Use a separate workflow to check the diff compilation

.github/workflows/check-dist.yml

@@ -0,0 +1,35 @@
+name: Check dist
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+      - 'releases/*'
+
+jobs:
+  verify-build: # make sure the checked in dist/ folder matches the output of a rebuild
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+
+      - name: Read .nvmrc
+        id: nvm
+        run: echo ::set-output name=NVMRC::$(cat .nvmrc)
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version: ${{ steps.nvm.outputs.NVMRC }}
+
+      - name: Install NPM dependencies
+        run: npm ci
+
+      - name: Rebuild the dist/ directory
+        run: npm run build
+
+      - name: Compare the expected and actual dist/ directories
+        run: script/check-diff

.github/workflows/ci.yml

@@ -13,15 +13,20 @@ jobs:
     name: CI
     runs-on: ubuntu-latest
     steps:
-    - name: Check out code
-      uses: actions/checkout@v2
-
-    - name: Setup nodejs
-      uses: actions/setup-node@v2
+    - uses: actions/checkout@v3
       with:
-        node-version: '16'
+        ref: ${{ github.event.pull_request.head.sha }}
 
-    - name: Install dependencies
+    - name: Read .nvmrc
+      id: nvm
+      run: echo ::set-output name=NVMRC::$(cat .nvmrc)
+
+    - name: Setup Node.js
+      uses: actions/setup-node@v3
+      with:
+        node-version: ${{ steps.nvm.outputs.NVMRC }}
+
+    - name: Install NPM dependencies
       run: npm ci
 
     - name: Run linter
@@ -29,6 +34,3 @@ jobs:
 
     - name: Run tests
       run: npm test
-
-    - name: Verify the build artefact is updated
-      run: npm run build && git diff --quiet

bin/check-diff

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+# Make sure we notice any untracked files generated by the build
+git add --intent-to-add .
+git diff --quiet dist/
+retVal=$?
+if [ $retVal -ne 0 ]; then
+  echo "Detected uncommitted changes after build:"
+  git --no-pager diff dist/
+  exit 1
+fi