Add missing whitespace when else is on same line as true condition `m…

…ultiline-if-else` Closes pinterest#1560
paul-dingemans · Aug 2, 2022 · bed5f8f · bed5f8f
1 parent e0693a0
commit bed5f8f
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -126,6 +126,7 @@ The callback function provided as parameter to the format function is now called
 * When a glob is specified then ensure that it matches files in the current directory and not only in subdirectories of the current directory ([#1533](https://github.com/pinterest/ktlint/issue/1533)).
 * Execute `ktlint` cli on default kotlin extensions only when an (existing) path to a directory is given. ([#917](https://github.com/pinterest/ktlint/issue/917)).
 * Invoke callback on `format` function for all errors including errors that are autocorrected ([#1491](https://github.com/pinterest/ktlint/issues/1491))
+* Add missing whitespace when else is on same line as true condition `multiline-if-else` ([#1560](https://github.com/pinterest/ktlint/issues/1560))
 
 
 ### Changed

diff --git a/...set-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/MultiLineIfElseRule.kt b/...set-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/MultiLineIfElseRule.kt
@@ -3,13 +3,18 @@ package com.pinterest.ktlint.ruleset.standard
 import com.pinterest.ktlint.core.Rule
 import com.pinterest.ktlint.core.ast.ElementType.ELSE
 import com.pinterest.ktlint.core.ast.ElementType.ELSE_KEYWORD
+import com.pinterest.ktlint.core.ast.ElementType.IF
 import com.pinterest.ktlint.core.ast.ElementType.LBRACE
 import com.pinterest.ktlint.core.ast.ElementType.RBRACE
 import com.pinterest.ktlint.core.ast.ElementType.RPAR
 import com.pinterest.ktlint.core.ast.ElementType.THEN
+import com.pinterest.ktlint.core.ast.ElementType.WHITE_SPACE
+import com.pinterest.ktlint.core.ast.isPartOf
 import com.pinterest.ktlint.core.ast.isPartOfComment
 import com.pinterest.ktlint.core.ast.isWhiteSpaceWithoutNewline
+import com.pinterest.ktlint.core.ast.nextSibling
 import com.pinterest.ktlint.core.ast.prevLeaf
+import com.pinterest.ktlint.core.ast.upsertWhitespaceBeforeMe
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
 import org.jetbrains.kotlin.com.intellij.psi.PsiWhiteSpace
 import org.jetbrains.kotlin.com.intellij.psi.impl.source.tree.LeafPsiElement
@@ -42,9 +47,17 @@ class MultiLineIfElseRule : Rule("multiline-if-else") {
 
     private fun autocorrect(node: ASTNode) {
         val prevLeaves =
-            node.leaves(forward = false).takeWhile { it.elementType !in listOf(RPAR, ELSE_KEYWORD) }.toList().reversed()
+            node
+                .leaves(forward = false)
+                .takeWhile { it.elementType !in listOf(RPAR, ELSE_KEYWORD) }
+                .toList()
+                .reversed()
         val nextLeaves =
-            node.leaves(forward = true).takeWhile { it.isWhiteSpaceWithoutNewline() || it.isPartOfComment() }.toList()
+            node
+                .leaves(forward = true)
+                .takeWhile { it.isWhiteSpaceWithoutNewline() || it.isPartOfComment() }
+                .toList()
+                .dropLastWhile { it.isWhiteSpaceWithoutNewline() }
         val rightBraceIndent = node.treeParent
             .prevLeaf { it is PsiWhiteSpace && it.textContains('\n') }?.text.orEmpty()
             .let { "\n${it.substringAfterLast("\n")}" }
@@ -62,8 +75,17 @@ class MultiLineIfElseRule : Rule("multiline-if-else") {
         }
 
         // Make sure else starts on same line as newly inserted right brace
-        if (node.elementType == THEN && node.treeNext?.treeNext?.elementType == ELSE_KEYWORD) {
-            node.treeParent.replaceChild(node.treeNext, PsiWhiteSpaceImpl(" "))
+        if (node.elementType == THEN) {
+            node
+                .nextSibling { !it.isPartOfComment() }
+                ?.let { nextSibling ->
+                    if (nextSibling.elementType == ELSE_KEYWORD) {
+                        (nextSibling as LeafPsiElement).upsertWhitespaceBeforeMe(" ")
+                    }
+                    if (nextSibling.elementType == WHITE_SPACE && nextSibling.text != " ") {
+                        (nextSibling as LeafPsiElement).rawReplaceWithText(" ")
+                    }
+                }
         }
     }
 }
diff --git a/...standard/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/MultiLineIfElseRuleTest.kt b/...standard/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/MultiLineIfElseRuleTest.kt
@@ -492,4 +492,27 @@ class MultiLineIfElseRuleTest {
             .hasLintViolation(6, 13, "Missing { ... }")
             .isFormattedAs(formattedCode)
     }
+
+    @Test
+    fun `Issue 1560 - Given an if statement with else keyword on same line as true branch`() {
+        val code =
+            """
+            fun foo() = if (bar())
+                "a" else
+                "b"
+            """.trimIndent()
+        val formattedCode =
+            """
+            fun foo() = if (bar()) {
+                "a"
+            } else {
+                "b"
+            }
+            """.trimIndent()
+        multiLineIfElseRuleAssertThat(code)
+            .hasLintViolations(
+                LintViolation(2, 5, "Missing { ... }"),
+                LintViolation(3, 5, "Missing { ... }")
+            ).isFormattedAs(formattedCode)
+    }
 }