FormatOps: handle if as if no else when keep

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

@@ -1689,6 +1689,7 @@ class FormatOps(
     def foldedNonEmptyNonComment(
         body: Tree,
         nlSplitFunc: Int => Split,
+        isKeep: Boolean,
         spaceIndents: Seq[Indent] = Seq.empty
     ): Seq[Split] = {
       def bheadFT = tokens.getHead(body)
@@ -1748,7 +1749,7 @@ class FormatOps(
       }
       val adjustedBody = getBlockStat(body)
       val (spaceSplit, nlSplit) = adjustedBody match {
-        case t: Term.If if ifWithoutElse(t) || hasStateColumn =>
+        case t: Term.If if isKeep || ifWithoutElse(t) || hasStateColumn =>
           val thenBeg = tokens.getHead(t.thenp)
           val thenHasLB = thenBeg.left.is[T.LeftBrace]
           val end = if (thenHasLB) thenBeg else prevNonComment(prev(thenBeg))
@@ -1789,10 +1790,11 @@ class FormatOps(
     private def foldedNonComment(
         body: Tree,
         nlSplitFunc: Int => Split,
+        isKeep: Boolean,
         spaceIndents: Seq[Indent]
     ): Seq[Split] =
       if (body.tokens.isEmpty) Seq(Split(Space, 0))
-      else foldedNonEmptyNonComment(body, nlSplitFunc, spaceIndents)
+      else foldedNonEmptyNonComment(body, nlSplitFunc, isKeep, spaceIndents)
 
     private def unfoldedSpaceNonEmptyNonComment(
         body: Tree,
@@ -1848,10 +1850,11 @@ class FormatOps(
     def folded(
         ft: FormatToken,
         body: Tree,
+        isKeep: Boolean,
         spaceIndents: Seq[Indent] = Seq.empty
     )(nlSplitFunc: Int => Split): Seq[Split] =
       checkComment(ft, nlSplitFunc) { _ =>
-        foldedNonComment(body, nlSplitFunc, spaceIndents)
+        foldedNonComment(body, nlSplitFunc, isKeep, spaceIndents)
       }
 
     def slbOnly(
@@ -1878,14 +1881,15 @@ class FormatOps(
             Seq(nlSplitFunc(0).forThisLine)
           case Newlines.classic =>
             Option(classicNoBreakFunc).fold {
-              foldedNonComment(body, nlSplitFunc, spaceIndents)
+              foldedNonComment(body, nlSplitFunc, isKeep = true, spaceIndents)
             } { func =>
               val spcSplit = func.forThisLine
               val nlSplit = nlSplitFunc(spcSplit.getCost(_ + 1, 0)).forThisLine
               Seq(spcSplit, nlSplit)
             }
-          case _ => // fold or keep without break
-            foldedNonComment(body, nlSplitFunc, spaceIndents)
+          case x => // fold or keep without break
+            val isKeep = x eq Newlines.keep
+            foldedNonComment(body, nlSplitFunc, isKeep, spaceIndents)
         }
       }
 

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

@@ -555,7 +555,10 @@ class Router(formatOps: FormatOps) {
             beforeMultiline.eq(Newlines.classic) ||
             getSingleStatExceptEndMarker(body).isEmpty
           ) withSlbSplit
-          else CtrlBodySplits.foldedNonEmptyNonComment(body, nlSplit(ft))
+          else {
+            val isKeep = beforeMultiline.eq(Newlines.keep)
+            CtrlBodySplits.foldedNonEmptyNonComment(body, nlSplit(ft), isKeep)
+          }
         }
       // New statement
       case tok @ FormatToken(_: T.Semicolon, _, StartsStatementRight(stmt))
@@ -2648,7 +2651,8 @@ class Router(formatOps: FormatOps) {
       case Newlines.unfold =>
         Seq(baseSplit.withSingleLine(expire), newlineSplit(1))
 
-      case _ => CtrlBodySplits.folded(ft, body)(newlineSplit)
+      case x =>
+        CtrlBodySplits.folded(ft, body, x eq Newlines.keep)(newlineSplit)
     }
   }
 

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

@@ -5842,3 +5842,74 @@ def allMatching(versionString: String,
                 partialFunctions: PartialFunction[options.Common, List[String]]*)
                (partialFunctions: PartialFunction[options.Common, List[String]]*)
   : List[String] = {}
+<<< #3173 beforeMultiline = keep
+newlines.beforeMultiline = keep
+===
+class Foo {
+  val foo = if (true) {
+    ""
+  } else {
+    "a"
+  }
+  val foo = if (true)
+    ""
+  else
+    "a"
+  val foo = if (true) "" else "a"
+  val foo = if (true) "aaaaa" else "bbbbb"
+  val foo = if (true) "aaaaa"
+  else "bbbbb"
+}
+>>>
+class Foo {
+  val foo = if (true) {
+    ""
+  } else {
+    "a"
+  }
+  val foo = if (true)
+    ""
+  else
+    "a"
+  val foo = if (true) "" else "a"
+  val foo =
+    if (true) "aaaaa" else "bbbbb"
+  val foo = if (true) "aaaaa"
+  else "bbbbb"
+}
+<<< #3173 beforeMultiline = fold
+newlines.beforeMultiline = fold
+===
+class Foo {
+  val foo = if (true) {
+    ""
+  } else {
+    "a"
+  }
+  val foo = if (true)
+    ""
+  else
+    "a"
+  val foo = if (true) "" else "a"
+  val foo = if (true) "aaaaa" else "bbbbb"
+  val foo = if (true) "aaaaa"
+  else "bbbbb"
+}
+>>>
+class Foo {
+  val foo =
+    if (true) {
+      ""
+    } else {
+      "a"
+    }
+  val foo =
+    if (true) ""
+    else "a"
+  val foo = if (true) "" else "a"
+  val foo =
+    if (true) "aaaaa" else "bbbbb"
+  val foo =
+    if (true) "aaaaa"
+    else "bbbbb"
+}

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

@@ -5602,3 +5602,33 @@ def allMatching(versionString: String,
                 partialFunctions: PartialFunction[options.Common, List[String]]*)
                (partialFunctions: PartialFunction[options.Common, List[String]]*)
   : List[String] = {}
+<<< #3173 beforeMultiline = fold
+newlines.beforeMultiline = fold
+===
+class Foo {
+  val foo = if (true) {
+    ""
+  } else {
+    "a"
+  }
+  val foo = if (true)
+    ""
+  else
+    "a"
+  val foo = if (true) "" else "a"
+  val foo = if (true) "aaaaa" else "bbbbb"
+  val foo = if (true) "aaaaa"
+  else "bbbbb"
+}
+>>>
+class Foo {
+  val foo =
+    if (true) { "" }
+    else { "a" }
+  val foo = if (true) "" else "a"
+  val foo = if (true) "" else "a"
+  val foo =
+    if (true) "aaaaa" else "bbbbb"
+  val foo =
+    if (true) "aaaaa" else "bbbbb"
+}