Reconsider CONFLICTING_PROVIDES_SCOPE diagnostic

[kevinguitar]

We have an use case internally facing the CONFLICTING_PROVIDES_SCOPE diagnostic. Essentially, it's a dependency that we want to encapsulate in a standalone Dependency Graph, and expose it in AppGraph.

I created a minimum diagnostic test:

// RENDER_DIAGNOSTICS_FULL_TEXT
@DependencyGraph(AppScope::class)
interface AppGraph

interface SyncScope

@DependencyGraph(SyncScope::class)
interface SyncGraph {
  val syncController: SyncController
}

@SingleIn(SyncScope::class)
@Inject
class SyncController

@ContributesTo(AppScope::class)
interface SyncExposedDependenciesModule {

  @SingleIn(AppScope::class)
  @Provides
  fun provideSyncGraph(): SyncGraph {
    return createGraph<SyncGraph>()
  }

  @Provides
  fun <!CONFLICTING_PROVIDES_SCOPE!>provideSyncController<!>(syncGraph: SyncGraph): SyncController = syncGraph.syncController
}

fun box(): String {
  val graph = createGraph<AppGraph>()
  return "OK"
}

In the example, SyncGraph has the same lifetime as AppGraph, but it helps us encapsulate dependencies into standalone graphs to not blow up AppGraph.

I think this is a valid use case, and would like to either remove this diagnostic or have an option to disable it (if you're open, I can send a PR for that). Let me know if you see it differently, thanks!

Reference:

metro/compiler/src/main/kotlin/dev/zacsweers/metro/compiler/fir/checkers/BindingContainerCallableChecker.kt

Lines 365 to 369 in f11928f

	reporter.reportOn(
	source,
	MetroDiagnostics.CONFLICTING_PROVIDES_SCOPE,
	"Provided type '${classTypeKey.render(short = false, includeQualifier = true)}' is already constructor-injected but declares a different scope. This is likely a bug.",
	)

[ZacSweers]

That's fair, graphs are special cases since they're not injected on their own. PR welcome to skip this on graphs.

Sidenote: not every diagnostic requires an option to disable, kotlin compiler also lets you disable them. That's why I picked a specific name for this one

[ZacSweers]

Actually upon reading at my laptop I'm realizing I misread. I think this is a valid case but this is also why it's a specific warning and I think you should just suppress it as needed

[kevinguitar]

Ohh let me try and suppress it, that'd be all I need 🙌 Thank you Zac!