ArchUnit's type predicate doesn't seem to match a class used in an array declaration, when that type predicate is used inside an or predicate, to define an exception to some global condition.

Class Bar.java has a method with this signature:

  static Foo[] baz()

Our rule over in ArchUnitArrayTest.java says Bar can depend on classes in its own package or java.lang or:

.or(type(Foo.class))

We expect the test to pass. But it fails with:

Exception in thread "main" java.lang.AssertionError: Architecture Violation [Priority: MEDIUM] - Rule 'classes that have simple name 'Bar' should only depend on classes that reside in a package 'core.sub' or reside in a package 'java.lang' or type core.Foo' was violated (1 times):
Method <core.sub.Bar.baz()> has return type <[Lcore.Foo;> in (Bar.java:0)
	at com.tngtech.archunit.lang.ArchRule$Assertions.assertNoViolation(ArchRule.java:91)
	at com.tngtech.archunit.lang.ArchRule$Assertions.check(ArchRule.java:81)
	at com.tngtech.archunit.lang.ArchRule$Factory$SimpleArchRule.check(ArchRule.java:195)
	at com.tngtech.archunit.lang.syntax.ObjectsShouldInternal.check(ObjectsShouldInternal.java:81)
	at core.ArchUnitArrayTest.main(ArchUnitArrayTest.java:22)

if you go over to Bar.java and eliminate the Foo[] reference by changing the baz() signature to:

static Foo baz()

…then ArchUnit will throw no exception.

Array declarations, seem to work in other situations. See, for instance, the definition of baz2():

static Quux[] baz2()

That signature generates no exception. ArchUnit recognizes that the array type is derived from Quux and that Quux resides in the core.sub package.

A workaround is to add a clause like this to the rule:

.or(type(Foo[].class))

But it seems wrong to have to explicitly mention array types.