Fixed prettier actions (alshedivat#2113)

After some thorough testing, finally made prettier on PR work. Since an
html file can't be used as comment on GitHub, changed to simply point to
the action that failed and to the file containing the html diff.

Signed-off-by: George Araújo <george.gcac@gmail.com>

.github/workflows/prettier-on-pr.yml

@@ -0,0 +1,45 @@
+name: Prettier code formatter (PR)
+
+on:
+  pull_request:
+    branches:
+      - master
+      - main
+
+jobs:
+  check:
+    # available images: https://github.com/actions/runner-images#available-images
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout 🛎️
+        uses: actions/checkout@v4
+      - name: Setup Node.js ⚙️
+        uses: actions/setup-node@v4
+      - name: Install Prettier 💾
+        run: npm install --save-dev --save-exact prettier @shopify/prettier-plugin-liquid
+      - name: Prettier Check 🔎
+        id: prettier
+        run: npx prettier . --check
+      - name: Create diff 📝
+        # https://docs.github.com/en/actions/learn-github-actions/expressions#failure
+        if: ${{ failure() }}
+        run: |
+          npx prettier . --write
+          git diff -- . ':(exclude)package-lock.json' ':(exclude)package.json' > diff.txt
+          npm install -g diff2html-cli
+          diff2html -i file -s side -F diff.html -- diff.txt
+      - name: Upload html diff ⬆️
+        id: artifact-upload
+        if: ${{ failure() && steps.prettier.conclusion == 'failure' }}
+        uses: actions/upload-artifact@v4
+        with:
+          name: HTML Diff
+          path: diff.html
+          retention-days: 7
+      - name: PR comment with diff 💬
+        if: ${{ failure() && steps.prettier.conclusion == 'failure' }}
+        uses: thollander/actions-comment-pull-request@v2
+        with:
+          comment_tag: prettier-failed
+          message: |
+            Failed [prettier code check](${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}). Check [this file](${{ steps.artifact-upload.outputs.artifact-url }}) for more information.

.github/workflows/prettier.yml → .github/workflows/prettier-on-push.yml

@@ -1,10 +1,6 @@
-name: Prettier code formatter
+name: Prettier code formatter (push)
 
 on:
-  pull_request:
-    branches:
-      - master
-      - main
   push:
     branches:
       - master
@@ -32,10 +28,11 @@ jobs:
           git diff -- . ':(exclude)package-lock.json' ':(exclude)package.json' > diff.txt
           npm install -g diff2html-cli
           diff2html -i file -s side -F diff.html -- diff.txt
-      - name: Upload html diff
+      - name: Upload html diff ⬆️
+        id: artifact-upload
         if: ${{ failure() && steps.prettier.conclusion == 'failure' }}
         uses: actions/upload-artifact@v4
         with:
           name: HTML Diff
           path: diff.html
-          retention-days: 3
+          retention-days: 7