Hint generation (i.e. multi-module aggregation) and top-level function injection only works on jvm/android targets

[r0adkll]

Description

I have a case where contributed bindings are not being found when compiling my iOS graph in a separate module. Take the example

// feature/commonMain/…/FeatureDependency.kt
interface FeatureDependency

@ContributesBinding(AppScope::class)
@Inject
class FeatureDependencyImpl : FeatureDependency 

// shared/iosMain/…/IosAppGraph.kt
@DependencyGraph(AppScope::class)
interface IosAppGraph : AppGraph {
  val featureDep: FeatureDependency
}

When running gw :shared:compileKotlinIosSimulatorArm64 it will fail with

e: file:///…/IosAppGraph.kt:13:3 [Metro/MissingBinding] Cannot find an @Inject constructor or @Provides-annotated function/property for: com.example.feature.FeatureDependency

    com.example.feature.FeatureDependency is requested at
        [com.example.metrobugreproduction.IosAppGraph] com.example.metrobugreproduction.IosAppGraph#featureDep

Self-contained Reproducer

See https://github.com/r0adkll/MetroBugs/tree/dh/ios-compilation

Steps to reproduce:

1. Run ./gradlew :shared:compileKotlinIosSimulatorArm64
2. See MissingBinding error

Metro version

0.3.2

Context

I ran into this in my migration where I have iOS specific app graph stuff for exposing/creating the compose UIViewController for the swift code and when migrating hit a bunch of these missing binding exceptions.

[ZacSweers]

This is expected right now unfortunately. Hints cannot currently be generated in IR in native targets due to https://youtrack.jetbrains.com/issue/KT-58886. Buuuuut that should hopefully be addressed soon 🤞. Right now they only work on native targets within the same compilation. Sorry for the confusion, I thought I had this documented somewhere but seems not yet

[gabrielittner]

Am I assuming correctly that this will also cause @ContributesGraphExtension to not properly work?

[ZacSweers]

Correct yeah. In the mean time you should be able to make those still work by manually extending the contributed graph's factory class. i.e.

@ContributesGraphExtension(...)
interface LoggedInGraph {
  @ContributesGraphExtension(AppScope::class)
  interface Factory { ... }
}

@DependencyGraph(AppScope::class)
interface AppGraph : LoggedInGraph.Factory {
  //                 ^^ Declare this manually
}

[chrisbanes]

Need to reopen this?

[ZacSweers]

Oop yep, I guess "resolves ___" are sticky even if you edit the description in the PR