Router: move to TreeOps getting lambda penalties

scalameta · Nov 25, 2024 · 2ae3560 · 2ae3560
1 parent 64306e0
commit 2ae3560
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Showing 2 changed files with 49 additions and 38 deletions.
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
@@ -452,34 +452,10 @@ class Router(formatOps: FormatOps) {
         val (nlCost, nlArrowPenalty) =
           if (!nl.isNL) (0, 0)
           else if (slbMod eq noSplitMod) (1 + nlPenalty, nlPenalty)
-          else {
-            def argClausePenalty(t: Term.ArgClause)(isFunc: Term => Boolean) =
-              t.values match {
-                case arg :: Nil =>
-                  if (isFunc(arg)) Some((nestedApplies(t), 2))
-                  else t.parent match {
-                    case Some(p: Term.Apply) =>
-                      Some((nestedApplies(p), treeDepth(p.fun)))
-                    case _ => None
-                  }
-                case _ => None
-              }
-            leftOwner match {
-              case t: Term.ArgClause =>
-                argClausePenalty(t)(_.is[Term.FunctionTerm])
-              case t: Term => t.parent match {
-                  case Some(p: Term.ArgClause) => argClausePenalty(p) {
-                      case Term.Block((_: Term.FunctionTerm) :: Nil) =>
-                        getHead(t) eq ft
-                      case _ => false
-                    }
-                  case _ => None
-                }
-              case _ => None
+          else getLambdaPenaltiesOnLeftBraceOnLeft(ft)
+            .fold((1, nlPenalty)) { case (sharedPenalty, herePenalty) =>
+              (sharedPenalty + herePenalty, sharedPenalty)
             }
-          }.fold((1, nlPenalty)) { case (sharedPenalty, herePenalty) =>
-            (sharedPenalty + herePenalty, sharedPenalty)
-          }
         val newlineBeforeClosingCurly = decideNewlinesOnlyBeforeClose(close)
         val nlPolicy = lambdaNLPolicy ==> newlineBeforeClosingCurly
         val nlSplit = Split(nl, nlCost, policy = nlPolicy)
@@ -1949,17 +1925,16 @@ class Router(formatOps: FormatOps) {
                 }
                 val exclude = insideBracesBlock(ft, end, parensToo = true)
                   .excludeCloseDelim
-                val bracesToParens = ftAfterRight.right.is[T.OpenDelim] &&
-                  (ftAfterRight.rightOwner match {
-                    case t: Member.ArgClause => t.values.lengthCompare(1) == 0
-                    case t: Term.Block => t.parent.is[Member.ArgClause]
-                    case _ => false
-                  }) && {
-                    implicit val ft: FT = next(ftAfterRight)
-                    val rb = matchingRight(ftAfterRight)
-                    getBracesToParensMod(rb, Space, isWithinBraces = true)._1 ne
-                      Space
-                  }
+                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
+                  val rb = matchingRight(ftAfterRight)
+                  getBracesToParensMod(rb, Space, isWithinBraces = true)._1 ne
+                    Space
+                }
                 val noSplit = Split(modSpace, 0)
                   .withSingleLine(end, exclude = exclude)
                 Seq(noSplit, nlSplitBase(if (bracesToParens) 0 else 1))

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
@@ -350,6 +350,42 @@ object TreeOps {
     math.max(res, treeDepth(t))
   }
 
+  def getSingleArgOnLeftBraceOnLeft(ft: FT)(implicit
+      ftoks: FormatTokens,
+  ): Option[(Term.ArgClause, Stat)] = ft.leftOwner match {
+    case ac: Term.ArgClause => (ac.values match {
+        case (t: Term.Block) :: Nil if ftoks.getHead(t) eq ft =>
+          getBlockSingleStat(t)
+        case t :: Nil => Some(t)
+        case _ => None
+      }).map(x => (ac, x))
+    case t: Term => t.parent match {
+        case Some(ac: Term.ArgClause) if ac.values.lengthCompare(1) == 0 =>
+          (t match {
+            case t: Term.Block if ftoks.getHead(ac) eq ft =>
+              getBlockSingleStat(t)
+            case _ => Some(t)
+          }).map(x => (ac, x))
+        case _ => None
+      }
+    case _ => None
+  }
+
+  def getSingleArgLambdaPenalties(
+      ac: Term.ArgClause,
+      arg: Stat,
+  ): Option[(Int, Int)] =
+    if (arg.is[Term.FunctionTerm]) Some((nestedApplies(ac), 2))
+    else ac.parent match {
+      case Some(p: Term.Apply) => Some((nestedApplies(p), treeDepth(p.fun)))
+      case _ => None
+    }
+
+  def getLambdaPenaltiesOnLeftBraceOnLeft(ft: FormatToken)(implicit
+      ftoks: FormatTokens,
+  ): Option[(Int, Int)] = getSingleArgOnLeftBraceOnLeft(ft)
+    .flatMap((getSingleArgLambdaPenalties _).tupled)
+
   final def canBreakAfterFuncArrow(func: Term.FunctionTerm)(implicit
       ftoks: FormatTokens,
       style: ScalafmtConfig,