Disadvantages of ARC

[Dejan Lekic]

On Thursday, 6 February 2014 at 11:37:59 UTC, Max Klyga wrote:
> Anti-GC crowd tries to promote ARC as an deterministic 
> alternative for memory management.
> I noticed that people promoting ARC do not provide any 
> disadvantages for proposed approach.
>
> The thing is in gamedev and other soft-realitime software 
> background only a handfull types of resources are really 
> managed by RC and memory usage patterns are VERY specific to 
> their domain (mostly linear allocation/deallocation and objects 
> with non deterministic lifetime are preallocated in pools).
>
> Trying to use RC as a general method of memory management leads 
> to some problems.
> A pretty detailed view by John Harrop (He is somewhat known for 
> trolling in PL community, but nonetheless knows what he is 
> talking about) - 
> http://www.quora.com/Computer-Programming/How-do-reference-counting-and-garbage-collection-compare/answer/Jon-Harrop-1?srid=3Gvg&share=1#
>
>
> So RC could also introduce unpredictable pause times at 
> undesired places.
>
> This is also confirmed by research from HP - 
> http://www.hpl.hp.com/personal/Hans_Boehm/popl04/refcnt.pdf
>
> My point is that we should not ruin the language ease of use. 
> We do need to deal with Phobos internal allocations, but we 
> should not switch to ARC as a default memory management scheme. 
> In practice people promoting ARC will probably not use phobos 
> anyway. Currently its just an excuse to not use D.
>
> Look at c++ and STL, etc. People will roll their own solutions 
> no matter what you try.

Nicely said.

I believe both approaches should be available. Those who must 
work without GC should be able to easily do that, but GC should 
be picked as default simply because it is better for general 
programming tasks. If D turns out to be used for something else, 
and majority of use-cases require GC to be off, perhaps D should 
switch to no-GC by default. I do not see this happening, to be 
honest.

This is somewhat similar to final-by-default crowd who wants 
class methods to be final, not virtual by default. Again, D 
should provide means to satisfy both crowds, because I think it 
is possible.