Add type hints

[Tatsh]

---

name: Pull request
about: Submit a pull request for this project
assignees: fabiocaccamo

---

Describe your changes
Add type hints.

Notes:

• Improvements can certainly come after 3.13 is the oldest version of Python supported. For now a lot of things have to return Any.
• The _KPT type used in __init__.py is less than ideal but it covers all bases of what is possible to use for a key, but there are still some functions that extend from Keyattr and those must take _K which defaults to str.
• typing.cast() is used instead of type assertions to avoid the error from Codacy (which has the Bandit rule about assertions). Overhead is likely minimal vs assert calls but the nice thing is they do get removed in optimised mode, so the overhead can be zero in that case. I see no real issue with assertions so if you want to use those instead of cast() I can revise this. I think making a Bandit config file can quiet Codacy about the issue.

I have tried this with my youtube-unofficial project and it works as expected.

The best way to use this is with typing is to add the type on assignment:

bd = benedict({'a': {'b': 1, 'c': 2}})
b: int = bd['a.b]
c: int = bd[('a', 'c')]

In the future the way to solve this is to have a TypeBenedict to specify a schema, and then have a Mypy plugin that would resolve the actual type. This is similar to what the Mypy Django plugin does with database models.

Related issue
Issue #157

Checklist before requesting a review

• I have performed a self-review of my code.
• I have added tests for the proposed changes.
• I have run the tests and there are not errors.

[Tatsh]

Until python/typing#548 is settled, we cannot have fully generic functions
in benedict.core. And a lot of things can be solved with the new generic syntax, but it requires Python 3.13.

[Tatsh]

@fabiocaccamo This is ready for review. Also inviting @pirate.

[pirate]

spent 10 minutes spot-checking this PR and it looks good to me, cant promise I didn't miss anything though

[codecov]

Codecov Report

❌ Patch coverage is 99.11504% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 97.68%. Comparing base (de5ea2d) to head (c307e3c).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
benedict/serializers/base64.py	89.47%	2 Missing ⚠️
benedict/dicts/base/base_dict.py	98.64%	1 Missing ⚠️
benedict/serializers/cli.py	91.66%	1 Missing ⚠️
benedict/serializers/csv.py	85.71%	1 Missing ⚠️
benedict/serializers/xls.py	94.11%	1 Missing ⚠️
benedict/utils/type_util.py	96.42%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #491      +/-   ##
==========================================
- Coverage   97.76%   97.68%   -0.08%     
==========================================
  Files          63       63              
  Lines        2011     2246     +235     
==========================================
+ Hits         1966     2194     +228     
- Misses         45       52       +7     

Flag	Coverage Δ
unittests	97.68% <99.11%> (-0.08%)	⬇️

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[fabiocaccamo]

@Tatsh @pirate thank you for the great work you did for this PR, and sorry for the late feedback.

I added mypy to pre-commit hooks - so it gets automatically executed when running the tests.

Could you please fix the failing checks/tests? I will be glad to merge this PR once all flags will be green.

[Tatsh]

@fabiocaccamo The type stubs deps have to be in pre-commit config for Mypy to work.

[fabiocaccamo]

@Tatsh @pirate thank you again for this great PR.