Router: use SpaceOrNoSplit instead of custom rule

This reverts a large part of #4153.

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

@@ -9,6 +9,7 @@ import org.scalafmt.config.ScalafmtOptimizer
 import org.scalafmt.config.TrailingCommas
 import org.scalafmt.internal.Length.Num
 import org.scalafmt.internal.Policy.NoPolicy
+import org.scalafmt.rewrite.RedundantBraces
 import org.scalafmt.util.InfixApp._
 import org.scalafmt.util._
 
@@ -2958,6 +2959,22 @@ class FormatOps(
   @inline
   def indentedPackage(pkg: Pkg): Boolean = indentedPackage(pkg.body)
 
+  def getBracesToParensModAndPolicy(rb: FormatToken, mod: Modification)(implicit
+      style: ScalafmtConfig,
+  ): (Modification, Policy) = {
+    if ((mod eq Space) && initStyle.rewrite.bracesToParensForOneLineApply)
+      RedundantBraces.noSplitForParensOnRightBrace(rb)
+    else None
+  }.fold((mod, Policy.noPolicy)) { rb =>
+    val beforeClose = prev(rb)
+    val end = Policy.End < rb.left
+    val policy = end ==> Policy.on(rb.left, "BracesToParens") {
+      case Decision(`beforeClose`, ss) => ss
+          .flatMap(s => if (s.isNL) None else Some(s.withMod(NoSplit)))
+    }
+    SpaceOrNoSplit(end) -> policy
+  }
+
 }
 
 object FormatOps {

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

@@ -13,7 +13,6 @@ import org.scalafmt.internal.ExpiresOn.Before
 import org.scalafmt.internal.Length.Num
 import org.scalafmt.internal.Length.StateColumn
 import org.scalafmt.internal.Policy.NoPolicy
-import org.scalafmt.rewrite.RedundantBraces
 import org.scalafmt.util._
 
 import org.scalameta.FileLine
@@ -390,34 +389,21 @@ class Router(formatOps: FormatOps) {
         }
 
         val noSplitMod = xmlSpace(leftOwner)
+        val (slbMod, slbParensPolicy) =
+          if (singleLineDecisionOpt.isEmpty) (noSplitMod, NoPolicy)
+          else getBracesToParensModAndPolicy(closeFT, noSplitMod)
         val singleLineSplitOpt = singleLineDecisionOpt.map { sld =>
           val sldPolicy = getSingleLinePolicy
           val expire = leftOwner.parent match {
             case Some(p: Term.ForYield)
                 if !sld && sldPolicy.isEmpty && style.newlines.fold &&
                   leftOwner.is[Term.EnumeratorsBlock] => getLastToken(p)
+            case _ if style.newlines.isBeforeOpenParenCallSite => close
             case _ => endOfSingleLineBlock(closeFT)
           }
-          val toParens = initStyle.rewrite.bracesToParensForOneLineApply &&
-            RedundantBraces.noSplitForParensOnRightBrace(closeFT).isDefined
-          if (toParens) Right {
-            val noCloseSpacePolicy = Policy.End < close ==>
-              Policy.on(close, "PAREN1LAPPLY") {
-                case Decision(FormatToken(_, `close`, _), ss) => ss.map { s =>
-                    if (s.isNL) s else s.withMod(NoSplit)
-                  }
-              }
-            // copy logic from `( ...`, binpack=never, defining `slbSplit`
-            val slbEnd =
-              if (style.newlines.isBeforeOpenParenCallSite) close
-              else endOfSingleLineBlock(closeFT)
-            Split(NoSplit, 0).withSingleLine(slbEnd, noSyntaxNL = true)
-              .andPolicy(sldPolicy & noCloseSpacePolicy)
-          }
-          else Left {
-            Split(noSplitMod, 0).withSingleLine(expire, noSyntaxNL = true)
-              .andPolicy(sldPolicy)
-          }
+          // copy logic from `( ...`, binpack=never, defining `slbSplit`
+          Split(slbMod, 0).withSingleLine(expire, noSyntaxNL = true)
+            .andPolicy(sldPolicy & slbParensPolicy)
         }
 
         val nlSplit = Split(nl, if (nl.isNL) 1 else 0)
@@ -428,10 +414,11 @@ class Router(formatOps: FormatOps) {
         val lambdaSplit =
           if (noLambdaSplit) Split.ignored
           else {
+            val nlPolicy = newlineBeforeClosingCurly
             val policy = singleLineSplitOpt match {
-              case Some(Left(slbSplit)) => Policy.after(lambdaExpire, "FNARR") {
+              case Some(slbSplit) if slbParensPolicy.isEmpty =>
+                Policy.after(lambdaExpire, "FNARR") {
                   case Decision(FormatToken(`lambdaExpire`, _, _), ss) =>
-                    val nlPolicy = newlineBeforeClosingCurly
                     var hadNoSplit = false
                     val nlSplits = ss.flatMap { s =>
                       if (s.isNL) Some(s.andPolicy(nlPolicy))
@@ -440,16 +427,15 @@ class Router(formatOps: FormatOps) {
                     if (hadNoSplit) slbSplit.withMod(Space) +: nlSplits
                     else nlSplits
                 }
-              case _ => newlineBeforeClosingCurly &
-                  decideNewlinesOnlyAfterToken(lambdaExpire)
+              case _ => decideNewlinesOnlyAfterToken(lambdaExpire) ==> nlPolicy
             }
             Split(noSplitMod, 0).withSingleLine(lambdaExpire).andPolicy(policy)
               .withIndent(lambdaIndent, close, Before)
           }
 
         val singleLineSplit = singleLineSplitOpt match {
-          case Some(Right(slbSplit)) => slbSplit
-          case Some(Left(slbSplit)) if lambdaSplit.isIgnored => slbSplit
+          case Some(slbSplit)
+              if slbParensPolicy.nonEmpty || lambdaSplit.isIgnored => slbSplit
           case _ => Split.ignored
         }
         val splits = Seq(singleLineSplit, lambdaSplit, nlSplit)
@@ -1528,17 +1514,11 @@ class Router(formatOps: FormatOps) {
                   .exists(x => isTokenLastOrAfter(x.left, roPos))
             }
           } =>
-        val slbParensSplit =
-          if (!initStyle.rewrite.bracesToParensForOneLineApply) None
-          else RedundantBraces.noSplitForParensOnRightBrace(matching(lb))
-            .map { rbft =>
-              // copy logic from `( ...`, binpack=never, defining `slbSplit`
-              val isBeforeOpenParen = style.newlines.isBeforeOpenParenCallSite
-              val optimal: T =
-                if (isBeforeOpenParen) rbft.left else endOfSingleLineBlock(rbft)
-              Split(NoSplit, 0).withSingleLine(optimal)
-            }
-        Seq(slbParensSplit.getOrElse(Split.ignored), Split(Space, 0))
+        val rb = matching(lb)
+        val (mod, toParensPolicy) = getBracesToParensModAndPolicy(rb, Space)
+        val policy = Policy
+          .RelayOnSplit { case (s, _) => s.isNL }(toParensPolicy, NoPolicy)
+        Seq(Split(mod, 0, policy = policy))
 
       // Delim
       case FormatToken(left, _: T.Comma, _)

scalafmt-tests-community/intellij/src/test/scala/org/scalafmt/community/intellij/CommunityIntellijScalaSuite.scala

@@ -13,7 +13,7 @@ abstract class CommunityIntellijScalaSuite(name: String)
 class CommunityIntellijScala_2024_2_Suite
     extends CommunityIntellijScalaSuite("intellij-scala-2024.2") {
 
-  override protected def totalStatesVisited: Option[Int] = Some(48193019)
+  override protected def totalStatesVisited: Option[Int] = Some(48163081)
 
   override protected def builds = Seq(getBuild(
     "2024.2.28",
@@ -51,7 +51,7 @@ class CommunityIntellijScala_2024_2_Suite
 class CommunityIntellijScala_2024_3_Suite
     extends CommunityIntellijScalaSuite("intellij-scala-2024.3") {
 
-  override protected def totalStatesVisited: Option[Int] = Some(48372795)
+  override protected def totalStatesVisited: Option[Int] = Some(48342732)
 
   override protected def builds = Seq(getBuild(
     "2024.3.4",

scalafmt-tests-community/scala2/src/test/scala/org/scalafmt/community/scala2/CommunityScala2Suite.scala

@@ -9,7 +9,7 @@ abstract class CommunityScala2Suite(name: String)
 
 class CommunityScala2_12Suite extends CommunityScala2Suite("scala-2.12") {
 
-  override protected def totalStatesVisited: Option[Int] = Some(35856745)
+  override protected def totalStatesVisited: Option[Int] = Some(35837156)
 
   override protected def builds =
     Seq(getBuild("v2.12.20", dialects.Scala212, 1277))
@@ -18,7 +18,7 @@ class CommunityScala2_12Suite extends CommunityScala2Suite("scala-2.12") {
 
 class CommunityScala2_13Suite extends CommunityScala2Suite("scala-2.13") {
 
-  override protected def totalStatesVisited: Option[Int] = Some(44618123)
+  override protected def totalStatesVisited: Option[Int] = Some(44596615)
 
   override protected def builds =
     Seq(getBuild("v2.13.14", dialects.Scala213, 1287))

scalafmt-tests-community/scala3/src/test/scala/org/scalafmt/community/scala3/CommunityScala3Suite.scala

@@ -9,15 +9,15 @@ abstract class CommunityScala3Suite(name: String)
 
 class CommunityScala3_2Suite extends CommunityScala3Suite("scala-3.2") {
 
-  override protected def totalStatesVisited: Option[Int] = Some(33385186)
+  override protected def totalStatesVisited: Option[Int] = Some(33365450)
 
   override protected def builds = Seq(getBuild("3.2.2", dialects.Scala32, 791))
 
 }
 
 class CommunityScala3_3Suite extends CommunityScala3Suite("scala-3.3") {
 
-  override protected def totalStatesVisited: Option[Int] = Some(36033019)
+  override protected def totalStatesVisited: Option[Int] = Some(36011287)
 
   override protected def builds = Seq(getBuild("3.3.3", dialects.Scala33, 861))
 

scalafmt-tests-community/spark/src/test/scala/org/scalafmt/community/spark/CommunitySparkSuite.scala

@@ -9,7 +9,7 @@ abstract class CommunitySparkSuite(name: String)
 
 class CommunitySpark3_4Suite extends CommunitySparkSuite("spark-3.4") {
 
-  override protected def totalStatesVisited: Option[Int] = Some(72481328)
+  override protected def totalStatesVisited: Option[Int] = Some(72398899)
 
   override protected def builds =
     Seq(getBuild("v3.4.1", dialects.Scala213, 2585))
@@ -18,7 +18,7 @@ class CommunitySpark3_4Suite extends CommunitySparkSuite("spark-3.4") {
 
 class CommunitySpark3_5Suite extends CommunitySparkSuite("spark-3.5") {
 
-  override protected def totalStatesVisited: Option[Int] = Some(76650858)
+  override protected def totalStatesVisited: Option[Int] = Some(76561809)
 
   override protected def builds =
     Seq(getBuild("v3.5.3", dialects.Scala213, 2756))

scalafmt-tests/shared/src/test/resources/newlines/source_classic.stat

@@ -10629,14 +10629,6 @@ convertStream(inputStream, tokenizer, handleHeader, parser.options.charset) { to
   safeParser.parse(tokens)
 }.flatten
 >>>
-Idempotency violated
-=> Diff (- obtained, + expected)
--convertStream(inputStream, tokenizer, handleHeader, parser.options.charset)(
--  tokens => safeParser.parse(tokens)
--).flatten
-+convertStream(
-+  inputStream,
-+  tokenizer,
-+  handleHeader,
-+  parser.options.charset
-+)(tokens => safeParser.parse(tokens)).flatten
+convertStream(inputStream, tokenizer, handleHeader, parser.options.charset) {
+  tokens => safeParser.parse(tokens)
+}.flatten

scalafmt-tests/shared/src/test/resources/newlines/source_fold.stat

@@ -9931,14 +9931,6 @@ convertStream(inputStream, tokenizer, handleHeader, parser.options.charset) { to
   safeParser.parse(tokens)
 }.flatten
 >>>
-Idempotency violated
-=> Diff (- obtained, + expected)
--convertStream(inputStream, tokenizer, handleHeader, parser.options.charset)(
--  tokens => safeParser.parse(tokens)
--).flatten
-+convertStream(
-+  inputStream,
-+  tokenizer,
-+  handleHeader,
-+  parser.options.charset
-+)(tokens => safeParser.parse(tokens)).flatten
+convertStream(inputStream, tokenizer, handleHeader, parser.options.charset) {
+  tokens => safeParser.parse(tokens)
+}.flatten

scalafmt-tests/shared/src/test/resources/newlines/source_keep.stat

@@ -10378,14 +10378,6 @@ convertStream(inputStream, tokenizer, handleHeader, parser.options.charset) { to
   safeParser.parse(tokens)
 }.flatten
 >>>
-Idempotency violated
-=> Diff (- obtained, + expected)
--convertStream(inputStream, tokenizer, handleHeader, parser.options.charset)(
--  tokens => safeParser.parse(tokens)
--).flatten
-+convertStream(
-+  inputStream,
-+  tokenizer,
-+  handleHeader,
-+  parser.options.charset
-+)(tokens => safeParser.parse(tokens)).flatten
+convertStream(inputStream, tokenizer, handleHeader, parser.options.charset) {
+  tokens => safeParser.parse(tokens)
+}.flatten

scalafmt-tests/shared/src/test/resources/newlines/source_unfold.stat

@@ -10759,14 +10759,6 @@ convertStream(inputStream, tokenizer, handleHeader, parser.options.charset) { to
   safeParser.parse(tokens)
 }.flatten
 >>>
-Idempotency violated
-=> Diff (- obtained, + expected)
--convertStream(inputStream, tokenizer, handleHeader, parser.options.charset)(
--  tokens => safeParser.parse(tokens)
--).flatten
-+convertStream(
-+  inputStream,
-+  tokenizer,
-+  handleHeader,
-+  parser.options.charset
-+)(tokens => safeParser.parse(tokens)).flatten
+convertStream(inputStream, tokenizer, handleHeader, parser.options.charset) {
+  tokens => safeParser.parse(tokens)
+}.flatten

scalafmt-tests/shared/src/test/scala/org/scalafmt/FormatTests.scala

@@ -138,7 +138,7 @@ class FormatTests extends FunSuite with CanRunTests with FormatAssertions {
     val explored = Debug.explored.get()
     logger.debug(s"Total explored: $explored")
     if (!onlyUnit && !onlyManual)
-      assertEquals(explored, 1499684, "total explored")
+      assertEquals(explored, 1498911, "total explored")
     val results = debugResults.result()
     // TODO(olafur) don't block printing out test results.
     // I don't want to deal with scalaz's Tasks :'(