Do not enforce multiline function signature when function has no para…

…meters Closes: #1773 Co-authored-by: Jeroen Tietema <jeroen.tietema@siriusxm.com> Co-authored-by: paul-dingemans <paul-dingemans@users.noreply.github.com>
pinterest · Jan 15, 2023 · f339e19 · f339e19
1 parent 480dd87
commit f339e19
Show file tree

Hide file tree

Showing 3 changed files with 55 additions and 4 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -9,6 +9,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 ### Removed
 
 ### Fixed
+* A function signature not having any parameters which exceeds the `max-line-length` should be ignored by rule `function-signature` ([#1773](https://github.com/pinterest/ktlint/issues/1773))
 
 ### Changed
 

diff --git a/...mental/src/main/kotlin/com/pinterest/ktlint/ruleset/experimental/FunctionSignatureRule.kt b/...mental/src/main/kotlin/com/pinterest/ktlint/ruleset/experimental/FunctionSignatureRule.kt
@@ -158,10 +158,17 @@ public class FunctionSignatureRule :
                 node.containsParameterPrecededByAnnotationOnSeparateLine()
         if (isMaxLineLengthSet()) {
             val singleLineFunctionSignatureLength = calculateFunctionSignatureLengthAsSingleLineSignature(node, emit, autoCorrect)
-            if (forceMultilineSignature ||
-                singleLineFunctionSignatureLength > maxLineLength ||
-                node.hasMinimumNumberOfParameters()
-            ) {
+            // Function signatures not having parameters, should not be reformatted automatically. It would result in function signatures
+            // like below, which are not acceptable:
+            //     fun aVeryLongFunctionName(
+            //     ) = "some-value"
+            //
+            //     fun aVeryLongFunctionName(
+            //     ): SomeVeryLongTypeName =
+            //         SomeVeryLongTypeName(...)
+            // Leave it up to the max-line-length rule to detect those violations so that the developer can handle it manually.
+            val rewriteFunctionSignatureWithParameters = node.countParameters() > 0 && singleLineFunctionSignatureLength > maxLineLength
+            if (forceMultilineSignature || rewriteFunctionSignatureWithParameters) {
                 fixWhiteSpacesInValueParameterList(node, emit, autoCorrect, multiline = true, dryRun = false)
                 // Due to rewriting the function signature, the remaining length on the last line of the multiline
                 // signature needs to be recalculated

diff --git a/...al/src/test/kotlin/com/pinterest/ktlint/ruleset/experimental/FunctionSignatureRuleTest.kt b/...al/src/test/kotlin/com/pinterest/ktlint/ruleset/experimental/FunctionSignatureRuleTest.kt
@@ -1075,6 +1075,49 @@ class FunctionSignatureRuleTest {
             .hasNoLintViolations()
     }
 
+    @Nested
+    inner class `Issue 1773 - Given a unction signature without parameters exceeding the max line length` {
+        @Test
+        fun `Given a function name between backticks and expression body`() {
+            val code =
+                """
+                // $MAX_LINE_LENGTH_MARKER                $EOL_CHAR
+                fun `a very long function name as found in a test case`() =
+                    "some-result"
+                """.trimIndent()
+            functionSignatureWrappingRuleAssertThat(code)
+                .setMaxLineLength()
+                .hasNoLintViolations()
+        }
+
+        @Test
+        fun `Given a function name not between backticks and expression body`() {
+            val code =
+                """
+                // $MAX_LINE_LENGTH_MARKER                $EOL_CHAR
+                fun aVeryLongFunctionNameAsFoundInATestCase() =
+                    "some-result"
+                """.trimIndent()
+            functionSignatureWrappingRuleAssertThat(code)
+                .setMaxLineLength()
+                .hasNoLintViolations()
+        }
+
+        @Test
+        fun `Given a function name not between backticks and a return type and body block`() {
+            val code =
+                """
+                // $MAX_LINE_LENGTH_MARKER                        $EOL_CHAR
+                fun aVeryLongFunctionNameAsFoundInATestCase(): String {
+                    return "some-result"
+                }
+                """.trimIndent()
+            functionSignatureWrappingRuleAssertThat(code)
+                .setMaxLineLength()
+                .hasNoLintViolations()
+        }
+    }
+
     private companion object {
         const val UNEXPECTED_SPACES = "  "
         const val NO_SPACE = ""