[Distutils] Module Installation Issues

[Steve Dower]

On 13Sep2016 1555, Donald Stufft wrote:
>
>> On Sep 13, 2016, at 6:41 PM, Steve Dower <steve.dower at python.org> wrote:
>>
>> I think it's one of these things where we should suck it up and let the 90% case work fine, then display a big fat warning if anything weird may have happened and let users sort it out themselves.
>
>
> I am unsure. One of the really egregious and hard to debug weirdness is going to be something like:
>
>
>>>> import foo.bar  # foo, and foo.bar are in sys.modules
>>>> pip.install(“thing”)  # This implicitly upgrades foo
>>>> import foo.widget  # the old foo is in sys.modules, but the new foo.widget.
>

Except my version of this goes more like:

 >>> import foo.bar  # foo, and foo.bar are in sys.modules
 >>> pip.install("thing")  # This implicitly upgrades foo
WARNING: Packages were updated. You need to restart Python now.
 >>> import foo.widget  # because I happily ignore messages starting 
with WARNING

Doesn't matter to me whether it's "safe" to keep going or not - if any 
files are overwritten at all then show the warning. (This is exactly the 
argument I was expecting when I said "those who want it to be perfect in 
every scenario" ;) )

Cheers,
Steve