Add Array stack check GitHub Action

.github/workflows/array-stack-check.yml

@@ -0,0 +1,88 @@
+# Generated by Array CLI - https://github.com/posthog/array
+# Blocks PRs until their downstack dependencies are merged
+
+name: Stack Check
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, edited]
+  pull_request_target:
+    types: [closed]
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request'
+    steps:
+      - name: Check stack dependencies
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const pr = context.payload.pull_request;
+            const baseBranch = pr.base.ref;
+            const trunk = ['main', 'master', 'develop'];
+
+            if (trunk.includes(baseBranch)) {
+              console.log('✓ Base is trunk, no dependencies');
+              return;
+            }
+
+            async function getBlockers(base, visited = new Set()) {
+              if (trunk.includes(base) || visited.has(base)) {
+                return [];
+              }
+              visited.add(base);
+
+              const { data: prs } = await github.rest.pulls.list({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                state: 'open',
+                head: `${context.repo.owner}:${base}`
+              });
+
+              if (prs.length === 0) {
+                return [];
+              }
+
+              const blocker = prs[0];
+              const upstream = await getBlockers(blocker.base.ref, visited);
+              return [{ number: blocker.number, title: blocker.title }, ...upstream];
+            }
+
+            const blockers = await getBlockers(baseBranch);
+
+            if (blockers.length > 0) {
+              const list = blockers.map(b => `#${b.number} (${b.title})`).join('\n  - ');
+              core.setFailed(`Blocked by:\n  - ${list}\n\nMerge these PRs first (bottom to top).`);
+            } else {
+              console.log('✓ All dependencies merged, ready to merge');
+            }
+
+  recheck-dependents:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request_target' && github.event.action == 'closed' && github.event.pull_request.merged == true
+    steps:
+      - name: Trigger recheck of dependent PRs
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const mergedBranch = context.payload.pull_request.head.ref;
+
+            const { data: dependentPRs } = await github.rest.pulls.list({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              base: mergedBranch,
+              state: 'open'
+            });
+
+            for (const pr of dependentPRs) {
+              console.log(`Re-checking PR #${pr.number}`);
+
+              // Update base to main since the branch will be deleted
+              await github.rest.pulls.update({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                pull_number: pr.number,
+                base: 'main'
+              });
+            }