Add null check for ParentJoinFieldMapper in ChildrenAggregationBuilder.joinFieldResolveConfig

[ebadyano]

A user received a NPE. It was reproduced on 6.3.1 with the following stack trace:

2019-06-06T13:26:49,963][DEBUG][o.e.a.s.TransportSearchAction] [hamilton] [mi_indice][2], node[ABwM3KQJQdWuKfnzwJ8pxw], [P], s[STARTED], a[id=cRQiXG2DTmijJ2IMjtYq5g]: Failed to execute [SearchRequest{searchType=QUERY_THEN_FETCH, indices=[mi_indice], indicesOptions=IndicesOptions[id=38, ignore_unavailable=false, allow_no_indices=true, expand_wildcards_open=true, expand_wildcards_closed=false, allow_aliases_to_multiple_indices=true, forbid_closed_indices=true, ignore_aliases=false], types=[], routing='null', preference='null', requestCache=null, scroll=null, maxConcurrentShardRequests=15, batchedReduceSize=512, preFilterShardSize=128, allowPartialSearchResults=true, source={"query":{"bool":{"must":[{"bool":{"must":[{"bool":{"should":[{"range":{"posting_date":{"from":"1900-01-01T00:00:00.000Z","to":"2019-05-30T18:25:49.967Z","include_lower":true,"include_upper":true,"boost":1.0}}}],"adjust_pure_negative":true,"boost":1.0}},{"term":{"externaljob_to_child_fields.name":{"value":"externaljob","boost":1.0}}}],"adjust_pure_negative":true,"boost":1.0}}],"adjust_pure_negative":true,"boost":1.0}},"aggregations":{"POSTING_DATES":{"date_range":{"field":"posting_date","ranges":[{"key":"ORA_LT07","from":"2019-05-23T18:25:50.006Z","to":"2019-05-30T18:25:50.006Z"},{"key":"ORA_LT30","from":"2019-04-30T18:25:50.006Z","to":"2019-05-30T18:25:50.006Z"},{"key":"ORA_GT30","from":"1900-01-01T00:00:00.000Z","to":"2019-04-30T18:25:50.006Z"}],"keyed":false}},"LOCATIONS":{"children":{"type":"externaljob_locs"}}}}}] lastShard [true]
org.elasticsearch.transport.RemoteTransportException: [washington][127.0.0.1:9302][indices:data/read/search[phase/query]]
Caused by: java.lang.NullPointerException
	at org.elasticsearch.join.aggregations.ChildrenAggregationBuilder.joinFieldResolveConfig(ChildrenAggregationBuilder.java:122) ~[?:?]
	at org.elasticsearch.join.aggregations.ChildrenAggregationBuilder.resolveConfig(ChildrenAggregationBuilder.java:113) ~[?:?]
	at org.elasticsearch.search.aggregations.support.ValuesSourceAggregationBuilder.doBuild(ValuesSourceAggregationBuilder.java:311) ~[elasticsearch-6.3.1.jar:6.3.1]
	at org.elasticsearch.search.aggregations.support.ValuesSourceAggregationBuilder.doBuild(ValuesSourceAggregationBuilder.java:38) ~[elasticsearch-6.3.1.jar:6.3.1]
	at org.elasticsearch.search.aggregations.AbstractAggregationBuilder.build(AbstractAggregationBuilder.java:139) ~[elasticsearch-6.3.1.jar:6.3.1]
	at org.elasticsearch.search.aggregations.AggregatorFactories$Builder.build(AggregatorFactories.java:329) ~[elasticsearch-6.3.1.jar:6.3.1]
	at org.elasticsearch.search.SearchService.parseSource(SearchService.java:766) ~[elasticsearch-6.3.1.jar:6.3.1]
	at org.elasticsearch.search.SearchService.createContext(SearchService.java:575) ~[elasticsearch-6.3.1.jar:6.3.1]

in ChildrenAggregationBuilder.joinFieldResolveConfig

private void joinFieldResolveConfig(SearchContext context, ValuesSourceConfig<WithOrdinals> config) {
        ParentJoinFieldMapper parentJoinFieldMapper = ParentJoinFieldMapper.getMapper(context.mapperService()); 
        ParentIdFieldMapper parentIdFieldMapper = parentJoinFieldMapper.getParentIdFieldMapper(childType, false);
        if (parentIdFieldMapper != null) {
...
        } else {
            config.unmapped(true);
        }

ParentJoinFieldMapper.getMapper returns null when there is no parent-join field in the mapping. We already check to see if parentIdFieldMapper is null and use an unmapped. Should probably be doing the same for parentJoinFieldMapper as well.

[elasticmachine]

Pinging @elastic/es-analytics-geo

[0xamogh]

Hi can I be assigned this issue?

[jasontedor]

We can not assign issues to non-members (GitHub restriction), though you are free to submit a pull request for this.

[0xamogh]

Okay! I am working on it

[shubh49]

@amogh-jrules Are you working on this? If not, i am willing to take this up.

[0xamogh]

@amogh-jrules Are you working on this? If not, i am willing to take this up.

I am working on it, as i said. about to submit a pull request

[hassan-alam]

@amogh-jrules Are you still working on this? Your PR hasn't been changed in a while, so if you're not on this anymore, I can take this up.

[MachSphere]

What is happening with this PR? It has stalled for about 2 months, is it because the commits were not squashed into 1 commit as stated in the CONTRIBUTING.md?

[Suchita94]

Since this bug has been open for a while, created pull request with code changes and test cases

[ebadyano]

@SD1998 It looks like it might still exist, but the method has been renamed to protected ValuesSourceConfig resolveConfig. Please feel free to submit a pull request for this.

[parthpunkster]

I see that this issue is still open, can I work on this?

[parthpunkster]

Can someone assign this to me?

[jimczi]

I see that this issue is still open, can I work on this?

Sure, please do. We don't assign issue so you can open a pr that links this issue and we'll review it.

[parthpunkster]

I see that this issue is still open, can I work on this?

Sure, please do. We don't assign issue so you can open a pr that links this issue and we'll review it.

I have worked on this one wanted some help around verifying the change and on the process of raising a pull request.

[parthpunkster]

@jimczi I have attached the pull request. Can you please review it.