From e78a86edaa0a31f6bf1e3c42411107ac479b3970 Mon Sep 17 00:00:00 2001
From: Albert Meltzer <7529386+kitbellew@users.noreply.github.com>
Date: Sun, 15 Dec 2024 19:07:43 -0800
Subject: [PATCH] Router: remove redundant check in braces-to-parens

---
 .../scala/org/scalafmt/internal/FormatOps.scala  | 15 +++++++++++++--
 .../scala/org/scalafmt/internal/Router.scala     | 16 ++++++----------
 2 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/FormatOps.scala b/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/FormatOps.scala
index 4425d057b9..782a11462b 100644
--- a/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/FormatOps.scala
+++ b/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/FormatOps.scala
@@ -3001,8 +3001,11 @@ class FormatOps(
     } else None
   }
 
-  def getBracesToParensMod(rb: FT, mod: Modification, isWithinBraces: Boolean)(
-      implicit
+  def getBracesToParensMod(
+      rb: FT,
+      mod: Modification = Space,
+      isWithinBraces: Boolean = true,
+  )(implicit
       style: ScalafmtConfig,
       ft: FT,
   ): (Modification, Option[TokenRanges]) = {
@@ -3011,6 +3014,14 @@ class FormatOps(
     else (SpaceOrNoSplit(Policy.End < rb), tr)
   }
 
+  @inline
+  def getBracesToParensModOnly(
+      rb: FT,
+      mod: Modification = Space,
+      isWithinBraces: Boolean = true,
+  )(implicit style: ScalafmtConfig, ft: FT): Modification =
+    getBracesToParensMod(rb, mod, isWithinBraces)._1
+
   @tailrec
   private def getSingleFunctionArg(
       values: List[Tree],
diff --git a/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/Router.scala b/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/Router.scala
index 5ef76a65eb..702eda74b8 100644
--- a/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/Router.scala
+++ b/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/Router.scala
@@ -361,7 +361,7 @@ class Router(formatOps: FormatOps) {
         val noSplitMod = braceSpace(leftOwner)
         val (slbMod, slbParensExclude) =
           if (singleLineDecisionOpt.isEmpty) (noSplitMod, None)
-          else getBracesToParensMod(close, noSplitMod, isWithinBraces = true)
+          else getBracesToParensMod(close, noSplitMod)
         val singleLineSplitOpt = {
           if (slbParensExclude eq null) None else singleLineDecisionOpt
         }.map { sld =>
@@ -1537,7 +1537,7 @@ class Router(formatOps: FormatOps) {
             }
           } =>
         val rb = matchingRight(ft)
-        val mod = getBracesToParensMod(rb, Space, isWithinBraces = false)._1
+        val mod = getBracesToParensModOnly(rb, isWithinBraces = false)
         Seq(Split(mod, 0))
 
       // Delim
@@ -1921,15 +1921,11 @@ class Router(formatOps: FormatOps) {
                           }.isDefined => ss.penalizeNL(1)
                   }
                 }.foldLeft(Policy.noPolicy) { case (res, pol) => pol ==> res }
-                val ftNextAfterRight = next(ftAfterRight)
-                val singleArg =
-                  if (!ftAfterRight.right.is[T.OpenDelim]) None
-                  else getSingleArgOnLeftBraceOnLeft(ftNextAfterRight).map(_._2)
-                val bracesToParens = singleArg.isDefined && {
-                  implicit val ft: FT = ftNextAfterRight
+                // include paren as it may have been a brace earlier (i.e. idempotence)
+                val bracesToParens = ftAfterRight.right.is[T.OpenDelim] && {
+                  implicit val ft: FT = next(ftAfterRight)
                   val rb = matchingRight(ftAfterRight)
-                  getBracesToParensMod(rb, Space, isWithinBraces = true)._1 ne
-                    Space
+                  getBracesToParensModOnly(rb) ne Space
                 }
                 val noSplit = Split(modSpace, 0)
                   .withSingleLine(end, exclude = exclude)