Pydantic integration and AnyPath polymorphic class

[jayqi]

• Adds AnyPath polymorphic class. Closes Add AnyPath class that will dispatch to either local or cloud #77.
  • This class' constructor will instantiate a cloud path instance or a pathlib.Path instance appropriately based on the input.
  • This class also overloads isinstance and issubclass logic so that it's a virtual superclass of CloudPath and Path.
  • New doc page: https://deploy-preview-130--gallant-agnesi-5f7bb3.netlify.app/anypath-polymorphism/
• Adds integration with Pydantic, so that any cloud path class or AnyPath can be used as a type declaration on a Pydantic model, and the validation will appropriately try to cast the input into the class. Closes Add pydantic validator support  #126.
  • New doc page: https://deploy-preview-130--gallant-agnesi-5f7bb3.netlify.app/integrations/
• Refactor the way we specify extras so that it's all compactly in one file.

Question:

• For now, I've just added pydantic to requirements-dev.txt for the tests. Should we make this an extras option instead? There's no direct runtime dependency by cloudpathlib on pydantic. You'd only actually need pydantic if you try to make a model and need to import BaseModel.

Note:

• mypy has its own subtype-checking logic that does not use issubclass, so the AnyPath implementation doesn't quite pass mypy. I'm currently just putting in some # type: ignores, but one may consider this implementation not-type-safe shenanigans. I may open an issue on mypy later to ask about if there is a recommended way to do things.

[codecov]

Codecov Report

Merging #130 (3d542de) into master (0eed4e9) will increase coverage by 0.2%.
The diff coverage is 100.0%.

@@           Coverage Diff            @@
##           master    #130     +/-   ##
========================================
+ Coverage    92.0%   92.2%   +0.2%     
========================================
  Files          19      20      +1     
  Lines        1066    1098     +32     
========================================
+ Hits          981    1013     +32     
  Misses         85      85             

Impacted Files	Coverage Δ
cloudpathlib/__init__.py	100.0% <100.0%> (ø)
cloudpathlib/anypath.py	100.0% <100.0%> (ø)
cloudpathlib/cloudpath.py	91.0% <100.0%> (+0.1%)	⬆️

[github-actions]

🚀 Deployed on https://deploy-preview-130--gallant-agnesi-5f7bb3.netlify.app

[pjbull]

For now, I've just added pydantic to requirements-dev.txt for the tests. Should we make this an extras option instead? There's no direct runtime dependency by cloudpathlib on pydantic. You'd only actually need pydantic if you try to make a model and need to import BaseModel.

Agreed to leave it out of the explicit requirements and just use it in dev.

[pjbull]

This is 🔥 🔥 🔥

One thought is I don't think this implementation will support Pure paths. I'm fine opening an issue and deciding how we want to handle that later, but just wanted to mention.

[jayqi]

I thought of the PurePath thing too, and I decided it makes sense not to support it, at least right now.

• We don't have any PureCloudPath classes. IIRC, use of cloudpathlib without authentication is undocumented and not explicitly supported.
• I don't think we can automatically distinguish between inputs to PurePath and Path for dispatch. We'd have to provide more information and we'd have to invent an interface for it.
• Most practical use cases that need to switch between cloud paths and local file paths probably care about interacting with real files and not a hypothetical filesystem.