NullPointerException in SolrMetricManager

[Hendrik Haddorp <he...@gmx.net>]

Hi,

we are seeing the following NPE sometimes when we delete a collection 
right after we modify the schema:

08:47:46.407 [zkCallback-5-thread-4] INFO 
org.apache.solr.rest.ManagedResource 209 processStoredData - Loaded 
initArgs {ignoreCase=true} for /schema/analysis/stopwords/text_ar
08:47:46.407 [zkCallback-5-thread-4] INFO 
org.apache.solr.rest.schema.analysis.ManagedWordSetResource 116 
onManagedDataLoadedFromStorage - Loaded 119 words for 
/schema/analysis/stopwords/text_ar
08:47:46.407 [zkCallback-5-thread-4] INFO 
org.apache.solr.rest.ManagedResource 117 notifyObserversDuringInit - 
Notified 8 observers of /schema/analysis/stopwords/text_ar
08:47:46.407 [zkCallback-5-thread-4] INFO 
org.apache.solr.rest.RestManager 668 addRegisteredResource - Registered 
new managed resource /schema/analysis/stopwords/text_ar
08:47:46.408 [zkCallback-5-thread-4] INFO 
org.apache.solr.schema.IndexSchema 592 readSchema - Loaded schema 
solr-config/1.6 with uniqueid field id
08:47:46.408 [zkCallback-5-thread-4] INFO 
org.apache.solr.schema.ZkIndexSchemaReader 177 updateSchema - Finished 
refreshing schema in 411 ms
08:47:46.415 [qtp254749889-20] INFO  org.apache.solr.core.SolrCore 1517 
close - [donald.test-query-1533026857986_shard1_replica_n1] CLOSING 
SolrCore org.apache.solr.core.SolrCore@62ef7f0c
08:47:46.415 [qtp254749889-20] INFO 
org.apache.solr.metrics.SolrMetricManager 1038 closeReporters - Closing 
metric reporters for 
registry=solr.core.donald.test-query-1533026857986.shard1.replica_n1, 
tag=62ef7f0c
08:47:46.416 [qtp254749889-20] INFO 
org.apache.solr.metrics.SolrMetricManager 1038 closeReporters - Closing 
metric reporters for 
registry=solr.collection.donald.test-query-1533026857986.shard1.leader, 
tag=62ef7f0c
08:47:46.416 [Thread-20] INFO 
org.apache.solr.metrics.reporters.SolrJmxReporter 112 doInit - JMX 
monitoring for 
'solr.core.donald.test-query-1533026857986.shard1.replica_n1' (registry 
'solr.core.donald.test-query-1533026857986.shard1.replica_n1') enabled 
at server: com.sun.jmx.mbeanserver.JmxMBeanServer@2698dc7
08:47:46.417 [Thread-20] WARN  org.apache.solr.cloud.ZkController 2689 
lambda$fireEventListeners$6 - listener throws error 
org.apache.solr.common.SolrException: Unable to reload core 
[donald.test-query-1533026857986_shard1_replica_n1]
      at 
org.apache.solr.core.CoreContainer.reload(CoreContainer.java:1411) 
~[solr-core-7.4.0.jar:7.4.0 9060ac689c270b02143f375de0348b7f626adebc - 
jpountz - 2018-06-18 16:55:13]
      at 
org.apache.solr.core.SolrCore.lambda$getConfListener$20(SolrCore.java:3029) 
~[solr-core-7.4.0.jar:7.4.0 9060ac689c270b02143f375de0348b7f626adebc - 
jpountz - 2018-06-18 16:55:13]
      at 
org.apache.solr.cloud.ZkController.lambda$fireEventListeners$6(ZkController.java:2687) 
~[solr-core-7.4.0.jar:7.4.0 9060ac689c270b02143f375de0348b7f626adebc - 
jpountz - 2018-06-18 16:55:13]
      at java.lang.Thread.run(Thread.java:748) [?:1.8.0_181]
Caused by: java.lang.NullPointerException
      at 
org.apache.solr.metrics.SolrMetricManager.loadShardReporters(SolrMetricManager.java:1146) 
~[solr-core-7.4.0.jar:7.4.0 9060ac689c270b02143f375de0348b7f626adebc - 
jpountz - 2018-06-18 16:55:13]
      at 
org.apache.solr.metrics.SolrCoreMetricManager.loadReporters(SolrCoreMetricManager.java:92) 
~[solr-core-7.4.0.jar:7.4.0 9060ac689c270b02143f375de0348b7f626adebc - 
jpountz - 2018-06-18 16:55:13]
      at org.apache.solr.core.SolrCore.<init>(SolrCore.java:909) 
~[solr-core-7.4.0.jar:7.4.0 9060ac689c270b02143f375de0348b7f626adebc - 
jpountz - 2018-06-18 16:55:13]
      at org.apache.solr.core.SolrCore.reload(SolrCore.java:663) 
~[solr-core-7.4.0.jar:7.4.0 9060ac689c270b02143f375de0348b7f626adebc - 
jpountz - 2018-06-18 16:55:13]
      at 
org.apache.solr.core.CoreContainer.reload(CoreContainer.java:1390) 
~[solr-core-7.4.0.jar:7.4.0 9060ac689c270b02143f375de0348b7f626adebc - 
jpountz - 2018-06-18 16:55:13]
      ... 3 more

regards,
Hendrik