Restrict murmur3 field type to sane options

docs/reference/migration/migrate_2_0.asciidoc

@@ -302,6 +302,10 @@ the user-friendly representation of boolean fields: `false`/`true`:
 ]
 ---------------
 
+=== Murmur3 Fields
+Fields of type `murmur3` can no longer change `doc_values` or `index` setting.
+They are always stored with doc values, and not indexed.
+
 === Codecs
 
 It is no longer possible to specify per-field postings and doc values formats

src/main/java/org/elasticsearch/index/mapper/core/Murmur3FieldMapper.java

@@ -22,6 +22,7 @@
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.FieldType;
 import org.apache.lucene.util.BytesRef;
+import org.elasticsearch.Version;
 import org.elasticsearch.common.Explicit;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.hash.MurmurHash3;
@@ -35,6 +36,7 @@
 import java.util.List;
 import java.util.Map;
 
+import static org.elasticsearch.common.xcontent.support.XContentMapValues.nodeBooleanValue;
 import static org.elasticsearch.index.mapper.MapperBuilders.murmur3Field;
 import static org.elasticsearch.index.mapper.core.TypeParsers.parseNumberField;
 
@@ -69,6 +71,17 @@ public static class TypeParser implements Mapper.TypeParser {
         @SuppressWarnings("unchecked")
         public Mapper.Builder parse(String name, Map<String, Object> node, ParserContext parserContext) throws MapperParsingException {
             Builder builder = murmur3Field(name);
+
+            // tweaking these settings is no longer allowed, the entire purpose of murmur3 fields is to store a hash
+            if (parserContext.indexVersionCreated().onOrAfter(Version.V_2_0_0)) {
+                if (node.get("doc_values") != null) {
+                    throw new MapperParsingException("Setting [doc_values] cannot be modified for field [" + name + "]");
+                }
+                if (node.get("index") != null) {
+                    throw new MapperParsingException("Setting [index] cannot be modified for field [" + name + "]");
+                }
+            }
+
             parseNumberField(builder, name, node, parserContext);
             // Because this mapper extends LongFieldMapper the null_value field will be added to the JSON when transferring cluster state
             // between nodes so we have to remove the entry here so that the validation doesn't fail

src/test/java/org/elasticsearch/index/mapper/core/Murmur3FieldMapperTests.java

@@ -0,0 +1,132 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.index.mapper.core;
+
+import org.apache.lucene.index.IndexOptions;
+import org.elasticsearch.Version;
+import org.elasticsearch.cluster.metadata.IndexMetaData;
+import org.elasticsearch.common.settings.ImmutableSettings;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.XContentFactory;
+import org.elasticsearch.index.IndexService;
+import org.elasticsearch.index.mapper.DocumentMapper;
+import org.elasticsearch.index.mapper.DocumentMapperParser;
+import org.elasticsearch.index.mapper.Mapper;
+import org.elasticsearch.index.mapper.MapperParsingException;
+import org.elasticsearch.test.ElasticsearchSingleNodeTest;
+import org.junit.Before;
+
+public class Murmur3FieldMapperTests extends ElasticsearchSingleNodeTest {
+
+    IndexService indexService;
+    DocumentMapperParser parser;
+
+    @Before
+    public void before() {
+        indexService = createIndex("test");
+        parser = indexService.mapperService().documentMapperParser();
+    }
+
+    public void testDocValuesSettingNotAllowed() throws Exception {
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
+            .startObject("properties").startObject("field")
+                .field("type", "murmur3")
+                .field("doc_values", false)
+            .endObject().endObject().endObject().endObject().string();
+        try {
+            parser.parse(mapping);
+            fail("expected a mapper parsing exception");
+        } catch (MapperParsingException e) {
+            assertTrue(e.getMessage().contains("Setting [doc_values] cannot be modified"));
+        }
+
+        // even setting to the default is not allowed, the setting is invalid
+        mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
+            .startObject("properties").startObject("field")
+                .field("type", "murmur3")
+                .field("doc_values", true)
+            .endObject().endObject().endObject().endObject().string();
+        try {
+            parser.parse(mapping);
+            fail("expected a mapper parsing exception");
+        } catch (MapperParsingException e) {
+            assertTrue(e.getMessage().contains("Setting [doc_values] cannot be modified"));
+        }
+    }
+
+    public void testIndexSettingNotAllowed() throws Exception {
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
+            .startObject("properties").startObject("field")
+                .field("type", "murmur3")
+                .field("index", "not_analyzed")
+            .endObject().endObject().endObject().endObject().string();
+        try {
+            parser.parse(mapping);
+            fail("expected a mapper parsing exception");
+        } catch (MapperParsingException e) {
+            assertTrue(e.getMessage().contains("Setting [index] cannot be modified"));
+        }
+
+        // even setting to the default is not allowed, the setting is invalid
+        mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
+            .startObject("properties").startObject("field")
+                .field("type", "murmur3")
+                .field("index", "no")
+            .endObject().endObject().endObject().endObject().string();
+        try {
+            parser.parse(mapping);
+            fail("expected a mapper parsing exception");
+        } catch (MapperParsingException e) {
+            assertTrue(e.getMessage().contains("Setting [index] cannot be modified"));
+        }
+    }
+
+    public void testDocValuesSettingBackcompat() throws Exception {
+        Settings settings = ImmutableSettings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, Version.V_1_4_2.id).build();
+        indexService = createIndex("test_bwc", settings);
+        parser = indexService.mapperService().documentMapperParser();
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
+            .startObject("properties").startObject("field")
+                .field("type", "murmur3")
+                .field("doc_values", false)
+            .endObject().endObject().endObject().endObject().string();
+
+        DocumentMapper docMapper = parser.parse(mapping);
+        Murmur3FieldMapper mapper = (Murmur3FieldMapper)docMapper.mappers().getMapper("field");
+        assertFalse(mapper.hasDocValues());
+    }
+
+    public void testIndexSettingBackcompat() throws Exception {
+        Settings settings = ImmutableSettings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, Version.V_1_4_2.id).build();
+        indexService = createIndex("test_bwc", settings);
+        parser = indexService.mapperService().documentMapperParser();
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
+            .startObject("properties").startObject("field")
+            .field("type", "murmur3")
+            .field("index", "not_analyzed")
+            .endObject().endObject().endObject().endObject().string();
+
+        DocumentMapper docMapper = parser.parse(mapping);
+        Murmur3FieldMapper mapper = (Murmur3FieldMapper)docMapper.mappers().getMapper("field");
+        assertEquals(IndexOptions.DOCS, mapper.fieldType().indexOptions());
+    }
+
+    // TODO: add more tests
+}