Memory Corruption with AAs

[Jordi]

dsimcha wrote:
> == Quote from Walter Bright (newshound1 at digitalmars.com)'s article
>> dsimcha wrote:
>>> == Quote from Walter Bright (newshound1 at digitalmars.com)'s article
>>>> dsimcha wrote:
>>>>> Has anyone else still been noticing difficult to reproduce memory corruption
>>>>> issues in the presence of associative arrays with 2.042?  They seem to happen
>>>>> very infrequently and non-deterministically.  I can only reproduce them in the
>>>>> context of a large program.  However, they don't occur in 2.040 (the release
>>>>> before the array stomping patch), and they are clearly a result of memory
>>>>> corruption, as contents of arrays change from what I expect them to be to
>>>>> completely random-looking values inside a loop that does a lot of memory
>>>>> management and uses AAs heavily but doesn't modify the values.
>>>> 1. is it multithreaded?
>>>> 2. does your code have any dangling pointers into AAs?
>>> The program as a whole is multithreaded, but the part where the bug occurs is an
>>> initialization routine that is executed before any threads other than the main one
>>> are launched.
>> It should be easier to find then, by removing all the main code and everything
>> it calls.
> 
> The code has so many dependencies (both other code from the same project and
> libraries) and is such a mess (because it's a research prototype that evolved more
> than it was designed and also has all kinds of speed hacks) that it would probably
> be easier to try to reproduce it from scratch.  I'll try tonight because I've got
> a long train ride with nothing else to do anyhow.
> 
>>> As far as the dangling pointers question, I don't understand how there could be
>>> dangling pointers into GC-managed memory, since if there are pointers to it, it
>>> won't be freed.  (Ignoring dirty tricks that I'm not using in this case.)
>> What I meant was, do you save any pointers into the AAs, as in:
>>      auto p = &aa[key];
>> ?
> 
> No, I definitely wasn't.  I almost never do this with any data structure other
> than an array because, even if it works for now, I consider it a horrible
> violation of encapsulation because you're relying on the details of how the data
> structure manipulates memory.  This is also why, when I designed RandAA I didn't
> see this as an issue until you pointed it out to me.

I am having exactly the same situation. My project, which is also quite 
big, crashes randomly in 2.041 and 2.042 (without patches), but it works 
fine in 2.040. I didn't bother reporting because i thought i was doing 
something wrong (being a newbie in D).

Mine is single-threaded, no pointers in AAs.

j.