From bfcde4859d13c3cae1484f215f4b272a34962111 Mon Sep 17 00:00:00 2001
From: Albert Meltzer <7529386+kitbellew@users.noreply.github.com>
Date: Sat, 12 Sep 2020 12:37:24 -0700
Subject: [PATCH] Router: beforeCurlyLambdaParams for paren lambdas

---
 .../scala/org/scalafmt/internal/Router.scala  | 13 ++++----
 .../src/test/resources/unit/Lambda.stat       | 33 ++++++++++---------
 2 files changed, 25 insertions(+), 21 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
index 570aa6506e..a9822a325c 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
@@ -592,15 +592,15 @@ class Router(formatOps: FormatOps) {
 
       // Term.Apply and friends
       case FormatToken(T.LeftParen(), _, _)
-          if style.optIn.configStyleArguments &&
-            !style.newlines.alwaysBeforeCurlyLambdaParams &&
-            getLambdaAtSingleArgCallSite(formatToken).isDefined => {
+          if getLambdaAtSingleArgCallSite(formatToken).isDefined =>
         val lambda = getLambdaAtSingleArgCallSite(formatToken).get
         val close = matching(formatToken.left)
         val newlinePolicy =
           if (!style.danglingParentheses.callSite) None
           else Some(decideNewlinesOnlyBeforeClose(close))
-        val noSplitMod = getNoSplit(formatToken, true)
+        val noSplitMod =
+          if (style.newlines.alwaysBeforeCurlyLambdaParams) null
+          else getNoSplit(formatToken, true)
 
         def multilineSpaceSplit(implicit line: sourcecode.Line): Split = {
           val lambdaLeft: Option[Token] =
@@ -631,15 +631,16 @@ class Router(formatOps: FormatOps) {
           )
         else {
           val newlinePenalty = 3 + nestedApplies(leftOwner)
+          val noMultiline = style.newlines.beforeCurlyLambdaParams eq
+            Newlines.BeforeCurlyLambdaParams.multiline
           Seq(
             Split(noSplitMod, 0).withSingleLine(close),
-            multilineSpaceSplit,
+            if (noMultiline) Split.ignored else multilineSpaceSplit,
             Split(Newline, newlinePenalty)
               .withPolicyOpt(newlinePolicy)
               .withIndent(style.continuationIndent.callSite, close, Before)
           )
         }
-      }
 
       case FormatToken(T.LeftParen(), T.RightParen(), _) =>
         val noNL = style.newlines.sourceIgnored || formatToken.noBreak
diff --git a/scalafmt-tests/src/test/resources/unit/Lambda.stat b/scalafmt-tests/src/test/resources/unit/Lambda.stat
index 56a37d856d..04ae6bdf08 100644
--- a/scalafmt-tests/src/test/resources/unit/Lambda.stat
+++ b/scalafmt-tests/src/test/resources/unit/Lambda.stat
@@ -213,15 +213,16 @@ object a {
   x.map {
     x => s"${x._1} -> ${x._2}"
   }
-  x.map(x => s"${x._1} -> ${x._2}")
+  x.map(
+      x => s"${x._1} -> ${x._2}")
   x.map {
     case (c, i) => s"$c -> $i"
   }
   x.zipWithIndex.map {
     x => s"${x._1} -> ${x._2}"
   }
-  x.zipWithIndex.map(x =>
-    s"${x._1} -> ${x._2}")
+  x.zipWithIndex.map(
+      x => s"${x._1} -> ${x._2}")
   x.zipWithIndex.map {
     case (c, i) => s"$c -> $i"
   }
@@ -233,11 +234,12 @@ object a {
     case (c, i) if c != i =>
       s"$c -> $i"
   }
-  x.flatMap(result =>
-    for {
-      _ <- a
-      _ <- b
-    } yield ())
+  x.flatMap(
+      result =>
+        for {
+          _ <- a
+          _ <- b
+        } yield ())
 }
 <<< #2099 beforeCurlyLambdaParams = multilineWithCaseOnly
 newlines.beforeCurlyLambdaParams = multilineWithCaseOnly
@@ -310,8 +312,8 @@ object a {
   x.zipWithIndex.map {
     x => s"${x._1} -> ${x._2}"
   }
-  x.zipWithIndex.map(x =>
-    s"${x._1} -> ${x._2}")
+  x.zipWithIndex.map(
+      x => s"${x._1} -> ${x._2}")
   x.zipWithIndex.map {
     case (c, i) => s"$c -> $i"
   }
@@ -323,9 +325,10 @@ object a {
     case (c, i) if c != i =>
       s"$c -> $i"
   }
-  x.flatMap(result =>
-    for {
-      _ <- a
-      _ <- b
-    } yield ())
+  x.flatMap(
+      result =>
+        for {
+          _ <- a
+          _ <- b
+        } yield ())
 }