Thanks for the pointer! I think Django is misbehaving by importing "from 
django.db.models import *" in "django/contrib/gis/db/models/__init__.py" 
while django.db.models doesn't declare an __all__, so the "functions" 
submodule can be imported there which obscures the version at 
contrib/gis/db/models/functions.py.

I updated the PR to to add __all__ as needed and that seems to fix the 
issue I was having.

https://github.com/django/django/pull/7348

On Friday, October 7, 2016 at 7:31:42 AM UTC-4, Peter Inglesby wrote:
>
> Hi Tim,
>
> Disappointingly, I don't think Django's doing anything off the wall here!
>
> When you import a package's submodule, the name of that submodule is added 
> to the package's namespace.  This is what allows you to put `import p.m`, 
> and to then to use `p.m` in your code -- module m is added to package p's 
> namespace.
>
> In the Django code, we end up importing django.db.models.functions (via 
> django.db.models.manager and django.db.models.query)  in 
> django/db/models/__init__.py.  `functions` gets added to the namespace of 
> the package django.db.models, which Python does by adding it to the 
>  __init__ module's locals(), which makes `functions` available as a label 
> in the remainder of the code.
>
> Note that I can't actually find the chapter and verse for how this works 
> in the Python docs, but I've been caught out by something similar in the 
> past!
>
> Hope this helps,
>
> Peter.
>
> On 7 October 2016 at 02:10, Tim Graham <timog...@gmail.com <javascript:>> 
> wrote:
>
>> I'm seeing an issue while running the Django test suite that I can't 
>> explain.
>>
>> If you add print(functions) before
>> from django.db.models.manager import Manager
>> in 
>> https://github.com/django/django/blob/master/django/db/models/__init__.py#L15,
>>  
>> it gives name 'functions' is not defined  as I would expect.
>>
>> However, if you add the same print on the line after, it gives <module 
>> 'django.db.models.functions' from 
>> '/home/tim/code/django/django/db/models/functions/__init__.py'>. A 
>> "functions" variable is magically defined!
>>
>> Why does importing django.db.models.manager have this side effect? 
>> manager.py imports django.db.models.query which imports 
>> django.db.models.functions. If I move the functions import to an inner 
>> import in query.py as done in https://github.com/django/django/pull/7348, 
>> there's no more magic "functions" variable available in 
>> db/models/__init__.py.
>>
>> Can you explain this? I checked all the "from *" imports in 
>> models/__init__.py to rule that out.
>>
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