Reset analysis driver after incremental changes.

pkg/analyzer/test/src/context/context_test.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.
 
 library analyzer.test.src.context.context_test;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 325 matching lines @@
         CacheState.INVALID);
     expect(
         context.getCacheEntry(source).modificationTime, file.modificationStamp);
   }
 
   void test_applyChanges_empty() {
     context.applyChanges(new ChangeSet());
     expect(context.performAnalysisTask().changeNotices, isNull);
   }
 
+  void test_applyChanges_incremental_resetDriver() {
+    context.analysisOptions = new AnalysisOptionsImpl()..incremental = true;
+    Source source = addSource(
+        "/test.dart",
+        r'''
+main() {
+  print(42);
+}
+''');
+    _performPendingAnalysisTasks();
+    expect(context.getErrors(source).errors, hasLength(0));
+    // Update the source to have a parse error.
+    // This is an incremental change, but we always invalidate DART_ERRORS.
+    context.setContents(
+        source,
+        r'''
+main() {
+  print(42)
+}
+''');
+    AnalysisCache cache = context.analysisCache;
+    expect(cache.getValue(source, PARSE_ERRORS), hasLength(1));
+    expect(cache.getState(source, DART_ERRORS), CacheState.INVALID);
+    // Perform enough analysis to prepare inputs (is not actually tested) for
+    // the DART_ERRORS computing task, but don't compute it yet.
+    context.performAnalysisTask();
+    context.performAnalysisTask();
+    expect(cache.getState(source, DART_ERRORS), CacheState.INVALID);
+    // Update the source so that PARSE_ERRORS is empty.
+    context.setContents(
+        source,
+        r'''
+main() {
+  print(42);
+}
+''');
+    expect(cache.getValue(source, PARSE_ERRORS), hasLength(0));
+    // After full analysis DART_ERRORS should also be empty.
+    _performPendingAnalysisTasks();
+    expect(cache.getValue(source, DART_ERRORS), hasLength(0));
+    expect(context.getErrors(source).errors, hasLength(0));
+  }
+
   void test_applyChanges_overriddenSource() {
     String content = "library test;";
     Source source = addSource("/test.dart", content);
     context.setContents(source, content);
     context.computeErrors(source);
     while (!context.sourcesNeedingProcessing.isEmpty) {
       context.performAnalysisTask();
     }
     // Adding the source as a changedSource should have no effect since
     // it is already overridden in the content cache.
@@ skipping 4826 matching lines @@
    * Initialize the visitor.
    */
   _ElementGatherer();
 
   @override
   void visitElement(Element element) {
     elements[element] = element;
     super.visitElement(element);
   }
 }