Fix gradle cache in CI.

Most of the tests in this repo are UI tests, so it would be really nice to not build the entire codebase twice to start running them.

I decreased the timeout as well since test shards no longer need to re-build.

Author: zach-klippenstein

.github/workflows/kotlin.yml

@@ -6,10 +6,7 @@ on:
   pull_request:
 
 env:
-  # Must use $HOME here, NOT a tilde, because of the order in which bash does expansion:
-  # Tilde happens before variables, so will be used literally, whereas $HOME will be
-  # recursively expanded.
-  GRADLE_CACHE_PATH: $HOME/.gradle/caches
+  GRADLE_HOME: ${{ github.workspace }}/gradle-home
 
 jobs:
   assemble:
@@ -29,7 +26,7 @@ jobs:
       - name: Cache gradle dependencies
         uses: actions/cache@v1
         with:
-          path: ${{ env.GRADLE_CACHE_PATH }}
+          path: ${{ env.GRADLE_HOME }}/caches
           # Include the SHA in the hash so this step always adds a cache entry. If we didn't use the SHA, the artifacts
           # would only get cached once for each build config hash.
           # Don't use ${{ runner.os }} in the key so we don't re-assemble for UI tests.
@@ -47,13 +44,13 @@ jobs:
       # and there's no way to modify the cache after the job that created it finishes.
       - name: Clean gradle build cache to assemble fresh
         run: |
-          ls -lhrt $GRADLE_CACHE_PATH || true
-          rm -rf $GRADLE_CACHE_PATH/build-cache-1
-          ls -lhrt $GRADLE_CACHE_PATH || true
+          ls -lhrt "$GRADLE_HOME/caches" || true
+          rm -rf "$GRADLE_HOME/caches/build-cache-1"
+          ls -lhrt "$GRADLE_HOME/caches" || true
 
       ## Actual task
       - name: Assemble with gradle
-        run: ./gradlew assemble --build-cache --no-daemon --stacktrace
+        run: ./gradlew assemble --build-cache --no-daemon --stacktrace --gradle-user-home "$GRADLE_HOME"
 
   # Runs all check tasks in parallel.
   check:
@@ -84,20 +81,20 @@ jobs:
       - name: Cache build artifacts
         uses: actions/cache@v1
         with:
-          path: ${{ env.GRADLE_CACHE_PATH }}
+          path: ${{ env.GRADLE_HOME }}/caches
           # Don't set restore-keys so cache is always only valid for the current build config.
           # Also don't use ${{ runner.os }} in the key so we don't re-assemble for UI tests.
           key: gradle-${{ hashFiles('**/gradle/wrapper/gradle-wrapper.properties') }}-${{ hashFiles('**/*.gradle*') }}-${{ hashFiles('**/buildSrc/**') }}-${{ github.sha }}
 
       ## Actual task
       - name: Check with Gradle
-        run: ./gradlew ${{ matrix.gradle-task }} --build-cache --no-daemon --stacktrace
+        run: ./gradlew ${{ matrix.gradle-task }} --build-cache --no-daemon --stacktrace --gradle-user-home "$GRADLE_HOME"
 
   instrumentation-tests:
     name: Instrumentation tests
     needs: assemble
     runs-on: macos-latest
-    timeout-minutes: 20
+    timeout-minutes: 15
     strategy:
       # Allow tests to continue on other devices if they fail on one device.
       fail-fast: false
@@ -119,7 +116,7 @@ jobs:
       - name: Cache build artifacts
         uses: actions/cache@v1
         with:
-          path: ${{ env.GRADLE_CACHE_PATH }}
+          path: ${{ env.GRADLE_HOME }}/caches
           # Don't set restore-keys so cache is always only valid for the current build config.
           # Also don't use ${{ runner.os }} in the key so we don't re-assemble for UI tests.
           key: gradle-${{ hashFiles('**/gradle/wrapper/gradle-wrapper.properties') }}-${{ hashFiles('**/*.gradle*') }}-${{ hashFiles('**/buildSrc/**') }}-${{ github.sha }}
@@ -130,4 +127,4 @@ jobs:
         with:
           api-level: ${{ matrix.api-level }}
           arch: x86_64
-          script: ./gradlew connectedCheck --build-cache --no-daemon --stacktrace
+          script: ./gradlew connectedCheck --build-cache --no-daemon --stacktrace --gradle-user-home "$GRADLE_HOME"