created
+      - deleted
+  # This event will run everytime a new PR review is initially submitted.
+  pull_request_review:
+    types:
+      - submitted
+  # This event runs anytime a PR review comment is created or deleted.
+  pull_request_review_comment:
+    types:
+      - created
+      - deleted
+
+# Cancels all previous workflow runs for pull requests that have not completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name for pull requests
+  # or the commit hash for any other events.
+  group: ${{ github.workflow }}-${{ contains( fromJSON( '["pull_request_target", "pull_request_review", "pull_request_review_comment"]' ), github.event_name ) && github.head_ref || github.sha }}
+  cancel-in-progress: true
+
+# Disable permissions for all available scopes by default.
+# Any needed permissions should be configured at the job level.
+permissions: {}
+
+jobs:
+  # Compiles a list of props for a pull request.
+  #
+  # Performs the following steps:
+  # - Collects a list of contributor props and leaves a comment.
+  # - Removes the props-bot label, if necessary.
+  props-bot:
+    name: Generate a list of props
+    runs-on: ubuntu-latest
+    permissions:
+      # The action needs permission `write` permission for PRs in order to add a comment.
+      pull-requests: write
+      contents: read
+    timeout-minutes: 20
+    # The job should only run if:
+    #
+    # - A pull request review is created or commented on.
+    # - An issue comment is added to a pull request.
+    # - A pull request is opened, synchronized, or reopened.
+    # - The `props-bot` label is added to the pull request.
+    if: |
+      contains( fromJSON( '["pull_request_review", "pull_request_review_comment"]' ), github.event_name ) ||
+      ( github.event_name == 'issue_comment' && github.event.issue.pull_request ) ||
+      github.event_name == 'pull_request_target' && github.event.action != 'labeled' ||
+      'props-bot' == github.event.label.name
+
+    steps:
+      - name: Gather a list of contributors
+        uses: WordPress/props-bot-action@trunk
+
+      - name: Remove the props-bot label
+        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
+        if: ${{ github.event.action == 'labeled' && 'props-bot' == github.event.label.name }}
+        with:
+          retries: 2
+          retry-exempt-status-codes: 418
+          script: |
+            github.rest.issues.removeLabel({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: '${{ github.event.number }}',
+              name: 'props-bot'
+            });