Do not ignore XML CDATA sections when parsing:

- handle startCDATA/endCDATA lexical events;
- keep track of the `inCDATA` state;
- capture text into appropriate Node subtype depending on that state;
- add createPCData()/makePCData() helpers;
- add unit tests.

Author: dubinsky

build.sbt

@@ -69,14 +69,12 @@ lazy val xml = crossProject(JSPlatform, JVMPlatform, NativePlatform)
         // to previous-version artifacts that were built on 8.  see scala/scala-xml#501
         exclude[DirectMissingMethodProblem]("scala.xml.include.sax.XIncluder.declaration"),
 
-        // caused by the switch from DefaultHandler to DefaultHandler2:
-        exclude[MissingTypesProblem]("scala.xml.parsing.FactoryAdapter"),
-        exclude[MissingTypesProblem]("scala.xml.parsing.NoBindingFactoryAdapter"),
+        // necessitated by the switch from DefaultHandler to DefaultHandler2 in FactoryAdapter:
+        exclude[MissingTypesProblem]("scala.xml.parsing.FactoryAdapter"),                         // see #549
 
-        exclude[DirectMissingMethodProblem]("scala.xml.parsing.FactoryAdapter.comment"),
-        exclude[ReversedMissingMethodProblem]("scala.xml.parsing.FactoryAdapter.createComment"),
-        exclude[DirectMissingMethodProblem]("scala.xml.parsing.FactoryAdapter.createComment"),
-        exclude[DirectMissingMethodProblem]("scala.xml.parsing.NoBindingFactoryAdapter.createComment")
+        // necessitated by the introduction of new abstract methods in FactoryAdapter:
+        exclude[ReversedMissingMethodProblem]("scala.xml.parsing.FactoryAdapter.createComment"),  // see #549
+        exclude[ReversedMissingMethodProblem]("scala.xml.parsing.FactoryAdapter.createPCData")    // see #558
       )
     },
 

jvm/src/test/scala/scala/xml/XMLTest.scala

@@ -580,13 +580,23 @@ class XMLTestJVM {
     XML.loadString(broken)
   }
 
+  def roundtrip(xml: String): Unit = assertEquals(xml, XML.loadString(xml).toString)
+
   @UnitTest
-  def issue508: Unit = {
-    def check(xml: String): Unit = assertEquals(xml, XML.loadString(xml).toString)
+  def issue508commentParsing: Unit = {
+    // confirm that comments are processed correctly now
+    roundtrip("<a><!-- comment --> suffix</a>")
+    roundtrip("<a>prefix <!-- comment --> suffix</a>")
+    roundtrip("<a>prefix <b><!-- comment --></b> suffix</a>")
+    roundtrip("<a>prefix <b><!-- multi-\nline\n comment --></b> suffix</a>")
+    roundtrip("""<a>prefix <b><!-- multi-
+                |line
+                | comment --></b> suffix</a>""".stripMargin)
 
-    check("<a><!-- comment --> suffix</a>")
-    check("<a>prefix <!-- comment --> suffix</a>")
-    check("<a>prefix <b><!-- comment --></b> suffix</a>")
+    // confirm that processing instructions were always processed correctly
+    roundtrip("<a><?target content ?> suffix</a>")
+    roundtrip("<a>prefix <?target content ?> suffix</a>")
+    roundtrip("<a>prefix <b><?target content?></b> suffix</a>")
 
     // TODO since XMLLoader retrieves FactoryAdapter.rootNode,
     // capturing comments before and after the root element is not currently possible
@@ -595,6 +605,17 @@ class XMLTestJVM {
     //check("<a>text</a><!-- epilogue -->")
   }
 
+  @UnitTest
+  def cdataParsing: Unit = {
+    roundtrip("<a><![CDATA[ cdata ]]> suffix</a>")
+    roundtrip("<a>prefix <![CDATA[ cdata ]]> suffix</a>")
+    roundtrip("<a>prefix <b><![CDATA[ cdata section]]></b> suffix</a>")
+    roundtrip("""<a>prefix <b><![CDATA[
+                | multi-
+                | line    cdata
+                |    section]]></b> suffix</a>""".stripMargin)
+  }
+
   @UnitTest
   def nodeSeqNs: Unit = {
     val x = {

shared/src/main/scala/scala/xml/factory/NodeFactory.scala

@@ -56,6 +56,8 @@ trait NodeFactory[A <: Node] {
   }
 
   def makeText(s: String): Text = Text(s)
+  def makePCData(s: String): PCData =
+    PCData(s)
   def makeComment(s: String): Seq[Comment] =
     if (ignoreComments) Nil else List(Comment(s))
   def makeProcInstr(t: String, s: String): Seq[ProcInstr] =

shared/src/main/scala/scala/xml/parsing/FactoryAdapter.scala

@@ -43,6 +43,8 @@ abstract class FactoryAdapter extends DefaultHandler2 with factory.XMLLoader[Nod
   var rootElem: Node = _
 
   val buffer = new StringBuilder()
+  private var inCDATA: Boolean = false
+
   /** List of attributes
     * 
     * Previously was a mutable [[scala.collection.mutable.Stack Stack]], but is now a mutable reference to an immutable [[scala.collection.immutable.List List]].
@@ -100,6 +102,13 @@ abstract class FactoryAdapter extends DefaultHandler2 with factory.XMLLoader[Nod
    */
   def createText(text: String): Text // abstract
 
+  /**
+   * creates a PCData node.
+   * @param text
+   * @return a new PCData node.
+   */
+  def createPCData(text: String): PCData // abstract
+
   /**
    * creates a new processing instruction node.
    */
@@ -117,7 +126,7 @@ abstract class FactoryAdapter extends DefaultHandler2 with factory.XMLLoader[Nod
   val normalizeWhitespace = false
 
   /**
-   * Characters.
+   * Capture characters, possibly normalizing whitespace.
    * @param ch
    * @param offset
    * @param length
@@ -139,7 +148,20 @@ abstract class FactoryAdapter extends DefaultHandler2 with factory.XMLLoader[Nod
     }
   }
 
-  private def splitName(s: String) = {
+  /**
+   * Start of a CDATA section.
+   */
+  override def startCDATA(): Unit = {
+    captureText()
+    inCDATA = true
+  }
+
+  /**
+   * End of a CDATA section.
+   */
+  override def endCDATA(): Unit = captureText()
+
+  private def splitName(s: String): (String, String) = {
     val idx = s indexOf ':'
     if (idx < 0) (null, s)
     else (s take idx, s drop (idx + 1))
@@ -185,13 +207,17 @@ abstract class FactoryAdapter extends DefaultHandler2 with factory.XMLLoader[Nod
     }
 
   /**
-   * captures text, possibly normalizing whitespace
+   * Captures text or cdata.
    */
   def captureText(): Unit = {
-    if (capture && buffer.nonEmpty)
-      hStack = createText(buffer.toString) :: hStack
+    if (capture && buffer.nonEmpty) {
+      val text: String = buffer.toString
+      val newNode: Node = if (inCDATA) createPCData(text) else createText(text)
+      hStack =  newNode :: hStack
+    }
 
     buffer.clear()
+    inCDATA = false
   }
 
   /**
@@ -232,6 +258,9 @@ abstract class FactoryAdapter extends DefaultHandler2 with factory.XMLLoader[Nod
     hStack = hStack.reverse_:::(createProcInstr(target, data).toList)
   }
 
+  /**
+   * Comment.
+   */
   override def comment(ch: Array[Char], start: Int, length: Int): Unit = {
     captureText()
     val commentText: String = String.valueOf(ch.slice(start, start + length))

shared/src/main/scala/scala/xml/parsing/NoBindingFactoryAdapter.scala

@@ -42,4 +42,7 @@ class NoBindingFactoryAdapter extends FactoryAdapter with NodeFactory[Elem] {
 
   /** Creates a comment. */
   override def createComment(characters: String): Seq[Comment] = makeComment(characters)
+
+  /** Creates a cdata. */
+  override def createPCData(characters: String): PCData = makePCData(characters)
 }

shared/src/test/scala/scala/xml/CommentTest.scala

@@ -1,7 +1,6 @@
 package scala.xml
 
 import org.junit.Assert.assertEquals
-import org.junit.Assert.assertTrue
 import org.junit.Test
 
 final class CommentTest {