Prevent the allInstances array from creating spurious references on future heap queries.

runtime/vm/service.cc

 // Copyright (c) 2013, 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.
 
 #include "vm/service.h"
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 #include "platform/globals.h"
 
@@ skipping 1943 matching lines @@
         parent_field_map = source_class.OffsetToFieldMap();
         intptr_t offset = slot_offset.Value();
         if (offset > 0 && offset < parent_field_map.Length()) {
           field ^= parent_field_map.At(offset);
           jselement.AddProperty("parentField", field);
         }
       } else {
         intptr_t element_index = slot_offset.Value();
         jselement.AddProperty("_parentWordOffset", element_index);
       }
-
-      // We nil out the array after generating the response to prevent
-      // reporting suprious references when repeatedly looking for the
-      // references to an object.
-      path.SetAt(i * 2, Object::null_object());
     }
   }
+
+  // We nil out the array after generating the response to prevent
+  // reporting suprious references when repeatedly looking for the
+  // references to an object.
+  for (intptr_t i = 0; i < path.Length(); i++) {
+    path.SetAt(i, Object::null_object());
+  }
+
   return true;
 }
 
 
 static const MethodParameter* get_inbound_references_params[] = {
   RUNNABLE_ISOLATE_PARAMETER,
   NULL,
 };
 
 
@@ skipping 91 matching lines @@
       } else {
         intptr_t element_index = slot_offset.Value();
         jselement.AddProperty("_parentWordOffset", element_index);
       }
     }
   }
 
   // We nil out the array after generating the response to prevent
   // reporting spurious references when looking for inbound references
   // after looking for a retaining path.
-  for (intptr_t i = 0; i < limit; ++i) {
-    path.SetAt(i * 2, Object::null_object());
+  for (intptr_t i = 0; i < path.Length(); i++) {
+    path.SetAt(i, Object::null_object());
   }
 
   return true;
 }
 
 
 static const MethodParameter* get_retaining_path_params[] = {
   RUNNABLE_ISOLATE_PARAMETER,
   NULL,
 };
@@ skipping 285 matching lines @@
       !obj.IsClass()) {
     PrintInvalidParamError(js, "classId");
     return true;
   }
   const Class& cls = Class::Cast(obj);
   Array& storage = Array::Handle(Array::New(limit));
   GetInstancesVisitor visitor(cls, storage);
   ObjectGraph graph(thread);
   graph.IterateObjects(&visitor);
   intptr_t count = visitor.count();
-  if (count < limit) {
-    // Truncate the list using utility method for GrowableObjectArray.
-    GrowableObjectArray& wrapper = GrowableObjectArray::Handle(
-        GrowableObjectArray::New(storage));
-    wrapper.SetLength(count);
-    storage = Array::MakeArray(wrapper);
-  }
   JSONObject jsobj(js);
   jsobj.AddProperty("type", "InstanceSet");
   jsobj.AddProperty("totalCount", count);
   {
     JSONArray samples(&jsobj, "samples");
-    for (int i = 0; i < storage.Length(); i++) {
+    for (int i = 0; (i < storage.Length()) && (i < count); i++) {
       const Object& sample = Object::Handle(storage.At(i));
       samples.AddValue(sample);
     }
   }
+
+  // We nil out the array after generating the response to prevent
+  // reporting spurious references when looking for inbound references
+  // after looking at allInstances.
+  for (intptr_t i = 0; i < storage.Length(); i++) {
+    storage.SetAt(i, Object::null_object());
+  }
+
   return true;
 }
 
 
 static const char* const report_enum_names[] = {
   SourceReport::kCallSitesStr,
   SourceReport::kCoverageStr,
   SourceReport::kPossibleBreakpointsStr,
   SourceReport::kProfileStr,
   NULL,
@@ skipping 1755 matching lines @@
     if (strcmp(method_name, method.name) == 0) {
       return &method;
     }
   }
   return NULL;
 }
 
 #endif  // !PRODUCT
 
 }  // namespace dart