assertj: Incompatibility with JDK 18-ea

Summary

AssertJ fails on JDK 18-ea when using SoftAssertion.assertThat(...) with a class compile for JDK 18.

Failures (1):
  JUnit Jupiter:EngineTestKitAllEventsDemo:verifyAllJupiterEvents()
    MethodSource [className = 'example.testkit.EngineTestKitAllEventsDemo', methodName = 'verifyAllJupiterEvents', methodParameterTypes = '']
    => java.lang.IllegalArgumentException: Could not create type
       org.assertj.core@3.20.2/org.assertj.core.internal.bytebuddy.TypeCache.findOrInsert(TypeCache.java:155)
       org.assertj.core@3.20.2/org.assertj.core.internal.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:366)
       org.assertj.core@3.20.2/org.assertj.core.api.SoftProxies.createSoftAssertionProxyClass(SoftProxies.java:128)
       org.assertj.core@3.20.2/org.assertj.core.api.SoftProxies.createSoftAssertionProxy(SoftProxies.java:114)
       org.assertj.core@3.20.2/org.assertj.core.api.AbstractSoftAssertions.proxy(AbstractSoftAssertions.java:48)
       [...]
     Caused by: java.lang.IllegalStateException: No code generation strategy available
       org.assertj.core@3.20.2/org.assertj.core.api.ClassLoadingStrategyFactory.classLoadingStrategy(ClassLoadingStrategyFactory.java:67)
       org.assertj.core@3.20.2/org.assertj.core.api.SoftProxies.generateProxyClass(SoftProxies.java:172)
       org.assertj.core@3.20.2/org.assertj.core.api.SoftProxies.lambda$createSoftAssertionProxyClass$0(SoftProxies.java:129)
       org.assertj.core@3.20.2/org.assertj.core.internal.bytebuddy.TypeCache.findOrInsert(TypeCache.java:153)
       [...]

I tried setting the net.bytebuddy.experimental system property to true but that didn’t help either.

Upgrading the shaded Byte Buddy should help: https://github.com/raphw/byte-buddy/blob/master/release-notes.md

Example

Please let me know if this is really needed in this case.