Improve handling of Java annotation parameters

plugins/base/src/main/kotlin/translators/psi/DefaultPsiToDocumentableTranslator.kt

@@ -692,8 +692,15 @@ class DefaultPsiToDocumentableTranslator(
             is PsiArrayInitializerMemberValue -> ArrayValue(initializers.mapNotNull { it.toValue() })
             is PsiReferenceExpression -> psiReference?.let { EnumValue(text ?: "", DRI.from(it)) }
             is PsiClassObjectAccessExpression -> {
-                val psiClass = ((type as PsiImmediateClassType).parameters.single() as PsiClassReferenceType).resolve()
-                psiClass?.let { ClassValue(text ?: "", DRI.from(psiClass)) }
+                val parameterType = (type as? PsiClassType)?.parameters?.firstOrNull()
+                val classType = when (parameterType) {
+                    is PsiClassType -> parameterType.resolve()
+                    // Notice: Array<String>::class will be passed down as String::class
+                    // should probably be Array::class instead but this reflects behaviour for Kotlin sources
+                    is PsiArrayType -> (parameterType.componentType as? PsiClassType)?.resolve()
+                    else -> null
+                }
+                classType?.let { ClassValue(it.name ?: "", DRI.from(it)) }
             }
             is PsiLiteralExpression -> toValue()
             else -> StringValue(text ?: "")

plugins/base/src/test/kotlin/model/annotations/JavaAnnotationsTest.kt

@@ -0,0 +1,195 @@
+package model.annotations
+
+import org.jetbrains.dokka.base.testApi.testRunner.BaseAbstractTest
+import org.jetbrains.dokka.model.*
+import org.junit.jupiter.api.Test
+import translators.findClasslike
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertNotNull
+import kotlin.test.assertTrue
+
+class JavaAnnotationsTest : BaseAbstractTest() {
+
+    val configuration = dokkaConfiguration {
+        sourceSets {
+            sourceSet {
+                sourceRoots = listOf("src/main/java")
+            }
+        }
+    }
+
+    @Test // see https://github.com/Kotlin/dokka/issues/2350
+    fun `should hande array used as annotation param value`() {
+        testInline(
+            """
+            |/src/main/java/annotation/TestClass.java
+            |package annotation;
+            |public class TestClass {
+            |    @SimpleAnnotation(clazz = String[].class)
+            |    public boolean simpleAnnotation() {
+            |        return false;
+            |    }
+            |}
+            |
+            |/src/main/java/annotation/SimpleAnnotation.java
+            |package annotation;
+            |@Retention(RetentionPolicy.RUNTIME)
+            |@Target(ElementType.METHOD)
+            |public @interface SimpleAnnotation {
+            |    Class<?> clazz();
+            |}
+            """.trimIndent(),
+            configuration
+        ) {
+            documentablesTransformationStage = { module ->
+                val testClass = module.findClasslike("annotation", "TestClass") as DClass
+                assertNotNull(testClass)
+
+                val annotatedFunction = testClass.functions.single { it.name == "simpleAnnotation" }
+                val annotation =
+                    annotatedFunction.extra[Annotations]?.directAnnotations?.entries?.single()?.value?.single()
+                assertNotNull(annotation) { "Expected to find an annotation on simpleAnnotation function, found none" }
+                assertEquals("annotation", annotation.dri.packageName)
+                assertEquals("SimpleAnnotation", annotation.dri.classNames)
+                assertEquals(1, annotation.params.size)
+
+                val param = annotation.params.values.single()
+                assertTrue(param is ClassValue)
+                // should probably be Array instead
+                // String matches parsing of Kotlin sources as of now
+                assertEquals("String", param.className)
+                assertEquals("java.lang", param.classDRI.packageName)
+                assertEquals("String", param.classDRI.classNames)
+            }
+        }
+    }
+
+    @Test // see https://github.com/Kotlin/dokka/issues/2551
+    fun `should hande annotation used within annotation params with class param value`() {
+        testInline(
+            """
+            |/src/main/java/annotation/TestClass.java
+            |package annotation;
+            |public class TestClass {
+            |    @XmlElementRefs({
+            |            @XmlElementRef(name = "NotOffered", namespace = "http://www.gaeb.de/GAEB_DA_XML/DA86/3.3", type = JAXBElement.class, required = false)
+            |    })
+            |    public List<JAXBElement<Object>> content;
+            |}
+            |
+            |/src/main/java/annotation/XmlElementRefs.java
+            |package annotation;
+            |public @interface XmlElementRefs {
+            |    XmlElementRef[] value();
+            |}
+            |
+            |/src/main/java/annotation/XmlElementRef.java
+            |package annotation;
+            |public @interface XmlElementRef {
+            |    String name();
+            |
+            |    String namespace();
+            |
+            |    boolean required();
+            |    
+            |    Class<JAXBElement> type();
+            |}
+            |
+            |/src/main/java/annotation/JAXBElement.java
+            |package annotation;
+            |public class JAXBElement<T> {
+            |}
+            """.trimIndent(),
+            configuration
+        ) {
+            documentablesTransformationStage = { module ->
+                val testClass = module.findClasslike("annotation", "TestClass") as DClass
+                assertNotNull(testClass)
+
+                val contentField = testClass.properties.find { it.name == "content" }
+                assertNotNull(contentField)
+
+                val annotation = contentField.extra[Annotations]?.directAnnotations?.entries?.single()?.value?.single()
+                assertNotNull(annotation) { "Expected to find an annotation on content field, found none" }
+                assertEquals("XmlElementRefs", annotation.dri.classNames)
+                assertEquals(1, annotation.params.size)
+
+                val arrayParam = annotation.params.values.single()
+                assertTrue(arrayParam is ArrayValue, "Expected single annotation param to be array")
+                assertEquals(1, arrayParam.value.size)
+
+                val arrayParamValue = arrayParam.value.single()
+                assertTrue(arrayParamValue is AnnotationValue)
+
+                val arrayParamAnnotationValue = arrayParamValue.annotation
+                assertEquals(4, arrayParamAnnotationValue.params.size)
+                assertEquals("XmlElementRef", arrayParamAnnotationValue.dri.classNames)
+
+                val annotationParams = arrayParamAnnotationValue.params.values.toList()
+
+                val nameParam = annotationParams[0]
+                assertTrue(nameParam is StringValue)
+                assertEquals("NotOffered", nameParam.value)
+
+                val namespaceParam = annotationParams[1]
+                assertTrue(namespaceParam is StringValue)
+                assertEquals("http://www.gaeb.de/GAEB_DA_XML/DA86/3.3", namespaceParam.value)
+
+                val typeParam = annotationParams[2]
+                assertTrue(typeParam is ClassValue)
+                assertEquals("JAXBElement", typeParam.className)
+                assertEquals("annotation", typeParam.classDRI.packageName)
+                assertEquals("JAXBElement", typeParam.classDRI.classNames)
+
+                val requiredParam = annotationParams[3]
+                assertTrue(requiredParam is BooleanValue)
+                assertFalse(requiredParam.value)
+            }
+        }
+    }
+
+    @Test // see https://github.com/Kotlin/dokka/issues/2509
+    fun `should handle generic class in annotation`() {
+        testInline(
+            """
+            |/src/main/java/annotation/Breaking.java
+            |package annotation;
+            |public class Breaking<Y> { 
+            |}
+            |
+            |/src/main/java/annotation/TestAnnotate.java
+            |package annotation;
+            |public @interface TestAnnotate {
+            |    Class<?> value();
+            |}
+            |
+            |/src/main/java/annotation/TestClass.java
+            |package annotation;
+            |@TestAnnotate(Breaking.class)
+            |public class TestClass {
+            |}
+            """.trimIndent(),
+            configuration
+        ) {
+            documentablesTransformationStage = { module ->
+                val testClass = module.findClasslike("annotation", "TestClass") as DClass
+                assertNotNull(testClass)
+
+                val annotation = testClass.extra[Annotations]?.directAnnotations?.entries?.single()?.value?.single()
+                assertNotNull(annotation) { "Expected to find an annotation on TestClass, found none" }
+
+                assertEquals("TestAnnotate", annotation.dri.classNames)
+                assertEquals(1, annotation.params.size)
+
+                val valueParameter = annotation.params.values.single()
+                assertTrue(valueParameter is ClassValue)
+
+                assertEquals("Breaking", valueParameter.className)
+
+                assertEquals("annotation", valueParameter.classDRI.packageName)
+                assertEquals("Breaking", valueParameter.classDRI.classNames)
+            }
+        }
+    }
+}