KSP2 crash when using @JsonQualifier

[Jean-Daniel]

When trying to generate Adapter for classes using a @JsonQualifier, KSP fails with the error:

> Task :app:kspDebugKotlin FAILED
e: [ksp] Error preparing ApiUserItem: jdk.proxy5/jdk.proxy5.$Proxy154.value(Unknown Source)
com.squareup.moshi.kotlin.codegen.ksp.MoshiApiUtilKt.generator(MoshiApiUtil.kt:77)
com.squareup.moshi.kotlin.codegen.ksp.JsonClassSymbolProcessor.adapterGenerator(JsonClassSymbolProcessorProvider.kt:122)
com.squareup.moshi.kotlin.codegen.ksp.JsonClassSymbolProcessor.process(JsonClassSymbolProcessorProvider.kt:92)
com.google.devtools.ksp.impl.KotlinSymbolProcessing.execute(KotlinSymbolProcessing.kt:538)
com.google.devtools.ksp.impl.KSPLoader$Companion.loadAndRunKSP(KSPLoader.kt:36)
com.google.devtools.ksp.impl.KSPLoader.loadAndRunKSP(KSPLoader.kt)
…

The class being compiled is simply:

@Retention(AnnotationRetention.RUNTIME)
@JsonQualifier
annotation class ISO8061

@JsonClass(generateAdapter = true)
open class ApiUserItem(
  @field:Json(name = "slug") val slug: String,
  @field:Json(name = "date_added") @field:ISO8061 val date: Long,
)

You can use this reduced test case to reproduce the bug.

git clone https://github.com/Jean-Daniel/moshiksp2
cd moshiksp2
./gradlew :app:assembleDebug
> Task :app:kspDebugKotlin FAILED
…

[ZacSweers]

Upstream KSP2 bug, please file with them

[ting-yuan]

This is caused by a breaking change in KSP2. @ZacSweers could this copy be deleted and let moshi use the implementation from KSP?

[ting-yuan]

Removing it doesn't seem to break any tests:
#1875

[Jean-Daniel]

Can this bug be reopened as this is clearly a Moshi bug as it is the moshi shadedUtil.kt version that is faulty.

[ZacSweers]

The linked fix isn't a useable fix because it's an unstable API. A more appropriate one would be to update the copied impl to the new one

[malikmudassarhussain]

While migrating to Koline 2.x I had to fallback to moshi-ksp from moshi-ir because of this IR issue and now I am stuck on the above error. Is there any quick fix as the IR one will be fixed in Kotlin 2.1.20

[Jean-Daniel]

Is there any quick fix as the IR one will be fixed in Kotlin 2.1.20

Yes, just keep using KSP 1 instead of KSP 2, as only KSP 2 is impacted by this issue.

[Jean-Daniel]

The linked fix isn't a useable fix because it's an unstable API. A more appropriate one would be to update the copied impl to the new one

I'm not sure I get the 'unstable API' argument.

Using an unstable API can cause mochi to stop working when updating KSP, but this is the same as copying the file, as updating KSP to a version with a different shadedUtil.kt file/API is also breaking Moshi, as shown here.