Match mypy primer comment code (#13318)

These actions diverged, making them more closely match makes it easier
to maintain

.github/workflows/mypy_primer.yml

@@ -57,18 +57,35 @@ jobs:
             --output concise \
             | tee diff_${{ matrix.shard-index }}.txt
           ) || [ $? -eq 1 ]
-      - name: Upload mypy_primer diff
-        uses: actions/upload-artifact@v4
-        with:
-          name: mypy_primer_diff_${{ matrix.shard-index }}
-          path: diff_${{ matrix.shard-index }}.txt
       - if: ${{ matrix.shard-index == 0 }}
         name: Save PR number
         run: |
           echo ${{ github.event.pull_request.number }} | tee pr_number.txt
-      - if: ${{ matrix.shard-index == 0 }}
-        name: Upload PR number
+      - name: Upload mypy_primer diff + PR number
         uses: actions/upload-artifact@v4
+        if: ${{ matrix.shard-index == 0 }}
         with:
-          name: mypy_primer_diff_pr_number
-          path: pr_number.txt
+          name: mypy_primer_diffs-${{ matrix.shard-index }}
+          path: |
+            diff_${{ matrix.shard-index }}.txt
+            pr_number.txt
+      - name: Upload mypy_primer diff
+        uses: actions/upload-artifact@v4
+        if: ${{ matrix.shard-index != 0 }}
+        with:
+          name: mypy_primer_diffs-${{ matrix.shard-index }}
+          path: diff_${{ matrix.shard-index }}.txt
+
+  join_artifacts:
+    name: Join artifacts
+    runs-on: ubuntu-latest
+    needs: [mypy_primer]
+    permissions:
+      contents: read
+    steps:
+      - name: Merge artifacts
+        uses: actions/upload-artifact/merge@v4
+        with:
+          name: mypy_primer_diffs
+          pattern: mypy_primer_diffs-*
+          delete-merged: true

.github/workflows/mypy_primer_comment.yml

@@ -1,4 +1,4 @@
-name: Post mypy_primer comment
+name: Comment with mypy_primer diff
 
 on:
   workflow_run:
@@ -14,8 +14,8 @@ permissions:
 jobs:
   comment:
     name: Comment PR from mypy_primer
-    if: ${{ github.event.workflow_run.conclusion == 'success' }}
     runs-on: ubuntu-latest
+    if: ${{ github.event.workflow_run.conclusion == 'success' }}
     steps:
       - name: Download diffs
         uses: actions/github-script@v7
@@ -27,20 +27,18 @@ jobs:
                repo: context.repo.repo,
                run_id: ${{ github.event.workflow_run.id }},
             });
-            const matchArtifacts = artifacts.data.artifacts.filter((artifact) =>
-              artifact.name.startsWith("mypy_primer_diff"));
+            const [matchArtifact] = artifacts.data.artifacts.filter((artifact) =>
+              artifact.name == "mypy_primer_diffs");
 
-            for (const matchArtifact of matchArtifacts) {
-              const download = await github.rest.actions.downloadArtifact({
-                 owner: context.repo.owner,
-                 repo: context.repo.repo,
-                 artifact_id: matchArtifact.id,
-                 archive_format: "zip",
-              });
-              fs.writeFileSync(`${matchArtifact.name}.zip`, Buffer.from(download.data));
-            }
+            const download = await github.rest.actions.downloadArtifact({
+               owner: context.repo.owner,
+               repo: context.repo.repo,
+               artifact_id: matchArtifact.id,
+               archive_format: "zip",
+            });
+            fs.writeFileSync("diff.zip", Buffer.from(download.data));
 
-      - run: for file in *.zip; do unzip $file; done
+      - run: unzip diff.zip
       - run: |
           cat diff_*.txt | tee fulldiff.txt
 
@@ -48,7 +46,7 @@ jobs:
         id: post-comment
         uses: actions/github-script@v7
         with:
-          github-token: ${{secrets.GITHUB_TOKEN}}
+          github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |
             const fs = require('fs')
             let data = fs.readFileSync('fulldiff.txt', { encoding: 'utf8' })
@@ -61,6 +59,9 @@ jobs:
               data = truncated_data + `\n\n... (truncated ${lines_truncated} lines) ...\n`
             }
 
+            console.log("Diff from mypy_primer:")
+            console.log(data)
+
             let body
             if (data.trim()) {
               body = 'Diff from [mypy_primer](https://github.com/hauntsaninja/mypy_primer), showing the effect of this PR on open source code:\n```diff\n' + data + '```'