how to debug memory errors

[Lodovico Giaretta via Digitalmars-d-learn]

On Tuesday, 8 November 2016 at 07:39:12 UTC, Era Scarecrow wrote:
> On Tuesday, 8 November 2016 at 06:04:59 UTC, thedeemon wrote:
>> On Tuesday, 8 November 2016 at 05:36:22 UTC, Era Scarecrow 
>> wrote:
>>
>>>  Hmmm.. I had the impression that if something was referenced 
>>> by another object, then it couldn't be collected,
>>
>> Another *live* object, I.e. reachable from globals and stack. 
>> If you have a big tree and it becomes unreachable (you only 
>> had a pointer to its root and you nulled it), then this whole 
>> tree becomes garbage, and its nodes and leafs will be 
>> collected in unpredictable order, with destructors being run 
>> in unpredictable order, even when these dead nodes reference 
>> each other.
>
>  And I can't help but hope it would start at the largest/base 
> object and work it's way up. Or the largest object and then 
> work it's way down. Alright...

One of the reasons it is not specified is that very often the 
hierarchy is not a simple tree, but a graph with possibly many 
cycles. As a matter of fact, very often child nodes have pointers 
to parent nodes, so that what is logically a tree is practically 
a graph with lots of cycles. So it is not possible to identify a 
root object which does not have incoming dead pointers, and no 
guarantee can be provided.