Yes @Nicolas Peltier<mailto:npelt...@adobe.com>, this makes sense and is in
alignment with JCR Observation where a JCR path containing [and] is considered
invalid and a RepositoryException is thrown. Let me look into the code and
figure out the right place to put a check. I’ll keep this thread posted!
-Rafiya
From: Nicolas Peltier <npelt...@adobe.com>
Date: Friday, 13 March 2020 at 9:54 PM
To: Rafiya Sirin <si...@adobe.com>, "users@sling.apache.org"
<users@sling.apache.org>
Cc: Sandeep Kambi Nanjundeshwara <s...@adobe.com>
Subject: Re: [Sling JCR resource] ResourceChangeListeners fail to register
Hey Rafiya,
Bubbling up to where those excluded paths are generated, I get to
ResourceProviderTracker.updateProviderContext crawling through its handler
keyset.
What seems awkward to me is that this path, with [ and ] chars is considered
valid. I would not have that path registered at all in the first place.
From: Rafiya Sirin <si...@adobe.com>
Date: Thursday 12 March 2020 at 22:09
To: "users@sling.apache.org" <users@sling.apache.org>, Nicolas Peltier
<npelt...@adobe.com>
Cc: Sandeep Kambi Nanjundeshwara <s...@adobe.com>
Subject: [Sling JCR resource] ResourceChangeListeners fail to register
Hi All,
I was trying to register a simple ResourceChangeListener and it failed with
the attached stack trace. A small snippet from it :
[org.apache.sling.api.resource.observation.ResourceChangeListener,
org.apache.sling.event.jobs.consumer.JobConsumer]] ServiceEvent REGISTERED
05.03.2020 23:39:00.728 *ERROR* [FelixDispatchQueue]
org.apache.sling.resourceresolver FrameworkEvent ERROR
(java.lang.NullPointerException)
java.lang.NullPointerException: null
at
org.apache.jackrabbit.oak.commons.PathUtils.unifyInExcludes(PathUtils.java:501)
[org.apache.jackrabbit.oak-commons:1.8.17]
at
org.apache.jackrabbit.oak.jcr.observation.ObservationManagerImpl.addEventListener(ObservationManagerImpl.java:240)
[org.apache.jackrabbit.oak-jcr:1.8.17]
at
org.apache.sling.jcr.resource.internal.JcrListenerBaseConfig.register(JcrListenerBaseConfig.java:136)
[org.apache.sling.jcr.resource:3.0.16.1]
On a deeper analysis, I found that it was due to getOakPath() [0] returning a
null for one of the paths. The path that returned null was
/libs/[/globalnav-page, /localnav-page]/xyzTargetIds.json.POST.servlet. This
is a servlet in our codebase which is registered in following manner :
SLING_SERVLET_RESOURCE_TYPES + "=[" + RT_GLOBALNAV_PAGE + "," +RT_LOCALNAV_PAGE
+ "]",
which caused the same path to be constructed and an oak path was expected to be
present for it. Since it wasn’t present, a null was stored in the excludes Set
which ultimately caused the NPE and listener failed to register.
When I changed the initialization of this servlet to follow the practices,
property = {
SLING_SERVLET_RESOURCE_TYPES + "=" + RT_GLOBALNAV_PAGE,
SLING_SERVLET_RESOURCE_TYPES + "=" + RT_LOCALNAV_PAGE,
issue is fixed.
I am working on raising a PR [OAK-8948] in oak-jcr to *warn* for paths which
return a null for getOakPath() for awareness and also a check for null in
PathUtils.java just in case.
Meanwhile, I think we should also have a check in Sling on the way context’s
exclude paths are constructed? Or maybe block it even earlier by not allowing
to go on and register in case of a bad path.
Let me know your thoughts on this.
Thanks,
Rafiya Sirin
[0] -
https://github.com/apache/jackrabbit-oak/blob/trunk/oak-jcr/src/main/java/org/apache/jackrabbit/oak/jcr/observation/ObservationManagerImpl.java#L394
