devops(roll): roll on Mon, Wed and Fri at night, unless a roll PR is open

Author: pavelfeldman

.github/workflows/roll.yml

@@ -11,6 +11,10 @@ on:
   # Apply needs-roll to an issue to roll to the tip of main; re-apply it to trigger another roll.
   issues:
     types: [labeled]
+  # Mon, Wed and Fri at 9:17 UTC: 2:17 at night Pacific time, 1:17 in winter. Not on the hour, when
+  # GitHub delays scheduled runs. A scheduled roll skips while a roll pull request is open.
+  schedule:
+  - cron: "17 9 * * 1,3,5"
   workflow_dispatch:
     inputs:
       ref:
@@ -48,14 +52,17 @@ jobs:
     name: Find the commit
     if: >-
       github.repository == 'microsoft/playwright-python' &&
-      (github.event_name == 'workflow_dispatch' || github.event.label.name == 'needs-roll')
+      (github.event_name == 'workflow_dispatch' || github.event_name == 'schedule' ||
+       github.event.label.name == 'needs-roll')
     runs-on: ubuntu-24.04
     permissions:
       contents: read
+      pull-requests: read
     outputs:
       old_commit: ${{ steps.versions.outputs.old_commit }}
       new_commit: ${{ steps.versions.outputs.new_commit }}
       new_short: ${{ steps.versions.outputs.new_short }}
+      open_roll: ${{ steps.open.outputs.pr }}
     steps:
     - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
     - name: Read the pinned and the new commit
@@ -71,11 +78,27 @@ jobs:
           echo "new_commit=${new_commit}"
           echo "new_short=${new_commit:0:10}"
         } >> "$GITHUB_OUTPUT"
+    # A label or a manual run rolls anyway: a maintainer asked for it.
+    - name: Look for an open roll pull request
+      id: open
+      if: github.event_name == 'schedule'
+      env:
+        GH_TOKEN: ${{ github.token }}
+        GH_REPO: ${{ github.repository }}
+      run: |
+        pr=$(gh pr list --state open --author app/microsoft-playwright-automation --json number,headRefName \
+          --jq '[.[] | select(.headRefName | startswith("roll/")) | .number] | first // empty')
+        if [[ -n "$pr" ]]; then
+          echo "pr=$pr" >> "$GITHUB_OUTPUT"
+          echo "Skipped: roll pull request #$pr is open." >> "$GITHUB_STEP_SUMMARY"
+        fi
 
   roll:
     name: Roll to ${{ needs.versions.outputs.new_short }}
     needs: versions
-    if: needs.versions.outputs.new_commit != needs.versions.outputs.old_commit
+    if: >-
+      needs.versions.outputs.new_commit != needs.versions.outputs.old_commit &&
+      needs.versions.outputs.open_roll == ''
     # The runner of CI: the skill runs ./test.sh, both suites on all its cores.
     runs-on: playwright-x64-ubuntu24-64-core
     timeout-minutes: 240

AGENTS.md

@@ -139,8 +139,9 @@ left).
 ## Rolls
 
 Use the `playwright-roll` skill. On CI, `.github/workflows/roll.yml` runs it and opens the
-PR. Apply the `needs-roll` label to an issue to roll to the tip of `main`, or start the
-workflow by hand with a branch, a tag or a commit.
+PR. It runs on Mon, Wed and Fri at night, unless a roll PR is open. Apply the `needs-roll`
+label to an issue to roll to the tip of `main`, or start the workflow by hand with a
+branch, a tag or a commit.
 
 ## Commits and PRs