[SOLR-16343] Handle MDC snapshot being null

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 9.1, main (10.0)
• Assignee: Kevin Risden
• Reporter: Dee Moore
• Created: 18/Aug/22 14:37
• Updated: 25/Jan/23 16:15
• Resolved: 12/Sep/22 15:16

Description

Using slf4j 2 with the jdk14 adapter, SLF4J uses the NOPMDCAdapter: https://www.slf4j.org/api/org/slf4j/helpers/NOPMDCAdapter.html. This always returns null from MDC.getCopyOfContextMap().

In MDCSnapshot.java, there is an assumption that the context map is never null. The SOLRDispatchFilter uses MDCSnapshot.

This results in the following traceback in our project using Solr 8.11.1 up:

java.lang.NullPointerException
at org.apache.solr.logging.MDCSnapshot.close(MDCSnapshot.java:53)
at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:185)
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:201)
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1626)
at com.sjsoft.jetty.AdminPasswordOrCertAuthFilter.doFilter(AdminPasswordOrCertAuthFilter.java:52)
at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)
at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1626)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:552)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:600)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1624)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1440)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:505)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1594)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1355)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:191)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
at org.eclipse.jetty.server.Server.handle(Server.java:516)
at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:487)
at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:732)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:479)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:277)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105)
at org.eclipse.jetty.io.ssl.SslConnection$DecryptedEndPoint.onFillable(SslConnection.java:555)
at org.eclipse.jetty.io.ssl.SslConnection.onFillable(SslConnection.java:410)
at org.eclipse.jetty.io.ssl.SslConnection$2.succeeded(SslConnection.java:164)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105)
at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:338)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:315)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:173)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce(EatWhatYouKill.java:137)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:883)
at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1034)
at java.base/java.lang.Thread.run(Unknown Source)

 

Changing MDCSnapshot to handle the possibility of a null snapshot fixes the issue.

Issue Links

• links to: GitHub Pull Request #978