New J2K: correctly convert main method with varargs argument

#KT-33756 fixed

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

@@ -7,39 +7,36 @@ package org.jetbrains.kotlin.nj2k.conversions
 
 import org.jetbrains.kotlin.j2k.ast.Nullability
 import org.jetbrains.kotlin.nj2k.NewJ2kConverterContext
-import org.jetbrains.kotlin.nj2k.tree.*
-import org.jetbrains.kotlin.nj2k.types.JKClassType
+import org.jetbrains.kotlin.nj2k.jvmAnnotation
+import org.jetbrains.kotlin.nj2k.tree.JKMethod
+import org.jetbrains.kotlin.nj2k.tree.JKTreeElement
+import org.jetbrains.kotlin.nj2k.tree.OtherModifier
+import org.jetbrains.kotlin.nj2k.tree.hasOtherModifier
 import org.jetbrains.kotlin.nj2k.types.JKJavaArrayType
-import org.jetbrains.kotlin.nj2k.types.updateNullability
+import org.jetbrains.kotlin.nj2k.types.arrayInnerType
+import org.jetbrains.kotlin.nj2k.types.isStringType
 
-
-//TODO temporary
 class MainFunctionConversion(context: NewJ2kConverterContext) : RecursiveApplicableConversionBase(context) {
     override fun applyToElement(element: JKTreeElement): JKTreeElement {
         if (element !is JKMethod) return recurse(element)
         if (element.isMainFunctionDeclaration()) {
             element.parameters.single().apply {
-                val oldType = type.type as JKJavaArrayType
-                val oldTypeParameter = oldType.type as JKClassType
-                val newType =
-                    JKJavaArrayType(
-                        oldTypeParameter.updateNullability(Nullability.NotNull),
-                        Nullability.NotNull
-                    )
-                type = JKTypeElement(newType)
+                type.type = JKJavaArrayType(typeFactory.types.string, Nullability.NotNull)
+                isVarArgs = false
             }
-            element.annotationList.annotations +=
-                JKAnnotation(
-                    symbolProvider.provideClassSymbol("kotlin.jvm.JvmStatic"),
-                    emptyList()
-                )
+            element.annotationList.annotations += jvmAnnotation("JvmStatic", symbolProvider)
         }
         return recurse(element)
     }
 
     private fun JKMethod.isMainFunctionDeclaration(): Boolean {
-        val type = parameters.singleOrNull()?.type?.type as? JKJavaArrayType ?: return false
-        val typeArgument = type.type as? JKClassType ?: return false
-        return name.value == "main" && typeArgument.classReference.name == "String"
+        if (name.value != "main") return false
+        if (!hasOtherModifier(OtherModifier.STATIC)) return false
+        val parameter = parameters.singleOrNull() ?: return false
+        return when {
+            parameter.type.type.arrayInnerType()?.isStringType() == true -> true
+            parameter.isVarArgs && parameter.type.type.isStringType() -> true
+            else -> false
+        }
     }
 }

nj2k/testData/newJ2k/function/mainVararg.java

@@ -0,0 +1,4 @@
+public class Main {
+    public static void main(String... args) {
+    }
+}

nj2k/testData/newJ2k/function/mainVararg.kt

@@ -0,0 +1,5 @@
+object Main {
+    @JvmStatic
+    fun main(args: Array<String>) {
+    }
+}

nj2k/testData/newJ2k/issues/kt-21189.kt

@@ -1,19 +1,7 @@
 object ArrayInitializerBugKt {
-    private val GREETING = byteArrayOf(
-        'H'.toByte(),
-        'e'.toByte(),
-        'l'.toByte(),
-        'l'.toByte(),
-        'o'.toByte(),
-        ','.toByte(),
-        ' '.toByte(),
-        'b'.toByte(),
-        'u'.toByte(),
-        'g'.toByte(),
-        '!'.toByte()
-    )
-
-    fun main(vararg args: String?) {
+    private val GREETING = byteArrayOf('H'.toByte(), 'e'.toByte(), 'l'.toByte(), 'l'.toByte(), 'o'.toByte(), ','.toByte(), ' '.toByte(), 'b'.toByte(), 'u'.toByte(), 'g'.toByte(), '!'.toByte())
+    @JvmStatic
+    fun main(args: Array<String>) {
         val greeting = String(GREETING)
         println(greeting)
     }

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

@@ -2388,6 +2388,11 @@ public class NewJavaToKotlinConverterSingleFileTestGenerated extends AbstractNew
             runTest("nj2k/testData/newJ2k/function/mainAndNullabilitySetting.java");
         }
 
+        @TestMetadata("mainVararg.java")
+        public void testMainVararg() throws Exception {
+            runTest("nj2k/testData/newJ2k/function/mainVararg.java");
+        }
+
         @TestMetadata("methodClassType.java")
         public void testMethodClassType() throws Exception {
             runTest("nj2k/testData/newJ2k/function/methodClassType.java");