SpyStatic trying to expand varargs when Mockito already expanded varargs

[meestchoo]

Describe the bug

When using SpyStatic + stubbing static method with varargs, Spock is trying to expand last method call argument, but Mockito already expanded varargs (check constructor of org.mockito.internal.invocation.InterceptedInvocation). Using Mockito 5.17.0.

To Reproduce

import spock.lang.Specification

class SpyStaticTest extends Specification {
    def "test"() {
        given:
        SpyStatic(SomeStaticClass)
        SomeStaticClass.someStaticVarargsMethod("test") >> true
        SomeStaticClass.someStaticVarargsMethod("test2") >> false

        when:
        def result = SomeStaticClass.someStaticVarargsMethod("test2")

        then:
        !result
    }
}

class SomeStaticClass {
    static boolean someStaticVarargsMethod(String str, String... varargs) {
        return true
    }
}

Expected behavior

It shouldn't take the last parameter varargs array.

Actual behavior

java.lang.IllegalArgumentException: Argument is not an array

	at org.spockframework.mock.constraint.PositionalArgumentListConstraint.expandVarArgs(PositionalArgumentListConstraint.java:91)
	at org.spockframework.mock.constraint.PositionalArgumentListConstraint.isSatisfiedBy(PositionalArgumentListConstraint.java:46)
	at org.spockframework.mock.runtime.MockInteraction.matches(MockInteraction.java:69)
	at org.spockframework.mock.runtime.MockInteractionDecorator.matches(MockInteractionDecorator.java:46)
	at org.spockframework.mock.runtime.InteractionScope.match(InteractionScope.java:94)
	at org.spockframework.mock.runtime.MockController.handle(MockController.java:47)
	at org.spockframework.mock.runtime.JavaMockInterceptor.intercept(JavaMockInterceptor.java:83)
	at org.spockframework.mock.runtime.mockito.MockitoMockMakerImpl$SpockMockHandler.handle(MockitoMockMakerImpl.java:265)
	at org.mockito.internal.creation.bytebuddy.access.MockMethodInterceptor.doIntercept(MockMethodInterceptor.java:84)
	at org.mockito.internal.creation.bytebuddy.MockMethodAdvice.handleStatic(MockMethodAdvice.java:150)
	at SomeStaticClass.someStaticVarargsMethod(SpyStaticTest.groovy:20)
	at SpyStaticTest.test(SpyStaticTest.groovy:11)

Java version

Tested on JDK 17 and 24.

Buildtool version

Tested on Maven 3.9.7

What operating system are you using

Windows

Dependencies

org.example:spock-static-class-test:jar:1.0-SNAPSHOT
+- org.apache.groovy:groovy:jar:4.0.26:compile
+- org.spockframework:spock-core:jar:2.4-M6-groovy-4.0:test
|  +- org.junit.platform:junit-platform-engine:jar:1.12.2:test
|  |  +- org.opentest4j:opentest4j:jar:1.3.0:test
|  |  +- org.junit.platform:junit-platform-commons:jar:1.12.2:test
|  |  \- org.apiguardian:apiguardian-api:jar:1.1.2:test
|  +- org.hamcrest:hamcrest:jar:3.0:test
|  \- io.leangen.geantyref:geantyref:jar:1.3.16:test
\- org.mockito:mockito-core:jar:5.17.0:test
   +- net.bytebuddy:byte-buddy:jar:1.15.11:test
   +- net.bytebuddy:byte-buddy-agent:jar:1.15.11:test
   \- org.objenesis:objenesis:jar:3.3:test

Additional context

No response

[Andreas Turban]

@meestchoo I could reproduce your issue with:
91c4034

I do not yet have a quick and good solution for the problem and I am currently not able to work on the issue.
So you need to be a bit patient.
Or if you have time give it a shot to fix it.