Spring Security mockAuthentication does not compile in Kotlin

Summary

The mutator mockAuthentication does not compile when used in Kotlin code. The same applies for mutators that use mockAuthentication internally, for example mockUser(UserDetails).

Error:(141, 29) Kotlin: Type parameter bound for T in fun mockAuthentication(p0: Authentication!): T! where T : MockServerConfigurer! is not satisfied: inferred type WebTestClientConfigurer! is not a subtype of MockServerConfigurer!

Sample

this.client
        .mutateWith(mockAuthentication(TestingAuthenticationToken("principal", "credentials")))
        .get()
        .uri("/")
        .exchange()

Kotlin version is 1.3.70

Comment From: mindhaq

I can confirm this for mockUser(UserDetails).

spring-security 5.3.1 kotlin 1.3.71

Comment From: rwinch

@mindhaq Would you mind creating another ticket for that please?

Comment From: mindhaq

@rwinch my case is actually already mentioned in the ticket description, so I guess there is no need for another ticket which would only be a duplicate of this one. I'll clarify my comment.

Comment From: sendilkumarn

Yeah same here, It looks like Kotlin cannot infer the bounded types. check out here for the failing compilation.

Comment From: mindhaq

In my case, this compiles now with Kotlin 1.4.

spring-security 5.3.4 kotlin 1.4.10

Comment From: eleftherias

This is fixed in Kotlin 1.4 and greater, where the Kotlin team added a new type inference algorithm. Users on Kotlin 1.3.40 can opt to use the new algorithm by setting:

kotlinOptions {
    freeCompilerArgs += '-XXLanguage:+NewInference'
}