Cannot 'reset' index settings to default

[nixfloyd]

Elasticsearch version:5.4.0

Plugins installed: []

JVM version (java -version):

# java -version
java version "1.8.0_102"
Java(TM) SE Runtime Environment (build 1.8.0_102-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.102-b14, mixed mode)

OS version

# cat /etc/centos-release
CentOS release 6.9 (Final)
# uname -a
Linux host1.domain.com 2.6.32-642.15.1.el6.x86_64 #1 SMP Fri Feb 24 14:31:22 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

Description of the problem including expected versus actual behavior:
According to #22870, it should be possible to 'revert/reset' an index' settings to default by using a null value. Unfortunately, this doesn't work on 5.4.0 (while it was working as expected on 5.0.2)

Steps to reproduce:
The index name/size/content doesn't really matter. On (at least) 5.0.2, this api call works as expected. On 5.4.0, it doesn't anymore, returning a null pointer exception.

On elasticsearch 5.0.2:

# curl -XPUT localhost:9200/indexname/_settings -d '{ "index.routing.allocation.require._ip": "10.0.0.11,10.0.0.12" }'
{"acknowledged":true}
# curl -XPUT localhost:9200/indexname/_settings -d '{ "index.routing.allocation.require._ip": null }'
{"acknowledged":true}

On elasticsearch 5.4.0:

# curl -XPUT localhost:9200/indexname/_settings -d '{ "index.routing.allocation.require._ip": "10.0.0.11,10.0.0.12" }'
{"acknowledged":true}
# curl -XPUT localhost:9200/indexname/_settings -d '{ "index.routing.allocation.require._ip": null }'
{
 "error" : {
   "root_cause" : [
     {
       "type" : "null_pointer_exception",
       "reason" : null
     }
   ],
   "type" : "null_pointer_exception",
   "reason" : null
 },
 "status" : 500
}

Provide logs (if relevant):

[2017-05-16T11:38:10,618][WARN ][r.suppressed             ] path: /indexname/_settings, params: {index=indexname}
java.lang.NullPointerException: null
	at org.elasticsearch.cluster.node.DiscoveryNodeFilters.lambda$static$0(DiscoveryNodeFilters.java:53) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.common.settings.Setting$3.get(Setting.java:908) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.common.settings.Setting$3.get(Setting.java:885) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.common.settings.AbstractScopedSettings.validate(AbstractScopedSettings.java:295) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.common.settings.AbstractScopedSettings.validate(AbstractScopedSettings.java:256) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.cluster.metadata.MetaDataUpdateSettingsService.updateSettings(MetaDataUpdateSettingsService.java:166) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.action.admin.indices.settings.put.TransportUpdateSettingsAction.masterOperation(TransportUpdateSettingsAction.java:89) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.action.admin.indices.settings.put.TransportUpdateSettingsAction.masterOperation(TransportUpdateSettingsAction.java:44) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.action.support.master.TransportMasterNodeAction.masterOperation(TransportMasterNodeAction.java:87) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.action.support.master.TransportMasterNodeAction$AsyncSingleAction$2.doRun(TransportMasterNodeAction.java:166) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:37) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.common.util.concurrent.EsExecutors$1.execute(EsExecutors.java:110) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.action.support.master.TransportMasterNodeAction$AsyncSingleAction.doStart(TransportMasterNodeAction.java:163) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.action.support.master.TransportMasterNodeAction$AsyncSingleAction.start(TransportMasterNodeAction.java:126) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.action.support.master.TransportMasterNodeAction.doExecute(TransportMasterNodeAction.java:104) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.action.support.master.TransportMasterNodeAction.doExecute(TransportMasterNodeAction.java:54) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.action.support.TransportAction$RequestFilterChain.proceed(TransportAction.java:170) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.action.support.TransportAction.execute(TransportAction.java:142) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.action.support.TransportAction.execute(TransportAction.java:84) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.client.node.NodeClient.executeLocally(NodeClient.java:83) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.client.node.NodeClient.doExecute(NodeClient.java:72) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.client.support.AbstractClient.execute(AbstractClient.java:408) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.client.support.AbstractClient$IndicesAdmin.execute(AbstractClient.java:1256) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.client.support.AbstractClient$IndicesAdmin.updateSettings(AbstractClient.java:1637) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.rest.action.admin.indices.RestUpdateSettingsAction.lambda$prepareRequest$0(RestUpdateSettingsAction.java:76) ~[elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.rest.BaseRestHandler.handleRequest(BaseRestHandler.java:80) [elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.rest.RestController.dispatchRequest(RestController.java:260) [elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.rest.RestController.dispatchRequest(RestController.java:199) [elasticsearch-5.4.0.jar:5.4.0]
	at org.elasticsearch.http.netty4.Netty4HttpServerTransport.dispatchRequest(Netty4HttpServerTransport.java:504) [transport-netty4-5.4.0.jar:5.4.0]
	at org.elasticsearch.http.netty4.Netty4HttpRequestHandler.channelRead0(Netty4HttpRequestHandler.java:72) [transport-netty4-5.4.0.jar:5.4.0]
	at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at org.elasticsearch.http.netty4.pipelining.HttpPipeliningHandler.channelRead(HttpPipeliningHandler.java:63) [transport-netty4-5.4.0.jar:5.4.0]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at org.elasticsearch.http.netty4.cors.Netty4CorsHandler.channelRead(Netty4CorsHandler.java:76) [transport-netty4-5.4.0.jar:5.4.0]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102) [netty-codec-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.handler.codec.MessageToMessageCodec.channelRead(MessageToMessageCodec.java:111) [netty-codec-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102) [netty-codec-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102) [netty-codec-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:293) [netty-codec-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:267) [netty-codec-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.ChannelInboundHandlerAdapter.channelRead(ChannelInboundHandlerAdapter.java:86) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1334) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:926) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:134) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:624) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.nio.NioEventLoop.processSelectedKeysPlain(NioEventLoop.java:524) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:478) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:438) [netty-transport-4.1.9.Final.jar:4.1.9.Final]
	at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:858) [netty-common-4.1.9.Final.jar:4.1.9.Final]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_102]

[danielmitterdorfer]

Thanks for the report @nixfloyd. This regression has been introduced in Elasticsearch 5.3.0 which I could reproduce locally.

[danielmitterdorfer]

This problem is still present on master. As we require a content-type header in 6.0, the full reproduction is:

curl -XPUT http://localhost:9200/test_index
curl -H "Content-Type: application/json" -XPUT localhost:9200/test_index/_settings -d '{ "index.routing.allocation.require._ip": "10.0.0.11,10.0.0.12" }'
curl -H "Content-Type: application/json" -XPUT localhost:9200/test_index/_settings -d '{ "index.routing.allocation.require._ip": null }'

[danielmitterdorfer]

The root cause seems to be that the IP validator that has been introduced in #22591 is not aware of null values. @abeyad can you please have a look?

[s1monw]

@abeyad I opened a PR for this here #24713