Fix static field inspection in debugger

runtime/vm/debugger.cc

 // Copyright (c) 2012, 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/debugger.h"
 
 #include "vm/code_index_table.h"
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
 #include "vm/compiler.h"
@@ skipping 719 matching lines @@
     result = isolate_->object_store()->sticky_error();
   }
   ignore_breakpoints_ = saved_ignore_flag;
   isolate_->set_long_jump_base(base);
   return result.raw();
 }
 
 
 RawObject* Debugger::GetStaticField(const Class& cls,
                                     const String& field_name) {
+  const Field& fld = Field::Handle(cls.LookupStaticField(field_name));
+  if (!fld.IsNull()) {
+    // Return the value in the field if it has been initialized already.
+    const Instance& value = Instance::Handle(fld.value());
+    ASSERT(value.raw() != Object::transition_sentinel());
+    if (value.raw() != Object::sentinel()) {
+      return value.raw();
+    }
+  }
+  // There is no field or the field has not been initialized yet.
+  // We must have a getter. Run the getter.
   const Function& getter_func =
       Function::Handle(cls.LookupGetterFunction(field_name));
   ASSERT(!getter_func.IsNull());
+  if (getter_func.IsNull()) {

[regis, 2012/04/05 22:33:05]

This contradicts the assert above. Left over debugging code?

[hausner, 2012/04/05 22:45:30]

I did this on purpose. Maybe it's not good style. This function should never be
called with the name of a non-existing field/getter. In a debug build I'd like
to know if someone tries to get the value of a non-existing field. In release
mode, I just silently ignore this and return null as the value.

[regis, 2012/04/05 23:03:07]

Don't you want to know that something is fishy in release mode too? Instead of
returning null, I would have called an UNREACHABLE() for a null function. But
maybe you need a more defensive coding style in the debugger? Up to you.

+    return Object::null();
+  }
 
   Object& result = Object::Handle();
   LongJump* base = isolate_->long_jump_base();
   LongJump jump;
   isolate_->set_long_jump_base(&jump);
   bool saved_ignore_flag = ignore_breakpoints_;
   ignore_breakpoints_ = true;
   if (setjmp(*jump.Set()) == 0) {
     GrowableArray<const Object*> noArguments;
     const Array& noArgumentNames = Array::Handle();
@@ skipping 331 matching lines @@
 }
 
 
 void Debugger::RegisterCodeBreakpoint(CodeBreakpoint* bpt) {
   ASSERT(bpt->next() == NULL);
   bpt->set_next(code_breakpoints_);
   code_breakpoints_ = bpt;
 }
 
 }  // namespace dart