Fix false positive when empty parameter list is in between trailing l…

…ambda's of a nested call expression (#2891) Closes #2884
pinterest · Dec 3, 2024 · 1bc924c · 1bc924c
1 parent e098f10
commit 1bc924c
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Showing 2 changed files with 28 additions and 2 deletions.
diff --git a/...pinterest/ktlint/ruleset/standard/rules/UnnecessaryParenthesesBeforeTrailingLambdaRule.kt b/...pinterest/ktlint/ruleset/standard/rules/UnnecessaryParenthesesBeforeTrailingLambdaRule.kt
@@ -2,7 +2,9 @@ package com.pinterest.ktlint.ruleset.standard.rules
 
 import com.pinterest.ktlint.rule.engine.core.api.AutocorrectDecision
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.CALL_EXPRESSION
+import com.pinterest.ktlint.rule.engine.core.api.ElementType.FUNCTION_LITERAL
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.LAMBDA_ARGUMENT
+import com.pinterest.ktlint.rule.engine.core.api.ElementType.LAMBDA_EXPRESSION
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.LPAR
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.RPAR
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.VALUE_ARGUMENT_LIST
@@ -14,6 +16,7 @@ import com.pinterest.ktlint.rule.engine.core.api.children
 import com.pinterest.ktlint.rule.engine.core.api.ifAutocorrectAllowed
 import com.pinterest.ktlint.rule.engine.core.api.isPartOf
 import com.pinterest.ktlint.rule.engine.core.api.nextCodeSibling
+import com.pinterest.ktlint.rule.engine.core.api.prevCodeSibling
 import com.pinterest.ktlint.ruleset.standard.StandardRule
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
 
@@ -27,8 +30,9 @@ public class UnnecessaryParenthesesBeforeTrailingLambdaRule : StandardRule("unne
         node: ASTNode,
         emit: (offset: Int, errorMessage: String, canBeAutoCorrected: Boolean) -> AutocorrectDecision,
     ) {
-        if (node.isPartOf(CALL_EXPRESSION) &&
-            node.isEmptyArgumentList() &&
+        if (node.isEmptyArgumentList() &&
+            node.isPartOf(CALL_EXPRESSION) &&
+            node.isNotPrecededByCallExpressionEndingWithLambdaArgument() &&
             node.nextCodeSibling()?.elementType == LAMBDA_ARGUMENT
         ) {
             emit(
@@ -46,6 +50,17 @@ public class UnnecessaryParenthesesBeforeTrailingLambdaRule : StandardRule("unne
             children()
                 .filterNot { it.elementType == LPAR || it.elementType == RPAR }
                 .none()
+
+    private fun ASTNode.isNotPrecededByCallExpressionEndingWithLambdaArgument() =
+        prevCodeSibling()
+            ?.takeIf { it.elementType == CALL_EXPRESSION }
+            ?.lastChildNode
+            ?.takeIf { it.elementType == LAMBDA_ARGUMENT }
+            ?.lastChildNode
+            ?.takeIf { it.elementType == LAMBDA_EXPRESSION }
+            ?.lastChildNode
+            ?.let { it.elementType != FUNCTION_LITERAL }
+            ?: true
 }
 
 public val UNNECESSARY_PARENTHESES_BEFORE_TRAILING_LAMBDA_RULE_ID: RuleId = UnnecessaryParenthesesBeforeTrailingLambdaRule().ruleId
diff --git a/...erest/ktlint/ruleset/standard/rules/UnnecessaryParenthesesBeforeTrailingLambdaRuleTest.kt b/...erest/ktlint/ruleset/standard/rules/UnnecessaryParenthesesBeforeTrailingLambdaRuleTest.kt
@@ -23,4 +23,15 @@ class UnnecessaryParenthesesBeforeTrailingLambdaRuleTest {
             .hasLintViolation(2, 24, "Empty parentheses in function call followed by lambda are unnecessary")
             .isFormattedAs(formattedCode)
     }
+
+    @Test
+    fun `Issue 2884 - Given some a call expression ending with a lambda argument, followed by an empty argument list followed by another lambda argument then do not remove empty parameter list`() {
+        val code =
+            """
+            fun fooBar(foo: () -> String): (() -> String) -> String = { bar -> foo().plus("  ").plus(bar()) }
+
+            val foobar = fooBar { "Hello" }() { "world" }
+            """.trimIndent()
+        unnecessaryParenthesesBeforeTrailingLambdaRuleAssertThat(code).hasNoLintViolations()
+    }
 }