ci: key the browser cache on the Playwright version alone (#182)

* ci: key the browser cache on the Playwright version alone

Hashing the whole version catalog meant any dependency bump paid the
60s cold browser install; the key now uses the Playwright version
itself, so the cache only invalidates when the browsers actually
change. Also answers the old inline comment wondering whether a
smarter key exists.

* ci: fix the canary's browser cache key too

The canary still carried the original key on reference-app/
build.gradle.kts — the earlier chromium-only change silently missed it
because its text differed — so it kept the stale-cache bug: a
Playwright bump would restore old browsers that
PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD then refuses to replace. Now keyed on
the Playwright version like the CI workflow.

Author: ardetrick

.github/workflows/gradle.yml

@@ -28,14 +28,18 @@ jobs:
           distribution: 'temurin'
       - name: Set up Gradle
         uses: gradle/actions/setup-gradle@v6
+      # Key the browser cache on the Playwright version alone so unrelated dependency
+      # bumps in the catalog do not trigger a browser reinstall.
+      - name: Resolve Playwright version
+        id: playwright-version
+        run: echo "version=$(grep -m1 '^playwright = ' gradle/libs.versions.toml | cut -d'"' -f2)" >> "$GITHUB_OUTPUT"
       - name: Setup ms-playwright cache
         id: setup-ms-playwright-cache
         uses: actions/cache@v6
         with:
           # Some dependencies are downloaded to this directory
           path: /home/runner/.cache/ms-playwright
-          # There probably is a smarter way to create this key but this should be ok for now.
-          key: ms-playwright-chromium-${{ runner.os }}-${{ hashFiles('gradle/libs.versions.toml') }}
+          key: ms-playwright-chromium-${{ runner.os }}-${{ steps.playwright-version.outputs.version }}
       - name: Install Playwright Dependencies
         if: steps.setup-ms-playwright-cache.outputs.cache-hit != 'true'
         # Chromium only — the only browser the tests use; one Gradle invocation.

.github/workflows/upstream-canary.yml

@@ -62,12 +62,17 @@ jobs:
           distribution: 'temurin'
       - name: Set up Gradle
         uses: gradle/actions/setup-gradle@v6
+      # Key the browser cache on the Playwright version alone so unrelated dependency
+      # bumps do not trigger a browser reinstall.
+      - name: Resolve Playwright version
+        id: playwright-version
+        run: echo "version=$(grep -m1 '^playwright = ' gradle/libs.versions.toml | cut -d'"' -f2)" >> "$GITHUB_OUTPUT"
       - name: Setup ms-playwright cache
         id: setup-ms-playwright-cache
         uses: actions/cache@v6
         with:
           path: /home/runner/.cache/ms-playwright
-          key: ms-playwright-cache-${{ runner.os }}-${{ hashFiles('reference-app/build.gradle.kts') }}
+          key: ms-playwright-chromium-${{ runner.os }}-${{ steps.playwright-version.outputs.version }}
       - name: Install Playwright Dependencies
         if: steps.setup-ms-playwright-cache.outputs.cache-hit != 'true'
         # Chromium only — the only browser the tests use; one Gradle invocation.