KotlinReflectionParameterNameDiscoverer doesn't support Kotlin Context Parameters

[IRus]

Background

Context Parameters were introduced in Kotlin 2.1.20 and are currently in Beta status in Kotlin 2.2.0 under the flag -Xcontext-parameters (announcement)

Issue

Spring's KotlinReflectionParameterNameDiscoverer cannot detect Context Parameters in Kotlin methods. The kotlinFunction property returns incomplete results - context parameters are completely absent from the reflection data.

Use Case

I'm migrating from Context Receivers to Context Parameters for implementing security via HandlerMethodArgumentResolver. My implementation:

• Uses a custom UserContext class as a context parameter
• Injects it into controller handler methods
• Propagates it through service method calls

Technical Details

• Current implementation relies on: KotlinReflectionParameterNameDiscoverer.java#L46
• Related Kotlin issues:
  • KT-78752: Context Parameters missing in reflection - I'm asking to fix kotlinFunction, hopefully in 2.1.22/2.2.10
  • KT-74529: Context parameters support in reflection - Card about support of context parameters targeting 2.2.20

Expected

1. Track support for Context Parameters in Spring Framework (if KT-78752 will be resolved)
2. Add support for the new parameter kind coming in Kotlin 2.2.20 when reflection API is available

[sdeleuze]

Let's explore that when Kotlin reflection will be fixed.

[IRus]

Reflection support landed in 2.2.20

[sdeleuze]

I think I need a bit more time to fully understand all the use cases in Spring, we need the support in other places like like CoroutinesUtils (see #35428 related PR), and in Kotlin 2.2.20 it is still experimental (Kind.CONTEXT is annotated with @ExperimentalContextParameters) so think that's probably more reasonable to not rush it for 7.0 and plan it for 7.1.

@IRus Any chance you could share a reproducer with the use case you try to get supported (the one you described in the description)?