[BUG]: Type hints in .pyi don't resolve all units

[TheTripleV]

Problem description

When type hints are generated, units are not properly resolved:
From robotpy-pathplannerlib:

class PathPlannerTrajectory():
    class PathPlannerState():
        def __init__(self) -> None: ...
        def interpolate(self, endVal: PathPlannerTrajectory.PathPlannerState, t: float) -> PathPlannerTrajectory.PathPlannerState: ...
        @property
        def acceleration(self) -> meters_per_second_squared:
            """
            :type: meters_per_second_squared
            """
        @property
        def angularAccel(self) -> units::unit_t<units::unit<std::__1::ratio<1l, 1l>, units::base_unit<std::__1::ratio<0l, 1l>, std::__1::ratio<0l, 1l>, std::__1::ratio<-2l, 1l>, std::__1::ratio<1l, 1l>, std::__1::ratio<0l, 1l>, std::__1::ratio<0l, 1l>, std::__1::ratio<0l, 1l>, std::__1::ratio<0l, 1l>, std::__1::ratio<0l, 1l> >, std::__1::ratio<0l, 1l>, std::__1::ratio<0l, 1l> >, double, units::linear_scale>:
            """
            :type: units::unit_t<units::unit<std::__1::ratio<1l, 1l>, units::base_unit<std::__1::ratio<0l, 1l>, std::__1::ratio<0l, 1l>, std::__1::ratio<-2l, 1l>, std::__1::ratio<1l, 1l>, std::__1::ratio<0l, 1l>, std::__1::ratio<0l, 1l>, std::__1::ratio<0l, 1l>, std::__1::ratio<0l, 1l>, std::__1::ratio<0l, 1l> >, std::__1::ratio<0l, 1l>, std::__1::ratio<0l, 1l> >, double, units::linear_scale>
            """
        @property
        def angularVel(self) -> radians_per_second:
            """
            :type: radians_per_second
            """
        @property
        def curveRadius(self) -> meters:
            """
            :type: meters
            """

Some types are left in C++ syntax (units::unit_t<units::unit<std::__1::ratio<1l, 1l>...) and others are simplified but not imported so they are not valid (meters).

robotpy-photonvision has the same issue.

Operating System

MacOS

Installed Python Packages

No response

Reproducible example code

No response

[auscompgeek]

I'm too lazy to move this issue, but it looks like robotpy-wpimath is missing a type caster for units/angular_acceleration.h (among a few other of the units headers). If we throw one in then we should get back out valid syntax.

On the undefined type aliases, yeah, it's definitely an issue, and I'm surprised nobody's raised it yet. mypy will treat them as Any when you import them (which is mostly fine), but I have noticed Pyright/Pylance will also show Any in VSCode. jedi-language-server returns the unresolved types though. Ideally we'd have meters: TypeAlias = float somewhere. I don't think we have a way of injecting things into the type stub output yet.

[virtuald]

Ideally we'd have meters: TypeAlias = float somewhere. I don't think we have a way of injecting things into the type stub output yet.

This would be the right way to fix it... but sounds like work. IMO it's better to have the names in there (and have the type hints be invalid) than to not have the names, since the units aren't always obvious.