SearchLookup to not require MapperService as a constructor argument (#64017)

SearchLookup currently takes the whole MapperService as an argument, and it passes it over to DocLookup and FieldsLookup. In practice, what they all need is only a way to lookup field types given a field name.

With this commit, SearchLookup requires a Function<String,MappedFieldType> to be created rather than the whole MapperService. This helps clarifying the dependency between MapperService and SearchLookup, especially as we introduce runtime fields defined in the search request: they can be exposed at QueryShardContext level, through its lookup methods, rather than at the MapperService level which QueryShardContext depends on.

Author: javanna

modules/lang-expression/src/main/java/org/elasticsearch/script/expression/ExpressionScriptEngine.java

@@ -458,7 +458,7 @@ private static DoubleValuesSource getDocValueSource(String variable, SearchLooku
         }
 
         String fieldname = parts[1].text;
-        MappedFieldType fieldType = lookup.doc().mapperService().fieldType(fieldname);
+        MappedFieldType fieldType = lookup.doc().fieldType(fieldname);
 
         if (fieldType == null) {
             throw new ParseException("Field [" + fieldname + "] does not exist in mappings", 5);

modules/lang-expression/src/test/java/org/elasticsearch/script/expression/ExpressionFieldScriptTests.java

@@ -22,7 +22,6 @@
 import org.elasticsearch.index.fielddata.IndexNumericFieldData;
 import org.elasticsearch.index.fielddata.LeafNumericFieldData;
 import org.elasticsearch.index.fielddata.SortedNumericDoubleValues;
-import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.NumberFieldMapper;
 import org.elasticsearch.script.FieldScript;
 import org.elasticsearch.script.ScriptException;
@@ -48,9 +47,6 @@ public void setUp() throws Exception {
         super.setUp();
 
         NumberFieldMapper.NumberFieldType fieldType = new NumberFieldMapper.NumberFieldType("field", NumberFieldMapper.NumberType.DOUBLE);
-        MapperService mapperService = mock(MapperService.class);
-        when(mapperService.fieldType("field")).thenReturn(fieldType);
-        when(mapperService.fieldType("alias")).thenReturn(fieldType);
 
         SortedNumericDoubleValues doubleValues = mock(SortedNumericDoubleValues.class);
         when(doubleValues.advanceExact(anyInt())).thenReturn(true);
@@ -64,7 +60,8 @@ public void setUp() throws Exception {
         when(fieldData.load(anyObject())).thenReturn(atomicFieldData);
 
         service = new ExpressionScriptEngine();
-        lookup = new SearchLookup(mapperService, (ignored, lookup) -> fieldData, null);
+        lookup = new SearchLookup(field -> field.equals("field") || field.equals("alias") ? fieldType : null,
+            (ignored, lookup) -> fieldData, null);
     }
 
     private FieldScript.LeafFactory compile(String expression) {

modules/lang-expression/src/test/java/org/elasticsearch/script/expression/ExpressionNumberSortScriptTests.java

@@ -25,7 +25,6 @@
 import org.elasticsearch.index.fielddata.LeafNumericFieldData;
 import org.elasticsearch.index.fielddata.IndexNumericFieldData;
 import org.elasticsearch.index.fielddata.SortedNumericDoubleValues;
-import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.NumberFieldMapper.NumberFieldType;
 import org.elasticsearch.index.mapper.NumberFieldMapper.NumberType;
 import org.elasticsearch.script.NumberSortScript;
@@ -47,9 +46,6 @@ public void setUp() throws Exception {
         super.setUp();
 
         NumberFieldType fieldType = new NumberFieldType("field", NumberType.DOUBLE);
-        MapperService mapperService = mock(MapperService.class);
-        when(mapperService.fieldType("field")).thenReturn(fieldType);
-        when(mapperService.fieldType("alias")).thenReturn(fieldType);
 
         SortedNumericDoubleValues doubleValues = mock(SortedNumericDoubleValues.class);
         when(doubleValues.advanceExact(anyInt())).thenReturn(true);
@@ -63,7 +59,8 @@ public void setUp() throws Exception {
         when(fieldData.load(anyObject())).thenReturn(atomicFieldData);
 
         service = new ExpressionScriptEngine();
-        lookup = new SearchLookup(mapperService, (ignored, lookup) -> fieldData, null);
+        lookup = new SearchLookup(field -> field.equals("field") || field.equals("alias") ? fieldType : null,
+            (ignored, lookup) -> fieldData, null);
     }
 
     private NumberSortScript.LeafFactory compile(String expression) {

modules/lang-expression/src/test/java/org/elasticsearch/script/expression/ExpressionTermsSetQueryTests.java

@@ -25,7 +25,6 @@
 import org.elasticsearch.index.fielddata.LeafNumericFieldData;
 import org.elasticsearch.index.fielddata.IndexNumericFieldData;
 import org.elasticsearch.index.fielddata.SortedNumericDoubleValues;
-import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.NumberFieldMapper.NumberFieldType;
 import org.elasticsearch.index.mapper.NumberFieldMapper.NumberType;
 import org.elasticsearch.script.ScriptException;
@@ -47,9 +46,6 @@ public void setUp() throws Exception {
         super.setUp();
 
         NumberFieldType fieldType = new NumberFieldType("field", NumberType.DOUBLE);
-        MapperService mapperService = mock(MapperService.class);
-        when(mapperService.fieldType("field")).thenReturn(fieldType);
-        when(mapperService.fieldType("alias")).thenReturn(fieldType);
 
         SortedNumericDoubleValues doubleValues = mock(SortedNumericDoubleValues.class);
         when(doubleValues.advanceExact(anyInt())).thenReturn(true);
@@ -63,7 +59,8 @@ public void setUp() throws Exception {
         when(fieldData.load(anyObject())).thenReturn(atomicFieldData);
 
         service = new ExpressionScriptEngine();
-        lookup = new SearchLookup(mapperService, (ignored, lookup) -> fieldData, null);
+        lookup = new SearchLookup(field -> field.equals("field") || field.equals("alias") ? fieldType : null,
+            (ignored, lookup) -> fieldData, null);
     }
 
     private TermsSetQueryScript.LeafFactory compile(String expression) {

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

@@ -81,6 +81,13 @@ public TypeFieldType(String type) {
             this.type = type;
         }
 
+        /**
+         * Returns the name of the current type
+         */
+        public String getType() {
+            return type;
+        }
+
         @Override
         public String typeName() {
             return CONTENT_TYPE;

server/src/main/java/org/elasticsearch/index/query/QueryShardContext.java

@@ -371,7 +371,7 @@ public Collection<String> queryTypes() {
     public SearchLookup lookup() {
         if (this.lookup == null) {
             this.lookup = new SearchLookup(
-                mapperService,
+                this::getFieldType,
                 (fieldType, searchLookup) -> indexFieldDataService.apply(fieldType, fullyQualifiedIndex.getName(), searchLookup),
                 types
             );
@@ -388,7 +388,7 @@ public SearchLookup newFetchLookup() {
          * Real customization coming soon, I promise!
          */
         return new SearchLookup(
-            mapperService,
+            this::getFieldType,
             (fieldType, searchLookup) -> indexFieldDataService.apply(fieldType, fullyQualifiedIndex.getName(), searchLookup),
             types
         );

server/src/main/java/org/elasticsearch/search/lookup/DocLookup.java

@@ -22,33 +22,33 @@
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.index.fielddata.IndexFieldData;
 import org.elasticsearch.index.mapper.MappedFieldType;
-import org.elasticsearch.index.mapper.MapperService;
 
 import java.util.function.Function;
 
-public class DocLookup {
+public final class DocLookup {
 
-    private final MapperService mapperService;
+    private final Function<String, MappedFieldType> fieldTypeLookup;
     private final Function<MappedFieldType, IndexFieldData<?>> fieldDataLookup;
     @Nullable
     private final String[] types;
 
-    DocLookup(MapperService mapperService, Function<MappedFieldType, IndexFieldData<?>> fieldDataLookup, @Nullable String[] types) {
-        this.mapperService = mapperService;
+    DocLookup(Function<String, MappedFieldType> fieldTypeLookup, Function<MappedFieldType, IndexFieldData<?>> fieldDataLookup,
+              @Nullable String[] types) {
+        this.fieldTypeLookup = fieldTypeLookup;
         this.fieldDataLookup = fieldDataLookup;
         this.types = types;
     }
 
-    public MapperService mapperService() {
-        return this.mapperService;
+    public MappedFieldType fieldType(String fieldName) {
+        return fieldTypeLookup.apply(fieldName);
     }
 
     public IndexFieldData<?> getForField(MappedFieldType fieldType) {
         return fieldDataLookup.apply(fieldType);
     }
 
     public LeafDocLookup getLeafDocLookup(LeafReaderContext context) {
-        return new LeafDocLookup(mapperService, fieldDataLookup, types, context);
+        return new LeafDocLookup(fieldTypeLookup, fieldDataLookup, types, context);
     }
 
     public String[] getTypes() {

server/src/main/java/org/elasticsearch/search/lookup/FieldLookup.java

@@ -44,7 +44,7 @@ public class FieldLookup {
         this.fieldType = fieldType;
     }
 
-    public MappedFieldType fieldType() {
+    MappedFieldType fieldType() {
         return fieldType;
     }
 

server/src/main/java/org/elasticsearch/search/lookup/FieldsLookup.java

@@ -20,21 +20,22 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.elasticsearch.common.Nullable;
-import org.elasticsearch.index.mapper.MapperService;
+import org.elasticsearch.index.mapper.MappedFieldType;
+
+import java.util.function.Function;
 
 public class FieldsLookup {
 
-    private final MapperService mapperService;
+    private final Function<String, MappedFieldType> fieldTypeLookup;
     @Nullable
     private final String[] types;
 
-    FieldsLookup(MapperService mapperService, @Nullable String[] types) {
-        this.mapperService = mapperService;
+    FieldsLookup(Function<String, MappedFieldType> fieldTypeLookup, @Nullable String[] types) {
+        this.fieldTypeLookup = fieldTypeLookup;
         this.types = types;
     }
 
     public LeafFieldsLookup getLeafFieldsLookup(LeafReaderContext context) {
-        return new LeafFieldsLookup(mapperService, types, context.reader());
+        return new LeafFieldsLookup(fieldTypeLookup, types, context.reader());
     }
-
 }

server/src/main/java/org/elasticsearch/search/lookup/LeafDocLookup.java

@@ -25,7 +25,6 @@
 import org.elasticsearch.index.fielddata.IndexFieldData;
 import org.elasticsearch.index.fielddata.ScriptDocValues;
 import org.elasticsearch.index.mapper.MappedFieldType;
-import org.elasticsearch.index.mapper.MapperService;
 
 import java.io.IOException;
 import java.security.AccessController;
@@ -45,8 +44,7 @@ public class LeafDocLookup implements Map<String, ScriptDocValues<?>> {
             "[types removal] Looking up doc types [_type] in scripts is deprecated.";
 
     private final Map<String, ScriptDocValues<?>> localCacheFieldData = new HashMap<>(4);
-
-    private final MapperService mapperService;
+    private final Function<String, MappedFieldType> fieldTypeLookup;
     private final Function<MappedFieldType, IndexFieldData<?>> fieldDataLookup;
 
     @Nullable
@@ -56,18 +54,14 @@ public class LeafDocLookup implements Map<String, ScriptDocValues<?>> {
 
     private int docId = -1;
 
-    LeafDocLookup(MapperService mapperService, Function<MappedFieldType, IndexFieldData<?>> fieldDataLookup, @Nullable String[] types,
-                  LeafReaderContext reader) {
-        this.mapperService = mapperService;
+    LeafDocLookup(Function<String, MappedFieldType> fieldTypeLookup, Function<MappedFieldType, IndexFieldData<?>> fieldDataLookup,
+                  @Nullable String[] types, LeafReaderContext reader) {
+        this.fieldTypeLookup = fieldTypeLookup;
         this.fieldDataLookup = fieldDataLookup;
         this.types = types;
         this.reader = reader;
     }
 
-    public MapperService mapperService() {
-        return this.mapperService;
-    }
-
     public void setDocument(int docId) {
         this.docId = docId;
     }
@@ -82,7 +76,7 @@ public ScriptDocValues<?> get(Object key) {
         String fieldName = key.toString();
         ScriptDocValues<?> scriptValues = localCacheFieldData.get(fieldName);
         if (scriptValues == null) {
-            final MappedFieldType fieldType = mapperService.fieldType(fieldName);
+            final MappedFieldType fieldType = fieldTypeLookup.apply(fieldName);
             if (fieldType == null) {
                 throw new IllegalArgumentException("No field found for [" + fieldName + "] in mapping with types " +
                         Arrays.toString(types));
@@ -110,13 +104,7 @@ public boolean containsKey(Object key) {
         // assume its a string...
         String fieldName = key.toString();
         ScriptDocValues<?> scriptValues = localCacheFieldData.get(fieldName);
-        if (scriptValues == null) {
-            MappedFieldType fieldType = mapperService.fieldType(fieldName);
-            if (fieldType == null) {
-                return false;
-            }
-        }
-        return true;
+        return scriptValues != null || fieldTypeLookup.apply(fieldName) != null;
     }
 
     @Override

server/src/main/java/org/elasticsearch/search/lookup/LeafFieldsLookup.java

@@ -22,25 +22,25 @@
 import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.index.fieldvisitor.SingleFieldsVisitor;
-import org.elasticsearch.index.mapper.DocumentMapper;
 import org.elasticsearch.index.mapper.MappedFieldType;
-import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.mapper.TypeFieldMapper;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.function.Function;
 
 import static java.util.Collections.singletonMap;
 
 public class LeafFieldsLookup implements Map {
 
-    private final MapperService mapperService;
+    private final Function<String, MappedFieldType> fieldTypeLookup;
 
     @Nullable
     private final String[] types;
@@ -51,8 +51,8 @@ public class LeafFieldsLookup implements Map {
 
     private final Map<String, FieldLookup> cachedFieldData = new HashMap<>();
 
-    LeafFieldsLookup(MapperService mapperService, @Nullable String[] types, LeafReader reader) {
-        this.mapperService = mapperService;
+    LeafFieldsLookup(Function<String, MappedFieldType> fieldTypeLookup, @Nullable String[] types, LeafReader reader) {
+        this.fieldTypeLookup = fieldTypeLookup;
         this.types = types;
         this.reader = reader;
     }
@@ -65,7 +65,6 @@ public void setDocument(int docId) {
         clearCache();
     }
 
-
     @Override
     public Object get(Object key) {
         return loadFieldData(key.toString());
@@ -134,32 +133,29 @@ public boolean containsValue(Object value) {
     private FieldLookup loadFieldData(String name) {
         FieldLookup data = cachedFieldData.get(name);
         if (data == null) {
-            MappedFieldType fieldType = mapperService.fieldType(name);
+            MappedFieldType fieldType = fieldTypeLookup.apply(name);
             if (fieldType == null) {
                 throw new IllegalArgumentException("No field found for [" + name + "] in mapping with types " + Arrays.toString(types));
             }
             data = new FieldLookup(fieldType);
             cachedFieldData.put(name, data);
         }
         if (data.fields() == null) {
+            MappedFieldType fieldType = data.fieldType();
             List<Object> values;
-            if (TypeFieldMapper.NAME.equals(data.fieldType().name())) {
+            if (TypeFieldMapper.NAME.equals(fieldType.name())) {
                 TypeFieldMapper.emitTypesDeprecationWarning();
-                values = new ArrayList<>(1);
-                final DocumentMapper mapper = mapperService.documentMapper();
-                if (mapper != null) {
-                    values.add(mapper.type());
-                }
+                values = Collections.singletonList(((TypeFieldMapper.TypeFieldType)fieldType).getType());
             } else {
-                values = new ArrayList<Object>(2);
-                SingleFieldsVisitor visitor = new SingleFieldsVisitor(data.fieldType(), values);
+                values = new ArrayList<>(2);
+                SingleFieldsVisitor visitor = new SingleFieldsVisitor(fieldType, values);
                 try {
                     reader.document(docId, visitor);
                 } catch (IOException e) {
                     throw new ElasticsearchParseException("failed to load field [{}]", e, name);
                 }
             }
-            data.fields(singletonMap(data.fieldType().name(), values));
+            data.fields(singletonMap(fieldType.name(), values));
         }
         return data;
     }