Null completion field should not throw IAE (#33268)

Ignore null value on the completion field

Closes #33200

server/src/main/java/org/elasticsearch/index/mapper/CompletionFieldMapper.java

@@ -435,8 +435,10 @@ public class CompletionFieldMapper extends FieldMapper implements ArrayValueMapp
         XContentParser parser = context.parser();
         Token token = parser.currentToken();
         Map<String, CompletionInputMetaData> inputMap = new HashMap<>(1);
+
+        // ignore null values
         if (token == Token.VALUE_NULL) {
-            throw new MapperParsingException("completion field [" + fieldType().name() + "] does not support null values");
+            return null;
         } else if (token == Token.START_ARRAY) {
             while ((token = parser.nextToken()) != Token.END_ARRAY) {
                 parse(context, token, parser, inputMap);

server/src/test/java/org/elasticsearch/index/mapper/CompletionFieldMapperTests.java

@@ -448,6 +448,17 @@ public class CompletionFieldMapperTests extends ESSingleNodeTestCase {
         assertNotNull(doc.docs().get(0).getField("_ignored"));
         IndexableField ignoredFields = doc.docs().get(0).getField("_ignored");
         assertThat(ignoredFields.stringValue(), equalTo("completion"));
+
+        // null inputs are ignored
+        ParsedDocument nullDoc = defaultMapper.parse(SourceToParse.source("test", "type1", "1", BytesReference
+                .bytes(XContentFactory.jsonBuilder()
+                    .startObject()
+                    .nullField("completion")
+                    .endObject()),
+            XContentType.JSON));
+        assertThat(nullDoc.docs().size(), equalTo(1));
+        assertNull(nullDoc.docs().get(0).get("completion"));
+        assertNull(nullDoc.docs().get(0).getField("_ignored"));
     }
 
     public void testPrefixQueryType() throws Exception {

server/src/test/java/org/elasticsearch/search/suggest/CompletionSuggestSearchIT.java

@@ -31,12 +31,10 @@ import org.elasticsearch.action.search.SearchPhaseExecutionException;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.action.support.master.AcknowledgedResponse;
 import org.elasticsearch.common.FieldMemoryStats;
-import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.Fuzziness;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
-import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.mapper.MapperParsingException;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.search.aggregations.AggregationBuilders;
@@ -1111,35 +1109,6 @@ public class CompletionSuggestSearchIT extends ESIntegTestCase {
         }
     }
 
-    // see issue #6399
-    public void testIndexingUnrelatedNullValue() throws Exception {
-        String mapping = Strings
-                .toString(jsonBuilder()
-                        .startObject()
-                        .startObject(TYPE)
-                        .startObject("properties")
-                        .startObject(FIELD)
-                        .field("type", "completion")
-                        .endObject()
-                        .endObject()
-                        .endObject()
-                        .endObject());
-
-        assertAcked(client().admin().indices().prepareCreate(INDEX).addMapping(TYPE, mapping, XContentType.JSON).get());
-        ensureGreen();
-
-        client().prepareIndex(INDEX, TYPE, "1").setSource(FIELD, "strings make me happy", FIELD + "_1", "nulls make me sad")
-                .setRefreshPolicy(IMMEDIATE).get();
-
-        try {
-            client().prepareIndex(INDEX, TYPE, "2").setSource(FIELD, null, FIELD + "_1", "nulls make me sad").get();
-            fail("Expected MapperParsingException for null value");
-        } catch (MapperParsingException e) {
-            // make sure that the exception has the name of the field causing the error
-            assertTrue(e.getDetailedMessage().contains(FIELD));
-        }
-    }
-
     public void testMultiDocSuggestions() throws Exception {
         final CompletionMappingBuilder mapping = new CompletionMappingBuilder();
         createIndexAndMapping(mapping);