[lucene-solr] branch branch_8x updated: SOLR-14351: Oops; add back null check for ZkController

[ds...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

dsmiley pushed a commit to branch branch_8x
in repository https://gitbox.apache.org/repos/asf/lucene-solr.git


The following commit(s) were added to refs/heads/branch_8x by this push:
     new 6c9024f  SOLR-14351: Oops; add back null check for ZkController
6c9024f is described below

commit 6c9024f77358ae1f372b3078691ada3f64a84e59
Author: David Smiley <ds...@salesforce.com>
AuthorDate: Sun May 3 10:23:16 2020 -0400

    SOLR-14351: Oops; add back null check for ZkController
    
    (cherry picked from commit e7c7a62a84927cf6c49d75229f9ebfbe2feb9df9)
---
 solr/core/src/java/org/apache/solr/core/ZkContainer.java | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/solr/core/src/java/org/apache/solr/core/ZkContainer.java b/solr/core/src/java/org/apache/solr/core/ZkContainer.java
index fcf7b75..0d0da26 100644
--- a/solr/core/src/java/org/apache/solr/core/ZkContainer.java
+++ b/solr/core/src/java/org/apache/solr/core/ZkContainer.java
@@ -44,7 +44,16 @@ import org.apache.zookeeper.KeeperException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+/**
+ * Used by {@link CoreContainer} to hold ZooKeeper / SolrCloud info, especially {@link ZkController}.
+ * Mainly it does some ZK initialization, and ensures a loading core registers in ZK.
+ * Even when in standalone mode, perhaps surprisingly, an instance of this class exists.
+ * If {@link #getZkController()} returns null then we're in standalone mode.
+ */
 public class ZkContainer {
+  // NOTE DWS: It's debatable if this in-between class is needed instead of folding it all into ZkController.
+  //  ZKC is huge though.
+
   private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
   
   protected ZkController zkController;
@@ -180,6 +189,10 @@ public class ZkContainer {
   public static volatile Predicate<CoreDescriptor> testing_beforeRegisterInZk;
 
   public void registerInZk(final SolrCore core, boolean background, boolean skipRecovery) {
+    if (zkController == null) {
+      return;
+    }
+
     CoreDescriptor cd = core.getCoreDescriptor(); // save this here - the core may not have it later
     Runnable r = () -> {
       MDCLoggingContext.setCore(core);
@@ -220,7 +233,6 @@ public class ZkContainer {
     } else {
       r.run();
     }
-
   }
   
   public ZkController getZkController() {