@ContributesRenderer code generator

Add a new KSP code generator that generates the code for `@ContributesRenderer` using Metro. The implementation is almost equivalent to the kotlin-inject implementation, except for that it's using Metro APIs. The big difference is that kotlin-inject implements map-multibindings by returning a `Pair<Abc, Def>` whereas Metro uses a `@ClassKey` annotation similar to Dagger 2. Therefore, we had to introduce the `@RendererKey` annotation specifically for Metro.

See #115

Author: vRallev

.github/workflows/ci.yml

@@ -141,7 +141,7 @@ jobs:
           gradle-encryption-key: ${{ secrets.GRADLE_ENCRYPTION_KEY }}
 
       - name: Test
-        run: ./gradlew :kotlin-inject-extensions:contribute:impl-code-generators:test --stacktrace --show-version --continue -Pksp.useKSP2=${{ matrix.use-ksp2 }}
+        run: ./gradlew :kotlin-inject-extensions:contribute:impl-code-generators:test :metro-extensions:contribute:impl-code-generators:test --stacktrace --show-version --continue -Pksp.useKSP2=${{ matrix.use-ksp2 }}
 
       - name: Upload Test Results
         uses: actions/upload-artifact@v4

buildSrc/src/main/kotlin/software/amazon/app/platform/gradle/buildsrc/BasePlugin.kt

@@ -64,6 +64,8 @@ public open class BasePlugin : Plugin<Project> {
         "${APP_PLATFORM_GROUP}:kotlin-inject-impl" to ":kotlin-inject:impl",
         "${APP_PLATFORM_GROUP}:ksp-common-public" to ":ksp-common:public",
         "${APP_PLATFORM_GROUP}:metro-public" to ":metro:public",
+        "${APP_PLATFORM_GROUP}:metro-contribute-impl-code-generators" to
+          ":metro-extensions:contribute:impl-code-generators",
         "${APP_PLATFORM_GROUP}:presenter-public" to ":presenter:public",
         "${APP_PLATFORM_GROUP}:presenter-molecule-public" to ":presenter-molecule:public",
         "${APP_PLATFORM_GROUP}:presenter-molecule-impl" to ":presenter-molecule:impl",

buildSrc/src/main/kotlin/software/amazon/app/platform/gradle/buildsrc/SdkPlugin.kt

@@ -24,11 +24,18 @@ internal object SdkPlugin {
     // :presenter:testing -> ${group}:presenter-testing:${version}
     val parent = requireNotNull(parent)
     val artifactId =
-      if (parent.name == "contribute" && parent.parent?.name == "kotlin-inject-extensions") {
-        // Change the artifact ID, because "contribute" alone is a weird name.
-        artifactId(libraryName = "kotlin-inject-contribute")
-      } else {
-        artifactId()
+      when {
+        parent.name == "contribute" && parent.parent?.name == "kotlin-inject-extensions" -> {
+          // Change the artifact ID, because "contribute" alone is a weird name.
+          artifactId(libraryName = "kotlin-inject-contribute")
+        }
+        parent.name == "contribute" && parent.parent?.name == "metro-extensions" -> {
+          // Change the artifact ID, because "contribute" alone is a weird name.
+          artifactId(libraryName = "metro-contribute")
+        }
+        else -> {
+          artifactId()
+        }
       }
     mavenPublish.coordinates(artifactId = artifactId)
     mavenPublish.pom { pom ->

kotlin-inject-extensions/contribute/impl-code-generators/src/test/kotlin/software/amazon/app/platform/inject/processor/ContributesRendererProcessorTest.kt

@@ -237,7 +237,7 @@ class ContributesRendererProcessorTest {
   }
 
   @Test
-  fun `the model type can be interred from the class hierarchy`() {
+  fun `the model type can be inferred from the class hierarchy`() {
     compile(
       """
             package software.amazon.test
@@ -261,7 +261,7 @@ class ContributesRendererProcessorTest {
   }
 
   @Test
-  fun `the model type can be interred from the class hierarchy with multiple levels`() {
+  fun `the model type can be inferred from the class hierarchy with multiple levels`() {
     compile(
       """
             package software.amazon.test

metro-extensions/contribute/impl-code-generators/build.gradle

@@ -0,0 +1,56 @@
+plugins {
+    id 'software.amazon.app.platform.lib.jvm'
+    id 'com.google.devtools.ksp'
+}
+
+appPlatformBuildSrc {
+    enablePublishing true
+}
+
+test {
+    useJUnitPlatform()
+
+    // Since Kotlin 2.0 we need more memory to run our tests.
+    maxHeapSize = "2g"
+}
+
+dependencies {
+    implementation libs.ksp.api
+
+    implementation libs.kotlin.poet
+    implementation libs.kotlin.poet.ksp
+
+    implementation libs.auto.service.annotations
+    ksp libs.auto.service.ksp
+
+    // Gives us access to annotations.
+    implementation project(':di-common:public')
+    implementation project(':ksp-common:public')
+    implementation project(':metro:public')
+    implementation project(':scope:public')
+    implementation libs.metro.runtime
+
+    testImplementation project(':ksp-common:testing')
+    testImplementation project(':metro:public')
+    testImplementation project(':presenter:public')
+    testImplementation project(':renderer:public')
+    testImplementation project(':robot:public')
+    testImplementation libs.kotlin.compile.testing.core
+    testImplementation libs.kotlin.compile.testing.ksp
+
+    // Added so that the compiler plugin is picked up in tests.
+    testImplementation libs.metro.compiler
+
+    // Bump transitive dependency.
+    testImplementation libs.kotlin.compiler.embeddable
+    testImplementation libs.ksp
+    testImplementation libs.ksp.embeddable
+}
+
+// We don't need the apiCheck in this module.
+tasks.named('apiCheck').configure {
+    it.enabled = false
+}
+tasks.named('apiDump').configure {
+    it.enabled = false
+}

metro-extensions/contribute/impl-code-generators/src/main/kotlin/software/amazon/app/platform/metro/KotlinInjectExtensionSymbolProcessorProvider.kt

@@ -0,0 +1,22 @@
+package software.amazon.app.platform.metro
+
+import com.google.auto.service.AutoService
+import com.google.devtools.ksp.processing.SymbolProcessor
+import com.google.devtools.ksp.processing.SymbolProcessorEnvironment
+import com.google.devtools.ksp.processing.SymbolProcessorProvider
+import software.amazon.app.platform.ksp.CompositeSymbolProcessor
+import software.amazon.app.platform.metro.processor.ContributesRendererProcessor
+
+/** Entry point for KSP to pick up our [SymbolProcessor]. */
+@AutoService(SymbolProcessorProvider::class)
+@Suppress("unused")
+public class KotlinInjectExtensionSymbolProcessorProvider : SymbolProcessorProvider {
+  override fun create(environment: SymbolProcessorEnvironment): SymbolProcessor {
+    return CompositeSymbolProcessor(
+      ContributesRendererProcessor(
+        codeGenerator = environment.codeGenerator,
+        logger = environment.logger,
+      )
+    )
+  }
+}

metro-extensions/contribute/impl-code-generators/src/main/kotlin/software/amazon/app/platform/metro/MetroContextAware.kt

@@ -0,0 +1,13 @@
+package software.amazon.app.platform.metro
+
+import dev.zacsweers.metro.Inject
+import dev.zacsweers.metro.Scope
+import software.amazon.app.platform.ksp.ContextAware
+
+internal interface MetroContextAware : ContextAware {
+  val injectFqName
+    get() = Inject::class.requireQualifiedName()
+
+  private val scopeFqName
+    get() = Scope::class.requireQualifiedName()
+}

metro-extensions/contribute/impl-code-generators/src/main/kotlin/software/amazon/app/platform/metro/Util.kt

@@ -0,0 +1,4 @@
+package software.amazon.app.platform.metro
+
+/** The package in which the App Platform extensions generate code. */
+internal const val METRO_LOOKUP_PACKAGE = "app.platform.inject.metro"