ci: Install Playwright in the background during E2E app builds

.github/actions/install-playwright/action.yml

@@ -7,6 +7,15 @@ inputs:
   cwd:
     description: 'The working directory to run Playwright in.'
     default: '.'
+  installed-version:
+    description:
+      'A Playwright version that an earlier run of this action already installed. Skips the install if it matches.'
+    default: ''
+
+outputs:
+  version:
+    description: 'The resolved Playwright version, empty if Playwright is not installed or the install was skipped.'
+    value: ${{ steps.playwright-version.outputs.version }}
 
 runs:
   using: 'composite'
@@ -18,8 +27,11 @@ runs:
       id: playwright-version
       run: |
         version=$(node -e "let v = ''; try { v = require('@playwright/test/package.json').version; } catch {} process.stdout.write(String(v));")
+        if [ "$version" = "$INSTALLED_VERSION" ]; then version=''; fi
         echo "version=$version" >> "$GITHUB_OUTPUT"
       shell: bash
+      env:
+        INSTALLED_VERSION: ${{ inputs.installed-version }}
       working-directory: ${{ inputs.cwd }}
 
     - name: Restore cached playwright binaries

.github/workflows/build.yml

@@ -1091,6 +1091,16 @@ jobs:
           name: build-layer-output
           path: ${{ env.BUILD_LAYER_PATH }}
 
+      # Installs the root workspace's Playwright version while the app builds. Most apps use the same version.
+      # The app's own version is only known after its build, so it gets installed then if it differs.
+      # Started after the artifact downloads: starting next to them made `download-artifact` fail to read the event file.
+      - name: Install Playwright
+        id: install-playwright
+        background: true
+        uses: ./.github/actions/install-playwright
+        with:
+          browsers: chromium
+
       - name: Prepare e2e tests
         run: yarn test:prepare
         working-directory: dev-packages/e2e-tests
@@ -1116,11 +1126,14 @@ jobs:
         env:
           SENTRY_E2E_WORKSPACE_ROOT: ${{ github.workspace }}
 
-      - name: Install Playwright
+      - wait: [install-playwright]
+
+      - name: Install Playwright for the app's version
         uses: ./.github/actions/install-playwright
         with:
           browsers: chromium
           cwd: ${{ runner.temp }}/test-application
+          installed-version: ${{ steps.install-playwright.outputs.version }}
 
       - name: Run E2E test
         working-directory: ${{ runner.temp }}/test-application
@@ -1220,6 +1233,16 @@ jobs:
           name: build-tarball-output
           path: ${{ env.TARBALL_ARTIFACT_DOWNLOAD_PATH }}
 
+      # Installs the root workspace's Playwright version while the app builds. Most apps use the same version.
+      # The app's own version is only known after its build, so it gets installed then if it differs.
+      # Started after the artifact downloads: starting next to them made `download-artifact` fail to read the event file.
+      - name: Install Playwright
+        id: install-playwright
+        background: true
+        uses: ./.github/actions/install-playwright
+        with:
+          browsers: chromium
+
       - name: Prepare E2E tests
         run: yarn test:prepare
         working-directory: dev-packages/e2e-tests
@@ -1243,11 +1266,14 @@ jobs:
         timeout-minutes: 7
         run: ${{ matrix.build-command || 'pnpm test:build' }}
 
-      - name: Install Playwright
+      - wait: [install-playwright]
+
+      - name: Install Playwright for the app's version
         uses: ./.github/actions/install-playwright
         with:
           browsers: chromium
           cwd: ${{ runner.temp }}/test-application
+          installed-version: ${{ steps.install-playwright.outputs.version }}
 
       - name: Run E2E test
         working-directory: ${{ runner.temp }}/test-application