Documenter fails when using functional endpoints (i.e. RouterFunction beans)

Hello,

It seems moduliths-docs doesn’t support projects leveraging functional web endpoints registration - be it either WebMvc.fn or WebFlux.fn (fails for both, checked myself).

Project setup: Java 11 + Kotlin (checked also Java 8) Spring Boot 2.4.1 (checked also using Spring Boot 2.3.7) Moduliths 1.1.0-M1 (checked also current main branch)

Test body (in Kotlin):

class DocumentingTest {

    @Test
    @Throws(IOException::class)
    fun verifyModularity() {
        val modules: Modules = Modules.of(ModulithsDemoApplication::class.java)

        modules.verify()

        // Generate documentation
        val documenter = Documenter(modules)
        val options: Options = Options.defaults() //
            .withExclusions { module -> module.getName().matches(".*core|.*support".toRegex()) }

        // Write overall diagram
        // FIXME This fails if RouterFunction is registered as a bean :(
        documenter.writeModulesAsPlantUml(options)

Stack-trace starting from the test-run:

java.lang.NullPointerException: Method may not be called before construction of hierarchy is complete

	at com.tngtech.archunit.thirdparty.com.google.common.base.Preconditions.checkNotNull(Preconditions.java:787)
	at com.tngtech.archunit.core.domain.JavaClass.getAllMethods(JavaClass.java:788)
	at org.moduliths.model.Module$ModuleDependency.fromMethodsOf(Module.java:523)
	at org.moduliths.model.Module$ModuleDependency.fromType(Module.java:499)
	at org.moduliths.model.Module.lambda$getDirectModuleDependencies$16(Module.java:361)
	at java.base/java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:271)
	at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1654)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
	at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)
	at org.moduliths.docs.Documenter.addDependencies(Documenter.java:266)
	at org.moduliths.docs.Documenter.lambda$getComponents$1(Documenter.java:126)
	at java.base/java.util.HashMap.forEach(HashMap.java:1336)
	at org.moduliths.docs.Documenter.getComponents(Documenter.java:126)
	at org.moduliths.docs.Documenter.lambda$addComponentsToView$13(Documenter.java:288)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
	at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
	at java.base/java.util.HashMap$ValueSpliterator.forEachRemaining(HashMap.java:1675)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
	at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
	at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)
	at org.moduliths.docs.Documenter.addComponentsToView(Documenter.java:289)
	at org.moduliths.docs.Documenter.createPlantUml(Documenter.java:370)
	at org.moduliths.docs.Documenter.writeModulesAsPlantUml(Documenter.java:145)
	at com.example.modulithsdemo.DocumentingTest.verifyModularity(DocumentingTest.kt:28)

I tried adding to org.springframework.web.servlet.function and org.springframework.web.reactive.function to org.moduliths.model.Modules#FRAMEWORK_PACKAGES, but this causes some further NPEs while rendering AsciiDoctor.

P.S. Thanks a lot (!) for this project and efforts put here, I think this represents a wide gap in current Java toolset.

[odrotbohm]

This is in place now in the current snapshots. The sample project provided builds fine with those used.

[odrotbohm]

Looks like this is caused by a special arrangement in declared and actually used types within ArchUnit. @codecholeric has a proposed fix for that in TNG/ArchUnit#530 but a workaround would be to add org.springframework.web.reactive into the framework packages to be explicitly scanned.

The aforementioned improvement in ArchUnit should actually make our explicit list of framework packages to include in the scanning obsolete. I’ll create a separate issue for that.