workflow: Add status label to PRs (#778)

.github/workflows/pr-status-label.yml

@@ -0,0 +1,169 @@
+name: Add "status:"-label to PRs based on current state
+
+on:
+  pull_request_review:
+    types: [submitted]
+  pull_request:
+    types: [opened]
+  schedule:
+    - cron: '0 * * * *' # every hour, on the hour
+
+permissions:
+  pull-requests: write
+
+jobs:
+  new_pr:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request' && github.event.action == 'opened'
+    steps:
+      - name: Label new PR as "status:waiting for review"
+        uses: actions/github-script@v7
+        with:
+          script: |
+            github.rest.issues.addLabels({
+              ...context.repo,
+              issue_number: context.payload.pull_request.number,
+              labels: ['status:waiting for review']
+            })
+
+  review_update:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request_review' && github.event.action == 'submitted'
+    steps:
+      - name: Update status labels based on review
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const pr = context.payload.pull_request
+            const review = context.payload.review
+            const owner = context.repo.owner
+            const repo = context.repo.repo
+
+            const R = review.user.login            // reviewer
+            const P = pr.user.login                // PR author
+            const O = owner                        // repo owner (by repo name)
+
+            // 1. Remove all "status:[...]" labels
+            const { data: existingLabels } = await github.rest.issues.listLabelsOnIssue({
+              owner,
+              repo,
+              issue_number: pr.number
+            })
+
+            const statusLabels = existingLabels.filter(l => l.name.startsWith('status:'))
+            for (const label of statusLabels) {
+              await github.rest.issues.removeLabel({
+                owner,
+                repo,
+                issue_number: pr.number,
+                name: label.name
+              }).catch(() => {}) // ignore if already removed
+            }
+
+            // 2. Determine new label
+            let newLabel = null
+
+            // https://github.com/Reviewable/Reviewable/issues/1163
+            // other users cannot approve reviewers, requires permissions to actually say `review.state == 'approved'`
+            const is_approved = review.state === 'approved' || review.body.includes("complete! all files reviewed, all discussions resolved")
+
+            if (is_approved && R === O) {
+              newLabel = 'status:approved'  // standard way of approval: owner appoves PR
+            } else if (is_approved && P === O && R !== O) {
+              newLabel = 'status:approved'  // if owner is author, someone else must approve
+            } else if (P === R) {
+              newLabel = 'status:waiting for review'
+            } else if (P !== R) {
+              newLabel = 'status:waiting for author'
+            } else {
+              core.info('No matching condition for new label.')
+              core.info(`Review state: ${review.state}, PR author: ${P}, Reviewer: ${R}, Repo owner: ${O}`)
+            }
+
+            if (newLabel) {
+              await github.rest.issues.addLabels({
+                owner,
+                repo,
+                issue_number: pr.number,
+                labels: [newLabel]
+              })
+              core.info(`Added label: ${newLabel}`)
+            } else {
+              core.info('No new status label added.')
+            }
+
+  promote_ready_to_merge:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'schedule'
+    steps:
+      - name: Promote approved PRs to "ready to merge"
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const owner = context.repo.owner
+            const repo = context.repo.repo
+            const now = new Date()
+
+            // 1. Search for open PRs with "status:approved"
+            const searchQuery = `repo:${owner}/${repo} is:pr is:open label:"status:approved"`
+            const { data: searchResults } = await github.rest.search.issuesAndPullRequests({ q: searchQuery })
+
+            for (const pr of searchResults.items) {
+              const prNumber = pr.number
+
+              // Get full PR info (for timestamps)
+              const { data: prData } = await github.rest.pulls.get({
+                owner,
+                repo,
+                pull_number: prNumber
+              })
+
+              const createdAt = new Date(prData.created_at)
+              const hoursSinceCreation = (now - createdAt) / (1000 * 60 * 60)
+              if (hoursSinceCreation < 24) {
+                core.info(`Skipping #${prNumber} (created ${hoursSinceCreation.toFixed(1)}h ago)`)
+                continue
+              }
+
+              // Find the last "status:" label change (via timeline events)
+              const { data: events } = await github.rest.issues.listEvents({
+                owner,
+                repo,
+                issue_number: prNumber,
+                per_page: 100
+              })
+
+              const lastStatusChange = events
+                .filter(e => e.event === 'labeled' || e.event === 'unlabeled')
+                .filter(e => e.label && e.label.name.startsWith('status:'))
+                .sort((a, b) => new Date(b.created_at) - new Date(a.created_at))[0]
+
+              if (lastStatusChange) {
+                const hoursSinceStatusChange = (now - new Date(lastStatusChange.created_at)) / (1000 * 60 * 60)
+                if (hoursSinceStatusChange < 12) {
+                  core.info(`Skipping #${prNumber} (status changed ${hoursSinceStatusChange.toFixed(1)}h ago)`)
+                  continue
+                }
+              }
+
+              // 2. Conditions met → remove "status:approved", add "status:ready to merge"
+              try {
+                await github.rest.issues.removeLabel({
+                  owner,
+                  repo,
+                  issue_number: prNumber,
+                  name: 'status:approved'
+                }).catch(() => {})
+
+                await github.rest.issues.addLabels({
+                  owner,
+                  repo,
+                  issue_number: prNumber,
+                  labels: ['status:ready to merge']
+                })
+
+                core.info(`Promoted #${prNumber} to status:ready to merge`)
+              } catch (err) {
+                core.warning(`Failed to update #${prNumber}: ${err.message}`)
+              }
+            }