Re: InvalidMemoryOperationError when calling functions from destructors

[Jacob Carlborg]

On 2013-04-25 17:50, Volfram wrote:
I've run into a problem which I'd like to hope is a bug, but let's see
if we can figure out if I'm doing something stupid first, eh?
When a destructor calls a function from another module, I get an
InvalidMemoryOperationError.  When a destructor calls a function from
another class in the same module, and that function calls the function I
was trying to call initially, everything seems to go fine.  When a
destructor calls a function in the same class, which calls a function in
a different module, I get the InvalidMemoryOperationError again.

This may have to do with garbage collector subtleties I'm not familiar
with.

Example:

File alpha.d
module alpha;

import beta;

class AlphaClass
{
     BetaClass bc;
     Alpha2Class a2c;

     void cleanup()
     {
         bc.cleanup();//if this is called from the destructor, expect an
error.
     }

     public:
     this()
     {
         bc = new BetaClass();
         a2c = new Alpha2Class(bc);
     }
     ~this
     {
         bc.cleanup();//this will cause an error.
         a2c.cleanup();//this works fine
         cleanup();//this will cause an error.
     }
}

You cannot access GC controlled memory in class destructors. There's no 
guarantee in which order the destructors will be called. You don't know 
if the memory is still valid in a destructor.

--
/Jacob Carlborg