[KSP2] Hilt incompatibility: `Did you forget to apply the Gradle Plugin?`

[SimonMarquis]

KSP tasks are failing because of a Hilt error when building with Kotlin 2.0.0-RC1 and KSP2 enabled:

• SimonMarquis/QrCode

  > Task :app:kspDebugKotlin
  e: [ksp*** [Hilt*** Class java.lang.Object is not annotated with @AssistedFactory.
  [Hilt*** Processing did not complete. See error above for details.
  e: [ksp*** [Hilt*** Expected @AndroidEntryPoint to have a value. Did you forget to apply the Gradle Plugin? (com.google.dagger.hilt.android)
  See https://dagger.dev/hilt/gradle-setup.html
  [Hilt*** Processing did not complete. See error above for details.
  e: [ksp*** [Hilt*** Expected @AndroidEntryPoint to have a value. Did you forget to apply the Gradle Plugin? (com.google.dagger.hilt.android)
  See https://dagger.dev/hilt/gradle-setup.html
  [Hilt*** Processing did not complete. See error above for details.
  e: [ksp*** [Hilt*** Expected @HiltAndroidApp to have a value. Did you forget to apply the Gradle Plugin? (com.google.dagger.hilt.android)
  See https://dagger.dev/hilt/gradle-setup.html

• android/nowinandroid

  > Task :ui-test-hilt-manifest:kspDemoDebugKotlin FAILED
  e: [ksp] [Hilt] Expected @AndroidEntryPoint to have a value. Did you forget to apply the Gradle Plugin? (com.google.dagger.hilt.android)
  See https://dagger.dev/hilt/gradle-setup.html
  [Hilt] Processing did not complete. See error above for details.
  
  > Task :core:analytics:kspDemoDebugKotlin FAILED
  e: [ksp] java.lang.NullPointerException: null cannot be cast to non-null type androidx.room.compiler.processing.XType

  This stacktrace also contains an error referenced in this KSP issue:

  • https://github.com/google/ksp/issues/1788

[ting-yuan]

@SimonMarquis Could you file the bug to Hilt and let them identify which part of KSP API is wrong first? We have very little knowledge of what those error messages mean and how they are thrown.