Use mypy and types in the code base

[punchagan]

No description provided.

[punchagan]

Here's a blog post by Zulip on how to add type annotations to an existing code-base.

[punchagan]

mypy also has some documentation for this, to help get started.

[vkrishnaswam]

Got mypy running, will update requirements.txt to include mypy.
Output of current mypy run below, without a config file, will work on fixing them next.

sotg_accreditation_tracker/settings.py:105: error: Cannot find module named 'dj_database_url'
sotg_accreditation_tracker/settings.py:105: note: See https://mypy.readthedocs.io/en/latest/running_mypy.html#missing-imports
tracker/models.py:10: error: Need type annotation for 'name'
tracker/models.py:11: error: Need type annotation for 'email'
tracker/models.py:12: error: Need type annotation for 'type'
tracker/models.py:15: error: Need type annotation for 'date'
tracker/models.py:24: error: Need type annotation for 'uc_username'
tracker/models.py:30: error: Need type annotation for 'wfdf_userid'
tracker/models.py:37: error: Need type annotation for 'last_modified_at'
tracker/migrations/0001_initial.py:10: error: Need type annotation for 'dependencies' (hint: "dependencies: List[<type>] = ...")
uc_api_helpers.py:10: error: Cannot find module named 'faker'
uc_api_helpers.py:15: error: Need type annotation for 'HEADERS' (hint: "HEADERS: Dict[<type>, <type>] = ...")
tracker/forms.py:1: error: Cannot find module named 'crispy_forms.helper'
tracker/forms.py:2: error: Cannot find module named 'crispy_forms.layout'
tracker/views.py:5: error: No library stub file for module 'arrow'
tracker/views.py:5: note: (Stub files are from https://github.com/python/typeshed)

[punchagan]

Got mypy running, will update requirements.txt to include mypy.

May be we should add a requirements-dev.txt where we add mypy, since we don't want it installed in Heroku? But then doing a pip freeze won't work unless we have a separate dev environment for developers, I guess. Need to figure out if there's a better workflow for doing this!

[punchagan]

https://pypi.org/project/pip-tools/ may be good tooling to do this kind of a thing. But, this could be done later, too, I suppose. (As a separate issue, and not a part of this).

[Adityar93]

Have to ask if this article <https://blogs.dropbox.com/tech/2019/09/our-journey-to-type-checking-4-million-lines-of-python/> started the push for typed Python :D

…

On Mon, Sep 16, 2019 at 4:24 PM Puneeth Chaganti ***@***.***> wrote: https://pypi.org/project/pip-tools/ may be good tooling to do this kind of a thing. But, this could be done later, too, I suppose. (As a separate issue, and not a part of this). — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#23>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACUED2N42E63VBBR7UB7P63QJ5QUZANCNFSM4IV6XLCQ> .

[punchagan]

Not really. The Zulip code base uses typed Python and has been one of the first medium-large projects to adopt mypy. It's been quite useful for the project both in terms of helping with catching bugs early and making it easier to grok the code for new contributors.

https://blog.zulip.org/2016/10/13/static-types-in-python-oh-mypy/

Also, some of the folks here also would like to contribute to Zulip - and learning some of the tooling in a smaller project might help. :)