title: Apache Solr atomic update results in NullPointerException
body: <p>Im trying to partially update a document via an atomic update, when I do so, the web sever responds with a 500 status with the stacktrace of</p>
  <pre><code>{
    &quot;responseHeader&quot;:{
      &quot;status&quot;:500,
      &quot;QTime&quot;:1},
    &quot;error&quot;:{
      &quot;trace&quot;:&quot;java.lang.NullPointerException\r\n\tat org.apache.solr.update.processor.AtomicUpdateDocumentMerger.getFieldFromHierarchy(AtomicUpdateDocumentMerger.java:301)\r\n\tat org.apache.solr.update.processor.AtomicUpdateDocumentMerger.mergeChildDoc(AtomicUpdateDocumentMerger.java:398)\r\n\tat org.apache.solr.update.processor.DistributedUpdateProcessor.getUpdatedDocument(DistributedUpdateProcessor.java:697)\r\n\tat org.apache.solr.update.processor.DistributedUpdateProcessor.doVersionAdd(DistributedUpdateProcessor.java:372)\r\n\tat org.apache.solr.update.processor.DistributedUpdateProcessor.lambda$versionAdd$0(DistributedUpdateProcessor.java:337)\r\n\tat org.apache.solr.update.VersionBucket.runWithLock(VersionBucket.java:50)\r\n\tat org.apache.solr.update.processor.DistributedUpdateProcessor.versionAdd(DistributedUpdateProcessor.java:337)\r\n\tat org.apache.solr.update.processor.DistributedUpdateProcessor.processAdd(DistributedUpdateProcessor.java:223)\r\n\tat org.apache.solr.update.processor.LogUpdateProcessorFactory$LogUpdateProcessor.processAdd(LogUpdateProcessorFactory.java:103)\r\n\tat org.apache.solr.update.processor.UpdateRequestProcessor.processAdd(UpdateRequestProcessor.java:55)\r\n\tat org.apache.solr.update.processor.AddSchemaFieldsUpdateProcessorFactory$AddSchemaFieldsUpdateProcessor.processAdd(AddSchemaFieldsUpdateProcessorFactory.java:475)\r\n\tat org.apache.solr.update.processor.UpdateRequestProcessor.processAdd(UpdateRequestProcessor.java:55)\r\n\tat org.apache.solr.update.processor.FieldMutatingUpdateProcessor.processAdd(FieldMutatingUpdateProcessor.java:118)\r\n\tat org.apache.solr.update.processor.UpdateRequestProcessor.processAdd(UpdateRequestProcessor.java:55)\r\n\tat org.apache.solr.update.processor.FieldMutatingUpdateProcessor.processAdd(FieldMutatingUpdateProcessor.java:118)\r\n\tat org.apache.solr.update.processor.UpdateRequestProcessor.processAdd(UpdateRequestProcessor.java:55)\r\n\tat org.apache.solr.update.processor.FieldMutatingUpdateProcessor.processAdd(FieldMutatingUpdateProcessor.java:118)\r\n\tat org.apache.solr.update.processor.UpdateRequestProcessor.processAdd(UpdateRequestProcessor.java:55)\r\n\tat org.apache.solr.update.processor.FieldMutatingUpdateProcessor.processAdd(FieldMutatingUpdateProcessor.java:118)\r\n\tat org.apache.solr.update.processor.UpdateRequestProcessor.processAdd(UpdateRequestProcessor.java:55)\r\n\tat org.apache.solr.update.processor.FieldNameMutatingUpdateProcessorFactory$1.processAdd(FieldNameMutatingUpdateProcessorFactory.java:75)\r\n\tat org.apache.solr.update.processor.UpdateRequestProcessor.processAdd(UpdateRequestProcessor.java:55)\r\n\tat org.apache.solr.update.processor.FieldMutatingUpdateProcessor.processAdd(FieldMutatingUpdateProcessor.java:118)\r\n\tat org.apache.solr.update.processor.UpdateRequestProcessor.processAdd(UpdateRequestProcessor.java:55)\r\n\tat org.apache.solr.update.processor.AbstractDefaultValueUpdateProcessorFactory$DefaultValueUpdateProcessor.processAdd(AbstractDefaultValueUpdateProcessorFactory.java:92)\r\n\tat org.apache.solr.handler.loader.JsonLoader$SingleThreadedJsonLoader.handleAdds(JsonLoader.java:507)\r\n\tat org.apache.solr.handler.loader.JsonLoader$SingleThreadedJsonLoader.processUpdate(JsonLoader.java:145)\r\n\tat org.apache.solr.handler.loader.JsonLoader$SingleThreadedJsonLoader.load(JsonLoader.java:121)\r\n\tat org.apache.solr.handler.loader.JsonLoader.load(JsonLoader.java:84)\r\n\tat org.apache.solr.handler.UpdateRequestHandler$1.load(UpdateRequestHandler.java:97)\r\n\tat org.apache.solr.handler.ContentStreamHandlerBase.handleRequestBody(ContentStreamHandlerBase.java:68)\r\n\tat org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:199)\r\n\tat org.apache.solr.core.SolrCore.execute(SolrCore.java:2566)\r\n\tat org.apache.solr.servlet.HttpSolrCall.execute(HttpSolrCall.java:756)\r\n\tat org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:542)\r\n\tat org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:397)\r\n\tat org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:343)\r\n\tat org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1602)\r\n\tat org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:540)\r\n\tat org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146)\r\n\tat org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)\r\n\tat org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)\r\n\tat org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257)\r\n\tat org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1588)\r\n\tat org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255)\r\n\tat org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1345)\r\n\tat org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203)\r\n\tat org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:480)\r\n\tat org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1557)\r\n\tat org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201)\r\n\tat org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1247)\r\n\tat org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)\r\n\tat org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:220)\r\n\tat org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126)\r\n\tat org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)\r\n\tat org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:335)\r\n\tat org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)\r\n\tat org.eclipse.jetty.server.Server.handle(Server.java:502)\r\n\tat org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:364)\r\n\tat org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)\r\n\tat org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:305)\r\n\tat org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)\r\n\tat org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)\r\n\tat org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)\r\n\tat org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)\r\n\tat org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)\r\n\tat org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126)\r\n\tat org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366)\r\n\tat org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:765)\r\n\tat org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:683)\r\n\tat java.base/java.lang.Thread.run(Thread.java:834)\r\n&quot;,
      &quot;code&quot;:500}}
  </code></pre>
  <p>Steps to reproduce:</p>
  <ol>
  <li><p>Start a new clean instance of apache solr</p>
  </li>
  <li><p>Create a new core</p>
  </li>
  <li><p>Add a new document with the following data (in development mode Solr should create fields automatically) using Solr Admin's document upload tool.</p>
  <p><code>{ &quot;id&quot;: &quot;1&quot;, &quot;network_s&quot;: &quot;original value&quot; }</code>
  <a href="https://i.stack.imgur.com/XUBrk.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/XUBrk.png" alt="example of adding a new document" /></a></p>
  </li>
  <li><p>Then proceed to upload a new JSON command to update the previously uploaded document.</p>
  </li>
  </ol>
  <p><code>[{&quot;id&quot;: &quot;1&quot;, &quot;network_s&quot;: {&quot;set&quot;:&quot;Something else&quot;}}]</code></p>
  <p><a href="https://i.stack.imgur.com/Xn1RW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Xn1RW.png" alt="example of updating a document" /></a></p>
  <p>I have a feeling I'm doing something wrong but I'm following the documentation exactly. Im using Solr version <code>8.1.1</code> and reading the <em>latest</em> documentation of 7.7.</p>