From 31c4c07d2457db9b9766cc6fb9573466cc4c3c5f Mon Sep 17 00:00:00 2001
From: Albert Meltzer <7529386+kitbellew@users.noreply.github.com>
Date: Sat, 28 Sep 2024 15:29:44 -0700
Subject: [PATCH] TreeOps: skip 1st stat in case body in NL optimizn

---
 .../main/scala/org/scalafmt/util/TreeOps.scala | 18 +++++++++++-------
 .../test/resources/newlines/source_fold.stat   |  5 ++---
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/scalafmt-core/shared/src/main/scala/org/scalafmt/util/TreeOps.scala b/scalafmt-core/shared/src/main/scala/org/scalafmt/util/TreeOps.scala
index 2ff81a60ee..fedbaaf841 100644
--- a/scalafmt-core/shared/src/main/scala/org/scalafmt/util/TreeOps.scala
+++ b/scalafmt-core/shared/src/main/scala/org/scalafmt/util/TreeOps.scala
@@ -108,10 +108,11 @@ object TreeOps {
       tree: Tree,
   )(implicit ftoks: FormatTokens): Seq[Tree] = tree match {
     case SingleArgInBraces(_, fun: Term.FunctionTerm, _) => fun :: Nil
-    case b: Term.FunctionTerm if isBlockFunction(b) => b.body :: Nil
+    case t: Term.FunctionTerm if isBlockFunction(t) => t.body :: Nil
     case t: Term.EnumeratorsBlock => getEnumStatements(t.enums)
-    case t: Tree.Block => t.stats
-    case t: CaseTree if t.body.tokens.nonEmpty => t.body :: Nil
+    case t @ Tree.Block(s) =>
+      if (!t.parent.is[CaseTree] || getSingleStatExceptEndMarker(s).isEmpty) s
+      else s.drop(1)
     case _ => Nil
   }
 
@@ -600,10 +601,13 @@ object TreeOps {
    * block contains only a single statement. NB: in FormatWriter, when choosing
    * to insert or remove end markers, we avoid such borderline cases.
    */
-  def getSingleStatExceptEndMarker(s: Seq[Stat]): Option[Stat] = s.headOption
-    .filter { _ =>
-      val len2 = s.lengthCompare(2)
-      len2 < 0 || len2 == 0 && s(1).is[Term.EndMarker]
+  def getSingleStatExceptEndMarker[A <: Tree](ss: List[A]): Option[A] =
+    ss match {
+      case s :: rs if (rs match {
+            case Nil | (_: Term.EndMarker) :: Nil => true
+            case _ => false
+          }) => Some(s)
+      case _ => None
     }
 
   def getSingleStatExceptEndMarker(t: Tree): Option[Tree] = t match {
diff --git a/scalafmt-tests/shared/src/test/resources/newlines/source_fold.stat b/scalafmt-tests/shared/src/test/resources/newlines/source_fold.stat
index 731b841de5..cbec2545ac 100644
--- a/scalafmt-tests/shared/src/test/resources/newlines/source_fold.stat
+++ b/scalafmt-tests/shared/src/test/resources/newlines/source_fold.stat
@@ -1958,9 +1958,8 @@ val strings = Seq(
   s"  $bestEPStr",
   "Metrics:",
   s"  $metricHeader: ${bestScore.score}"
-) ++ otherMetricHeaders.zip(bestScore.otherScores).map { case (h, s) =>
-  s"  $h: $s"
-} ++ outputPath.toSeq.map { p =>
+) ++ otherMetricHeaders.zip(bestScore.otherScores)
+  .map { case (h, s) => s"  $h: $s" } ++ outputPath.toSeq.map { p =>
   s"The best variant params can be found in $p"
 }
 <<< 8.6: assignment with short expression