Adjust workflow to work for forked PRs (#1635)

Save the triggering PR as an artifact when building the gem as it will
be required by the triggered workflow to determine the PR that triggered
it since Github does not populate the event data if the PR is a forked
PR.

.github/workflows/build-gem-package-notify.yml

@@ -11,6 +11,35 @@ jobs:
     name: Add artifact links to pull request
     runs-on: ubuntu-22.04
     steps:
+      - name: 'Download artifact'
+        uses: actions/github-script@v5
+        with:
+          script: |
+            const artifacts = await github.paginate(
+              github.rest.actions.listWorkflowRunArtifacts, {
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                run_id: ${{github.event.workflow_run.id }},
+              },
+            );
+            if (!artifacts.length) {
+              return core.error(`No artifacts found`);
+            }
+            var matchArtifact = artifacts.find((artifact) => {
+              return artifact.name == "pr"
+            });
+            if (matchArtifact === undefined) {
+              return core.error(`No PR artifact found`);
+            }
+            var download = await github.rest.actions.downloadArtifact({
+               owner: context.repo.owner,
+               repo: context.repo.repo,
+               artifact_id: matchArtifact.id,
+               archive_format: 'zip',
+            });
+            var fs = require('fs');
+            fs.writeFileSync('${{github.workspace}}/pr.zip', Buffer.from(download.data));
+      - run: unzip pr.zip
       - uses: actions/github-script@v5
         with:
           # This snippet is public-domain, taken from
@@ -37,21 +66,19 @@ jobs:
             }
             const {owner, repo} = context.repo;
             const run_id = ${{github.event.workflow_run.id}};
-            const pull_requests = ${{ toJSON(github.event.workflow_run.pull_requests) }};
-            if (!pull_requests.length) {
-              return core.error("This workflow doesn't match any pull requests!");
-            }
             const artifacts = await github.paginate(
               github.rest.actions.listWorkflowRunArtifacts, {owner, repo, run_id});
             if (!artifacts.length) {
               return core.error(`No artifacts found`);
             }
+            var fs = require('fs');
+            var issue_number = Number(fs.readFileSync('./NR'));
             let body = `Download the latest artifacts for this pull request here:\n`;
             for (const art of artifacts) {
+              if (art.name == 'pr') {
+                continue;
+              }
               body += `\n* [${art.name}.zip](https://nightly.link/${owner}/${repo}/actions/artifacts/${art.id}.zip)`;
             }
             core.info("Review thread message body:", body);
-            for (const pr of pull_requests) {
-              await upsertComment(owner, repo, pr.number,
-                "nightly-link", body);
-            }
+            await upsertComment(owner, repo, issue_number, "nightly-link", body);

.github/workflows/publish-gem-package.yml

@@ -37,6 +37,18 @@ jobs:
       with:
         name: ${{ steps.artifact_name.outputs.artifact_name }}
         path: pkg/**.gem
+    # workflow_run doesn't receive a list of the pull requests triggering if it's
+    # from a fork, so use this to save the PR number for use in the notify job
+    - name: Save PR number
+      if: github.ref != 'refs/heads/main'
+      run: |
+        mkdir -p ./pr
+        echo ${{ github.event.number }} > ./pr/NR
+    - uses: actions/upload-artifact@v2
+      if: github.ref != 'refs/heads/main'
+      with:
+        name: pr
+        path: pr/
 
   publish-package:
     needs: build-package