Fix computation of errors to not run extra tasks

pkg/analyzer/lib/src/task/dart.dart

 // Copyright (c) 2015, 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.src.task.dart;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 2786 matching lines @@
     return new LibraryErrorsReadyTask(context, target);
   }
 }
 
 /**
  * A task that merges all of the errors for a single source into a single list
  * of errors.
  */
 class LibraryUnitErrorsTask extends SourceBasedAnalysisTask {
   /**
+   * The name of the [BUILD_DIRECTIVES_ERRORS] input.
+   */
+  static const String BUILD_DIRECTIVES_ERRORS_INPUT = 'BUILD_DIRECTIVES_ERRORS';
+
+  /**
+   * The name of the [BUILD_LIBRARY_ERRORS] input.
+   */
+  static const String BUILD_LIBRARY_ERRORS_INPUT = 'BUILD_LIBRARY_ERRORS';
+
+  /**
    * The name of the [HINTS] input.
    */
   static const String HINTS_INPUT = 'HINTS';
 
   /**
    * The name of the [INFER_STATIC_VARIABLE_TYPES_ERRORS] input.
    */
   static const String INFER_STATIC_VARIABLE_TYPES_ERRORS_INPUT =
       'INFER_STATIC_VARIABLE_TYPES_ERRORS';
 
@@ skipping 40 matching lines @@
 
   @override
   TaskDescriptor get descriptor => DESCRIPTOR;
 
   @override
   void internalPerform() {
     //
     // Prepare inputs.
     //
     List<List<AnalysisError>> errorLists = <List<AnalysisError>>[];
+    errorLists.add(getRequiredInput(BUILD_DIRECTIVES_ERRORS_INPUT));
+    errorLists.add(getRequiredInput(BUILD_LIBRARY_ERRORS_INPUT));
     errorLists.add(getRequiredInput(HINTS_INPUT));
     errorLists.add(getRequiredInput(INFER_STATIC_VARIABLE_TYPES_ERRORS_INPUT));
     errorLists.add(getRequiredInput(PARTIALLY_RESOLVE_REFERENCES_ERRORS_INPUT));
     errorLists.add(getRequiredInput(RESOLVE_FUNCTION_BODIES_ERRORS_INPUT));
     errorLists.add(getRequiredInput(RESOLVE_TYPE_NAMES_ERRORS_INPUT));
     errorLists.add(getRequiredInput(VARIABLE_REFERENCE_ERRORS_INPUT));
     errorLists.add(getRequiredInput(VERIFY_ERRORS_INPUT));
     //
     // Record outputs.
     //
     outputs[LIBRARY_UNIT_ERRORS] = AnalysisError.mergeLists(errorLists);
   }
 
   /**
    * Return a map from the names of the inputs of this kind of task to the task
    * input descriptors describing those inputs for a task with the
    * given [unit].
    */
   static Map<String, TaskInput> buildInputs(AnalysisTarget target) {
     LibrarySpecificUnit unit = target;
-    return <String, TaskInput>{
+    Map<String, TaskInput> inputs = <String, TaskInput>{
       HINTS_INPUT: HINTS.of(unit),
       INFER_STATIC_VARIABLE_TYPES_ERRORS_INPUT:
           INFER_STATIC_VARIABLE_TYPES_ERRORS.of(unit),
       PARTIALLY_RESOLVE_REFERENCES_ERRORS_INPUT:
           PARTIALLY_RESOLVE_REFERENCES_ERRORS.of(unit),
       RESOLVE_FUNCTION_BODIES_ERRORS_INPUT:
           RESOLVE_FUNCTION_BODIES_ERRORS.of(unit),
       RESOLVE_TYPE_NAMES_ERRORS_INPUT: RESOLVE_TYPE_NAMES_ERRORS.of(unit),
       VARIABLE_REFERENCE_ERRORS_INPUT: VARIABLE_REFERENCE_ERRORS.of(unit),
       VERIFY_ERRORS_INPUT: VERIFY_ERRORS.of(unit)
     };
+    Source source = unit.source;
+    if (unit.library == source) {
+      inputs[BUILD_DIRECTIVES_ERRORS_INPUT] =
+          BUILD_DIRECTIVES_ERRORS.of(source);
+      inputs[BUILD_LIBRARY_ERRORS_INPUT] = BUILD_LIBRARY_ERRORS.of(source);
+    } else {
+      inputs[BUILD_DIRECTIVES_ERRORS_INPUT] =
+          new ConstantTaskInput(AnalysisError.NO_ERRORS);
+      inputs[BUILD_LIBRARY_ERRORS_INPUT] =
+          new ConstantTaskInput(AnalysisError.NO_ERRORS);
+    }
+    return inputs;
   }
 
   /**
    * Create a [LibraryUnitErrorsTask] based on the given [target] in the given
    * [context].
    */
   static LibraryUnitErrorsTask createTask(
       AnalysisContext context, AnalysisTarget target) {
     return new LibraryUnitErrorsTask(context, target);
   }
@@ skipping 1190 matching lines @@
 
   @override
   bool moveNext() {
     if (_newSources.isEmpty) {
       return false;
     }
     currentTarget = _newSources.removeLast();
     return true;
   }
 }