Router: use template to break before extends

In older versions of scalameta, `extends` was not part of template, and we had to identify the tree just preceding it. Also, make sure to handle cases when the template is empty (in that case there's no reason to break before a non-existent `extends`).
scalameta · Jul 7, 2023 · 5bfe04b · 5bfe04b
1 parent bb93f55
commit 5bfe04b
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Showing 3 changed files with 12 additions and 19 deletions.
diff --git a/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/FormatOps.scala b/scalafmt-core/shared/src/main/scala/org/scalafmt/internal/FormatOps.scala
@@ -374,6 +374,13 @@ class FormatOps(
     new Policy.Delay(policy, Policy.End.Before(from))
   }
 
+  val WithTemplateOnLeft = new ExtractFromMeta(ft =>
+    ft.meta.leftOwner match {
+      case lo: Stat.WithTemplate => Some(lo.templ)
+      case _ => None
+    }
+  )
+
   def templateCurlyFt(template: Template): Option[FormatToken] =
     getStartOfTemplateBody(template).map(tokenBefore)
 

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
@@ -817,14 +817,10 @@ class Router(formatOps: FormatOps) {
       case FormatToken(
             _: T.KwObject | _: T.KwClass | _: T.KwTrait | _: T.KwEnum,
             _,
-            _
+            WithTemplateOnLeft(template)
           ) =>
-        def expire = defnTemplate(leftOwner)
-          .flatMap {
-            getTemplateGroups(_).flatMap(
-              _.lastOption.flatMap(_.headOption.flatMap(_.tokens.headOption))
-            )
-          }
+        def expire = getTemplateGroups(template)
+          .flatMap(_.last.headOption.flatMap(_.tokens.headOption))
           .getOrElse(getLastToken(leftOwner))
         def forceNewlineBeforeExtends = Policy.before(expire) {
           case Decision(FormatToken(_, soft.ExtendsOrDerives(), m), s)
@@ -834,8 +830,8 @@ class Router(formatOps: FormatOps) {
         val policy =
           if (style.binPack.keepParentConstructors) None
           else
-            defnBeforeTemplate(leftOwner).map { x =>
-              val policyEnd = Policy.End.On(x.tokens.last)
+            template.tokens.headOption.map { head =>
+              val policyEnd = Policy.End.Before(head)
               delayedBreakPolicy(policyEnd)(forceNewlineBeforeExtends)
             }
         Seq(Split(Space, 0).withPolicyOpt(policy))

diff --git a/scalafmt-core/shared/src/main/scala/org/scalafmt/util/TokenOps.scala b/scalafmt-core/shared/src/main/scala/org/scalafmt/util/TokenOps.scala
@@ -123,16 +123,6 @@ object TokenOps {
       case _ => None
     }
 
-  def defnBeforeTemplate(tree: Tree): Option[Tree] =
-    tree match {
-      case t: Defn.Object => Some(t.name)
-      case t: Defn.Class => Some(t.ctor)
-      case t: Defn.Trait => Some(t.ctor)
-      case t: Defn.Enum => Some(t.ctor)
-      case t: Pkg.Object => Some(t.name)
-      case _ => None
-    }
-
   val formatOnCode = Set(
     "@formatter:on", // IntelliJ
     "format: on" // scalariform