ci: comment on PRs for helpful fixes (#7451)

A new action to comment on PRs that come from forks help contributors
fix their errors

Author: mscolnick

.github/actions/pr-comment-on-failure/action.yaml

@@ -0,0 +1,63 @@
+name: "PR Comment on Failure"
+description: "Comments on PRs from forks when checks fail"
+inputs:
+  check-name:
+    description: "The name of the check that failed"
+    required: true
+  command:
+    description: "The command that contributors should run"
+    required: true
+  github-token:
+    description: "GitHub token for commenting"
+    required: true
+
+runs:
+  using: "composite"
+  steps:
+    - name: Comment on PR
+      if: github.event.pull_request.head.repo.fork == true
+      uses: actions/github-script@v7
+      with:
+        github-token: ${{ inputs.github-token }}
+        script: |
+          const checkName = '${{ inputs.check-name }}';
+          const command = '${{ inputs.command }}';
+
+          const body = `👋 It looks like the **${checkName}** check failed.
+
+          To fix this locally, please run:
+
+          \`\`\`bash
+          ${command}
+          \`\`\`
+          `;
+
+          // Check if we already commented
+          const { data: comments } = await github.rest.issues.listComments({
+            owner: context.repo.owner,
+            repo: context.repo.repo,
+            issue_number: context.issue.number,
+          });
+
+          const botComment = comments.find(comment =>
+            comment.user.type === 'Bot' &&
+            comment.body.includes(checkName)
+          );
+
+          if (botComment) {
+            // Update existing comment
+            await github.rest.issues.updateComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              comment_id: botComment.id,
+              body: body
+            });
+          } else {
+            // Create new comment
+            await github.rest.issues.createComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.issue.number,
+              body: body
+            });
+          }

.github/workflows/test_be.yaml

@@ -7,6 +7,7 @@ on:
 
 permissions:
   contents: read
+  pull-requests: write
 
 env:
   MARIMO_SKIP_UPDATE_CHECK: 1
@@ -46,8 +47,17 @@ jobs:
         uses: pypa/hatch@install
 
       - name: 📚 Build docs
+        id: docs
         run: hatch run docs:build --strict
 
+      - name: Comment on docs failure
+        if: failure() && steps.docs.outcome == 'failure'
+        uses: ./.github/actions/pr-comment-on-failure
+        with:
+          check-name: "docs build"
+          command: "hatch run docs:build --strict"
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
   test_check:
     needs: changes
     if: ${{ needs.changes.outputs.backend == 'true' }}
@@ -64,11 +74,29 @@ jobs:
         uses: pypa/hatch@install
 
       - name: 🧹 Lint
+        id: lint
         run: hatch run lint
 
       - name: 🔍 Typecheck
+        id: typecheck
         run: hatch run typecheck:check
 
+      - name: Comment on lint failure
+        if: failure() && steps.lint.outcome == 'failure'
+        uses: ./.github/actions/pr-comment-on-failure
+        with:
+          check-name: "lint"
+          command: "hatch run lint"
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Comment on typecheck failure
+        if: failure() && steps.typecheck.outcome == 'failure'
+        uses: ./.github/actions/pr-comment-on-failure
+        with:
+          check-name: "typecheck"
+          command: "hatch run typecheck:check"
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
   # For PRs, we only run the tests for the changed files.
   # If there is a `test-all` label, we run the tests across unchanged files as well.
   test_python:

.github/workflows/test_fe.yaml

@@ -1,6 +1,7 @@
 name: Test FE
 permissions:
   contents: read
+  pull-requests: write
 
 on:
   push:
@@ -51,11 +52,29 @@ jobs:
 
       - name: 📦 pnpm dedupe
         if: github.event_name == 'pull_request'
+        id: dedupe
         run: pnpm dedupe --check
 
       - name: 🧹 Lint
+        id: lint
         run: pnpm turbo lint
 
+      - name: Comment on lint failure
+        if: failure() && steps.lint.outcome == 'failure'
+        uses: ./.github/actions/pr-comment-on-failure
+        with:
+          check-name: "lint"
+          command: "pnpm turbo lint"
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Comment on dedupe failure
+        if: failure() && steps.dedupe.outcome == 'failure'
+        uses: ./.github/actions/pr-comment-on-failure
+        with:
+          check-name: "dedupe"
+          command: "pnpm dedupe"
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
   test_frontend:
     needs: changes
     if: ${{ needs.changes.outputs.frontend == 'true' }}
@@ -80,11 +99,29 @@ jobs:
         uses: ./.github/actions/install
 
       - name: 🔎 Type check
+        id: typecheck
         run: pnpm turbo typecheck
 
       - name: 🧪 Test
+        id: test
         run: pnpm turbo test
 
+      - name: Comment on typecheck failure
+        if: failure() && steps.typecheck.outcome == 'failure'
+        uses: ./.github/actions/pr-comment-on-failure
+        with:
+          check-name: "typecheck"
+          command: "pnpm turbo typecheck"
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Comment on test failure
+        if: failure() && steps.test.outcome == 'failure'
+        uses: ./.github/actions/pr-comment-on-failure
+        with:
+          check-name: "test"
+          command: "pnpm turbo test"
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
   build_frontend:
     needs: changes
     if: ${{ needs.changes.outputs.frontend == 'true' }}
@@ -120,6 +157,7 @@ jobs:
           fi
 
       - name: 📦 Build
+        id: build
         run: pnpm turbo build
         env:
           NODE_ENV: production
@@ -133,3 +171,11 @@ jobs:
           npm version 0.0.0 --no-git-tag-version
           pnpm turbo build:islands
           ./islands/validate.sh
+
+      - name: Comment on build failure
+        if: failure() && steps.build.outcome == 'failure'
+        uses: ./.github/actions/pr-comment-on-failure
+        with:
+          check-name: "build"
+          command: "pnpm turbo build"
+          github-token: ${{ secrets.GITHUB_TOKEN }}