Create diff_comment.yml

.github/workflows/diff_comment.yml

@@ -0,0 +1,29 @@
+name: OpenAPI diff comment
+
+on:
+  workflow_run:
+    workflows: ["Lint and validate OpenAPI specs"]
+    types: [completed]
+
+jobs:
+  comment:
+    runs-on: ubuntu-latest
+    if: github.event.workflow_run.outputs.diff_generated == 'openapi-diff-log'
+    permissions:
+      issues: write
+    steps:
+      - name: Download diff
+        uses: actions/download-artifact@v4
+        with:
+          name: openapi-diff-log
+      - name: Create PR comment
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const diff = require('fs').readFileSync('diff.md', 'utf8');
+            github.rest.issues.createComment({
+              issue_number: github.event.workflow_run.pull_requests[0].number, 
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: '## OpenAPI diff:\n\n' + diff
+            })