Split: keep 2 instances of FileLine, for debugging

scalafmt-core/shared/src/main/scala/org/scalafmt/internal/FileLineStack.scala

@@ -0,0 +1,40 @@
+package org.scalafmt.internal
+
+import org.scalameta.FileLine
+
+class FileLineStack private (
+    val fileLineHead: FileLine,
+    val fileLineLast: FileLine,
+) extends Ordered[FileLineStack] {
+  override def toString: String = s"$fileLineHead->$fileLineLast"
+
+  def forThisLine(implicit
+      file: sourcecode.File,
+      line: sourcecode.Line,
+  ): FileLineStack = new FileLineStack(
+    fileLineHead = fileLineHead,
+    fileLineLast = FileLine.generate,
+  )
+
+  override def compare(that: FileLineStack): Int = {
+    val cmpLast = Integer
+      .compare(this.fileLineLast.line.value, that.fileLineLast.line.value)
+    if (cmpLast != 0) cmpLast
+    else Integer
+      .compare(this.fileLineHead.line.value, that.fileLineHead.line.value)
+  }
+}
+
+object FileLineStack {
+  implicit def generate(implicit
+      file: sourcecode.File,
+      line: sourcecode.Line,
+      fileLineHead: FileLine,
+  ): FileLineStack = new FileLineStack(fileLineHead, FileLine.generate)
+
+  def nextLine(implicit fl: FileLine): FileLine = {
+    val line = fl.line
+    new FileLine(fl.file, line.copy(value = line.value + 1))
+  }
+
+}

scalafmt-core/shared/src/main/scala/org/scalafmt/internal/FormatOps.scala

@@ -1532,7 +1532,7 @@ class FormatOps(
         .forThisLine(nextLine)
       def getSplits(spaceSplit: Split, nlCost: Int = 1) = (
         spaceSplit.withIndents(spaceIndents),
-        getNlSplit(1, nlCost)(nextLine(spaceSplit.fileLine)),
+        getNlSplit(1, nlCost)(spaceSplit.fileLine),
       )
       def getSlb(end: T, excl: TokenRanges)(implicit fileLine: FileLine) =
         SingleLineBlock(end, exclude = excl, noSyntaxNL = true)
@@ -1938,7 +1938,7 @@ class FormatOps(
         Seq(Split(Newline, 0).withIndent(indent).withPolicy(nlPolicy))
       else Seq(
         Split(Space, 0).withSingleLine(slbExpire.left).withIndent(indent),
-        Split(Newline, 1)(nextLine).withIndent(indent).withPolicy(nlPolicy),
+        Split(Newline, 1).withIndent(indent).withPolicy(nlPolicy),
       )
     }
 

scalafmt-core/shared/src/main/scala/org/scalafmt/internal/Router.scala

@@ -533,13 +533,13 @@ class Router(formatOps: FormatOps) {
           case _ => false
         }
         val bodyIsEmpty = isEmptyTree(body)
-        def baseSplit = Split(Space, 0)
+        def baseSplit(implicit l: FileLine) = Split(Space, 0)
         def nlSplit(ft: FormatToken)(cost: Int)(implicit l: FileLine) =
           Split(Newline2x(ft), cost)
         CtrlBodySplits.checkComment(nlSplit(ft)) { nft =>
           def withSlbSplit(implicit l: FileLine) = Seq(
             baseSplit.withSingleLine(getLastNonTrivialToken(body)),
-            nlSplit(nft)(1)(nextLine),
+            nlSplit(nft)(1),
           )
           implicit val beforeMultiline = style.newlines.getBeforeMultiline
           if (

scalafmt-core/shared/src/main/scala/org/scalafmt/internal/Split.scala

@@ -54,7 +54,7 @@ case class Split(
     activeTags: Set[SplitTag] = Set.empty,
     policy: Policy = NoPolicy,
     optimalAt: Option[OptimalToken] = None,
-)(implicit val fileLine: FileLine) {
+)(implicit val fileLineStack: FileLineStack) {
   import PolicyOps._
 
   def withNoIndent: Split = mod match {
@@ -63,6 +63,9 @@ case class Split(
     case _ => this
   }
 
+  @inline
+  def fileLine: FileLine = fileLineStack.fileLineLast
+
   @inline
   def indentation: String = modExt.indentation
 
@@ -133,7 +136,8 @@ case class Split(
     if (isIgnored) this else splitTag.fold(this)(preActivateFor)
 
   def forThisLine(implicit fileLine: FileLine): Split =
-    if (isIgnored) this else copy()(fileLine = fileLine)
+    if (isIgnored) this
+    else copy()(fileLineStack.forThisLine(fileLine.file, fileLine.line))
 
   def getCost(ifActive: Int => Int, ifIgnored: => Int): Int =
     if (isIgnored) ifIgnored else ifActive(cost)
@@ -319,22 +323,23 @@ case class Split(
         else ""
       }
     val opt = optimalAt.fold("")(", opt=" + _)
-    s"""$prefix${modExt
-        .mod}:[$fileLine](cost=$cost, indents=$indentation, $policy$opt)"""
+    s"""$prefix$mod:[$fileLineStack](cost=$cost, indents=$indentation, $policy$opt)"""
   }
 }
 
 object Split {
 
   private val ignoredTags = Set[SplitTag](null)
 
-  def ignored(implicit fileLine: FileLine) = Split(ModExt(NoSplit), 0).ignored
+  def ignored(implicit fileLineStack: FileLineStack) = Split(ModExt(NoSplit), 0)
+    .ignored
 
   def apply(ignore: Boolean, cost: Int)(modExt: => ModExt)(implicit
-      fileLine: FileLine,
+      fileLineStack: FileLineStack,
   ): Split = if (ignore) ignored else Split(modExt, cost)
 
-  def opt(mod: Modification, cost: Int)(implicit fileLine: FileLine): Split =
-    if (mod eq null) ignored else Split(mod, cost)
+  def opt(mod: Modification, cost: Int)(implicit
+      fileLineStack: FileLineStack,
+  ): Split = if (mod eq null) ignored else Split(mod, cost)
 
 }

scalafmt-core/shared/src/main/scala/org/scalafmt/internal/State.scala

@@ -364,10 +364,21 @@ object State {
     private def compareSplitOrigin(s1: State, s2: State): Int = {
       // We assume the same number of splits, see compareSplitsLength
       // Break ties by the last split's line origin.
-      val r = Integer
-        .compare(s1.split.fileLine.line.value, s2.split.fileLine.line.value)
-      if (r != 0 || s1.prev.depth == 0) r
-      else compareSplitOrigin(s1.prev, s2.prev)
+      val flStack1 = s1.split.fileLineStack
+      val flStack2 = s2.split.fileLineStack
+      val r = Integer.compare(
+        flStack1.fileLineLast.line.value,
+        flStack2.fileLineLast.line.value,
+      )
+      if (r != 0) r
+      else {
+        val r = Integer.compare(
+          flStack1.fileLineHead.line.value,
+          flStack2.fileLineHead.line.value,
+        )
+        if (r != 0 || s1.prev.depth == 0) r
+        else compareSplitOrigin(s1.prev, s2.prev)
+      }
     }
   }