[Python-Dev] is sys.modules not meant to be replaced?

[Benjamin Peterson]

2011/7/24 Eric Snow <ericsnowcurrently at gmail.com>:
> On Sat, Jul 23, 2011 at 10:55 PM, Benjamin Peterson <benjamin at python.org> wrote:
>> 2011/7/23 Eric Snow <ericsnowcurrently at gmail.com>:
>>> The documentation[1] doesn't say, but the implementation of the imp
>>> module makes me wonder if sys.modules was not meant to be replaceable.
>>>  No doubt this has to do with its tie to the interpreter's modules
>>> dict.  I ran into this doing "sys.modules = sys.modules.copy()" to
>>> protect the actual sys.modules dict during some import related test
>>> cases.  If the modules I imported were extension modules it broke.
>>>
>>> So, is sys.modules not meant to be open to re-binding?
>>
>> Not any more or less than other global mutable objects. You can expect
>> other code to be holding on to old references.
>
> But, isn't sys.modules a little different because other modules (at
> least the imp module) don't use it.  From what I understand the
> interpreter object's modules dict (to which sys.modules is initially
> bound) is used directly instead.  So rebinding sys.modules causes a
> disconnect.  That's why I am wondering if sys.modules is not meant to
> be rebound.

Sure. I'm not sure what point you're trying to make, though.

>
> Are there other objects in the interpreter state that are exposed in
> sys that would have the same problem?

Is it problematic?

-- 
Regards,
Benjamin