ci: add CI for checking generated changesets

Author: cabljac

.github/workflows/tests.yaml

@@ -14,6 +14,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
 
       - name: Setup Node.js
         uses: actions/setup-node@v4
@@ -31,6 +33,39 @@ jobs:
       - name: Run format check
         run: pnpm format
 
+      - name: Check for changesets
+        run: |
+          # For pull requests, compare against the base branch
+          if [ "${{ github.event_name }}" = "pull_request" ]; then
+            BASE_SHA="${{ github.event.pull_request.base.sha }}"
+            HEAD_SHA="${{ github.event.pull_request.head.sha }}"
+          else
+            # For pushes to main, compare against the previous commit
+            BASE_SHA="${{ github.event.before }}"
+            HEAD_SHA="${{ github.event.after }}"
+          fi
+          
+          # Check if there are any changes to packages that would need a release
+          if git diff --name-only "$BASE_SHA" "$HEAD_SHA" | grep -E '^(packages/|src/)' > /dev/null; then
+            if [ -z "$(ls .changeset/*.md 2>/dev/null)" ]; then
+              echo "❌ Changes detected in packages but no changesets found."
+              echo ""
+              echo "Please create a changeset with 'pnpm changeset' for changes that should be released."
+              echo "If these changes don't need a release, please add a comment explaining why."
+              echo ""
+              echo "Changed files:"
+              git diff --name-only "$BASE_SHA" "$HEAD_SHA" | grep -E '^(packages/|src/)' || true
+              exit 1
+            else
+              echo "✅ Found changesets for package changes"
+              echo ""
+              echo "Changesets:"
+              ls .changeset/*.md
+            fi
+          else
+            echo "ℹ️  No package changes detected, skipping changeset check"
+          fi
+
   test:
     runs-on: ubuntu-latest
     needs: quality