Extract Android sources logic to simplify plugin

paparazzi-gradle-plugin/src/main/java/app/cash/paparazzi/gradle/AndroidVariantSources.kt

@@ -0,0 +1,56 @@
+package app.cash.paparazzi.gradle
+
+import app.cash.paparazzi.gradle.utils.artifactsFor
+import com.android.build.api.variant.Variant
+import com.android.build.gradle.internal.publishing.AndroidArtifacts
+import org.gradle.api.artifacts.component.ProjectComponentIdentifier
+import org.gradle.api.file.Directory
+import org.gradle.api.file.FileCollection
+import org.gradle.api.provider.Provider
+
+/**
+ * All the relevant sources for a given Android variant.
+ */
+internal class AndroidVariantSources(
+  private val variant: Variant
+) {
+  val localResourceDirs: Provider<List<Directory>>? by lazy {
+    variant.sources.res?.all?.map { layers -> layers.flatten() }
+  }
+
+  // https://android.googlesource.com/platform/tools/base/+/96015063acd3455a76cdf1cc71b23b0828c0907f/build-system/gradle-core/src/main/java/com/android/build/gradle/tasks/MergeResources.kt#875
+  val moduleResourceDirs: FileCollection by lazy {
+    variant.runtimeConfiguration
+      .artifactsFor(AndroidArtifacts.ArtifactType.ANDROID_RES.type) { it is ProjectComponentIdentifier }
+      .artifactFiles
+  }
+
+  val aarExplodedDirs: FileCollection by lazy {
+    variant.runtimeConfiguration
+      .artifactsFor(AndroidArtifacts.ArtifactType.ANDROID_RES.type) { it !is ProjectComponentIdentifier }
+      .artifactFiles
+  }
+
+  val localAssetDirs: Provider<List<Directory>>? by lazy {
+    variant.sources.assets?.all?.map { layers -> layers.flatten() }
+  }
+
+  // https://android.googlesource.com/platform/tools/base/+/96015063acd3455a76cdf1cc71b23b0828c0907f/build-system/gradle-core/src/main/java/com/android/build/gradle/tasks/MergeResources.kt#875
+  val moduleAssetDirs: FileCollection by lazy {
+    variant.runtimeConfiguration
+      .artifactsFor(AndroidArtifacts.ArtifactType.ASSETS.type) { it is ProjectComponentIdentifier }
+      .artifactFiles
+  }
+
+  val aarAssetDirs: FileCollection by lazy {
+    variant.runtimeConfiguration
+      .artifactsFor(AndroidArtifacts.ArtifactType.ASSETS.type) { it !is ProjectComponentIdentifier }
+      .artifactFiles
+  }
+
+  val packageAwareArtifactFiles: FileCollection by lazy {
+    variant.runtimeConfiguration
+      .artifactsFor(AndroidArtifacts.ArtifactType.SYMBOL_LIST_WITH_PACKAGE_NAME.type)
+      .artifactFiles
+  }
+}

paparazzi-gradle-plugin/src/main/java/app/cash/paparazzi/gradle/PaparazziPlugin.kt

@@ -16,24 +16,24 @@
 package app.cash.paparazzi.gradle
 
 import app.cash.paparazzi.gradle.utils.artifactViewFor
-import app.cash.paparazzi.gradle.utils.artifactsFor
 import app.cash.paparazzi.gradle.utils.relativize
 import com.android.build.api.variant.AndroidComponentsExtension
 import com.android.build.api.variant.ApplicationAndroidComponentsExtension
 import com.android.build.api.variant.DynamicFeatureAndroidComponentsExtension
 import com.android.build.api.variant.HasUnitTest
 import com.android.build.api.variant.LibraryAndroidComponentsExtension
 import com.android.build.gradle.BaseExtension
-import com.android.build.gradle.internal.publishing.AndroidArtifacts.ArtifactType
 import org.gradle.api.DefaultTask
 import org.gradle.api.Plugin
 import org.gradle.api.Project
-import org.gradle.api.artifacts.component.ProjectComponentIdentifier
 import org.gradle.api.artifacts.type.ArtifactTypeDefinition
 import org.gradle.api.artifacts.type.ArtifactTypeDefinition.ARTIFACT_TYPE_ATTRIBUTE
+import org.gradle.api.file.Directory
 import org.gradle.api.file.FileCollection
 import org.gradle.api.internal.artifacts.transform.UnzipTransform
 import org.gradle.api.logging.LogLevel.LIFECYCLE
+import org.gradle.api.provider.Provider
+import org.gradle.api.provider.ProviderFactory
 import org.gradle.api.reporting.ReportingExtension
 import org.gradle.api.tasks.Delete
 import org.gradle.api.tasks.PathSensitivity
@@ -47,7 +47,11 @@ import java.util.Locale
 
 @Suppress("unused")
 public class PaparazziPlugin : Plugin<Project> {
+  private lateinit var providerFactory: ProviderFactory
+
   override fun apply(project: Project) {
+    providerFactory = project.providers
+
     val supportedPlugins = listOf("com.android.application", "com.android.library", "com.android.dynamic-feature")
     project.afterEvaluate {
       check(supportedPlugins.any { project.plugins.hasPlugin(it) }) {
@@ -114,33 +118,7 @@ public class PaparazziPlugin : Plugin<Project> {
       val gradleUserHomeDir = project.gradle.gradleUserHomeDir
       val reportOutputDir = project.extensions.getByType(ReportingExtension::class.java).baseDirectory.dir("paparazzi/${variant.name}")
 
-      val localResourceDirs = variant.sources.res?.all ?: project.provider { emptyList() }
-
-      // https://android.googlesource.com/platform/tools/base/+/96015063acd3455a76cdf1cc71b23b0828c0907f/build-system/gradle-core/src/main/java/com/android/build/gradle/tasks/MergeResources.kt#875
-
-      val moduleResourceDirs = variant.runtimeConfiguration
-        .artifactsFor(ArtifactType.ANDROID_RES.type) { it is ProjectComponentIdentifier }
-        .artifactFiles
-
-      val aarExplodedDirs = variant.runtimeConfiguration
-        .artifactsFor(ArtifactType.ANDROID_RES.type) { it !is ProjectComponentIdentifier }
-        .artifactFiles
-
-      val localAssetDirs = variant.sources.assets?.all ?: project.provider { emptyList() }
-
-      // https://android.googlesource.com/platform/tools/base/+/96015063acd3455a76cdf1cc71b23b0828c0907f/build-system/gradle-core/src/main/java/com/android/build/gradle/tasks/MergeResources.kt#875
-
-      val moduleAssetDirs = variant.runtimeConfiguration
-        .artifactsFor(ArtifactType.ASSETS.type) { it is ProjectComponentIdentifier }
-        .artifactFiles
-
-      val aarAssetDirs = variant.runtimeConfiguration
-        .artifactsFor(ArtifactType.ASSETS.type) { it !is ProjectComponentIdentifier }
-        .artifactFiles
-
-      val packageAwareArtifactFiles = variant.runtimeConfiguration
-        .artifactsFor(ArtifactType.SYMBOL_LIST_WITH_PACKAGE_NAME.type)
-        .artifactFiles
+      val sources = AndroidVariantSources(variant)
 
       val writeResourcesTask = project.tasks.register(
         "preparePaparazzi${variantSlug}Resources",
@@ -152,27 +130,19 @@ public class PaparazziPlugin : Plugin<Project> {
         val gradleHomeDir = projectDirectory.dir(project.gradle.gradleUserHomeDir.path)
 
         task.packageName.set(android.packageName())
-        task.artifactFiles.from(packageAwareArtifactFiles)
+        task.artifactFiles.from(sources.packageAwareArtifactFiles)
         task.nonTransitiveRClassEnabled.set(nonTransitiveRClassEnabled)
         task.targetSdkVersion.set(android.targetSdkVersion())
-
-        val localResourcePaths = localResourceDirs
-          .map { layers -> layers.flatten() }
-          .map { dirs -> dirs.map { projectDirectory.relativize(it.asFile) }.asReversed() }
-
-        task.projectResourceDirs.set(localResourcePaths)
-        task.moduleResourceDirs.set(moduleResourceDirs.relativize(projectDirectory))
-        task.aarExplodedDirs.set(aarExplodedDirs.relativize(gradleHomeDir))
+        task.projectResourceDirs.set(
+          sources.localResourceDirs.relativize(projectDirectory).reversed()
+        )
+        task.moduleResourceDirs.set(sources.moduleResourceDirs.relativize(projectDirectory))
+        task.aarExplodedDirs.set(sources.aarExplodedDirs.relativize(gradleHomeDir))
         task.projectAssetDirs.set(
-          run {
-            val localAssetPaths = localAssetDirs
-              .map { layers -> layers.flatten() }
-              .map { dirs -> dirs.map { projectDirectory.relativize(it.asFile) }.asReversed() }
-            val moduleAssetPaths = moduleAssetDirs.relativize(projectDirectory)
-            localAssetPaths.zip(moduleAssetPaths, List<String>::plus)
-          }
+          sources.localAssetDirs.relativize(projectDirectory).reversed()
+            .zip(sources.moduleAssetDirs.relativize(projectDirectory), List<String>::plus)
         )
-        task.aarAssetDirs.set(aarAssetDirs.relativize(gradleHomeDir))
+        task.aarAssetDirs.set(sources.aarAssetDirs.relativize(gradleHomeDir))
         task.paparazziResources.set(buildDirectory.file("intermediates/paparazzi/${variant.name}/resources.json"))
       }
 
@@ -222,16 +192,16 @@ public class PaparazziPlugin : Plugin<Project> {
         test.inputs.property("paparazzi.test.record", isRecordRun)
         test.inputs.property("paparazzi.test.verify", isVerifyRun)
 
-        test.inputs.files(localResourceDirs)
+        test.inputs.files(sources.localResourceDirs)
           .withPropertyName("paparazzi.localResourceDirs")
           .withPathSensitivity(PathSensitivity.RELATIVE)
-        test.inputs.files(moduleResourceDirs)
+        test.inputs.files(sources.moduleResourceDirs)
           .withPropertyName("paparazzi.moduleResourceDirs")
           .withPathSensitivity(PathSensitivity.RELATIVE)
-        test.inputs.files(localAssetDirs)
+        test.inputs.files(sources.localAssetDirs)
           .withPropertyName("paparazzi.localAssetDirs")
           .withPathSensitivity(PathSensitivity.RELATIVE)
-        test.inputs.files(moduleAssetDirs)
+        test.inputs.files(sources.moduleAssetDirs)
           .withPropertyName("paparazzi.moduleAssetDirs")
           .withPathSensitivity(PathSensitivity.RELATIVE)
         test.inputs.files(layoutlibNativeRuntimeFileCollection)
@@ -330,6 +300,12 @@ public class PaparazziPlugin : Plugin<Project> {
   private fun BaseExtension.targetSdkVersion(): String =
     defaultConfig.targetSdkVersion?.apiLevel?.toString()
       ?: DEFAULT_COMPILE_SDK_VERSION.toString()
+
+  private fun Provider<List<Directory>>?.relativize(directory: Directory): Provider<List<String>> =
+    this?.map { dirs -> dirs.map { directory.relativize(it.asFile) } }
+      ?: providerFactory.provider { emptyList() }
+
+  private fun <T> Provider<List<T>>.reversed(): Provider<List<T>> = this.map { it.asReversed() }
 }
 
 private const val DEFAULT_COMPILE_SDK_VERSION = 34