Make assignment indent conforms with indent for expression bodies (KT-28484)

Do not make plain list of binary expression for assignment expressions.

 #KT-28484 Fixed

idea/formatter/src/org/jetbrains/kotlin/idea/formatter/KotlinCommonBlock.kt

@@ -434,9 +434,14 @@ abstract class KotlinCommonBlock(
         val childNodes = when {
             overrideChildren != null -> overrideChildren.asSequence()
             node.elementType == KtNodeTypes.BINARY_EXPRESSION -> {
-                val binaryExpressionChildren = mutableListOf<ASTNode>()
+                val binaryExpression = node.psi as? KtBinaryExpression
-                collectBinaryExpressionChildren(node, binaryExpressionChildren)
+                if (binaryExpression != null && ALL_ASSIGNMENTS.contains(binaryExpression.operationToken)) {
-                binaryExpressionChildren.asSequence()
+                    node.children()
+                } else {
+                    val binaryExpressionChildren = mutableListOf<ASTNode>()
+                    collectBinaryExpressionChildren(node, binaryExpressionChildren)
+                    binaryExpressionChildren.asSequence()
+                }
             }
             else -> node.children()
         }
@@ -725,6 +730,21 @@ private val INDENT_RULES = arrayOf(
         }
         .continuationIf(KotlinCodeStyleSettings::CONTINUATION_INDENT_FOR_EXPRESSION_BODIES),
 
+    strategy("Assignment expressions")
+        .within(KtNodeTypes.BINARY_EXPRESSION)
+        .within {
+            val binaryExpression = it.psi as? KtBinaryExpression
+                ?: return@within false
+
+            return@within KtTokens.ALL_ASSIGNMENTS.contains(binaryExpression.operationToken)
+        }
+        .forElement {
+            val psi = it.psi
+            val binaryExpression = psi?.parent as? KtBinaryExpression
+            binaryExpression?.right == psi
+        }
+        .continuationIf(KotlinCodeStyleSettings::CONTINUATION_INDENT_FOR_EXPRESSION_BODIES),
+
     strategy("Indent for parts")
         .within(KtNodeTypes.PROPERTY, KtNodeTypes.FUN, KtNodeTypes.DESTRUCTURING_DECLARATION, KtNodeTypes.SECONDARY_CONSTRUCTOR)
         .notForType(
@@ -755,7 +775,9 @@ private val INDENT_RULES = arrayOf(
 
     strategy("Binary expressions")
         .within(BINARY_EXPRESSIONS)
-        .forElement { node -> !node.suppressBinaryExpressionIndent() }
+        .forElement { node ->
+            !node.suppressBinaryExpressionIndent()
+        }
         .set(Indent.getContinuationWithoutFirstIndent(false)),
 
     strategy("Parenthesized expression")

idea/formatter/src/org/jetbrains/kotlin/idea/formatter/NodeIndentStrategy.kt

@@ -38,7 +38,10 @@ abstract class NodeIndentStrategy {
         private var indentCallback: (CodeStyleSettings) -> Indent = { Indent.getNoneIndent() }
 
         private val within = ArrayList<IElementType>()
+        private var withinCallback: ((ASTNode) -> Boolean)? = null
+
         private val notIn = ArrayList<IElementType>()
+
         private val forElement = ArrayList<IElementType>()
         private val notForElement = ArrayList<IElementType>()
         private var forElementCallback: ((ASTNode) -> Boolean)? = null
@@ -72,6 +75,11 @@ abstract class NodeIndentStrategy {
             return this
         }
 
+        fun within(callback: (ASTNode) -> Boolean): PositionStrategy {
+            withinCallback = callback
+            return this
+        }
+
         fun notWithin(parentType: IElementType, vararg orParentTypes: IElementType): PositionStrategy {
             fillTypes(notIn, parentType, orParentTypes)
             return this
@@ -129,6 +137,10 @@ abstract class NodeIndentStrategy {
                 if (notIn.contains(parent.elementType)) {
                     return null
                 }
+
+                if (withinCallback?.invoke(parent) == false) {
+                    return null
+                }
             }
             else {
                 if (!within.isEmpty()) {

idea/testData/formatter/BinaryExpressionsWithoutAlignment.after.inv.kt

@@ -35,4 +35,5 @@ fun test() {
             1..2
 }
 
-// SET_TRUE: ALIGN_MULTILINE_BINARY_OPERATION
+// SET_TRUE: ALIGN_MULTILINE_BINARY_OPERATION
+// SET_FALSE: CONTINUATION_INDENT_FOR_EXPRESSION_BODIES

idea/testData/formatter/BinaryExpressionsWithoutAlignment.after.kt

@@ -2,19 +2,19 @@ fun test() {
     var a = 12
 
     a =
-            12
+        12
 
     a +=
-            12
+        12
 
     a -=
-            12
+        12
 
     a *=
-            12
+        12
 
     a /=
-            12
+        12
 
     a is
             String
@@ -35,4 +35,5 @@ fun test() {
             1..2
 }
 
-// SET_TRUE: ALIGN_MULTILINE_BINARY_OPERATION
+// SET_TRUE: ALIGN_MULTILINE_BINARY_OPERATION
+// SET_FALSE: CONTINUATION_INDENT_FOR_EXPRESSION_BODIES

idea/testData/formatter/BinaryExpressionsWithoutAlignment.kt

@@ -35,4 +35,5 @@ fun test() {
             1..2
 }
 
-// SET_TRUE: ALIGN_MULTILINE_BINARY_OPERATION
+// SET_TRUE: ALIGN_MULTILINE_BINARY_OPERATION
+// SET_FALSE: CONTINUATION_INDENT_FOR_EXPRESSION_BODIES

idea/testData/formatter/ContinuationIndentInAssigments.after.inv.kt

@@ -0,0 +1,36 @@
+var a: Any? = null
+var b: Any? = null
+
+var i = 0
+var j = 0
+
+fun test() {
+    a1 =
+            1
+
+    a =
+            b
+
+    a =
+            "Some"
+
+    i +=
+            j * j
+
+    i =
+            j ?: 0
+
+    i -=
+            j
+
+    i *=
+            0
+
+    i %=
+            5
+
+    i /=
+            2
+}
+
+// SET_FALSE: CONTINUATION_INDENT_FOR_EXPRESSION_BODIES

idea/testData/formatter/ContinuationIndentInAssigments.after.kt

@@ -0,0 +1,36 @@
+var a: Any? = null
+var b: Any? = null
+
+var i = 0
+var j = 0
+
+fun test() {
+    a1 =
+        1
+
+    a =
+        b
+
+    a =
+        "Some"
+
+    i +=
+        j * j
+
+    i =
+        j ?: 0
+
+    i -=
+        j
+
+    i *=
+        0
+
+    i %=
+        5
+
+    i /=
+        2
+}
+
+// SET_FALSE: CONTINUATION_INDENT_FOR_EXPRESSION_BODIES

idea/testData/formatter/ContinuationIndentInAssigments.kt

@@ -0,0 +1,36 @@
+var a: Any? = null
+var b: Any? = null
+
+var i = 0
+var j = 0
+
+fun test() {
+    a1 =
+    1
+
+    a =
+    b
+
+    a =
+    "Some"
+
+    i +=
+    j * j
+
+    i =
+    j ?: 0
+
+    i -=
+    j
+
+    i *=
+    0
+
+    i %=
+    5
+
+    i /=
+    2
+}
+
+// SET_FALSE: CONTINUATION_INDENT_FOR_EXPRESSION_BODIES

idea/tests/org/jetbrains/kotlin/formatter/FormatterTestGenerated.java

@@ -171,6 +171,11 @@ public class FormatterTestGenerated extends AbstractFormatterTest {
             runTest("idea/testData/formatter/CommentInFunctionLiteral.after.kt");
         }
 
+        @TestMetadata("ContinuationIndentInAssigments.after.kt")
+        public void testContinuationIndentInAssigments() throws Exception {
+            runTest("idea/testData/formatter/ContinuationIndentInAssigments.after.kt");
+        }
+
         @TestMetadata("ContinuationIndentInParameterLists.after.kt")
         public void testContinuationIndentInParameterLists() throws Exception {
             runTest("idea/testData/formatter/ContinuationIndentInParameterLists.after.kt");
@@ -1136,6 +1141,11 @@ public class FormatterTestGenerated extends AbstractFormatterTest {
             runTest("idea/testData/formatter/ContinuationIndentForExpressionBodies.after.inv.kt");
         }
 
+        @TestMetadata("ContinuationIndentInAssigments.after.inv.kt")
+        public void testContinuationIndentInAssigments() throws Exception {
+            runTest("idea/testData/formatter/ContinuationIndentInAssigments.after.inv.kt");
+        }
+
         @TestMetadata("DelegationList.after.inv.kt")
         public void testDelegationList() throws Exception {
             runTest("idea/testData/formatter/DelegationList.after.inv.kt");