Cannot inject a generic mock in a superclass

[julien-breda]

Hello !

The context

I'm trying to update Mockito from version 1 to 5.3.1 (there's some work to do)
I'm facing an issue and I built a tiny project to illustrate it : mockito-upgrade.zip

The environment

I'm using OpenJDK 11.0.14.1, Maven 3.6.1, JUnit 4.11, on Windows 10.

The code

There's an EntryPoint extending AbstractGenericClass. This last one uses a ParameterizerInjectedObject. The class Something was only created to specify generics.
When I try to test EntryPoint, with EntryPointTest, I uses Mockito to inject a mock of ParameterizerInjectedObject in my EntryPoint instance.

The problem

The problem is that the mock isn't injected.
If I remove all generics it works but this is not an acceptable solution.

If you run my test you'll have a NPE because AbstractGenericClass.object isn't initialized : it is intended to demonstrate the problem.
If you initialize it by replacing
private ParameterizedInjectedObject<T> object;
with
private ParameterizedInjectedObject<T> object = new ParameterizedInjectedObject<>();

you'll see the following failure :

Wanted but not invoked:
injected.init();
-> at test.ParameterizedInjectedObject.init(ParameterizedInjectedObject.java:7)
Actually, there were zero interactions with this mock.
at test.ParameterizedInjectedObject.init(ParameterizedInjectedObject.java:7)
at test.EntryPointTest.testInit(EntryPointTest.java:23)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.mockito.internal.runners.DefaultInternalRunner$1$1.evaluate(DefaultInternalRunner.java:55)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.mockito.internal.runners.DefaultInternalRunner$1.run(DefaultInternalRunner.java:100)
at org.mockito.internal.runners.DefaultInternalRunner.run(DefaultInternalRunner.java:107)
at org.mockito.internal.runners.StrictRunner.run(StrictRunner.java:41)
at org.mockito.junit.MockitoJUnitRunner.run(MockitoJUnitRunner.java:163)

My analyzis

When I downgrade to version 5.2.0 I'm facing this issue : #2958
The fix for this one, introduced in version 5.3.0, doesn't seem to handle my case.

I tried to debug Mockito and I think there's a problem with TypeBasedCandidateFilter, starting at line 140 when AbstractGenericClass is analyzed to see if parameter Something is valid for the injection point.

Thanks for reading,

[philsttr]

I believe logstash-logback-encoder is running into this same problem.

Here's a small project (mockito-parameterized-type-injection.zip) with a unit tests that fails to inject a mock with mockito 5.3.1. The test works with mockito 5.1.1, so something regressed after 5.1.1

[thomasrichner-oviva]

I'm pretty sure I'm running into the same issue.
Interestingly it works if the generic type happens to be a String, but not if its an `Object. See minimal reproducer attached.
reproducer.zip

[LordMaduz]

I also experienced the same issue today with mockito version 5.8.0.
Interestingly, when I downgrade version back to 5.1.1 it works fine.

[melloware]

+1