Partially fix the cache invalidation problem during incremental resolution.

pkg/analyzer/lib/src/context/cache.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.context.cache;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/src/generated/engine.dart'
@@ skipping 234 matching lines @@
  */
 class CacheEntry {
   /**
    * The index of the flag indicating whether the source was explicitly added to
    * the context or whether the source was implicitly added because it was
    * referenced by another source.
    */
   static int _EXPLICITLY_ADDED_FLAG = 0;
 
   /**
+   * The next invalidation process identifier.
+   */
+  static int nextInvalidateId = 0;
+
+  /**
    * The target this entry is about.
    */
   final AnalysisTarget target;
 
   /**
    * The partition that is responsible for this entry.
    */
   CachePartition _partition;
 
   /**
@@ skipping 168 matching lines @@
     if (state == CacheState.ERROR) {
       throw new ArgumentError('use setErrorState() to set the state to ERROR');
     }
     if (state == CacheState.VALID) {
       throw new ArgumentError('use setValue() to set the state to VALID');
     }
     _validateStateChange(descriptor, state);
     if (state == CacheState.INVALID) {
       ResultData data = _resultMap[descriptor];
       if (data != null) {
-        _invalidate(descriptor, delta);
+        _invalidate(nextInvalidateId++, descriptor, delta, 0);
       }
     } else {
       ResultData data = getResultData(descriptor);
       data.state = state;
       if (state != CacheState.IN_PROCESS) {
         //
         // If the state is in-process, we can leave the current value in the
         // cache for any 'get' methods to access.
         //
         data.value = descriptor.defaultValue;
@@ skipping 29 matching lines @@
     data.state = CacheState.VALID;
     data.value = value == null ? descriptor.defaultValue : value;
   }
 
   /**
    * Set the value of the result represented by the given [descriptor] to the
    * given [value], keep its dependency, invalidate all the dependent result.
    */
   void setValueIncremental(ResultDescriptor descriptor, dynamic value) {
     ResultData data = getResultData(descriptor);
-    _invalidateDependentResults(data, null);
+    _invalidateDependentResults(null, data, null, 0);
     data.state = CacheState.VALID;
     data.value = value;
   }
 
   @override
   String toString() {
     StringBuffer buffer = new StringBuffer();
     _writeOn(buffer);
     return buffer.toString();
   }
 
   /**
    * Return the value of the flag with the given [index].
    */
   bool _getFlag(int index) => BooleanArray.get(_flags, index);
 
   /**
    * Invalidate the result represented by the given [descriptor] and propagate
    * invalidation to other results that depend on it.
    */
-  void _invalidate(ResultDescriptor descriptor, Delta delta) {
+  void _invalidate(
+      int id, ResultDescriptor descriptor, Delta delta, int level) {
+    ResultData thisData = _resultMap[descriptor];
+    if (thisData == null) {
+      return;
+    }
+    // Stop if already validated.
+    if (delta != null) {
+      if (thisData.invalidateId == id) {
+        return;
+      }
+      thisData.invalidateId = id;
+    }
+    // Ask the delta to validate.
     DeltaResult deltaResult = null;
     if (delta != null) {
       deltaResult = delta.validate(_partition.context, target, descriptor);
       if (deltaResult == DeltaResult.STOP) {
-//        print('not-invalidate $descriptor for $target');
         return;
       }
     }
-//    print('invalidate $descriptor for $target');
-    ResultData thisData;
     if (deltaResult == null || deltaResult == DeltaResult.INVALIDATE) {
-      thisData = _resultMap.remove(descriptor);
-    }
-    if (deltaResult == DeltaResult.KEEP_CONTINUE) {
-      thisData = _resultMap[descriptor];
-    }
-    if (thisData == null) {
-      return;
+      _resultMap.remove(descriptor);
+//      {

[Brian Wilkerson, 2015/09/18 18:37:42]

If you didn't intend to leave this debug code, please remove it.

+//        String indent = '  ' * level;
+//        print('[$id]$indent invalidate $descriptor for $target');
+//      }
     }
     // Stop depending on other results.
     TargetedResult thisResult = new TargetedResult(target, descriptor);
     for (TargetedResult dependedOnResult in thisData.dependedOnResults) {
       ResultData data = _partition._getDataFor(dependedOnResult);
       if (data != null && deltaResult != DeltaResult.KEEP_CONTINUE) {
         data.dependentResults.remove(thisResult);
       }
     }
     // Invalidate results that depend on this result.
-    _invalidateDependentResults(thisData, delta);
+    _invalidateDependentResults(id, thisData, delta, level + 1);
     // If empty, remove the entry altogether.
     if (_resultMap.isEmpty) {
       _partition._targetMap.remove(target);
       _partition._removeIfSource(target);
     }
     // Notify controller.
     _partition.onResultInvalidated
         .add(new InvalidatedResult(this, descriptor, thisData.value));
   }
 
   /**
    * Invalidates all the results of this entry, with propagation.
    */
   void _invalidateAll() {
     List<ResultDescriptor> results = _resultMap.keys.toList();
     for (ResultDescriptor result in results) {
-      _invalidate(result, null);
+      _invalidate(null, result, null, 0);
     }
   }
 
   /**
    * Invalidate results that depend on [thisData].
    */
-  void _invalidateDependentResults(ResultData thisData, Delta delta) {
+  void _invalidateDependentResults(
+      int id, ResultData thisData, Delta delta, int level) {
     List<TargetedResult> dependentResults = thisData.dependentResults.toList();
     for (TargetedResult dependentResult in dependentResults) {
       CacheEntry entry = _partition.get(dependentResult.target);
       if (entry != null) {
-        entry._invalidate(dependentResult.result, delta);
+        entry._invalidate(id, dependentResult.result, delta, level);
       }
     }
   }
 
   /**
    * Set the [dependedOn] on which this result depends.
    */
   void _setDependedOnResults(ResultData thisData, TargetedResult thisResult,
       List<TargetedResult> dependedOn) {
     thisData.dependedOnResults.forEach((TargetedResult dependedOnResult) {
@@ skipping 510 matching lines @@
    */
   CacheState state;
 
   /**
    * The value being cached, or the default value for the result if there is no
    * value (for example, when the [state] is [CacheState.INVALID]).
    */
   Object value;
 
   /**
+   * The identifier of the invalidation process that most recently checked
+   * this value. If it is the same as the current invalidation identifier,
+   * then there is no reason to check it (and its subtree again).
+   */
+  int invalidateId = -1;
+
+  /**
    * A list of the results on which this result depends.
    */
   List<TargetedResult> dependedOnResults = <TargetedResult>[];
 
   /**
    * A list of the results that depend on this result.
    */
   Set<TargetedResult> dependentResults = new Set<TargetedResult>();
 
   /**
@@ skipping 60 matching lines @@
   void resultAccessed(TargetedResult result) {}
 
   @override
   List<TargetedResult> resultStored(TargetedResult newResult, newValue) {
     return TargetedResult.EMPTY_LIST;
   }
 
   @override
   void targetRemoved(AnalysisTarget target) {}
 }