SI-4267 - fix to avoid XMLEventReader swallows IO/Parse exception

src/main/scala/scala/xml/pull/XMLEventReader.scala

@@ -92,12 +92,19 @@ class XMLEventReader(src: Source)
 
     override def run() {
       curInput = input
-      interruptibly { this.initialize.document() }
+      try {
+        interruptibly { this.initialize.document() }
+      } catch {
+        case e:Exception => setEvent(ExceptionEvent(e))
+      }
       setEvent(POISON)
     }
   }
 }
 
+// An internal class used to propagate exception from helper threads to API end users.
+private case class ExceptionEvent(exception:Exception) extends XMLEvent
+
 // An iterator designed for one or more producers to generate
 // elements, and a single consumer to iterate.  Iteration will continue
 // until closeIterator() is called, after which point producers
@@ -143,6 +150,7 @@ trait ProducerConsumerIterator[T >: Null] extends Iterator[T] {
   def next() = {
     if (eos()) throw new NoSuchElementException("ProducerConsumerIterator")
     if (buffer == null) fillBuffer()
+    if (buffer.isInstanceOf[ExceptionEvent]) throw buffer.asInstanceOf[ExceptionEvent].exception
 
     drainBuffer()
   }

src/test/scala/scala/xml/pull/XMLEventReaderTest.scala

@@ -40,4 +40,22 @@ class XMLEventReaderTest {
     er.stop  // allow thread to be garbage-collected
   }
 
-}
+ @Test(expected = classOf[Exception]) 
+ def missingTagTest: Unit = {
+   val data=
+      """<?xml version="1.0" ?>
+        |<verbosegc xmlns="http://www.ibm.com/j9/verbosegc">
+        |
+        |<initialized id="1" timestamp="2013-10-04T00:11:08.389">
+        |</initialized>
+        | 
+        |<exclusive-start id="2" timestamp="2013-10-04T00:11:09.185" intervalms="796.317">
+        |<response-info timems="0.007" idlems="0.007" threads="0" />
+        |</exclusive-start>
+        |""".stripMargin
+
+   val er = new XMLEventReader(Source.fromString(data))
+   while(er.hasNext) er.next()
+   er.stop()
+ }
+}