Issue 26355. Don't overwrite full index with declarations-only one.

pkg/analysis_server/lib/src/services/index/index.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/generated/engine.dart' show AnalysisContext;
 import 'package:analyzer/src/generated/source.dart';
@@ skipping 252 matching lines @@
   Future<List<Location>> getUnresolvedMemberReferences(String name) async {
     return _mergeLocations((_PackageIndexRequester requester) {
       return requester.getUnresolvedMemberReferences(context, name);
     });
   }
 
   /**
    * Index declarations in the given partially resolved [unit].
    */
   void indexDeclarations(CompilationUnit unit) {
-    PackageIndexAssembler assembler = new PackageIndexAssembler();
-    assembler.indexDeclarations(unit);
-    _putUnitIndexBuilder(unit, assembler);
+    String key = _getUnitKeyForElement(unit.element);
+    if (!indexMap.containsKey(key)) {
+      PackageIndexAssembler assembler = new PackageIndexAssembler();
+      assembler.indexDeclarations(unit);
+      _putUnitIndexBuilder(key, assembler);
+    }
   }
 
   /**
    * Index the given fully resolved [unit].
    */
   void indexUnit(CompilationUnit unit) {
+    String key = _getUnitKeyForElement(unit.element);
     PackageIndexAssembler assembler = new PackageIndexAssembler();
     assembler.indexUnit(unit);
-    _putUnitIndexBuilder(unit, assembler);
+    _putUnitIndexBuilder(key, assembler);
   }
 
   /**
    * Remove index information about the unit.
    */
   void removeUnit(Source librarySource, Source unitSource) {
     String key = _getUnitKeyForSource(librarySource, unitSource);
     indexMap.remove(key);
   }
 
@@ skipping 13 matching lines @@
       List<Location> callback(_PackageIndexRequester requester)) async {
     List<Location> locations = <Location>[];
     for (PackageIndex index in indexMap.values) {
       _PackageIndexRequester requester = new _PackageIndexRequester(index);
       List<Location> indexLocations = callback(requester);
       locations.addAll(indexLocations);
     }
     return locations;
   }
 
-  void _putUnitIndexBuilder(
-      CompilationUnit unit, PackageIndexAssembler assembler) {
+  void _putUnitIndexBuilder(String key, PackageIndexAssembler assembler) {
     PackageIndexBuilder indexBuilder = assembler.assemble();
     // Put the index into the map.
     List<int> indexBytes = indexBuilder.toBuffer();
     PackageIndex index = new PackageIndex.fromBuffer(indexBytes);
-    String key = _getUnitKeyForElement(unit.element);
     indexMap[key] = index;
   }
 }
 
 /**
  * Helper for requesting information from a single [PackageIndex].
  */
 class _PackageIndexRequester {
   final PackageIndex index;
 
@@ skipping 239 matching lines @@
           unitUnitUri,
           unitIndex.usedNameKinds[i],
           unitIndex.usedNameOffsets[i],
           name.length,
           unitIndex.usedNameIsQualifiedFlags[i],
           false));
     }
     return locations;
   }
 }