More precise annotations of utils.timezone functions that return instances of tzinfo subclasses.

[filiplajszczak]

Current annotations for get_fixed_timezone, get_default_timezone and get_current_timezone follow the docstrings of the functions that broadly name returned objects as tzinfo instance. It is true, but imprecise, as the returned objects are instances of subclasses of tzinfo. Mypy complains when any of the methods of that subclasses are called on the returned instance eg. error: "tzinfo" has no attribute "localize"

Proposed changes should fix it.

[bluetech]

I also ran into this issue, will be good to fix. Left some comments.

[bluetech]

It looks good to me now, though I would add a comment like this above get_current_timezone():

Strictly speaking, it is possible to activate() a non-pytz timezone, in which
case BaseTzInfo is incorrect. However, this is unlikely, so we use it anyway,
to keep things ergonomic for most users.

[filiplajszczak]

OK @bluetech It's included as suggested.

Also, what is breaking the build? I see the output, but what is the difference with the master that causes problems?

[filiplajszczak]

@sobolevn Looks like that one has the same build problem as #211

[sobolevn]

Yes, I will be able to fix it in the evening (Moscow time). Sorry for the inconvenience.

[sobolevn]

Something broke during this time period:

My wild guess is that git submodule changed somehow. Diff:

• Working: f452d4232e1c14269bf2f1bd234d6e4ef462dc55 https://travis-ci.com/typeddjango/django-stubs/jobs/246235546#L183
• Failing: f452d4232e1c14269bf2f1bd234d6e4ef462dc55 https://travis-ci.com/typeddjango/django-stubs/jobs/246498019#L183

At first sight - it does not look like something has changed at all.
I have tried to reset build cache, didn't work.

Local build also fails with the very same reason.

Then, I have tried to update django-sources to 2.2.6:

--- Subproject commit f452d4232e1c14269bf2f1bd234d6e4ef462dc55
+++ Subproject commit aa28213eb51ba26b349c2e51f2defcc7cc87780e

Still no luck, the error remains. I am out of ideas. And sadly don't have any more time for now.
I would appreciate any help 🙂

[mkurnikov]

@sobolevn FYI, CI failure happened because of unpinned mypy version. 0.740 broke tests typechecking.

[sobolevn]

That's why I use poetry everywhere 🙂