An if-else followed by an elvis operator should not be wrapped in an …

…else-block (#1923) * An if-else followed by an elvis operator should not be wrapped in an else-block Closes #1904
pinterest · Apr 7, 2023 · 5e46778 · 5e46778
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -292,6 +292,7 @@ if (node.isRoot()) {
 * Add newline after adding trailing comma in parameter list of a function literal `trailing-comma-on-declaration-site` ([#1911](https://github.com/pinterest/ktlint/issues/1911))
 * Wrap annotations before class constructor in code style `ktlint_official`. `annotation` ([#1916](https://github.com/pinterest/ktlint/issues/1916))
 * Annotations on type projections should be wrapped in same way as other annotations `annotation` ([#1917](https://github.com/pinterest/ktlint/issues/1917))
+* An if-else followed by an elvis operator should not be wrapped in an else-block `multiline-if-else` ([#1904](https://github.com/pinterest/ktlint/issues/1904))
 
 ### Changed
 * Wrap the parameters of a function literal containing a multiline parameter list (only in `ktlint_official` code style) `parameter-list-wrapping` ([#1681](https://github.com/pinterest/ktlint/issues/1681)).

diff --git a/...andard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultiLineIfElseRule.kt b/...andard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultiLineIfElseRule.kt
@@ -1,6 +1,8 @@
 package com.pinterest.ktlint.ruleset.standard.rules
 
+import com.pinterest.ktlint.rule.engine.core.api.ElementType.BINARY_EXPRESSION
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.BLOCK
+import com.pinterest.ktlint.rule.engine.core.api.ElementType.DOT_QUALIFIED_EXPRESSION
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.ELSE
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.ELSE_KEYWORD
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.IF
@@ -52,29 +54,54 @@ public class MultiLineIfElseRule :
         autoCorrect: Boolean,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> Unit,
     ) {
-        if (node.elementType == THEN || node.elementType == ELSE) {
-            if (node.firstChildNode?.elementType == BLOCK) {
+        if (node.elementType != THEN && node.elementType != ELSE) {
+            return
+        }
+
+        // Ignore when already wrapped in a block
+        if (node.firstChildNode?.elementType == BLOCK) {
+            return
+        }
+
+        if (node.elementType == ELSE && node.firstChildNode?.elementType == BINARY_EXPRESSION) {
+            // Allow
+            //    val foo = if (bar1) {
+            //       "bar1"
+            //   } else {
+            //       null
+            //   } ?: "something-else"
+            return
+        }
+
+        if (node.elementType == ELSE && node.firstChildNode?.elementType == DOT_QUALIFIED_EXPRESSION) {
+            // Allow
+            //    val foo = if (bar1) {
+            //       "bar1"
+            //   } else {
+            //       "bar2"
+            //   }.plus("foo")
+            return
+        }
+
+        if (!node.treePrev.textContains('\n')) {
+            if (node.firstChildNode.elementType == IF) {
+                // Allow single line for:
+                // else if (...)
                 return
             }
-
-            if (!node.treePrev.textContains('\n')) {
-                if (node.firstChildNode.elementType == IF) {
-                    // Allow single line for:
-                    // else if (...)
-                    return
-                }
-                if (!node.treeParent.textContains('\n')) {
-                    // Allow single line if statements as long as they are really simple (e.g. do not contain newlines)
-                    //    if (...) <statement> // no else statement
-                    //    if (...) <statement> else <statement>
-                    return
-                }
+            if (!node.treeParent.textContains('\n')) {
+                // Allow single line if statements as long as they are really simple (e.g. do not contain newlines)
+                //    if (...) <statement> // no else statement
+                //    if (...) <statement> else <statement>
+                return
             }
 
-            emit(node.firstChildNode.startOffset, "Missing { ... }", true)
-            if (autoCorrect) {
-                autocorrect(node)
-            }
+            Unit
+        }
+
+        emit(node.firstChildNode.startOffset, "Missing { ... }", true)
+        if (autoCorrect) {
+            autocorrect(node)
         }
     }
 

diff --git a/...rd/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultiLineIfElseRuleTest.kt b/...rd/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/rules/MultiLineIfElseRuleTest.kt
@@ -569,4 +569,32 @@ class MultiLineIfElseRuleTest {
                 LintViolation(3, 10, "Missing { ... }"),
             ).isFormattedAs(formattedCode)
     }
+
+    @Test
+    fun `Issue 1904 - Given an nested if else statement followed by an elvis operator`() {
+        val code =
+            """
+            val foo = if (bar1) {
+                "bar1"
+            } else {
+                null
+            } ?: "something-else"
+            """.trimIndent()
+        multiLineIfElseRuleAssertThat(code).hasNoLintViolations()
+    }
+
+    @Test
+    fun `Issue 1904 - Given an nested if else statement and else which is part of a dot qualified expression`() {
+        val code =
+            """
+            val foo = if (bar1) {
+                "bar1"
+            } else if (bar2) {
+                "bar2"
+            } else {
+                "bar3"
+            }.plus("foo")
+            """.trimIndent()
+        multiLineIfElseRuleAssertThat(code).hasNoLintViolations()
+    }
 }