[KSP] Crash with primitive-named assisted parameters

[ZacSweers]

The following code snippet crashes the KSP processor with Dagger version 2.47

package com.squareup.test

import dagger.assisted.Assisted
import dagger.assisted.AssistedFactory
import dagger.assisted.AssistedInject

data class AssistedService @AssistedInject constructor(
  val int: Int,
  @Assisted val string: String,
  @Assisted val long: Long
)

@AssistedFactory
interface AssistedServiceFactory {
  fun create(long: Long, other: String): AssistedService
}

Trace

e: Error occurred in KSP, check log for detail
e: [ksp] java.lang.IllegalArgumentException: not a valid name: long
	at com.squareup.javapoet.Util.checkArgument(Util.java:53)
	at com.squareup.javapoet.ParameterSpec.builder(ParameterSpec.java:117)
	at dagger.internal.codegen.xprocessing.MethodSpecs.overriding(MethodSpecs.java:52)
	at dagger.internal.codegen.processingstep.AssistedFactoryProcessingStep$AssistedFactoryImplGenerator.topLevelTypes(AssistedFactoryProcessingStep.java:306)
	at dagger.internal.codegen.processingstep.AssistedFactoryProcessingStep$AssistedFactoryImplGenerator.topLevelTypes(AssistedFactoryProcessingStep.java:232)
	at dagger.internal.codegen.base.SourceFileGenerator.generate(SourceFileGenerator.java:77)
	at dagger.internal.codegen.processingstep.AssistedFactoryProcessingStep.process(AssistedFactoryProcessingStep.java:114)
	at dagger.internal.codegen.processingstep.AssistedFactoryProcessingStep.process(AssistedFactoryProcessingStep.java:76)
	at dagger.internal.codegen.processingstep.TypeCheckingProcessingStep.lambda$process$0(TypeCheckingProcessingStep.java:82)
	at com.google.common.collect.SingletonImmutableBiMap.forEach(SingletonImmutableBiMap.java:68)
	at dagger.internal.codegen.processingstep.TypeCheckingProcessingStep.process(TypeCheckingProcessingStep.java:70)
	at dagger.internal.codegen.processingstep.TypeCheckingProcessingStep.process(TypeCheckingProcessingStep.java:48)
	at dagger.spi.shaded.androidx.room.compiler.processing.XProcessingStep.process(XProcessingStep.kt:59)
	at dagger.spi.shaded.androidx.room.compiler.processing.CommonProcessorDelegate.processRound(XBasicAnnotationProcessor.kt:130)
	at dagger.spi.shaded.androidx.room.compiler.processing.ksp.KspBasicAnnotationProcessor.process(KspBasicAnnotationProcessor.kt:62)

[bcorso]

Thanks for reporting this!

In theory, I think this is likely an issue for any parameter name in a user's sources that Dagger ends up using in generated sources, though it may be the case that AssistedInject is where this is easiest to hit. It mostly works for KAPT today because KAPT either completely elides elements that have java keywords as names, or it just renames them.

However, given that Dagger is still generating Java source, I'm leaning towards just reporting an error in these cases (i.e. it wouldn't be allowed in KAPT or KSP). I'll talk it over with the team, but also if you have concerns with this feel free to state them.

[ZacSweers]

Interesting! Good to know this is easy to fix on the consumer side, I completely missed that this was the parameter name and thought it was about the parameter type at first.