Type Annotate the *heck* out of social-core

[offbyone]

Proposed changes

This is implementing the type checking I suggested in #949.

Types of changes

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• Release (new release request)
• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (PEP8, lint, formatting, renaming, etc)
• Refactoring (no functional changes, no api changes)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Build related changes (build process, tests runner, etc)
• Other (please describe):

Checklist

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• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added documentation to https://github.com/python-social-auth/social-docs

Other information

This touches most of social-core, and entails some compromises due to overrides that pyright really does not like. These can be broken down into a few categories:

• cases where a value can be None but is being treated as not, because it's set outside of the scope of the method. In these cases, I have added assert <var> statements to tell the type checker that the value is non-null; this code would have raised an exception at this point anyway
• method overrides that are incompatible with the base class. get_user_id() and get_user_details() and the like are particularly egregious in this regard; I have added type:ignore comments in these cases.
• Incorrect types in library values. These probably bugs. Look for TODO comments on these; I didn't try fix them here out of an abundance of caution, since I don't use those authentication providers.
• the Model mixins all used get() methods, which actually led to type confusion, since sometimes more than one was mixed in. I renamed get() on Nonce to get_nonce() and on Association to get_association() in those cases.
• The signature types are definitely wrong somehow; public_key = RSAAlgorithm.from_jwk(...) is not returning a public key, it's returning an allowed keys type, at least with modern pyca-cryptography; it is probably wrong, but it's working. type:ignore'd
• Annotated several return types that were mis-inferred. Often pyright would infer a literal return type, because pyright is overly picky.

[codecov]

Codecov Report

Attention: Patch coverage is 77.87611% with 25 lines in your changes missing coverage. Please review.

Project coverage is 77.93%. Comparing base (326d4b3) to head (6792dad).
Report is 38 commits behind head on master.

Files with missing lines	Patch %	Lines
social_core/backends/apple.py	50.00%	2 Missing and 1 partial ⚠️
social_core/backends/mediawiki.py	0.00%	3 Missing ⚠️
social_core/backends/uffd.py	0.00%	3 Missing ⚠️
social_core/backends/oauth.py	86.66%	1 Missing and 1 partial ⚠️
social_core/storage.py	75.00%	0 Missing and 2 partials ⚠️
social_core/tests/backends/test_saml.py	66.66%	2 Missing ⚠️
social_core/tests/test_exceptions.py	0.00%	1 Missing and 1 partial ⚠️
social_core/backends/auth0.py	0.00%	1 Missing ⚠️
social_core/backends/bitbucket.py	66.66%	0 Missing and 1 partial ⚠️
social_core/backends/facebook.py	0.00%	1 Missing ⚠️
... and 5 more

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #986      +/-   ##
==========================================
+ Coverage   77.88%   77.93%   +0.05%     
==========================================
  Files         347      347              
  Lines       10669    10698      +29     
  Branches      504      455      -49     
==========================================
+ Hits         8310     8338      +28     
  Misses       2200     2200              
- Partials      159      160       +1     

Flag	Coverage Δ
unittests	77.93% <77.87%> (+0.05%)	⬆️

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[nijel]

Can you please constantly use future typing with Type | None syntax instead of mixing it with Optional[Type] in some files?

[offbyone]

No... I just accidentally left in a test assertion. Fixing...

[offbyone]

Can you please constantly use future typing with Type | None syntax instead of mixing it with Optional[Type] in some files?

Happy to; that was accidental in the early steps, where I forgot that we had Python new enough to use it. I'll revise ASAP.

[nijel]

Merged, thanks for your contribution!

[nijel]

This introduced API changes that break storage modules, #1020 reverts that part.