Enable gradle build cache within each pipeline

in order to speed up the CI.

This does not enable the build cache on local dev machines.

.gitlab-ci.yml

@@ -14,6 +14,7 @@ workflow:
 
 .base:
   before_script:
+    - echo "org.gradle.caching=true" >> gradle.properties
     - test -e /etc/apt/sources.list.d/bullseye-backports.list
         || echo "deb http://deb.debian.org/debian bullseye-backports main" >> /etc/apt/sources.list
     - apt update
@@ -27,11 +28,15 @@ workflow:
     - export GRADLE_USER_HOME=$PWD/.gradle
     - export ANDROID_COMPILE_SDK=`sed -n 's,.*compileSdkVersion\s*\([0-9][0-9]*\).*,\1,p' app/build.gradle`
     - echo y | sdkmanager "platforms;android-${ANDROID_COMPILE_SDK}" > /dev/null
+    # index-v1.jar tests need SHA1 support still, TODO use apksig to validate JAR sigs
+    - sed -i 's,SHA1 denyAfter 20[0-9][0-9],SHA1 denyAfter 2024,'
+      /usr/lib/jvm/default-java/conf/security/java.security
   after_script:
     # this file changes every time but should not be cached
     - rm -f $GRADLE_USER_HOME/caches/modules-2/modules-2.lock
     - rm -fr $GRADLE_USER_HOME/caches/*/plugin-resolution/
   cache:
+    key: '${CI_PROJECT_PATH}_${CI_COMMIT_REF_NAME}_${CI_COMMIT_SHA}'
     paths:
       - .gradle/wrapper
       - .gradle/caches
@@ -52,12 +57,11 @@ workflow:
       - build/reports
     expire_in: 1 week
     when: on_failure
-  before_script:
-    # index-v1.jar tests need SHA1 support still, TODO use apksig to validate JAR sigs
-    - sed -i 's,SHA1 denyAfter 20[0-9][0-9],SHA1 denyAfter 2024,'
-      /usr/lib/jvm/default-java/conf/security/java.security
   after_script:
     - echo "Download debug artifacts from https://gitlab.com/${CI_PROJECT_PATH}/-/jobs"
+    # this file changes every time but should not be cached
+    - rm -f $GRADLE_USER_HOME/caches/modules-2/modules-2.lock
+    - rm -fr $GRADLE_USER_HOME/caches/*/plugin-resolution/
 
 .always-on-these-changes: &always-on-these-changes
   changes:

libs/database/build.gradle

@@ -96,6 +96,10 @@ dependencies {
     androidTestImplementation 'commons-io:commons-io:2.6'
 }
 
+plugins.withId("kotlin-kapt") {
+    kapt.useBuildCache = true
+}
+
 signing {
     useGpgCmd()
 }