Help wanted: compiling mockito with native-image

[eiswind]

I am trying to compile mockito with mock-maker-proxy with graalvm native image, and I got stuck with the plugin mechanism (At least the stacktrace point to that). (In preparation for having some mockito suppport in spring-native spring-attic/spring-native#1063)

I know this maybe a little of topic, but having at least "some" mockito when running native tests made me get started with this.

What I've got so far is

• some proxy config
• some reflection config
• basic compiler args

When I compile this example
https://github.com/eiswind/native-mock-example

I get a NPE at:

     Caused by: java.lang.NullPointerException
       org.mockito.internal.configuration.plugins.Plugins.getStackTraceCleanerProvider(Plugins.java:26)
       org.mockito.internal.exceptions.stacktrace.StackTraceFilter.<clinit>(StackTraceFilter.java:20)
       com.oracle.svm.core.classinitialization.ClassInitializationInfo.invokeClassInitializer(ClassInitializationInfo.java:375)
       com.oracle.svm.core.classinitialization.ClassInitializationInfo.initialize(ClassInitializationInfo.java:295)

from which I would guess that registry itself is null, but that makes only little sense.
I added some --initialize-at-runtime for the plugins package but that didn't do it.

So for know I can only hope that this is something of interest and I really would appreciate some pointers what to try.

[TimvdLippe]

@raphw Does oracle/graal#3969 resolve this issue as well?

[raphw]

Possibly, but this would require a detection run prior. There's not much of a point, in my opinion, to run one-off tests with Graal native image, though. The efficiency comes from repeated startup in of an unchanged code. That's not really our niche.

[eiswind]

I really think there is a point in running the tests with native image, as we can detect many configuration errors that happen only at runtime.

[raphw]

You are right, that's a use case. We will only be able to support Graal native image with the subclass mock maker for now, unfortunately, which requires a bunch of add-opens on the command line to work with Java 17. But in theory, it is definitely possible that this would work then.

[mhalbritter]

I've added support for Mockito to the GraalVM reachability metadata and got the ProxyMockMaker to work, see here for more details.

The reachability metadata repo is a way to get non-compliant libraries to work nonetheless on GraalVM. Feel free to copy the GraalVM metadata files directly in the Mockito codebase (actually I would be very happy about that :)).

What is the status of the other mock makers (particularly one which allows mocking of classes) on GraalVM?

[raphw]

It works already: https://gist.github.com/raphw/e0f6864ddcad69630d839c2eebaad818

But it requires some prework. As far as I know, the Graal team is working on something to ease this.