Allow replacementOffset and Length overriding

pkg/analysis_server/lib/src/domain_completion.dart

 // Copyright (c) 2014, 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:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/constants.dart';
@@ skipping 103 matching lines @@
 
     //
     // Add the fixes produced by plugins to the server-generated fixes.
     //
     if (pluginFutures != null) {
       List<plugin.Response> responses = await waitForResponses(pluginFutures,
           requestParameters: requestParams);
       for (plugin.Response response in responses) {
         plugin.CompletionGetSuggestionsResult result =
             new plugin.CompletionGetSuggestionsResult.fromResponse(response);
-        suggestions.addAll(result.results);
+        if (result.results != null && result.results.isNotEmpty) {
+          if (suggestions.isEmpty) {
+            request.replacementOffset = result.replacementOffset;
+            request.replacementLength = result.replacementLength;
+          } else if (request.replacementOffset != result.replacementOffset &&
+              request.replacementLength != result.replacementLength) {
+            server.instrumentationService
+                .logError('Plugin completion-results dropped due to conflicting'
+                    ' replacement offset/length: ${result.toJson()}');
+            continue;
+          }
+          suggestions.addAll(result.results);
+        }
       }
     }
     //
     // Return the result.
     //
     return new CompletionResult(
         request.replacementOffset, request.replacementLength, suggestions);
   }
 
   @override
@@ skipping 153 matching lines @@
   final int replacementOffset;
 
   /**
    * The suggested completions.
    */
   final List<CompletionSuggestion> suggestions;
 
   CompletionResult(
       this.replacementOffset, this.replacementLength, this.suggestions);
 }