We've recently upgraded from Solr 6.6 to 7.7.2 and are getting NPE when attempting to index content in our development environment.
The error in the log is: 019-06-20 13:18:29.609 ERROR (qtp363988129-21) [ x:govwalesd8_fb] o.a.s.h.RequestHandlerBase org.apache.solr.common.SolrException: ERROR: [doc=gdizkb-beta_content-entity:node/23458:en] Error adding field 'sort_X3b_en_node_grants'='node_access_all:0' msg=null at org.apache.solr.update.DocumentBuilder.toDocument(DocumentBuilder.java:220) at org.apache.solr.update.AddUpdateCommand.getLuceneDocument(AddUpdateCommand.java:102) at org.apache.solr.update.DirectUpdateHandler2.updateDocOrDocValues(DirectUpdateHandler2.java:967) at org.apache.solr.update.DirectUpdateHandler2.doNormalUpdate(DirectUpdateHandler2.java:341) at org.apache.solr.update.DirectUpdateHandler2.addDoc0(DirectUpdateHandler2.java:288) at org.apache.solr.update.DirectUpdateHandler2.addDoc(DirectUpdateHandler2.java:235) at org.apache.solr.update.processor.RunUpdateProcessor.processAdd(RunUpdateProcessorFactory.java:67) at org.apache.solr.update.processor.UpdateRequestProcessor.processAdd(UpdateRequestProcessor.java:55) at org.apache.solr.update.processor.DistributedUpdateProcessor.doLocalAdd(DistributedUpdateProcessor.java:1002) at org.apache.solr.update.processor.DistributedUpdateProcessor.doVersionAdd(DistributedUpdateProcessor.java:1233) at org.apache.solr.update.processor.DistributedUpdateProcessor.lambda$versionAdd$2(DistributedUpdateProcessor.java:1082) at org.apache.solr.update.VersionBucket.runWithLock(VersionBucket.java:50) at org.apache.solr.update.processor.DistributedUpdateProcessor.versionAdd(DistributedUpdateProcessor.java:1082) at org.apache.solr.update.processor.DistributedUpdateProcessor.processAdd(DistributedUpdateProcessor.java:694) at org.apache.solr.update.processor.LogUpdateProcessorFactory$LogUpdateProcessor.processAdd(LogUpdateProcessorFactory.java:103) at org.apache.solr.handler.loader.XMLLoader.processUpdate(XMLLoader.java:261) at org.apache.solr.handler.loader.XMLLoader.load(XMLLoader.java:188) at org.apache.solr.handler.UpdateRequestHandler$1.load(UpdateRequestHandler.java:97) at org.apache.solr.handler.ContentStreamHandlerBase.handleRequestBody(ContentStreamHandlerBase.java:68) at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:199) at org.apache.solr.core.SolrCore.execute(SolrCore.java:2551) at org.apache.solr.servlet.HttpSolrCall.execute(HttpSolrCall.java:711) at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:516) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:395) at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:341) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1602) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:540) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1588) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1345) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:480) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1557) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1247) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:220) at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:335) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.Server.handle(Server.java:502) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:364) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:305) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103) at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:765) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:683) at java.lang.Thread.run(Thread.java:748) I'd expect to see a value in msg but it's null. Is this a bug in Solr? I get the error on Solr 7.7.2 on Debian 8, but it's fine when I run Solr 7.7.2 in a local docker container.