Hey folks I'm trying to write kotlin compiler plug...

# compiler

[Roman Rastiehaiev]

Hey folks
I'm trying to write kotlin compiler plugin.
I published my plugin to gradle portal, and I try to use it in 2 different repos

In the first repo it works fine, in the second - no.
In the second repository I receive the error when my plugin tries to get a resolved type from method return type
The code in those two repos is the same, except in the second one I also use kotlin serialization plugin.
I checked - if I disable it, my plugin works fine

Does someone know why it may happen and how to fix it?

[Vampire]

I guess whoever might be able to help at least needs to know which error you get, otherwise it's hard to guess what you problem might be.

[Roman Rastiehaiev]

Here's the stacktrace:

Caused by: org.jetbrains.kotlin.utils.exceptions.KotlinIllegalArgumentExceptionWithAttachments: Expected FirResolvedTypeRef with ConeKotlinType but was FirImplicitTypeRefImplWithoutSource
        at org.jetbrains.kotlin.fir.types.FirTypeUtilsKt.getConeType(FirTypeUtils.kt:201)
        at io.github.rastiehaiev.fir.SuspendifyFirSupertypeGenerator.computeAdditionalSupertypes(SuspendifyFirSupertypeGenerator.kt:56)
        at org.jetbrains.kotlin.fir.resolve.transformers.FirSupertypeResolverVisitor.addSupertypesFromExtensions(FirSupertypesResolution.kt:495)
        at org.jetbrains.kotlin.fir.resolve.transformers.FirSupertypeResolverVisitor.resolveSpecificClassLikeSupertypes$lambda$15(FirSupertypesResolution.kt:472)
        at org.jetbrains.kotlin.fir.resolve.transformers.FirSupertypeResolverVisitor.resolveSpecificClassLikeSupertypes(FirSupertypesResolution.kt:402)
        at org.jetbrains.kotlin.fir.resolve.transformers.FirSupertypeResolverVisitor.resolveSpecificClassLikeSupertypes(FirSupertypesResolution.kt:445)
        at org.jetbrains.kotlin.fir.resolve.transformers.FirSupertypeResolverVisitor.visitRegularClass(FirSupertypesResolution.kt:425)
        at org.jetbrains.kotlin.fir.resolve.transformers.FirSupertypeResolverVisitor.visitRegularClass(FirSupertypesResolution.kt:226)
        at org.jetbrains.kotlin.fir.declarations.FirRegularClass.accept(FirRegularClass.kt:48)
        at org.jetbrains.kotlin.fir.declarations.impl.FirFileImpl.acceptChildren(FirFileImpl.kt:57)
        at org.jetbrains.kotlin.fir.resolve.transformers.FirSupertypeResolverVisitor.visitDeclarationContent(FirSupertypesResolution.kt:413)
        at org.jetbrains.kotlin.fir.resolve.transformers.FirSupertypeResolverVisitor.visitFile(FirSupertypesResolution.kt:593)
        at org.jetbrains.kotlin.fir.resolve.transformers.FirSupertypeResolverVisitor.visitFile(FirSupertypesResolution.kt:226)
        at org.jetbrains.kotlin.fir.declarations.FirFile.accept(FirFile.kt:42)
        at org.jetbrains.kotlin.fir.resolve.transformers.FirSupertypeResolverTransformer.transformFile(FirSupertypesResolution.kt:71)
        ... 43 more

This happens when I try to do FirSimpleFunction.returnTypeRef.coneType

[Roman Rastiehaiev]

Here's my code:
https://github.com/rastiehaiev/suspendify/blob/main/plugin-kotlin/src/main/kotlin/io/github/rastiehaiev/fir/SuspendifyFirExtensionRegistrar.kt#L236

(I replaced coneType with coneTypeOrNull so it doesn't fail compilation, but plugin doesn't generate any methods/classes because of this)

[Javier]

Try to apply the plugins in a different order

[Roman Rastiehaiev]

I tried, it didn't help 🙂

[bnorm]

It is unsafe to use the return type of a declaration during classifier generation. The presence of a FirSupertypeGenerationExtension causes all nested classifier declaration generation to happen during the SUPER_TYPES phase, when function return types haven't been resolved yet. The serialization plugin has one of these extensions, which is why adding the plugin causes yours to fail.

From the stacktrace, I also see a SuspendifyFirSupertypeGenerator.computeAdditionalSupertypes call which is not present in your repository, so it would seem you also now have one of these extensions?

[Roman Rastiehaiev]

Hey @bnorm
thanks, that explains why it fails in my case..
I had SuspendifyFirSupertypeGenerator, but then I removed it (as didn't know how to implement and use it honestly)

if I cannot use function/value parameters' return types in FirSupertypeGenerationExtension, do you know how can I generate my classes/methods? I implemented IR part, and with current FIR implementation it works, but it fails if I use other plugins, like serialization

[Roman Rastiehaiev]

So as far as I understand, serialization plugin drags my plugin execution into the SUPER_TYPES phase, so I cannot use return types as at this phase they are not resolved.
What I need to achieve is this:

@Suspendify
class Repository {
   fun save(id: String): Entity { /*…*/ }
}

fun main() = runBlocking {
    val repo = Repository()
    
    // 'suspendify' is generated by plugin:
    val suspendifiedRepository = repo.suspendify(with = <http://Dispatchers.IO|Dispatchers.IO>)
    
    // 'save' is also generated by plugin, and it's suspend:
    suspendifiedRepository.save("123")
}

To generate the save function in FIR, I need to know function's return type and value parameter return type
If I don't generate this method in FIR, the IDE will not "see" it.

What is the best practice to achieve my idea?

[dmitriy.novozhilov]

But why do you generate this function with FirSupertypeGenerationExtension?
For generation of new members there is a FirDeclarationGenerationExtension.generateFunctions method, which is called at STATUS phase or later. At this phase all explicitly written types on functions are resolved and you can access them.

Note that it won't work for implicit types and there is no way to workaround it:

class Repository {
   fun save(id: String) = createEntity(...)
}

In this case the return type of save function will be computed at IMPLICIT_TYPES_BODY_RESOLVE, which is too late

[Roman Rastiehaiev]

I don't generate function in FirSupertypeGenerationExtension, I do it in `FirDeclarationGenerationExtension`:
https://github.com/rastiehaiev/suspendify/blob/main/plugin-kotlin/src/main/kotlin/io/github/rastiehaiev/fir/SuspendifyFirExtensionRegistrar.kt#L127

I don't use FirSupertypeGenerationExtension at all. As far as I understood, kotlin serialization plugin forces my plugin to execute in earlier stage (SUPER_TYPES), where the resolving isn't done yet. That's why my plugin doesn't work

[dmitriy.novozhilov]

The problem here that you collect information about functions during class generation, not members for class generation.
You should move the computation of toFunction from line 97 somewhere to generateFunctions

[Roman Rastiehaiev]

okay, I'll try, thanks!

[Roman Rastiehaiev]

it worked!

[Roman Rastiehaiev]

thank you!