Use immutable.Seq in utilities

Author: lrytz

build.sbt

@@ -87,6 +87,8 @@ lazy val xml = crossProject(JSPlatform, JVMPlatform, NativePlatform)
         // Synthetic static accessors (for Java interop) have a changed return type
         ProblemFilters.exclude[IncompatibleResultTypeProblem]("scala.xml.Null.apply"),
         ProblemFilters.exclude[IncompatibleResultTypeProblem]("scala.xml.Null.value"),
+        ProblemFilters.exclude[IncompatibleResultTypeProblem]("scala.xml.Utility.parseAttributeValue"),
+        ProblemFilters.exclude[IncompatibleResultTypeProblem]("scala.xml.Utility.trimProper"),
 
         // used to be a declared method, now a bridge without generic signature
         ProblemFilters.exclude[IncompatibleSignatureProblem]("scala.xml.MetaData.apply"),
@@ -99,6 +101,9 @@ lazy val xml = crossProject(JSPlatform, JVMPlatform, NativePlatform)
         ProblemFilters.exclude[IncompatibleSignatureProblem]("scala.xml.Document.theSeq"),
         ProblemFilters.exclude[IncompatibleSignatureProblem]("scala.xml.Group.theSeq"),
         ProblemFilters.exclude[IncompatibleSignatureProblem]("scala.xml.Node.theSeq"),
+        ProblemFilters.exclude[IncompatibleSignatureProblem]("scala.xml.TextBuffer.toText"),
+        ProblemFilters.exclude[IncompatibleSignatureProblem]("scala.xml.Utility.trimProper"),
+        ProblemFilters.exclude[IncompatibleSignatureProblem]("scala.xml.Utility.parseAttributeValue"),
 
         // Option[c.Seq] => Option[i.Seq] results in a changed generic signature
         ProblemFilters.exclude[IncompatibleSignatureProblem]("scala.xml.MetaData.get"),

shared/src/main/scala-2.12/scala/xml/ScalaVersionSpecific.scala

@@ -23,6 +23,7 @@ private[xml] object ScalaVersionSpecific {
     override def apply(): mutable.Builder[Node, NodeSeq] = NodeSeq.newBuilder
   }
   type SeqOfNode = scala.collection.Seq[Node]
+  type SeqOfText = scala.collection.Seq[Text]
 }
 
 private[xml] trait ScalaVersionSpecificNodeSeq extends SeqLike[Node, NodeSeq] { self: NodeSeq =>
@@ -37,3 +38,7 @@ private[xml] trait ScalaVersionSpecificNodeBuffer { self: NodeBuffer =>
 private[xml] trait ScalaVersionSpecificNode { self: Node => }
 
 private[xml] trait ScalaVersionSpecificMetaData { self: MetaData => }
+
+private[xml] trait ScalaVersionSpecificTextBuffer { self: TextBuffer => }
+
+private[xml] trait ScalaVersionSpecificUtility { self: Utility.type => }

shared/src/main/scala-2.13+/scala/xml/ScalaVersionSpecific.scala

@@ -25,6 +25,7 @@ private[xml] object ScalaVersionSpecific {
     def fromSpecific(from: Coll)(it: IterableOnce[Node]): NodeSeq = (NodeSeq.newBuilder ++= from).result()
   }
   type SeqOfNode = scala.collection.immutable.Seq[Node]
+  type SeqOfText = scala.collection.immutable.Seq[Text]
 }
 
 private[xml] trait ScalaVersionSpecificNodeSeq
@@ -70,3 +71,12 @@ private[xml] trait ScalaVersionSpecificMetaData { self: MetaData =>
 
   def value: scala.collection.Seq[Node]
 }
+
+private[xml] trait ScalaVersionSpecificTextBuffer { self: TextBuffer =>
+  def toText: scala.collection.Seq[Text]
+}
+
+private[xml] trait ScalaVersionSpecificUtility { self: Utility.type =>
+  def trimProper(x: Node): scala.collection.Seq[Node]
+  def parseAttributeValue(value: String): scala.collection.Seq[Node]
+}

shared/src/main/scala/scala/xml/TextBuffer.scala

@@ -14,6 +14,7 @@ package scala
 package xml
 
 import scala.collection.Seq
+import scala.collection.immutable.{Seq => ISeq}
 import Utility.isSpace
 
 object TextBuffer {
@@ -26,7 +27,7 @@ object TextBuffer {
  *  appended with the `append` method will be replaced by a single space
  *  character, and leading and trailing space will be removed completely.
  */
-class TextBuffer {
+class TextBuffer extends ScalaVersionSpecificTextBuffer {
   val sb: StringBuilder = new StringBuilder()
 
   /**
@@ -45,8 +46,8 @@ class TextBuffer {
    *
    *  @return the text without whitespaces.
    */
-  def toText: Seq[Text] = sb.toString.trim match {
+  def toText: ScalaVersionSpecific.SeqOfText = sb.toString.trim match {
     case "" => Nil
-    case s  => Seq(Text(s))
+    case s  => ISeq(Text(s))
   }
 }

shared/src/main/scala/scala/xml/Utility.scala

@@ -25,7 +25,7 @@ import scala.collection.immutable.{Seq => ISeq}
  *
  * @author Burak Emir
  */
-object Utility extends AnyRef with parsing.TokenTests {
+object Utility extends AnyRef with parsing.TokenTests with ScalaVersionSpecificUtility {
   final val SU: Char = '\u001A'
 
   // [Martin] This looks dubious. We don't convert StringBuilders to
@@ -66,7 +66,7 @@ object Utility extends AnyRef with parsing.TokenTests {
    * trim a child of an element. `Attribute` values and `Atom` nodes that
    *  are not `Text` nodes are unaffected.
    */
-  def trimProper(x: Node): Seq[Node] = x match {
+  def trimProper(x: Node): ScalaVersionSpecific.SeqOfNode = x match {
     case Elem(pre, lab, md, scp, child@_*) =>
       val children = combineAdjacentTextNodes(child).flatMap(trimProper)
       Elem(pre, lab, md, scp, children.isEmpty, children: _*)
@@ -355,7 +355,7 @@ object Utility extends AnyRef with parsing.TokenTests {
   }
 
   // unused, untested
-  def parseAttributeValue(value: String): Seq[Node] = {
+  def parseAttributeValue(value: String): ScalaVersionSpecific.SeqOfNode = {
     val sb: StringBuilder = new StringBuilder
     var rfb: StringBuilder = null
     val nb: NodeBuffer = new NodeBuffer()