Fix endless loop caused by aborted subsequent PI or comment (#124)

This closes #124

Author: joehni

src/main/java/org/codehaus/plexus/util/xml/pull/MXParser.java

@@ -3964,7 +3964,7 @@ private char more()
             fillBuf();
             // this return value should be ignored as it is used in epilog parsing ...
             if ( reachedEnd )
-                return (char) -1;
+                throw new EOFException( "no more data available" + getPositionDescription() );
         }
         final char ch = buf[pos++];
         // line/columnNumber

src/test/java/org/codehaus/plexus/util/xml/pull/MXParserTest.java

@@ -726,6 +726,58 @@ public void testSubsequentMalformedProcessingInstructionNoClosingQuestionMark()
      *
      * @throws java.lang.Exception if any.
      */
+    @Test
+    public void testSubsequentAbortedProcessingInstruction()
+        throws Exception
+    {
+        MXParser parser = new MXParser();
+        StringBuilder sb = new StringBuilder();
+        sb.append( "<project />" );
+        sb.append( "<?aborted" );
+
+        parser.setInput( new StringReader( sb.toString() ) );
+
+        try
+        {
+            assertEquals( XmlPullParser.START_TAG, parser.next() );
+            assertEquals( XmlPullParser.END_TAG, parser.next() );
+            assertEquals( XmlPullParser.PROCESSING_INSTRUCTION, parser.next() );
+
+            fail( "Should fail since it has aborted PI" );
+        }
+        catch ( XmlPullParserException ex )
+        {
+            assertTrue( ex.getMessage().contains( "@1:21" ) );
+            assertTrue( ex.getMessage().contains( "processing instruction started on line 1 and column 12 was not closed" ) );
+        }
+    }
+
+    @Test
+    public void testSubsequentAbortedComment()
+        throws Exception
+    {
+        MXParser parser = new MXParser();
+        StringBuilder sb = new StringBuilder();
+        sb.append( "<project />" );
+        sb.append( "<!-- aborted" );
+
+        parser.setInput( new StringReader( sb.toString() ) );
+
+        try
+        {
+            assertEquals( XmlPullParser.START_TAG, parser.next() );
+            assertEquals( XmlPullParser.END_TAG, parser.next() );
+            assertEquals( XmlPullParser.PROCESSING_INSTRUCTION, parser.next() );
+
+            fail( "Should fail since it has aborted comment" );
+        }
+        catch ( XmlPullParserException ex )
+        {
+            assertTrue( ex.getMessage().contains( "@1:24" ) );
+            assertTrue( ex.getMessage().contains( "comment started on line 1 and column 12 was not closed" ) );
+        }
+    }
+
     @Test
     public void testMalformedXMLRootElement()
         throws Exception