Automation to unassign inactive reviewers from open pull requests

.github/workflows/pr-auto-unassign-stale.yml

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+name: Auto-unassign stale PR assignees
+
+on:
+  schedule:
+    - cron: "*/15 * * * *"   # run every 15 minutes
+  workflow_dispatch:
+    inputs:
+      enabled:
+        description: "Enable this automation"
+        type: boolean
+        default: true
+      max_age_minutes:
+        description: "Unassign if assigned longer than X minutes"
+        type: number
+        default: 60
+      dry_run:
+        description: "Preview only; do not change assignees"
+        type: boolean
+        default: false
+
+permissions:
+  pull-requests: write
+  issues: write
+
+env:
+  # Defaults (can be overridden via workflow_dispatch inputs)
+  ENABLED: "true"
+  MAX_ASSIGN_AGE_MINUTES: "60"
+  DRY_RUN: "false"
+
+jobs:
+  sweep:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Resolve inputs into env
+        run: |
+          # Prefer manual run inputs when present
+          if [ "${{ github.event_name }}" = "workflow_dispatch" ]; then
+            echo "ENABLED=${{ inputs.enabled }}" >> $GITHUB_ENV
+            echo "MAX_ASSIGN_AGE_MINUTES=${{ inputs.max_age_minutes }}" >> $GITHUB_ENV
+            echo "DRY_RUN=${{ inputs.dry_run }}" >> $GITHUB_ENV
+          fi
+          echo "Effective config: ENABLED=$ENABLED, MAX_ASSIGN_AGE_MINUTES=$MAX_ASSIGN_AGE_MINUTES, DRY_RUN=$DRY_RUN"
+
+      - name: Exit if disabled
+        if: ${{ env.ENABLED != 'true' && env.ENABLED != 'True' && env.ENABLED != 'TRUE' }}
+        run: echo "Disabled via ENABLED=$ENABLED. Exiting." && exit 0
+
+      - name: Unassign stale assignees
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const owner = context.repo.owner;
+            const repo  = context.repo.repo;
+
+            const MAX_MIN = parseInt(process.env.MAX_ASSIGN_AGE_MINUTES || "60", 10);
+            const DRY_RUN = ["true","True","TRUE","1","yes"].includes(String(process.env.DRY_RUN));
+            const now = new Date();
+
+            core.info(`Scanning open PRs. Threshold = ${MAX_MIN} minutes. DRY_RUN=${DRY_RUN}`);
+
+            // List all open PRs
+            const prs = await github.paginate(github.rest.pulls.list, {
+              owner, repo, state: "open", per_page: 100
+            });
+
+            let totalUnassigned = 0;
+
+            for (const pr of prs) {
+              if (!pr.assignees || pr.assignees.length === 0) continue;
+
+              const number = pr.number;
+              core.info(`PR #${number}: "${pr.title}" — assignees: ${pr.assignees.map(a => a.login).join(", ")}`);
+
+              // Pull reviews (to see if an assignee started a review)
+              const reviews = await github.paginate(github.rest.pulls.listReviews, {
+                owner, repo, pull_number: number, per_page: 100
+              });
+
+              // Issue comments (general comments)
+              const issueComments = await github.paginate(github.rest.issues.listComments, {
+                owner, repo, issue_number: number, per_page: 100
+              });
+
+              // Review comments (file-level)
+              const reviewComments = await github.paginate(github.rest.pulls.listReviewComments, {
+                owner, repo, pull_number: number, per_page: 100
+              });
+
+              // Issue events (to find assignment timestamps)
+              const issueEvents = await github.paginate(github.rest.issues.listEvents, {
+                owner, repo, issue_number: number, per_page: 100
+              });
+
+              for (const a of pr.assignees) {
+                const assignee = a.login;
+
+                // Find the most recent "assigned" event for this assignee
+                const assignedEvents = issueEvents
+                  .filter(e => e.event === "assigned" && e.assignee && e.assignee.login === assignee)
+                  .sort((x, y) => new Date(y.created_at) - new Date(x.created_at));
+
+                if (assignedEvents.length === 0) {
+                  core.info(`  - @${assignee}: no 'assigned' event found; skipping.`);
+                  continue;
+                }
+
+                const assignedAt = new Date(assignedEvents[0].created_at);
+                const ageMin = (now - assignedAt) / 60000;
+
+                // Has the assignee commented (issue or review comments) or reviewed?
+                const hasIssueComment = issueComments.some(c => c.user?.login === assignee);
+                const hasReviewComment = reviewComments.some(c => c.user?.login === assignee);
+                const hasReview = reviews.some(r => r.user?.login === assignee);
+
+                const eligible =
+                  ageMin >= MAX_MIN &&
+                  !hasIssueComment &&
+                  !hasReviewComment &&
+                  !hasReview &&
+                  pr.state === "open";
+
+                core.info(`  - @${assignee}: assigned ${ageMin.toFixed(1)} min ago; commented=${hasIssueComment || hasReviewComment}; reviewed=${hasReview}; open=${pr.state==='open'} => ${eligible ? 'ELIGIBLE' : 'skip'}`);
+
+                if (!eligible) continue;
+
+                if (DRY_RUN) {
+                  core.notice(`Would unassign @${assignee} from PR #${number}`);
+                } else {
+                  try {
+                    await github.rest.issues.removeAssignees({
+                      owner, repo, issue_number: number, assignees: [assignee]
+                    });
+                    totalUnassigned += 1;
+                    // Optional: leave a gentle heads-up comment
+                    await github.rest.issues.createComment({
+                      owner, repo, issue_number: number,
+                      body: `👋 Unassigning @${assignee} due to inactivity (> ${MAX_MIN} min without comments/reviews). This PR remains open for other reviewers.`
+                    });
+                    core.info(`    Unassigned @${assignee} from #${number}`);
+                  } catch (err) {
+                    core.warning(`    Failed to unassign @${assignee} from #${number}: ${err.message}`);
+                  }
+                }
+              }
+            }
+
+            core.summary
+              .addHeading('Auto-unassign report')
+              .addRaw(`Threshold: ${MAX_MIN} minutes\n\n`)
+              .addRaw(`Total unassignments: ${totalUnassigned}\n`)
+              .write();
+
+          result-encoding: string