Re: Remove support for cloning generators

I agree. The less tricky code the better :) Thanks. Dmitry. On Mon, Mar 25, 2013 at 9:16 PM, Nikita Popov <nikita.ppv@gmail.com> wrote: > Hi internals! > > Now that we're in the beta phase I want to put some finishing touches on > the generators implementation. The first thing I'd like to do is remove > support for cloning generators. There are a few reasons for this: > > a) The cloning basically works, but the implementation is rather fragile > and easy enough to break. I just had another look at the code and found two > new ways to make it segfault. I could fix those issues, but I'm pretty sure > that they are not the only bugs in there (that's in the nature of that > code). > > b) Especially if objects are involved, the cloning can result in weird > behavior. E.g. if a generator is cloned that makes use of an SplStack, > after cloning both generators will make use of the same stack, which makes > little sense. Just cloning all objects instead of just adding a ref doesn't > make sense either, because cloning would be the wrong thing to do for > objects passed as arguments. One would basically have to clone only objects > created inside the generator, or something like that, which is not > technically possible. > > c) Most importantly, there is very little use for the cloning. At first I > thought it would be nice to use cloning in order to implement forking when > using coroutines as a means of multitasking, but this doesn't really work > well due to b). Apart from that I can think of no use for cloning at all. > > Patch for removing cloning is here: > > > https://github.com/nikic/php-src/commit/805b244d8f106431f01b5c013d4e66f9bb88d09b > > If no one objects I'll commit it sometime soon. > > Thanks, > Nikita >