Fix for loop conversion when multiple initializers are present

#KT-35074 fixed

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

@@ -885,6 +885,14 @@ class JavaToJKTreeBuilder constructor(
             }
         }
 
+        fun PsiStatement?.asJKStatementsList() = when (this) {
+            null -> emptyList()
+            is PsiExpressionListStatement -> expressionList.expressions.map { expression ->
+                JKExpressionStatement(with(expressionTreeMapper) { expression.toJK() })
+            }
+            else -> listOf(toJK())
+        }
+
         fun PsiStatement?.toJK(): JKStatement {
             return when (this) {
                 null -> JKExpressionStatement(JKStubExpression())
@@ -909,15 +917,9 @@ class JavaToJKTreeBuilder constructor(
 
 
                 is PsiForStatement -> JKJavaForLoopStatement(
-                    initialization.toJK(),
+                    initialization.asJKStatementsList(),
                     with(expressionTreeMapper) { condition.toJK() },
-                    when (update) {
-                        is PsiExpressionListStatement ->
-                            (update as PsiExpressionListStatement).expressionList.expressions.map {
-                                JKExpressionStatement(with(expressionTreeMapper) { it.toJK() })
-                            }
-                        else -> listOf(update.toJK())
-                    },
+                    update.asJKStatementsList(),
                     body.toJK()
                 )
                 is PsiForeachStatement ->

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

@@ -40,11 +40,13 @@ class ForConversion(context: NewJ2kConverterContext) : RecursiveApplicableConver
             else JKLiteralExpression("true", JKLiteralExpression.LiteralType.BOOLEAN)
         val whileStatement = JKWhileStatement(condition, whileBody)
 
-        if (loopStatement.initializer is JKEmptyStatement) return whileStatement
+        if (loopStatement.initializers.isEmpty()
+            || loopStatement.initializers.singleOrNull() is JKEmptyStatement
+        ) return whileStatement
 
         val convertedFromForLoopSyntheticWhileStatement =
             JKKtConvertedFromForLoopSyntheticWhileStatement(
-                loopStatement::initializer.detached(),
+                loopStatement::initializers.detached(),
                 whileStatement
             )
 
@@ -81,8 +83,7 @@ class ForConversion(context: NewJ2kConverterContext) : RecursiveApplicableConver
         val body = continueStatementConverter.applyToElement(loopStatement::body.detached())
 
         if (body is JKBlockStatement) {
-            val initializer = loopStatement.initializer
-            val hasNameConflict =
+            val hasNameConflict = loopStatement.initializers.any { initializer ->
                 initializer is JKDeclarationStatement && initializer.declaredStatements.any { loopVar ->
                     loopVar is JKLocalVariable && body.statements.any { statement ->
                         statement is JKDeclarationStatement && statement.declaredStatements.any {
@@ -90,6 +91,7 @@ class ForConversion(context: NewJ2kConverterContext) : RecursiveApplicableConver
                         }
                     }
                 }
+            }
 
             val statements =
                 if (hasNameConflict) {
@@ -106,8 +108,8 @@ class ForConversion(context: NewJ2kConverterContext) : RecursiveApplicableConver
     }
 
     private fun convertToForeach(loopStatement: JKJavaForLoopStatement): JKForInStatement? {
-        val loopVar =
-            (loopStatement.initializer as? JKDeclarationStatement)?.declaredStatements?.singleOrNull() as? JKLocalVariable ?: return null
+        val initializer = loopStatement.initializers.singleOrNull() ?: return null
+        val loopVar = (initializer as? JKDeclarationStatement)?.declaredStatements?.singleOrNull() as? JKLocalVariable ?: return null
         val loopVarPsi = loopVar.psi<PsiLocalVariable>() ?: return null
         val condition = loopStatement.condition as? JKBinaryExpression ?: return null
         if (!loopVarPsi.hasWriteAccesses(referenceSearcher, loopStatement.body.psi())
@@ -276,7 +278,7 @@ class ForConversion(context: NewJ2kConverterContext) : RecursiveApplicableConver
     }
 
     private fun JKJavaForLoopStatement.hasNameConflict(): Boolean {
-        val names = initializer.declaredVariableNames()
+        val names = initializers.flatMap { it.declaredVariableNames() }
         if (names.isEmpty()) return false
 
         val factory = PsiElementFactory.SERVICE.getInstance(context.project)
@@ -301,7 +303,7 @@ class ForConversion(context: NewJ2kConverterContext) : RecursiveApplicableConver
         when (this) {
             is JKDeclarationStatement ->
                 declaredStatements.filterIsInstance<JKVariable>().map { it.name.value }
-            is JKJavaForLoopStatement -> initializer.declaredVariableNames()
+            is JKJavaForLoopStatement -> initializers.flatMap { it.declaredVariableNames() }
             else -> emptyList()
         }
 

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

@@ -13,7 +13,7 @@ import org.jetbrains.kotlin.nj2k.tree.*
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
 
-class LabeledStatementConversion(context : NewJ2kConverterContext) : RecursiveApplicableConversionBase(context) {
+class LabeledStatementConversion(context: NewJ2kConverterContext) : RecursiveApplicableConversionBase(context) {
     override fun applyToElement(element: JKTreeElement): JKTreeElement {
         if (element !is JKExpressionStatement) return recurse(element)
         val labeledStatement = element.expression as? JKLabeledExpression ?: return recurse(element)
@@ -26,13 +26,11 @@ class LabeledStatementConversion(context : NewJ2kConverterContext) : RecursiveAp
 
         return recurse(
             JKBlockStatementWithoutBrackets(
-                listOf(
-                    convertedFromForLoopSyntheticWhileStatement::variableDeclaration.detached(),
-                    JKLabeledExpression(
-                        convertedFromForLoopSyntheticWhileStatement::whileStatement.detached(),
-                        labeledStatement::labels.detached()
-                    ).asStatement()
-                )
+                convertedFromForLoopSyntheticWhileStatement::variableDeclarations.detached() +
+                        JKLabeledExpression(
+                            convertedFromForLoopSyntheticWhileStatement::whileStatement.detached(),
+                            labeledStatement::labels.detached()
+                        ).asStatement()
             )
         )
     }

nj2k/src/org/jetbrains/kotlin/nj2k/printing/JKCodeBuilder.kt

@@ -548,7 +548,11 @@ internal class JKCodeBuilder(context: NewJ2kConverterContext) {
         override fun visitKtConvertedFromForLoopSyntheticWhileStatementRaw(
             ktConvertedFromForLoopSyntheticWhileStatement: JKKtConvertedFromForLoopSyntheticWhileStatement
         ) {
-            ktConvertedFromForLoopSyntheticWhileStatement.variableDeclaration.accept(this)
+            printer.renderList(
+                ktConvertedFromForLoopSyntheticWhileStatement.variableDeclarations,
+                { printer.println() }) {
+                it.accept(this)
+            }
             printer.println()
             ktConvertedFromForLoopSyntheticWhileStatement.whileStatement.accept(this)
         }

nj2k/src/org/jetbrains/kotlin/nj2k/tree/statements.kt

@@ -83,10 +83,10 @@ class JKKtWhenStatement(
 }
 
 class JKKtConvertedFromForLoopSyntheticWhileStatement(
-    variableDeclaration: JKStatement,
+    variableDeclarations: List<JKStatement>,
     whileStatement: JKWhileStatement
 ) : JKStatement() {
-    var variableDeclaration: JKStatement by child(variableDeclaration)
+    var variableDeclarations: List<JKStatement> by children(variableDeclarations)
     var whileStatement: JKWhileStatement by child(whileStatement)
     override fun accept(visitor: JKVisitor) = visitor.visitKtConvertedFromForLoopSyntheticWhileStatement(this)
 }
@@ -154,7 +154,7 @@ class JKJavaAssertStatement(condition: JKExpression, description: JKExpression)
 }
 
 class JKJavaForLoopStatement(
-    initializer: JKStatement,
+    initializers: List<JKStatement>,
     condition: JKExpression,
     updaters: List<JKStatement>,
     body: JKStatement
@@ -162,7 +162,7 @@ class JKJavaForLoopStatement(
     override var body by child(body)
     var updaters by children(updaters)
     var condition by child(condition)
-    var initializer by child(initializer)
+    var initializers by children(initializers)
 
     override fun accept(visitor: JKVisitor) = visitor.visitJavaForLoopStatement(this)
 }

nj2k/testData/newJ2k/for/emptyInitializers.java

@@ -0,0 +1,7 @@
+public class SomeClass {
+    void doSomeFor() {
+        int i = 0, u = 0;
+        for (; i < 42; i++) {
+        }
+    }
+}

nj2k/testData/newJ2k/for/emptyInitializers.kt

@@ -0,0 +1,9 @@
+class SomeClass {
+    fun doSomeFor() {
+        var i = 0
+        val u = 0
+        while (i < 42) {
+            i++
+        }
+    }
+}

nj2k/testData/newJ2k/for/multipleInitializers.java

@@ -0,0 +1,7 @@
+public class SomeClass {
+    void doSomeFor() {
+        int i, u;
+        for (i = 0, u = 0; i < 42; i++) {
+        }
+    }
+}

nj2k/testData/newJ2k/for/multipleInitializers.kt

@@ -0,0 +1,11 @@
+class SomeClass {
+    fun doSomeFor() {
+        var i: Int
+        val u: Int
+        i = 0
+        u = 0
+        while (i < 42) {
+            i++
+        }
+    }
+}

nj2k/testData/newJ2k/for/multipleInitializersWithvariableDeclarations.java

@@ -0,0 +1,6 @@
+public class SomeClass {
+    void doSomeFor() {
+        for (int i = 0, u = 0; i < 42; i++) {
+        }
+    }
+}

nj2k/testData/newJ2k/for/multipleInitializersWithvariableDeclarations.kt

@@ -0,0 +1,9 @@
+class SomeClass {
+    fun doSomeFor() {
+        var i = 0
+        val u = 0
+        while (i < 42) {
+            i++
+        }
+    }
+}

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

@@ -2023,6 +2023,11 @@ public class NewJavaToKotlinConverterSingleFileTestGenerated extends AbstractNew
             runTest("nj2k/testData/newJ2k/for/downTo4.java");
         }
 
+        @TestMetadata("emptyInitializers.java")
+        public void testEmptyInitializers() throws Exception {
+            runTest("nj2k/testData/newJ2k/for/emptyInitializers.java");
+        }
+
         @TestMetadata("falseArrayIndicesReversed.java")
         public void testFalseArrayIndicesReversed() throws Exception {
             runTest("nj2k/testData/newJ2k/for/falseArrayIndicesReversed.java");
@@ -2153,6 +2158,16 @@ public class NewJavaToKotlinConverterSingleFileTestGenerated extends AbstractNew
             runTest("nj2k/testData/newJ2k/for/infiniteFor.java");
         }
 
+        @TestMetadata("multipleInitializers.java")
+        public void testMultipleInitializers() throws Exception {
+            runTest("nj2k/testData/newJ2k/for/multipleInitializers.java");
+        }
+
+        @TestMetadata("multipleInitializersWithvariableDeclarations.java")
+        public void testMultipleInitializersWithvariableDeclarations() throws Exception {
+            runTest("nj2k/testData/newJ2k/for/multipleInitializersWithvariableDeclarations.java");
+        }
+
         @TestMetadata("nameConflict1.java")
         public void testNameConflict1() throws Exception {
             runTest("nj2k/testData/newJ2k/for/nameConflict1.java");