From 1d41320989717c60da3f3d25941cd43c2677c4c8 Mon Sep 17 00:00:00 2001
From: Paul Dingemans <paul-dingemans@users.noreply.github.com>
Date: Sat, 27 Apr 2024 10:54:34 +0200
Subject: [PATCH] Handle trailing space on preceding line in call to
 `lineLengthWithoutNewlinePrefix` (#2644)

---
 .../rule/engine/core/api/ASTNodeExtension.kt  |  2 +-
 .../engine/core/api/ASTNodeExtensionTest.kt   | 26 +++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtension.kt b/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtension.kt
index f37b022576..da78cdda89 100644
--- a/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtension.kt
+++ b/ktlint-rule-engine-core/src/main/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtension.kt
@@ -502,7 +502,7 @@ public fun ASTNode.lineLength(excludeEolComment: Boolean = false): Int = leavesO
  */
 public fun Sequence<ASTNode>.lineLengthWithoutNewlinePrefix(): Int {
     val first = firstOrNull() ?: return 0
-    require(first.text.startsWith('\n') || first.prevLeaf() == null) {
+    require(first.textContains('\n') || first.prevLeaf() == null) {
         "First node in non-empty sequence must be a whitespace containing a newline"
     }
     return joinToString(separator = "") { it.text }
diff --git a/ktlint-rule-engine-core/src/test/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtensionTest.kt b/ktlint-rule-engine-core/src/test/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtensionTest.kt
index 56a5e7aa11..657fa0f6ff 100644
--- a/ktlint-rule-engine-core/src/test/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtensionTest.kt
+++ b/ktlint-rule-engine-core/src/test/kotlin/com/pinterest/ktlint/rule/engine/core/api/ASTNodeExtensionTest.kt
@@ -18,7 +18,9 @@ import com.pinterest.ktlint.rule.engine.core.api.ElementType.TYPE_REFERENCE
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.VALUE_PARAMETER
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.VALUE_PARAMETER_LIST
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.WHITE_SPACE
+import com.pinterest.ktlint.test.SPACE
 import org.assertj.core.api.Assertions.assertThat
+import org.assertj.core.api.Assertions.assertThatNoException
 import org.assertj.core.api.Assertions.entry
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
 import org.jetbrains.kotlin.com.intellij.lang.FileASTNode
@@ -761,6 +763,30 @@ class ASTNodeExtensionTest {
                 "        val foo4".length,
             )
         }
+
+        @Suppress("DEPRECATION")
+        @Test
+        fun `xxGiven some lines containing identifiers at different indentation levels then get line length exclusive the leading newline characters until and including the identifier`() {
+            val code =
+                """
+                val foo1 = "foo1"$SPACE
+                val foo2 = "foo2"
+                """.trimIndent()
+
+            assertThatNoException()
+                .isThrownBy {
+                    transformCodeToAST(code)
+                        .firstChildLeafOrSelf()
+                        .leaves()
+                        .filter { it.elementType == IDENTIFIER }
+                        .map { identifier ->
+                            identifier
+                                .leavesOnLine()
+                                .takeWhile { it.prevLeaf() != identifier }
+                                .lineLengthWithoutNewlinePrefix()
+                        }.toList()
+                }
+        }
     }
 
     @Nested