Add quantity stub file?

[adrn]

When I use parametric Quantity's for typing, I get loads of mypy errors like "type[Quantity] is not generic and not indexable". I think this is because mypy only recognizes subscriptability for classes that inherit from typing.Generic, so it doesn't understand plum.parametric's __class_getitem__ at runtime.

This adds a minimal .pyi stub declaring Quantity and AbstractParametricQuantity as Generic[_T] (_T: LiteralString), plus most of the relevant operators inherited from the quax_blocks mixins. I think with this, mypy should accept Quantity["time"] and treat Quantity["time"] and Quantity["length"] as distinct types.

This is minimal so far and doesn't replicate the full mixin hierarchy, but I think that's ok for type checking purposes?

(btw: ty handles plum.parametric correctly without the stub, so I guess this is specific to mypy?)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.11%. Comparing base (e9deafa) to head (d0e7e3b).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #617      +/-   ##
==========================================
- Coverage   96.29%   94.11%   -2.19%     
==========================================
  Files          57       46      -11     
  Lines        2540     2414     -126     
  Branches      127      121       -6     
==========================================
- Hits         2446     2272     -174     
- Misses         71      121      +50     
+ Partials       23       21       -2     

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[Copilot]

Pull request overview

Adds a typing stub for unxt.quantity to help mypy accept Plum-parametric Quantity[...] usage by declaring AbstractParametricQuantity/Quantity as generics.

Changes:

• Introduces src/unxt/quantity.pyi defining AbstractQuantity, AbstractParametricQuantity, and Quantity as typed/generic stubs.
• Adds operator method signatures intended to mirror quax_blocks mixins for basic arithmetic typing.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.18%. Comparing base (e9deafa) to head (d63cafa).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #617      +/-   ##
==========================================
- Coverage   96.29%   96.18%   -0.12%     
==========================================
  Files          57       46      -11     
  Lines        2540     2414     -126     
  Branches      127      121       -6     
==========================================
- Hits         2446     2322     -124     
+ Misses         71       70       -1     
+ Partials       23       22       -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

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[nstarman]

If this fixes mypy errors then that's good. But does this limit ty's inference?

[nstarman]

I think this is correct. It annotates the set types while keeping the init general

[adrn]

If this fixes mypy errors then that's good. But does this limit ty's inference?

ty is borked for me on any parametric Quantity, but I don't understand why. Potentially related to: astral-sh/ty#2294

[nstarman]

We should add a ty job to CI.