Router: increase NL penalty within interpolation

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

@@ -31,7 +31,7 @@ object Constants {
   val BracketPenalty = 20
   val ExceedColumnPenalty = 1000
   // Breaking a line like s"aaaaaaa${111111 + 22222}" should be last resort.
-  val BreakSingleLineInterpolatedString = 10 * ExceedColumnPenalty
+  val BreakSingleLineInterpolatedString = 1000 * ExceedColumnPenalty
 }
 
 /** Assigns splits to format tokens.

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

@@ -630,3 +630,78 @@ println(
        |A very long string
        |with multiple lines
        |""".stripMargin)
+<<< #4067 avoid classic
+preset = default
+maxColumn = 120
+newlines {
+  inInterpolation = avoid
+}
+===
+object a {
+  throw new Exception(
+    s"Can't create a new SpecialThingamer when forwarding without specialUserId/specialDetails. SpecialUserID: ${x.maybeSpecialUserId}, Special details count: ${maybeSpecialDetails.map(_.length).getOrElse(0)}"
+  )
+}
+>>>
+object a {
+  throw new Exception(
+    s"Can't create a new SpecialThingamer when forwarding without specialUserId/specialDetails. SpecialUserID: ${x.maybeSpecialUserId}, Special details count: ${maybeSpecialDetails.map(_.length).getOrElse(0)}"
+  )
+}
+<<< #4067 avoid keep
+preset = default
+maxColumn = 120
+newlines {
+  inInterpolation = avoid
+  source = keep
+}
+===
+object a {
+  throw new Exception(
+    s"Can't create a new SpecialThingamer when forwarding without specialUserId/specialDetails. SpecialUserID: ${x.maybeSpecialUserId}, Special details count: ${maybeSpecialDetails.map(_.length).getOrElse(0)}"
+  )
+}
+>>>
+object a {
+  throw new Exception(
+    s"Can't create a new SpecialThingamer when forwarding without specialUserId/specialDetails. SpecialUserID: ${x.maybeSpecialUserId}, Special details count: ${maybeSpecialDetails.map(_.length).getOrElse(0)}"
+  )
+}
+<<< #4067 avoid fold
+preset = default
+maxColumn = 120
+newlines {
+  inInterpolation = avoid
+  source = fold
+}
+===
+object a {
+  throw new Exception(
+    s"Can't create a new SpecialThingamer when forwarding without specialUserId/specialDetails. SpecialUserID: ${x.maybeSpecialUserId}, Special details count: ${maybeSpecialDetails.map(_.length).getOrElse(0)}"
+  )
+}
+>>>
+object a {
+  throw new Exception(
+    s"Can't create a new SpecialThingamer when forwarding without specialUserId/specialDetails. SpecialUserID: ${x.maybeSpecialUserId}, Special details count: ${maybeSpecialDetails.map(_.length).getOrElse(0)}"
+  )
+}
+<<< #4067 avoid unfold
+preset = default
+maxColumn = 120
+newlines {
+  inInterpolation = avoid
+  source = unfold
+}
+===
+object a {
+  throw new Exception(
+    s"Can't create a new SpecialThingamer when forwarding without specialUserId/specialDetails. SpecialUserID: ${x.maybeSpecialUserId}, Special details count: ${maybeSpecialDetails.map(_.length).getOrElse(0)}"
+  )
+}
+>>>
+object a {
+  throw new Exception(
+    s"Can't create a new SpecialThingamer when forwarding without specialUserId/specialDetails. SpecialUserID: ${x.maybeSpecialUserId}, Special details count: ${maybeSpecialDetails.map(_.length).getOrElse(0)}"
+  )
+}