Invert if condition intention: do not remove line breaks #KT-11740 Fixed

idea/src/org/jetbrains/kotlin/idea/intentions/InvertIfConditionIntention.kt

@@ -22,6 +22,7 @@ import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptorIfAny
 import org.jetbrains.kotlin.idea.core.moveCaret
 import org.jetbrains.kotlin.idea.core.replaced
 import org.jetbrains.kotlin.idea.core.unblockDocument
+import org.jetbrains.kotlin.idea.refactoring.getLineNumber
 import org.jetbrains.kotlin.idea.util.CommentSaver
 import org.jetbrains.kotlin.idea.util.psi.patternMatching.matches
 import org.jetbrains.kotlin.lexer.KtTokens
@@ -89,7 +90,21 @@ class InvertIfConditionIntention : SelfTargetingIntention<KtIfExpression>(KtIfEx
         else
             thenBranch
 
-        return ifExpression.replaced(psiFactory.createIf(newCondition, newThen, newElse))
+        var thenSpace = " "
+        var elseSpace = " "
+        if (ifExpression.condition?.getLineNumber(false) != thenBranch.getLineNumber()
+            || ifExpression.elseKeyword?.getLineNumber() != elseBranch.getLineNumber()
+        ) {
+            if (newThen !is KtBlockExpression) thenSpace = "\n"
+            if (newElse !is KtBlockExpression) elseSpace = "\n"
+        }
+        val newIf = if (newElse == null) {
+            psiFactory.createExpressionByPattern("if ($0)$thenSpace$1", newCondition, newThen)
+        } else {
+            psiFactory.createExpressionByPattern("if ($0)$thenSpace$1${thenSpace}else$elseSpace$2", newCondition, newThen, newElse)
+        } as KtIfExpression
+
+        return ifExpression.replaced(newIf)
     }
 
     private fun handleSpecialCases(ifExpression: KtIfExpression, newCondition: KtExpression): KtIfExpression? {

idea/testData/intentions/invertIfCondition/branchingIfStatements.kt.after

@@ -6,5 +6,6 @@ fun main() {
             a + 1
         else
             a + 2
-    } else a
+    } else
+        a
 }

idea/testData/intentions/invertIfCondition/notBlock.kt

@@ -0,0 +1,6 @@
+fun foo(i: Int): Int {
+    return <caret>if (i > 0)
+        i
+    else
+        i + 1
+}

idea/testData/intentions/invertIfCondition/notBlock.kt.after

@@ -0,0 +1,6 @@
+fun foo(i: Int): Int {
+    return if (i <= 0)
+        i + 1
+    else
+        i
+}

idea/testData/intentions/invertIfCondition/notBlock2.kt

@@ -0,0 +1,6 @@
+fun foo(i: Int): Int {
+    return <caret>if (i > 0) {
+        i
+    } else
+        i + 1
+}

idea/testData/intentions/invertIfCondition/notBlock2.kt.after

@@ -0,0 +1,7 @@
+fun foo(i: Int): Int {
+    return if (i <= 0)
+        i + 1
+    else {
+        i
+    }
+}

idea/testData/intentions/invertIfCondition/notBlock3.kt

@@ -0,0 +1,8 @@
+fun foo(i: Int) {
+    <caret>if (i > 0)
+        bar()
+    else {
+    }
+}
+
+fun bar() {}

idea/testData/intentions/invertIfCondition/notBlock3.kt.after

@@ -0,0 +1,7 @@
+fun foo(i: Int) {
+    if (i <= 0) {
+    } else
+        bar()
+}
+
+fun bar() {}

idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java

@@ -9687,6 +9687,24 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("notBlock.kt")
+        public void testNotBlock() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/invertIfCondition/notBlock.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("notBlock2.kt")
+        public void testNotBlock2() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/invertIfCondition/notBlock2.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("notBlock3.kt")
+        public void testNotBlock3() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/invertIfCondition/notBlock3.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("notIn.kt")
         public void testNotIn() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/invertIfCondition/notIn.kt");