build(android): Download Robolectric android-all jars with Gradle

build-logic/build.gradle.kts

@@ -42,6 +42,10 @@ gradlePlugin {
       id = "io.sentry.animalsniffer.android"
       implementationClass = "io.sentry.gradle.SentryAnimalSnifferAndroidPlugin"
     }
+    register("sentryRobolectric") {
+      id = "io.sentry.robolectric"
+      implementationClass = "io.sentry.gradle.SentryRobolectricPlugin"
+    }
     register("sentrySpringBootMatrix") {
       id = "io.sentry.spring-boot-matrix"
       implementationClass = "io.sentry.gradle.SpringBootMatrixPlugin"

build-logic/src/main/kotlin/io/sentry/gradle/SentryRobolectricPlugin.kt

@@ -0,0 +1,115 @@
+package io.sentry.gradle
+
+import com.android.build.api.dsl.LibraryExtension
+import java.util.Properties
+import org.gradle.api.DefaultTask
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+import org.gradle.api.file.ConfigurableFileCollection
+import org.gradle.api.file.RegularFileProperty
+import org.gradle.api.provider.MapProperty
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.InputFiles
+import org.gradle.api.tasks.Internal
+import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.PathSensitive
+import org.gradle.api.tasks.PathSensitivity
+import org.gradle.api.tasks.TaskAction
+import org.gradle.process.CommandLineArgumentProvider
+import org.gradle.work.DisableCachingByDefault
+
+/**
+ * The android-all jars our Robolectric tests run against, by API level. Robolectric picks the
+ * version for each level itself (see its DefaultSdkProvider), so a Robolectric upgrade can change
+ * them, and a test on a level missing here fails with "no artifacts found for
+ * org.robolectric:android-all-instrumented:...".
+ */
+private val ANDROID_ALL_VERSIONS =
+  mapOf(
+    21 to "5.0.2_r3-robolectric-r0",
+    24 to "7.0.0_r1-robolectric-r1",
+    28 to "9-robolectric-4913185-2",
+    29 to "10-robolectric-5803371",
+    30 to "11-robolectric-6757853",
+    31 to "12-robolectric-7732740",
+    33 to "13-robolectric-9030017",
+    35 to "15-robolectric-12650502",
+  )
+
+/** The instrumentation revision Robolectric appends to every android-all version. */
+private const val ANDROID_ALL_INSTRUMENTATION = "i7"
+
+/**
+ * Has Gradle download the android-all jars that Robolectric runs tests against, instead of
+ * Robolectric fetching them from Maven Central while the tests run.
+ *
+ * Gradle caches them with every other dependency, so CI restores them with the Gradle cache, and
+ * fetches them before any test JVM starts. See
+ * https://robolectric.org/blog/2023/11/11/improving-android-all-downloading/. Unlike the post,
+ * which copies the jars into `robolectric.dependency.dir`, the tests read them straight from
+ * Gradle's cache through a `robolectric-deps.properties` file, so no module keeps a 1 GB copy.
+ */
+class SentryRobolectricPlugin : Plugin<Project> {
+  override fun apply(project: Project) {
+    val coordinatesToJar =
+      ANDROID_ALL_VERSIONS.values.associate { version ->
+        val coordinates =
+          "org.robolectric:android-all-instrumented:$version-$ANDROID_ALL_INSTRUMENTATION"
+        // One configuration per jar, because resolving them together would keep only the highest
+        // version.
+        coordinates to
+          project.configurations.detachedConfiguration(project.dependencies.create(coordinates))
+      }
+
+    val writeDeps =
+      project.tasks.register("writeRobolectricDeps", WriteRobolectricDeps::class.java) {
+        coordinatesToJar.forEach { (coordinates, jar) ->
+          jars.put(coordinates, jar.elements.map { it.single().asFile.absolutePath })
+        }
+        propertiesFile.set(project.layout.buildDirectory.file("robolectric/deps.properties"))
+      }
+
+    project.plugins.withId("com.android.library") {
+      project.extensions.getByType(LibraryExtension::class.java).testOptions.unitTests.all { test ->
+        // The properties file holds absolute paths, so it can't be a test input without breaking
+        // build cache hits across machines. The jars are the input instead.
+        test.dependsOn(writeDeps)
+        test.jvmArgumentProviders.add(
+          project.objects.newInstance(RobolectricDepsArgument::class.java).apply {
+            androidAllJars.from(coordinatesToJar.values)
+            propertiesFile.set(writeDeps.flatMap { it.propertiesFile })
+          }
+        )
+      }
+    }
+  }
+}
+
+/**
+ * Writes the file Robolectric's PropertiesDependencyResolver reads: each android-all coordinate
+ * mapped to its jar.
+ */
+@DisableCachingByDefault(because = "Writing a few lines is cheaper than caching them")
+abstract class WriteRobolectricDeps : DefaultTask() {
+  @get:Input abstract val jars: MapProperty<String, String>
+
+  @get:OutputFile abstract val propertiesFile: RegularFileProperty
+
+  @TaskAction
+  fun write() {
+    val properties = Properties()
+    properties.putAll(jars.get())
+    propertiesFile.get().asFile.outputStream().use { properties.store(it, null) }
+  }
+}
+
+abstract class RobolectricDepsArgument : CommandLineArgumentProvider {
+  @get:InputFiles
+  @get:PathSensitive(PathSensitivity.NONE)
+  abstract val androidAllJars: ConfigurableFileCollection
+
+  @get:Internal abstract val propertiesFile: RegularFileProperty
+
+  override fun asArguments(): List<String> =
+    listOf("-Drobolectric-deps.properties=${propertiesFile.get().asFile.absolutePath}")
+}

gradle/libs.versions.toml

@@ -306,6 +306,7 @@ okhttp-mockwebserver4 = { module = "com.squareup.okhttp3:mockwebserver", version
 okhttp-tls = { module = "com.squareup.okhttp3:okhttp-tls", version.ref = "okhttp" }
 okio = { module = "com.squareup.okio:okio", version = "1.13.0" }
 rhino = { module = "org.mozilla:rhino", version = "1.8.0" }
+# Upgrading Robolectric can change the android-all jars it needs, see SentryRobolectricPlugin.
 roboelectric = { module = "org.robolectric:robolectric", version = "4.15" }
 
 [bundles]

sentry-android-core/build.gradle.kts

@@ -12,6 +12,7 @@ plugins {
   id("io.sentry.jdk-target")
   id("io.sentry.publish")
   id("io.sentry.api-validation")
+  id("io.sentry.robolectric")
 }
 
 android {

sentry-android-distribution/build.gradle.kts

@@ -9,6 +9,7 @@ plugins {
   id("io.sentry.jdk-target")
   id("io.sentry.publish")
   id("io.sentry.api-validation")
+  id("io.sentry.robolectric")
 }
 
 android {

sentry-android-navigation/build.gradle.kts

@@ -11,6 +11,7 @@ plugins {
   id("io.sentry.jdk-target")
   id("io.sentry.publish")
   id("io.sentry.api-validation")
+  id("io.sentry.robolectric")
 }
 
 android {

sentry-android-navigation3/build.gradle.kts

@@ -12,6 +12,7 @@ plugins {
   id("io.sentry.jdk-target")
   id("io.sentry.publish")
   id("io.sentry.api-validation")
+  id("io.sentry.robolectric")
 }
 
 android {

sentry-android-ndk-outproc/build.gradle.kts

@@ -8,6 +8,7 @@ plugins {
   id("io.sentry.jdk-target")
   id("io.sentry.publish")
   id("io.sentry.api-validation")
+  id("io.sentry.robolectric")
 }
 
 android {

sentry-android-replay/build.gradle.kts

@@ -13,6 +13,7 @@ plugins {
   id("io.sentry.jdk-target")
   id("io.sentry.publish")
   id("io.sentry.api-validation")
+  id("io.sentry.robolectric")
 }
 
 android {

sentry-compose/build.gradle.kts

@@ -16,6 +16,7 @@ plugins {
   id("io.sentry.jdk-target")
   id("io.sentry.publish.multiplatform")
   id("io.sentry.api-validation")
+  id("io.sentry.robolectric")
 }
 
 kotlin {