Saxon

In private email, Johann Schinnerl reports

             at org.eclipse.jetty.server.Dispatcher.forward(Dispatcher.java:161) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.Dispatcher.forward(Dispatcher.java:79) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.exist.http.urlrewrite.Forward.doRewrite(Forward.java:51) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.http.urlrewrite.XQueryURLRewrite.doRewrite(XQueryURLRewrite.java:525) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.http.urlrewrite.XQueryURLRewrite.service(XQueryURLRewrite.java:344) ~[exist-core-5.2.0.jar:5.2.0]
             at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) ~[javax.servlet-api-3.1.0.jar:3.1.0]
             at org.eclipse.jetty.servlet.ServletHolder$NotAsyncServlet.service(ServletHolder.java:1386) ~[jetty-servlet-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:755) ~[jetty-servlet-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1617) ~[jetty-servlet-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:226) ~[websocket-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1604) ~[jetty-servlet-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:545) ~[jetty-servlet-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:566) ~[jetty-security-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1607) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1297) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:485) ~[jetty-servlet-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1577) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1212) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:221) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.gzip.GzipHandler.handle(GzipHandler.java:767) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.Server.handle(Server.java:500) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:383) ~[jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:547) [jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:375) [jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:270) [jetty-server-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311) [jetty-io-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103) [jetty-io-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117) [jetty-io-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:806) [jetty-util-9.4.26.v20200117.jar:9.4.26.v20200117]
             at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:938) [jetty-util-9.4.26.v20200117.jar:9.4.26.v20200117]
             at java.lang.Thread.run(Thread.java:748) [?:1.8.0_222-4-redhat]
Caused by: java.lang.NullPointerException
             at net.sf.saxon.functions.SystemProperty.getProperty(SystemProperty.java:129) ~[saxon9pe.jar:?]
             at net.sf.saxon.functions.SystemProperty.call(SystemProperty.java:86) ~[saxon9pe.jar:?]
             at net.sf.saxon.functions.SystemProperty.call(SystemProperty.java:31) ~[saxon9pe.jar:?]
             at net.sf.saxon.expr.FunctionCall.iterate(FunctionCall.java:532) ~[saxon9pe.jar:?]
             at net.sf.saxon.expr.Expression.evaluateItem(Expression.java:846) ~[saxon9pe.jar:?]
             at net.sf.saxon.expr.parser.Evaluator$6.evaluate(Evaluator.java:213) ~[saxon9pe.jar:?]
             at net.sf.saxon.expr.SystemFunctionCall.evaluateArguments(SystemFunctionCall.java:446) ~[saxon9pe.jar:?]
             at net.sf.saxon.expr.FunctionCall.iterate(FunctionCall.java:530) ~[saxon9pe.jar:?]
             at net.sf.saxon.style.UseWhenFilter.evaluateStatic(UseWhenFilter.java:666) ~[saxon9pe.jar:?]
             at net.sf.saxon.style.UseWhenFilter.processStaticVariable(UseWhenFilter.java:376) ~[saxon9pe.jar:?]
             at net.sf.saxon.style.UseWhenFilter.startElement(UseWhenFilter.java:209) ~[saxon9pe.jar:?]
             at net.sf.saxon.event.StartTagBuffer.startContent(StartTagBuffer.java:246) ~[saxon9pe.jar:?]
             at net.sf.saxon.event.ProxyReceiver.startContent(ProxyReceiver.java:177) ~[saxon9pe.jar:?]
             at net.sf.saxon.event.ProxyReceiver.startContent(ProxyReceiver.java:177) ~[saxon9pe.jar:?]
             at net.sf.saxon.event.ReceivingContentHandler.startElement(ReceivingContentHandler.java:446) ~[saxon9pe.jar:?]
             at org.exist.util.serializer.ReceiverToSAX.startElement(ReceiverToSAX.java:105) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.storage.serializers.XIncludeFilter.startElement(XIncludeFilter.java:233) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.storage.serializers.NativeSerializer.serializeToReceiver(NativeSerializer.java:271) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.storage.serializers.NativeSerializer.serializeToReceiver(NativeSerializer.java:273) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.storage.serializers.NativeSerializer.serializeToReceiver(NativeSerializer.java:130) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.storage.serializers.Serializer.toSAX(Serializer.java:856) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.xslt.StylesheetResolverAndCompiler.compileTemplates(StylesheetResolverAndCompiler.java:149) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.xslt.StylesheetResolverAndCompiler.templates(StylesheetResolverAndCompiler.java:99) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.xslt.StylesheetResolverAndCompiler.newTransformerHandler(StylesheetResolverAndCompiler.java:127) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.xquery.functions.transform.Transform.createHandler(Transform.java:384) ~[exist-core-5.2.0.jar:5.2.0]
             ... 74 more

Johann Schinnerl

to which I responded

Well, it certainly takes us a big step forward, but it doesn't actually solve it.

At the time of the crash, we're evaluating a call on the system-property() function that appears probably in the select expression of a static variable. The code in question is

Configuration config = rsc.getConfiguration();
String edition = rsc.getPackageData().getTargetEdition();
where rsc is the RetainedStaticContext of the expression (the function call), and it's telling us that the RetainedStaticContext exists but has no PackageData. Now we have to work out why, which ain't easy.

The line numbers in UseWhenFilter are slightly out from my version; the commit log points to bugs 4326 and 4546, but neither seems directly relevant.

The stack trace shows

at net.sf.saxon.event.ProxyReceiver.startContent(ProxyReceiver.java:177) ~[saxon9pe.jar:?]
             at net.sf.saxon.event.ReceivingContentHandler.startElement(ReceivingContentHandler.java:446) ~[saxon9pe.jar:?]
             at org.exist.util.serializer.ReceiverToSAX.startElement(ReceiverToSAX.java:105) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.storage.serializers.XIncludeFilter.startElement(XIncludeFilter.java:233) ~[exist-core-5.2.0.jar:5.2.0]
             at org.exist.storage.serializers.NativeSerializer.serializeToReceiver(NativeSerializer.java:271) ~[exist-core-5.2.0.jar:5.2.0]

which implies that the stylesheet content is being piped directly into Saxon via SAX events, and this suggests that the initialization is incomplete in some way. I guess the most likely way they do this is via the JAXP TemplatesHandler interface. The TemplatesHandlerImpl initialization does

UseWhenFilter useWhenFilter = new UseWhenFilter(compilation, builder, NestedIntegerValue.TWO);

The third argument is the import precedence and I've no idea why this is set to 2! But this doesn't feel relevant.

More to the point, the "compilation" object that's being passed in here doesn't have its PackageData initialized and this could well account for the subsequent NPE. So I guess I need to do some tests of the JAXP TemplatesHandler using 3.0 constructs that access package data.

I'll raise an issue.

Michael Kay Saxonica

reported against 9.9.1.5