InfoDiscovery crashes with NPE after server annouced feature w/o var

[Daniel Gultsch]

I get the following crash when running serviceDiscoveryManager.discoverInformation(server).getResult().getFeatures(); on a buggy Prosody server that sends out empty features.

Exception in thread "main" java.lang.NullPointerException
    at java.base/java.util.TreeMap.compare(TreeMap.java:1291)
    at java.base/java.util.TreeMap.put(TreeMap.java:536)
    at java.base/java.util.TreeSet.add(TreeSet.java:255)
    at java.base/java.util.stream.ReduceOps$3ReducingSink.accept(ReduceOps.java:169)
    at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
    at java.base/java.util.TreeMap$KeySpliterator.forEachRemaining(TreeMap.java:2739)
    at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
    at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
    at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913)
    at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578)
    at rocks.xmpp.extensions.disco.model.info.InfoDiscovery.getFeatures(InfoDiscovery.java:133)
    at im.conversations.compliance.xmpp.tests.AbstractDiscoTest.run(AbstractDiscoTest.java:28)
    at im.conversations.compliance.xmpp.TestExecutor.executeTestsFor(TestExecutor.java:52)
    at im.conversations.compliance.CommandLineLauncher.main(CommandLineLauncher.java:73)

Relevant XML

 <iq from="riotcat.org" id="1bea8660-ce42-4de6-8bb1-01697f4fccc1" to="[e-mail]/caas" type="result">
  <query xmlns="http://jabber.org/protocol/disco#info">
    <identity category="proxy" type="bytestreams" name="SOCKS5 Bytestreams Service"></identity>
    <identity category="pubsub" type="pep" name="Prosody"></identity>
    <identity category="server" type="im" name="Prosody"></identity>
    <identity category="store" type="file" name="HTTP File Upload"></identity>
    <feature></feature>
    <feature var="http://jabber.org/protocol/bytestreams"></feature>
    …
</iq>

[Daniel Gultsch]

Got the actual XML from another client.

<feature xmlns="urn:xmpp:archive"><optional xmlns="urn:xmpp:archive"><default xmlns="urn:xmpp:archive"/></optional></feature>

So that feature is of a different namespace and thus should be ignored. So probably not really a buggy prosody.

[Christian Schudt]

XEP-136 is really weird in this regard :-/

Should have been done with the default Disco namespace and additional features (optional / default) as with XEP-0060.

I'll have a look into it, thanks for reporting.

[Christian Schudt]

Fix NPE in InfoDiscovery#getFeatures()

Fixes issue #146

→ <<cset 4f057ba45915>>

[Daniel Gultsch]

Hi. Thanks for the fix. Wouldn’t it be better to just ignore feature elements with a namespace other than disco#info instead of parsing it and then deal with the lack of a var attribute? Also; will this be ported to 0.8.1?

[Christian Schudt]

An empty <feature/> as in your XML has the same (correct) namespace the other feature elements, it just lacks the var, which eventually caused the NPE.

I will put it into the 0.8 branch for future bugfix releases.

[Christian Schudt]

Fix NPE in InfoDiscovery#getFeatures()

Fixes issue #146

→ <<cset 3a835ac3de71>>