New J2K: Wrap single annotation parameter to arrayOf if array type is required

#KT-31726 fixed

nj2k/src/org/jetbrains/kotlin/nj2k/conversions/AnnotationConversion.kt

@@ -5,8 +5,11 @@
 
 package org.jetbrains.kotlin.nj2k.conversions
 
+import com.intellij.psi.PsiClass
+import com.intellij.psi.PsiMethod
+import org.jetbrains.kotlin.load.java.structure.JavaArrayType
 import org.jetbrains.kotlin.nj2k.NewJ2kConverterContext
-import org.jetbrains.kotlin.nj2k.isVarargsArgument
+import org.jetbrains.kotlin.nj2k.primaryConstructor
 import org.jetbrains.kotlin.nj2k.toExpression
 import org.jetbrains.kotlin.nj2k.tree.*
 import org.jetbrains.kotlin.nj2k.tree.impl.JKAnnotationNameParameterImpl
@@ -37,7 +40,7 @@ class AnnotationConversion(private val context: NewJ2kConverterContext) : Recurs
                                 .detached()
                                 .map { JKAnnotationParameterImpl(it) }
                         annotationParameter is JKAnnotationNameParameter
-                                && annotation.isVarargsArgument(index)
+                                && annotation.isVarargsArgument(annotationParameter.name.value)
                                 && annotation.classSymbol.target is JKClass
                                 && annotationParameter.value !is JKKtAnnotationArrayInitializerExpression -> {
                             listOf(
@@ -64,4 +67,34 @@ class AnnotationConversion(private val context: NewJ2kConverterContext) : Recurs
         annotation.arguments = newParameters
     }
 
+    private fun PsiMethod.isVarArgsAnnotationMethod(isNamedArgument: Boolean) =
+        isVarArgs || returnType is JavaArrayType || name == "value" && !isNamedArgument
+
+    private fun JKParameter.isVarArgsAnnotationParameter(isNamedArgument: Boolean) =
+        isVarArgs || type.type.isArrayType() || name.value == "value" && !isNamedArgument
+
+    private fun JKAnnotation.isVarargsArgument(index: Int) =
+        when (val target = classSymbol.target) {
+            is JKClass -> target.primaryConstructor()
+                ?.parameters
+                ?.getOrNull(index)
+                ?.isVarArgsAnnotationParameter(isNamedArgument = false)
+            is PsiClass -> target.methods
+                .getOrNull(index)
+                ?.isVarArgsAnnotationMethod(isNamedArgument = false)
+            else -> false
+        } ?: false
+
+
+    private fun JKAnnotation.isVarargsArgument(name: String): Boolean =
+        when (val target = classSymbol.target) {
+            is JKClass -> target.primaryConstructor()
+                ?.parameters
+                ?.firstOrNull { it.name.value == name }
+                ?.isVarArgsAnnotationParameter(isNamedArgument = true)
+            is PsiClass -> target.methods
+                .firstOrNull { it.name == name }
+                ?.isVarArgsAnnotationMethod(isNamedArgument = true)
+            else -> false
+        } ?: false
 }

nj2k/src/org/jetbrains/kotlin/nj2k/expressions.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.nj2k
 
+import com.intellij.psi.PsiArrayType
 import com.intellij.psi.PsiClass
 import com.intellij.psi.tree.TokenSet
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
@@ -482,16 +483,6 @@ fun JKClass.primaryConstructor(): JKKtPrimaryConstructor? = classBody.declaratio
 fun List<JKExpression>.toArgumentList(): JKArgumentList =
     JKArgumentListImpl(map { JKArgumentImpl(it) })
 
-fun JKAnnotation.isVarargsArgument(index: Int): Boolean {
-    val target = classSymbol.target
-    return when (target) {
-        is JKClass -> target.primaryConstructor()?.parameters?.getOrNull(index)?.isVarArgs
-        is PsiClass -> target.methods.getOrNull(index)?.let {
-            it.isVarArgs || it.name == "value"
-        }
-        else -> false
-    } ?: false
-}
 
 
 fun JKExpression.asStatement(): JKExpressionStatement =

nj2k/testData/newJ2k/annotations/kt-31726.java

@@ -0,0 +1,7 @@
+//Annotation class:
+public @interface Special {
+    String[] names(); //array is used
+}
+//Class with annotation:
+@Special(names = "name1")
+public class JClass {}

nj2k/testData/newJ2k/annotations/kt-31726.kt

@@ -0,0 +1,6 @@
+//Annotation class:
+annotation class Special(val names: Array<String> //array is used
+) //Class with annotation:
+
+@Special(names = ["name1"])
+class JClass

nj2k/tests/org/jetbrains/kotlin/nj2k/NewJavaToKotlinConverterSingleFileTestGenerated.java

@@ -111,6 +111,11 @@ public class NewJavaToKotlinConverterSingleFileTestGenerated extends AbstractNew
             runTest("nj2k/testData/newJ2k/annotations/jetbrainsNullable.java");
         }
 
+        @TestMetadata("kt-31726.java")
+        public void testKt_31726() throws Exception {
+            runTest("nj2k/testData/newJ2k/annotations/kt-31726.java");
+        }
+
         @TestMetadata("modifiersToAnnotationsFromPropertyAccessors.java")
         public void testModifiersToAnnotationsFromPropertyAccessors() throws Exception {
             runTest("nj2k/testData/newJ2k/annotations/modifiersToAnnotationsFromPropertyAccessors.java");