[Python-Dev] PEP 550 v4

[Greg Ewing]

Yury Selivanov wrote:
>     def foo():
>          var = ContextVar()
>          var.set(1)
> 
>     for _ in range(10**6): foo()
> 
> If 'var' is strongly referenced, we would have a bunch of them.

Erk. This is not how I envisaged context vars would be
used. What I thought you would do is this:

    my_context_var = ContextVar()

    def foo():
       my_context_var.set(1)

This problem would also not arise if context vars
simply had names instead of being magic key objects:

    def foo():
       contextvars.set("mymodule.myvar", 1)

That's another thing I think would be an improvement,
but it's orthogonal to what we're talking about here
and would be best discussed separately.

-- 
Greg