State: keep explicit penalty to detect overflow

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

@@ -197,8 +197,9 @@ private class BestFirstSearch private (
                   if (null == nextNextState) null
                   else traverseSameLine(nextNextState, depth)
                 if (null != furtherState) {
-                  val delta = furtherState.totalCost - nextNextState.totalCost
-                  if (delta > Constants.ExceedColumnPenalty)
+                  val overflow =
+                    furtherState.appliedPenalty > nextNextState.appliedPenalty
+                  if (overflow)
                     Q.enqueue(nextNextState)
                   else {
                     optimalNotFound = false

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

@@ -4,7 +4,7 @@ import scala.meta.tokens.Token
 
 import org.scalafmt.util.LoggerOps
 
-class PolicySummary(val policies: Seq[Policy]) {
+class PolicySummary(val policies: Seq[Policy]) extends AnyVal {
   import LoggerOps._
 
   @inline def noDequeue = policies.exists(_.noDequeue)

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

@@ -23,6 +23,7 @@ final case class State(
     pushes: Seq[ActualIndent],
     column: Int,
     allAltAreNL: Boolean,
+    appliedPenalty: Int, // penalty applied from overflow
     delayedPenalty: Int // apply if positive, ignore otherwise
 ) {
 
@@ -117,6 +118,7 @@ final case class State(
       nextIndents,
       nextStateColumn,
       nextAllAltAreNL,
+      appliedPenalty + penalty,
       nextDelayedPenalty
     )
   }
@@ -258,7 +260,6 @@ final case class State(
     }
   }
 
-  def totalCost: Int = cost + math.max(0, delayedPenalty)
 }
 
 object State {
@@ -273,6 +274,7 @@ object State {
     Seq.empty,
     0,
     false,
+    0,
     0
   )
 

scalafmt-tests/src/test/resources/default/String.stat

@@ -185,7 +185,8 @@ object a {
 >>>
 object a {
   intercept[TestException] {
-    val ct = Thread.currentThread() // Ensure that the thunk is executed in the tests thread
+    val ct =
+      Thread.currentThread() // Ensure that the thunk is executed in the tests thread
     val ct =
       Thread.currentThread() // Ensure that the thunk is executed in the tests thread
   }

scalafmt-tests/src/test/resources/scalajs/Apply.stat

@@ -915,3 +915,42 @@ object a {
     case foo bar (baz @ qux) =>
   }
 }
+<<< [from scala-js] changed with incorect overflow detection
+preset = default
+maxColumn = 74
+binPack.preset = true
+newlines.source = keep
+newlines.avoidForSimpleOverflow = [tooLong, punct, slc]
+binPack.unsafeCallSite = oneline
+===
+object a {
+  @tailrec
+  def constructOptimized(revAlts: List[(js.Tree, js.Tree)],
+      elsep: js.Tree): js.Tree = {
+    revAlts match {
+      case foo =>
+        // cannot use flatMap due to tailrec
+        foo match {
+          case bar =>
+            constructOptimized(revAltsRest,
+                js.If(cond, newBody, elsep)(tpe)(cond.pos))
+        }
+    }
+  }
+}
+>>>
+object a {
+  @tailrec
+  def constructOptimized(revAlts: List[(js.Tree, js.Tree)],
+      elsep: js.Tree): js.Tree = {
+    revAlts match {
+      case foo =>
+        // cannot use flatMap due to tailrec
+        foo match {
+          case bar =>
+            constructOptimized(revAltsRest,
+              js.If(cond, newBody, elsep)(tpe)(cond.pos))
+        }
+    }
+  }
+}