Fixed issue where parent & child queries can fail if a segment doesn'…

…t have documents with the targeted type or associated parent type

Closes #2537

src/main/java/org/elasticsearch/index/query/HasChildQueryBuilder.java

@@ -66,8 +66,8 @@ public HasChildQueryBuilder boost(float boost) {
     /**
      * Defines how the scores from the matching child documents are mapped into the parent document.
      */
-    public HasChildQueryBuilder scoreType(String executionType) {
-        this.scoreType = executionType;
+    public HasChildQueryBuilder scoreType(String scoreType) {
+        this.scoreType = scoreType;
         return this;
     }
 

src/main/java/org/elasticsearch/index/search/child/ChildCollector.java

@@ -66,11 +66,14 @@ public Map<Object, FixedBitSet> parentDocs() {
 
     @Override
     public void setScorer(Scorer scorer) throws IOException {
-
     }
 
     @Override
     public void collect(int doc) throws IOException {
+        if (typeCache == null) {
+            return;
+        }
+
         HashedBytesArray parentId = typeCache.parentIdByDoc(doc);
         if (parentId == null) {
             return;

src/main/java/org/elasticsearch/index/search/child/ChildrenQuery.java

@@ -324,6 +324,10 @@ static class ChildUidCollector extends NoopCollector {
 
         @Override
         public void collect(int doc) throws IOException {
+            if (typeCache == null) {
+                return;
+            }
+
             HashedBytesArray parentUid = typeCache.parentIdByDoc(doc);
             float previousScore = uidToScore.get(parentUid);
             float currentScore = scorer.score();
@@ -367,6 +371,10 @@ static class AvgChildUidCollector extends ChildUidCollector {
 
         @Override
         public void collect(int doc) throws IOException {
+            if (typeCache == null) {
+                return;
+            }
+
             HashedBytesArray parentUid = typeCache.parentIdByDoc(doc);
             float previousScore = uidToScore.get(parentUid);
             float currentScore = scorer.score();

src/main/java/org/elasticsearch/index/search/child/HasChildFilter.java

@@ -192,7 +192,11 @@ static class UidCollector extends NoopCollector {
 
             @Override
             public void collect(int doc) throws IOException {
-                collectedUids.add(typeCache.parentIdByDoc(doc));
+                // It can happen that for particular segment no document exist for an specific type. This prevents NPE
+                if (typeCache != null) {
+                    collectedUids.add(typeCache.parentIdByDoc(doc));
+                }
+
             }
 
             @Override

src/main/java/org/elasticsearch/index/search/child/HasParentFilter.java

@@ -158,7 +158,10 @@ static class ParentUidsCollector extends NoopCollector {
             }
 
             public void collect(int doc) throws IOException {
-                collectedUids.add(typeCache.idByDoc(doc));
+                // It can happen that for particular segment no document exist for an specific type. This prevents NPE
+                if (typeCache != null) {
+                    collectedUids.add(typeCache.idByDoc(doc));
+                }
             }
 
             public void setNextReader(IndexReader reader, int docBase) throws IOException {
@@ -193,7 +196,12 @@ public DocIdSet getDocIdSet(IndexReader reader) throws IOException {
                 throw new ElasticSearchIllegalStateException("has_parent filter hasn't executed properly");
             }
 
-            return new ChildrenDocSet(reader, parentDocs, context, parentType);
+            IdReaderTypeCache currentTypeCache = context.idCache().reader(reader).type(parentType);
+            if (currentTypeCache == null) {
+                return null;
+            } else {
+                return new ChildrenDocSet(reader, currentTypeCache, parentDocs, context, parentType);
+            }
         }
 
         public void clear() {
@@ -207,10 +215,10 @@ static class ChildrenDocSet extends GetDocSet {
             final Tuple<IndexReader, IdReaderTypeCache>[] readersToTypeCache;
             final Map<Object, FixedBitSet> parentDocs;
 
-            ChildrenDocSet(IndexReader currentReader, Map<Object, FixedBitSet> parentDocs,
-                           SearchContext context, String parentType) {
+            ChildrenDocSet(IndexReader currentReader, IdReaderTypeCache currentTypeCache,
+                           Map<Object, FixedBitSet> parentDocs, SearchContext context, String parentType) {
                 super(currentReader.maxDoc());
-                this.currentTypeCache = context.idCache().reader(currentReader).type(parentType);
+                this.currentTypeCache = currentTypeCache;
                 this.currentReader = currentReader;
                 this.parentDocs = parentDocs;
                 this.readersToTypeCache = new Tuple[context.searcher().subReaders().length];

src/main/java/org/elasticsearch/index/search/child/ParentQuery.java

@@ -158,6 +158,10 @@ static class ParentUidCollector extends NoopCollector {
 
         @Override
         public void collect(int doc) throws IOException {
+            if (typeCache == null) {
+                return;
+            }
+
             HashedBytesArray parentUid = typeCache.idByDoc(doc);
             uidToScore.put(parentUid, scorer.score());
         }

src/test/java/org/elasticsearch/test/integration/search/child/SimpleChildQuerySearchTests.java

@@ -1077,4 +1077,65 @@ public void testScoreForParentChildQueries() throws Exception {
         assertThat(response.hits().hits()[6].score(), equalTo(5f));
     }
 
+    @Test
+    // https://github.com/elasticsearch/elasticsearch/issues/2536
+    public void testParentChildQueriesCanHandleNoRelevantTypesInIndex() throws Exception {
+        client.admin().indices().prepareDelete().execute().actionGet();
+
+        client.admin().indices().prepareCreate("test")
+                .addMapping("parent", jsonBuilder()
+                        .startObject()
+                        .startObject("parent")
+                        .endObject()
+                        .endObject()
+                ).addMapping("child", jsonBuilder()
+                .startObject()
+                .startObject("child")
+                .startObject("_parent")
+                .field("type", "parent")
+                .endObject()
+                .endObject()
+                .endObject()
+        ).setSettings(
+                ImmutableSettings.settingsBuilder()
+                        .put("index.number_of_shards", 1)
+                        .put("index.number_of_replicas", 0)
+        ).execute().actionGet();
+        client.admin().cluster().prepareHealth().setWaitForGreenStatus().execute().actionGet();
+
+        SearchResponse response = client.prepareSearch("test")
+                .setQuery(QueryBuilders.hasChildQuery("child", matchQuery("text", "value")))
+                .execute().actionGet();
+        assertThat(response.failedShards(), equalTo(0));
+        assertThat(response.hits().totalHits(), equalTo(0l));
+
+        client.prepareIndex("test", "child1").setSource(jsonBuilder().startObject().field("text", "value").endObject())
+                .setRefresh(true)
+                .execute().actionGet();
+
+        client.prepareSearch("test")
+                .setQuery(QueryBuilders.hasChildQuery("child", matchQuery("text", "value")).executionType(getExecutionMethod()))
+                .execute().actionGet();
+        assertThat(response.failedShards(), equalTo(0));
+        assertThat(response.hits().totalHits(), equalTo(0l));
+
+        client.prepareSearch("test")
+                .setQuery(QueryBuilders.hasChildQuery("child", matchQuery("text", "value")).scoreType("max"))
+                .execute().actionGet();
+        assertThat(response.failedShards(), equalTo(0));
+        assertThat(response.hits().totalHits(), equalTo(0l));
+
+        client.prepareSearch("test")
+                .setQuery(QueryBuilders.hasParentQuery("child", matchQuery("text", "value")).executionType(getExecutionMethod()))
+                .execute().actionGet();
+        assertThat(response.failedShards(), equalTo(0));
+        assertThat(response.hits().totalHits(), equalTo(0l));
+
+        client.prepareSearch("test")
+                .setQuery(QueryBuilders.hasParentQuery("child", matchQuery("text", "value")).scoreType("score"))
+                .execute().actionGet();
+        assertThat(response.failedShards(), equalTo(0));
+        assertThat(response.hits().totalHits(), equalTo(0l));
+    }
+
 }