[Python-ideas] Store shared/locked state inside of the lock object

[Antoine Pitrou]

On Sat, 8 Nov 2014 14:05:07 +0100
Masklinn <masklinn at masklinn.net> wrote:
> 
> A fairly small technical change I've been considering to improve this
> situation is to store the state-set inside the lock object, and only
> yield it through the context manager: that the state-set is protected
> by a lock is made obvious, and so is the relation between lock and
> state-set. I was delighted to discover that Rust's sync::Mutex[1] and
> sync::RWLock[2] follow a very similar strategy of owning the state-set
> 
> It's not a panacea, it doesn't fix issues of lock acquisition ordering
> for instance, but I think it would go a fairly long way towards making
> correct use of locks easier in Python.
> 
> The basic changes would be:
> * threading.Lock and threading.RLock would now take an optional
>   `data` parameter
> * the parameter would be stored internally and not directly accessible
>   by users of the lock
> * that parameter would be returned by __enter__ and provided to the
>   current "owner" of the lock

For clarity it should probably be a separate class (or set of classes),
e.g. DataLock.

Regards

Antoine.