slackhq · ZacSweers · Jun 30, 2025 · Jun 27, 2025 · Jun 28, 2025 · Jun 28, 2025
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -4,6 +4,8 @@ Changelog
 Unreleased
 ----------
 
+- Fix `@AssistedFactory` code gen for Metro to use standard nested class semantics.
+
 0.29.0
 ------
 

diff --git a/circuit-codegen/src/main/kotlin/com/slack/circuit/codegen/CircuitSymbolProcessorProvider.kt b/circuit-codegen/src/main/kotlin/com/slack/circuit/codegen/CircuitSymbolProcessorProvider.kt
@@ -23,10 +23,8 @@ import com.google.devtools.ksp.symbol.KSClassDeclaration
 import com.google.devtools.ksp.symbol.KSDeclaration
 import com.google.devtools.ksp.symbol.KSFunctionDeclaration
 import com.google.devtools.ksp.symbol.KSType
-import com.google.devtools.ksp.symbol.KSValueParameter
 import com.google.devtools.ksp.symbol.Visibility
 import com.slack.circuit.codegen.CodegenMode.KOTLIN_INJECT_ANVIL
-import com.slack.circuit.codegen.CodegenMode.METRO
 import com.squareup.kotlinpoet.ClassName
 import com.squareup.kotlinpoet.CodeBlock
 import com.squareup.kotlinpoet.FileSpec
@@ -427,7 +425,7 @@ private class CircuitSymbolProcessor(
         val creatorOrConstructor: KSFunctionDeclaration?
         val targetClass: KSClassDeclaration
         if (isAssisted) {
-          if (codegenMode == KOTLIN_INJECT_ANVIL || codegenMode == METRO) {
+          if (codegenMode == KOTLIN_INJECT_ANVIL) {
             creatorOrConstructor = injectableConstructor
             targetClass = declaration
           } else {
@@ -519,46 +517,6 @@ private class CircuitSymbolProcessor(
                 constructorParams.add(ParameterSpec.builder("factory", factoryLambda).build())
                 CodeBlock.of("factory(%L)", assistedParams)
               }
-              METRO -> {
-                val assistedFactory =
-                  declaration.declarations.filterIsInstance<KSClassDeclaration>().find { nestedClass
-                    ->
-                    nestedClass.isAnnotationPresentWithLeniency(
-                      codegenMode.runtime.assistedFactory!!
-                    )
-                  }
-                requireNotNull(assistedFactory) {
-                  "No assisted factory found for ${declaration.qualifiedName?.asString()}"
-                }
-                val constructorAssistedParameters =
-                  assistedKSParams.map { it.toAssistedParameterType("factory") }
-                val assistedFactoryCreate =
-                  assistedFactory.getAllFunctions().find { assistedFactoryFunction ->
-                    val assistedFunctionParameters =
-                      assistedFactoryFunction.parameters
-                        .filter { it.isAnnotationPresentWithLeniency(codegenMode.runtime.assisted) }
-                        .map { it.toAssistedParameterType("factory") }
-                    val assistedParamsMatch =
-                      constructorAssistedParameters == assistedFunctionParameters
-                    val numberOfFunctionParamsMatch =
-                      constructorAssistedParameters.size == assistedFactoryFunction.parameters.size
-
-                    assistedParamsMatch && numberOfFunctionParamsMatch
-                  }
-                requireNotNull(assistedFactoryCreate) {
-                  "No assisted factory create function found " +
-                    "for ${declaration.qualifiedName?.asString()}"
-                }
-
-                constructorParams.add(
-                  ParameterSpec.builder("factory", assistedFactory.toClassName()).build()
-                )
-                CodeBlock.of(
-                  "factory.%L(%L)",
-                  assistedFactoryCreate.simpleName.getShortName(),
-                  assistedParams,
-                )
-              }
               else -> {
                 constructorParams.add(
                   ParameterSpec.builder("factory", declaration.toClassName()).build()
@@ -582,9 +540,6 @@ private class CircuitSymbolProcessor(
 
 private data class AssistedType(val factoryName: String, val type: TypeName, val name: String)
 
-private fun KSValueParameter.toAssistedParameterType(factoryName: String) =
-  AssistedType(factoryName = factoryName, name = name!!.getShortName(), type = type.toTypeName())
-
 /**
  * Returns a [CodeBlock] representation of all named assisted parameters on this
  * [KSFunctionDeclaration] to be used in generated invocation code.

diff --git a/circuit-codegen/src/main/kotlin/com/slack/circuit/codegen/CodegenMode.kt b/circuit-codegen/src/main/kotlin/com/slack/circuit/codegen/CodegenMode.kt
@@ -22,7 +22,7 @@ internal enum class CodegenMode {
   /**
    * The Anvil Codegen mode
    *
-   * This mode annotates generated factory types with [ContributesMultibinding], allowing for Anvil
+   * This mode annotates generated factory types with `ContributesMultibinding`, allowing for Anvil
    * to automatically wire the generated class up to Dagger's multibinding system within a given
    * scope (e.g. AppScope).
    *
@@ -60,7 +60,7 @@ internal enum class CodegenMode {
    * The Hilt Codegen mode
    *
    * This mode provides an additional type, a Hilt module, which binds the generated factory, wiring
-   * up multibinding in the Hilt DI framework. The scope provided via [CircuitInject] is used to
+   * up multibinding in the Hilt DI framework. The scope provided via `CircuitInject` is used to
    * define the dagger component the factory provider is installed in.
    *
    * ```kotlin

diff --git a/circuit-codegen/src/test/kotlin/com/slack/circuit/codegen/CircuitSymbolProcessorTest.kt b/circuit-codegen/src/test/kotlin/com/slack/circuit/codegen/CircuitSymbolProcessorTest.kt
@@ -1483,14 +1483,15 @@ class CircuitSymbolProcessorTest {
         import dev.zacsweers.metro.Inject
 
         @Inject
-        @CircuitInject(FavoritesScreen::class, AppScope::class)
         class FavoritesPresenter(
           @Assisted private val navigator: Navigator
         ) : Presenter<FavoritesScreen.State> {
+          @CircuitInject(FavoritesScreen::class, AppScope::class)
           @AssistedFactory
           fun interface Factory {
             fun create(@Assisted navigator: Navigator): FavoritesPresenter
           }
+
           @Composable
           override fun present(): FavoritesScreen.State {
             throw NotImplementedError()
@@ -1531,53 +1532,6 @@ class CircuitSymbolProcessorTest {
     )
   }
 
-  @Test
-  fun invalidAssistedInjection_metro() {
-    assertProcessingError(
-      sourceFile =
-        kotlin(
-          "FavoritesPresenter.kt",
-          """
-        package test
-
-        import com.slack.circuit.codegen.annotations.CircuitInject
-        import com.slack.circuit.runtime.Navigator
-        import com.slack.circuit.runtime.presenter.Presenter
-        import androidx.compose.runtime.Composable
-        import dev.zacsweers.metro.Assisted
-        import dev.zacsweers.metro.AppScope
-        import dev.zacsweers.metro.AssistedFactory
-        import dev.zacsweers.metro.Inject
-
-        @Inject
-        @CircuitInject(FavoritesScreen::class, AppScope::class)
-        class FavoritesPresenter(
-          @Assisted private val navigator: Navigator
-        ) : Presenter<FavoritesScreen.State> {
-
-          // No AssistedFactory
-
-          @Composable
-          override fun present(): FavoritesScreen.State {
-            throw NotImplementedError()
-          }
-        }
-        """
-            .trimIndent(),
-        ),
-      codegenMode = CodegenMode.METRO,
-    ) { messages ->
-      assertThat(messages).contains("No assisted factory found")
-    }
-  }
-
-  private enum class CodegenMode {
-    ANVIL,
-    HILT,
-    KOTLIN_INJECT_ANVIL,
-    METRO,
-  }
-
   private fun assertGeneratedFile(
     sourceFile: SourceFile,
     generatedFilePath: String,

diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
@@ -77,6 +77,7 @@ kotlin-plugin-parcelize = { id = "org.jetbrains.kotlin.plugin.parcelize", versio
 kotlin-plugin-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }
 ksp = { id = "com.google.devtools.ksp", version.ref = "ksp" }
 mavenPublish = { id = "com.vanniktech.maven.publish", version.ref = "mavenPublish" }
+metro = { id = "dev.zacsweers.metro", version = "0.4.0" }
 roborazzi = { id = "io.github.takahirom.roborazzi", version.ref = "roborazzi" }
 skie = { id = "co.touchlab.skie", version.ref = "skie" }
 spotless = { id = "com.diffplug.spotless", version.ref = "spotless" }

diff --git a/samples/bottom-navigation/build.gradle.kts b/samples/bottom-navigation/build.gradle.kts
@@ -14,7 +14,8 @@ android {
   namespace = "com.slack.circuit.sample.navigation"
   defaultConfig {
     minSdk = 21
-    targetSdk = 36
+    // TODO update once robolectric supports 36
+    targetSdk = 35
   }
   testOptions { unitTests { isIncludeAndroidResources = true } }
 }

diff --git a/samples/interop/build.gradle.kts b/samples/interop/build.gradle.kts
@@ -11,7 +11,8 @@ android {
   namespace = "com.slack.circuit.sample.interop"
   defaultConfig {
     minSdk = 28
-    targetSdk = 36
+    // TODO update once robolectric supports 36
+    targetSdk = 35
     versionCode = 1
     versionName = "1"
     testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"

diff --git a/samples/star/apk/build.gradle.kts b/samples/star/apk/build.gradle.kts
@@ -9,7 +9,7 @@ plugins {
 android {
   namespace = "com.slack.circuit.sample.star.apk"
   defaultConfig {
-    minSdk = 28
+    minSdk = 30
     targetSdk = 36
     versionCode = 1
     versionName = "1"

diff --git a/samples/star/build.gradle.kts b/samples/star/build.gradle.kts
@@ -1,29 +1,24 @@
 // Copyright (C) 2022 Slack Technologies, LLC
 // SPDX-License-Identifier: Apache-2.0
-import com.google.devtools.ksp.gradle.KspAATask
 import java.util.Locale
 import org.jetbrains.kotlin.gradle.ExperimentalKotlinGradlePluginApi
 import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
 import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSetTree
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
   alias(libs.plugins.kotlin.multiplatform)
   alias(libs.plugins.compose)
   alias(libs.plugins.kotlin.plugin.compose)
   alias(libs.plugins.agp.library)
-  alias(libs.plugins.kotlin.kapt)
   alias(libs.plugins.kotlin.plugin.parcelize)
   alias(libs.plugins.kotlin.plugin.serialization)
   alias(libs.plugins.roborazzi)
-  alias(libs.plugins.anvil)
   alias(libs.plugins.ksp)
   alias(libs.plugins.sqldelight)
   alias(libs.plugins.emulatorWtf)
+  alias(libs.plugins.metro)
 }
 
-anvil { kspContributingAnnotations.add("com.slack.circuit.codegen.annotations.CircuitInject") }
-
 kotlin {
   jvm()
   androidTarget {
@@ -94,17 +89,12 @@ kotlin {
     }
     maybeCreate("jvmCommonMain").apply {
       dependencies {
-        api(libs.anvil.annotations)
-        api(libs.anvil.annotations.optional)
         implementation(libs.compose.material.icons)
-        implementation(libs.dagger)
         implementation(libs.jsoup)
         implementation(libs.coil.network.okhttp)
         implementation(libs.ktor.client.engine.okhttp)
         implementation(libs.okhttp)
         implementation(libs.okhttp.loggingInterceptor)
-        val kapt by configurations.getting
-        kapt.dependencies.addLater(libs.dagger.compiler)
       }
     }
     maybeCreate("jvmCommonTest").apply {
@@ -210,7 +200,7 @@ android {
   namespace = "com.slack.circuit.star"
 
   defaultConfig {
-    minSdk = 28
+    minSdk = 30
     testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     testApplicationId = "com.slack.circuit.star.apk.androidTest"
   }
@@ -248,21 +238,7 @@ fun String.capitalizeUS() = replaceFirstChar {
 
 val kspTargets = kotlin.targets.names.map { it.capitalizeUS() }
 
-// Workaround for https://youtrack.jetbrains.com/issue/KT-59220
-afterEvaluate {
-  for (target in kspTargets) {
-    if (target != "Android" && target != "Jvm") continue
-    val buildType = if (target == "Android") "Release" else ""
-    val kspTaskName = "ksp${buildType}Kotlin${target}"
-    val generatedKspKotlinFiles =
-      tasks.named<KspAATask>(kspTaskName).flatMap { it.kspConfig.kotlinOutputDir }
-    tasks.named<KotlinCompile>("kaptGenerateStubs${buildType}Kotlin${target}").configure {
-      source(generatedKspKotlinFiles)
-    }
-  }
-}
-
-ksp { arg("circuit.codegen.lenient", "true") }
+ksp { arg("circuit.codegen.mode", "metro") }
 
 dependencies {
   for (target in kspTargets) {

diff --git a/...ar/src/androidInstrumentedTest/kotlin/com/slack/circuit/star/BasePresenterTest.android.kt b/...ar/src/androidInstrumentedTest/kotlin/com/slack/circuit/star/BasePresenterTest.android.kt
@@ -0,0 +1,5 @@
+// Copyright (C) 2025 Slack Technologies, LLC
+// SPDX-License-Identifier: Apache-2.0
+package com.slack.circuit.star
+
+actual abstract class BasePresenterTest
diff --git a/samples/star/src/androidMain/kotlin/com/slack/circuit/star/MainActivity.kt b/samples/star/src/androidMain/kotlin/com/slack/circuit/star/MainActivity.kt
@@ -28,7 +28,6 @@ import com.slack.circuit.star.animation.HomeAnimatedScreenTransform
 import com.slack.circuit.star.animation.PetDetailAnimatedScreenTransform
 import com.slack.circuit.star.benchmark.ListBenchmarksScreen
 import com.slack.circuit.star.di.ActivityKey
-import com.slack.circuit.star.di.AppScope
 import com.slack.circuit.star.home.HomeScreen
 import com.slack.circuit.star.navigation.OpenUrlScreen
 import com.slack.circuit.star.petdetail.PetDetailScreen
@@ -37,15 +36,18 @@ import com.slack.circuitx.android.AndroidScreen
 import com.slack.circuitx.android.IntentScreen
 import com.slack.circuitx.android.rememberAndroidScreenAwareNavigator
 import com.slack.circuitx.gesturenavigation.GestureNavigationDecorationFactory
-import com.squareup.anvil.annotations.ContributesMultibinding
-import javax.inject.Inject
+import dev.zacsweers.metro.AppScope
+import dev.zacsweers.metro.ContributesIntoMap
+import dev.zacsweers.metro.Inject
+import dev.zacsweers.metro.binding
 import kotlinx.collections.immutable.persistentListOf
 import okhttp3.HttpUrl.Companion.toHttpUrl
 
 @OptIn(ExperimentalCircuitApi::class)
-@ContributesMultibinding(AppScope::class, boundType = Activity::class)
+@ContributesIntoMap(AppScope::class, binding = binding<Activity>())
 @ActivityKey(MainActivity::class)
-class MainActivity @Inject constructor(private val circuit: Circuit) : AppCompatActivity() {
+@Inject
+class MainActivity(private val circuit: Circuit) : AppCompatActivity() {
 
   @OptIn(ExperimentalSharedTransitionApi::class)
   override fun onCreate(savedInstanceState: Bundle?) {

diff --git a/samples/star/src/androidMain/kotlin/com/slack/circuit/star/StarApp.kt b/samples/star/src/androidMain/kotlin/com/slack/circuit/star/StarApp.kt
@@ -6,13 +6,12 @@ import android.app.Application
 import coil3.ImageLoader
 import coil3.PlatformContext
 import coil3.SingletonImageLoader
-import com.slack.circuit.star.di.AppComponent
+import com.slack.circuit.star.di.AppGraph
+import dev.zacsweers.metro.createGraphFactory
 
 class StarApp : Application(), SingletonImageLoader.Factory {
 
-  private val appComponent by lazy { AppComponent.create(this) }
+  val appGraph by lazy { createGraphFactory<AppGraph.Factory>().create(this) }
 
-  fun appComponent() = appComponent
-
-  override fun newImageLoader(context: PlatformContext): ImageLoader = appComponent.imageLoader
+  override fun newImageLoader(context: PlatformContext): ImageLoader = appGraph.imageLoader
 }
diff --git a/samples/star/src/androidMain/kotlin/com/slack/circuit/star/data/ContextStarAppDirs.kt b/samples/star/src/androidMain/kotlin/com/slack/circuit/star/data/ContextStarAppDirs.kt
@@ -3,21 +3,22 @@
 package com.slack.circuit.star.data
 
 import android.content.Context
-import com.slack.circuit.star.di.AppScope
 import com.slack.circuit.star.di.ApplicationContext
-import com.squareup.anvil.annotations.ContributesBinding
-import com.squareup.anvil.annotations.optional.SingleIn
-import javax.inject.Inject
+import dev.zacsweers.metro.AppScope
+import dev.zacsweers.metro.ContributesBinding
+import dev.zacsweers.metro.Inject
+import dev.zacsweers.metro.SingleIn
 import okio.FileSystem
 import okio.Path
 import okio.Path.Companion.toOkioPath
 
 @SingleIn(AppScope::class)
 @ContributesBinding(AppScope::class)
-class ContextStarAppDirs
 @Inject
-constructor(@ApplicationContext private val context: Context, override val fs: FileSystem) :
-  StarAppDirs {
+class ContextStarAppDirs(
+  @ApplicationContext private val context: Context,
+  override val fs: FileSystem,
+) : StarAppDirs {
 
   override val userConfig: Path by lazy {
     (context.filesDir.toOkioPath() / "config").also(fs::createDirectories)

diff --git a/...s/star/src/androidMain/kotlin/com/slack/circuit/star/data/InjectedTokenStorage.android.kt b/...s/star/src/androidMain/kotlin/com/slack/circuit/star/data/InjectedTokenStorage.android.kt
-Original file line number
+Diff line change
@@ Expand Up / @@ -4,6 +4,8 @@ Changelog @@
     Unreleased
     ----------
+    - Fix `@AssistedFactory` code gen for Metro to use standard nested class semantics.
 .29.0
     ------
@@ Expand Down @@