Router: combine two case splits via policies

scalameta · Aug 10, 2024 · 7996a8a · 7996a8a
1 parent 7296035
commit 7996a8a
Show file tree

Hide file tree

Showing 5 changed files with 34 additions and 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
@@ -2096,12 +2096,13 @@ class Router(formatOps: FormatOps) {
         }
         val arrow = arrowFt.left
         val postArrowFt = nextNonCommentSameLine(arrowFt)
+        val postArrow = postArrowFt.left
         val ownerEnd = getLastOpt(owner)
         val expire = ownerEnd.fold(postArrowFt)(nextNonCommentSameLine).left
 
         val bodyBlock = isCaseBodyABlock(arrowFt, owner)
-        def defaultPolicy = decideNewlinesOnlyAfterToken(postArrowFt.left)
-        val policy =
+        def defaultPolicy = decideNewlinesOnlyAfterToken(postArrow)
+        val postArrowPolicy =
           if (bodyBlock || isAttachedCommentThenBreak(arrowFt)) NoPolicy
           else if (isCaseBodyEnclosedAsBlock(postArrowFt, owner)) {
             val postParenFt = nextNonCommentSameLineAfter(postArrowFt)
@@ -2135,12 +2136,23 @@ class Router(formatOps: FormatOps) {
           Indent(arrowIndent, arrow, After),
         )
         val mod = ModExt(Space, indents)
-        val slbSplitOpt = (ownerEnd match {
+        val slbExpireOpt = ownerEnd match {
           case None => Some(postArrowFt)
           case Some(x) => prevNotTrailingComment(x).toOption
-        }).map(x => Split(mod, 0).withSingleLine(x.left, killOnFail = true))
-        val splits = Split(mod, 0, policy = policy) :: Nil
-        slbSplitOpt.fold(splits)(_ :: splits)
+        }
+        val policy = slbExpireOpt.fold(postArrowPolicy) { slbExpireFt =>
+          val slbExpire = slbExpireFt.left
+          val onArrowPolicy = Policy.End == arrow ==>
+            Policy.after(postArrow, "CASESLB>ARROW") { case Decision(_, ss) =>
+              ss.flatMap { s =>
+                val nonSlbSplit = s.andPolicy(postArrowPolicy)
+                if (s.isNL) Seq(nonSlbSplit)
+                else Seq(s.withSingleLine(slbExpire, extend = true), nonSlbSplit)
+              }
+            }
+          Policy.RelayOnSplit((s, _) => s.isNL)(onArrowPolicy, postArrowPolicy)
+        }
+        Seq(Split(mod, 0, policy = policy))
 
       case FormatToken(_, cond: T.KwIf, _) if rightOwner.is[Case] =>
         if (style.newlines.keepBreak(newlines)) Seq(Split(Newline, 0))

diff --git a/scalafmt-tests/src/test/resources/newlines/source_classic.stat b/scalafmt-tests/src/test/resources/newlines/source_classic.stat
@@ -3752,7 +3752,7 @@ object a {
       case None => Command.invalid
     }
 }
-<<< ONLY complex match case triggering SLB precedence rule
+<<< complex match case triggering SLB precedence rule
 object a {
   val breakpoints = (breaks.map {
       case Break(point) =>

diff --git a/scalafmt-tests/src/test/resources/newlines/source_fold.stat b/scalafmt-tests/src/test/resources/newlines/source_fold.stat
@@ -3437,7 +3437,7 @@ object a {
     case None => Command.invalid
   }
 }
-<<< ONLY complex match case triggering SLB precedence rule
+<<< complex match case triggering SLB precedence rule
 object a {
   val breakpoints = (breaks.map {
       case Break(point) =>

diff --git a/scalafmt-tests/src/test/resources/newlines/source_keep.stat b/scalafmt-tests/src/test/resources/newlines/source_keep.stat
@@ -3556,7 +3556,7 @@ object a {
     case None => Command.invalid
   }
 }
-<<< ONLY complex match case triggering SLB precedence rule
+<<< complex match case triggering SLB precedence rule
 object a {
   val breakpoints = (breaks.map {
       case Break(point) =>

diff --git a/scalafmt-tests/src/test/resources/newlines/source_unfold.stat b/scalafmt-tests/src/test/resources/newlines/source_unfold.stat
@@ -3701,7 +3701,7 @@ object a {
         Command.invalid
     }
 }
-<<< ONLY complex match case triggering SLB precedence rule
+<<< complex match case triggering SLB precedence rule
 object a {
   val breakpoints = (breaks.map {
       case Break(point) =>
@@ -3713,17 +3713,18 @@ object a {
     }).mkString("\n\n")
 }
 >>>
-BestFirstSearch:289 Failed to format
-UNABLE TO FORMAT,
-tok #17/52: =>∙s: RightArrow [69..71) [LF] Interpolation.Id(s) [82..83)
-policies:
-  NA:[Router:2096]>71d
-  (NB:[Router:229]@280d & NA:[Router:300]>71d)
-  SLB:[Router:2063]@281!d
-  NB:[Router:229]@300d
-splits (before policy):
-  Newline:[Router:517](cost=0, indents=[], NoPolicy)
-splits (after policy):
+object a {
+  val breakpoints =
+    (
+      breaks.map { case Break(point) =>
+        s"""|send "stop at $MainObject$$:$point\\r"
+              |sleep $CommandWait
+              |expect "breakpoint $MainObject$$:$point"
+              |expect -re $$
+              """.stripMargin
+      }
+    ).mkString("\n\n")
+}
 <<< #2137
 pubSubMessage match {
   case message: IngestionMessage => (