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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (GEODE-3306) Parsing of cache.xml with whitespace fails with Apache Xerces
Date Sun, 13 Aug 2017 06:28:00 GMT

    [ https://issues.apache.org/jira/browse/GEODE-3306?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16124826#comment-16124826
] 

ASF GitHub Bot commented on GEODE-3306:
---------------------------------------

Github user darrenfoong commented on the issue:

    https://github.com/apache/geode/pull/668
  
    Thanks Jared! Will find time to make the changes and get feedback on the mailing list.


> Parsing of cache.xml with whitespace fails with Apache Xerces
> -------------------------------------------------------------
>
>                 Key: GEODE-3306
>                 URL: https://issues.apache.org/jira/browse/GEODE-3306
>             Project: Geode
>          Issue Type: Bug
>          Components: management
>    Affects Versions: 1.2.0
>            Reporter: Darren Foong
>            Priority: Minor
>             Fix For: 1.2.0
>
>
> I am using Geode 1.2.0 and Apache Xerces 2.11.0 (not the one included in the Oracle JDK),
and I encountered the following error when I tried to programmatically start a cache:
> {noformat}
> org.apache.geode.InternalGemFireError: Did not expected a java.lang.StringBuffer on top
of the stack.
> Exception in thread "main" org.apache.geode.InternalGemFireError: Did not expected a
java.lang.StringBuffer on top of the stack.
> 	at org.apache.geode.internal.Assert.throwError(Assert.java:94)
> 	at org.apache.geode.internal.Assert.assertTrue(Assert.java:117)
> 	at org.apache.geode.internal.cache.xmlcache.CacheXmlParser.endRegionAttributes(CacheXmlParser.java:1257)
> 	at org.apache.geode.internal.cache.xmlcache.CacheXmlParser.endElement(CacheXmlParser.java:2909)
> 	at org.apache.geode.internal.cache.xmlcache.CacheXmlParser$DefaultHandlerDelegate.endElement(CacheXmlParser.java:3374)
> 	at org.apache.xerces.parsers.AbstractSAXParser.endElement(Unknown Source)
> 	at org.apache.xerces.parsers.AbstractXMLDocumentParser.emptyElement(Unknown Source)
> 	at org.apache.xerces.impl.xs.XMLSchemaValidator.emptyElement(Unknown Source)
> 	at org.apache.xerces.impl.XMLNSDocumentScannerImpl.scanStartElement(Unknown Source)
> 	at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown
Source)
> 	at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
> 	at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
> 	at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
> 	at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
> 	at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
> 	at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
> 	at org.apache.xerces.jaxp.SAXParserImpl.parse(Unknown Source)
> 	at javax.xml.parsers.SAXParser.parse(SAXParser.java:195)
> 	at org.apache.geode.internal.cache.xmlcache.CacheXmlParser.parse(CacheXmlParser.java:224)
> 	at org.apache.geode.internal.cache.GemFireCacheImpl.loadCacheXml(GemFireCacheImpl.java:4287)
> 	at org.apache.geode.internal.cache.GemFireCacheImpl.initializeDeclarativeCache(GemFireCacheImpl.java:1390)
> 	at org.apache.geode.internal.cache.GemFireCacheImpl.initialize(GemFireCacheImpl.java:1195)
> 	at org.apache.geode.internal.cache.GemFireCacheImpl.basicCreate(GemFireCacheImpl.java:758)
> 	at org.apache.geode.internal.cache.GemFireCacheImpl.create(GemFireCacheImpl.java:745)
> 	at org.apache.geode.cache.CacheFactory.create(CacheFactory.java:173)
> 	at org.apache.geode.cache.CacheFactory.create(CacheFactory.java:212)
> 	at server.ServerWhitespace.main(ServerWhitespace.java:8)
> {noformat}
> However, this does not happen when I don't use Apache Xerces, i.e. I rely on the version
in the Oracle JDK (1.8).
> After getting the Geode source code and stepping through the parsing using the Eclipse
debugger, I realised that there were unexpected StringBuffers pushed onto the parse stack,
thus causing the problem.
> These StringBuffers were created and pushed by the {{characters()}} method (https://github.com/apache/geode/blob/develop/geode-core/src/main/java/org/apache/geode/internal/cache/xmlcache/CacheXmlParser.java#L3270).
Changing the log level to {{TRACE}} and examining the parse stack showed that these StringBuffers
contained the whitespace (including newlines) between the XML tags in {{cache.xml}}.
> When using the Oracle JDK's version of Xerces, these StringBuffers did not appear on
the parse stack despite the whitespace.
> I have a proof of concept on GitHub: https://github.com/darrenfoong/geode-parser-poc
The {{cache.xml}} file without whitespace between the tags was parsed without errors by both
versions of Xerces.
> It could be the case that the JDK Xerces strips out whitespace while Apache Xerces doesn't;
but this could be implemented in {{characters()}} by only pushing non-whitespace char arrays
in the {{else}} block. However, there could be other XML parsing edge cases that I am unaware
of.
> There should be others who need Apache Xerces for their projects; a fix would be appreciated.



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