Fetch PR details first to get the correct commit sha

Author: st0012

.github/workflows/cloudflare-preview.yml

@@ -26,12 +26,37 @@ jobs:
         with:
           ref: ${{ github.event.pull_request.head.ref }}
 
+      # For fork PRs that are manually triggered, we need to get the PR details first
+      - name: Get PR details for fork
+        if: ${{ github.event_name == 'workflow_dispatch' }}
+        id: pr_details
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const prNumber = ${{ inputs.pull_request_number }};
+
+            // Get PR details to find the head SHA
+            const { data: pr } = await github.rest.pulls.get({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              pull_number: prNumber
+            });
+
+            console.log(`Fork PR head SHA: ${pr.head.sha}`);
+            console.log(`Fork PR head ref: ${pr.head.ref}`);
+            console.log(`Fork PR repo: ${pr.head.repo.full_name}`);
+
+            // Set outputs for checkout step
+            core.setOutput('head_sha', pr.head.sha);
+            core.setOutput('head_ref', pr.head.ref);
+            core.setOutput('repo_full_name', pr.head.repo.full_name);
+
       - name: Checkout for manually triggered fork PR
         if: ${{ github.event_name == 'workflow_dispatch' }}
         uses: actions/checkout@v4
         with:
-          ref: ${{ github.sha }}
-          repository: ${{ github.event.pull_request.head.repo.full_name }}
+          ref: ${{ steps.pr_details.outputs.head_sha }}
+          repository: ${{ steps.pr_details.outputs.repo_full_name }}
 
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
@@ -77,8 +102,8 @@ jobs:
             if ('${{ github.event_name }}' === 'pull_request') {
               commitSha = '${{ github.event.pull_request.head.sha }}';
             } else {
-              // For workflow_dispatch, get the SHA from the current commit
-              commitSha = '${{ github.sha }}';
+              // For workflow_dispatch, get the SHA from the PR details
+              commitSha = '${{ steps.pr_details.outputs.head_sha }}';
             }
 
             // Get all comments on the PR