traits-stubs is missing several definitions

[mdickinson]

(Reported in another communication channel by @rahulporuri)

it looks like there are a few objects/type declarations missing from the traits.api module

Notably, HasStrictTraits, Interface and provides are missing, but it's likely that these are not the only ones.

As I understand it, completeness was not an initial goal for the stubs, but the three items above are very widely used.

[rahulporuri]

(Sorry for the delay in creating an issue. Given that an issue has been created, I thought i'd just append to the issue) The following object/type declarations are missing -

NOTE : I initially tested this on an internal project but i can see most of these errors when i test traitsui with mypy after installing the traits stubs (there's a lot A LOT of noise but in that noise, you should see a number of errors of the type "traitsui\wx\history_control.py:25: error: Module 'traits.api' has no attribute 'HasPrivateTraits'")

• [ ] traits.api.AdaptationError
• [ ] traits.api.Adapter
• [ ] traits.api.Array
• [ ] traits.api.ArrayOrNone
• [x] traits.api.BaseTraitHandler
• [ ] traits.api.CArray
• [x] traits.api.CTrait
• [x] traits.api.HasStrictTraits
• [x] traits.api.HasPrivateTraits
• [x] traits.api.Interface
• [ ] traits.api.TraitError
• [ ] traits.api.TraitDictEvent
• [x] traits.api.TraitHandler
• [ ] traits.api.TraitListEvent
• [ ] traits.api.Undefined
• [ ] traits.api.adapt
• [x] traits.api.cached_property
• [x] traits.api.on_trait_change
• [ ] traits.api.pop_exception_handler
• [x] traits.api.provides
• [ ] traits.api.push_exception_handler
• [ ] traits.api.register_factory
• [ ] traits.adaptation.* module
• [ ] traits.etsconfig.api module
• [ ] traits.interface_checker module
• [ ] traits.testing.api module
• [ ] traits.trait_base module
• [ ] traits.trait_converters module
• [ ] traits.trait_errors module
• [ ] traits.trait_notifiers module
• [ ] traits.trait_numeric module
• [ ] traits.util.weakiddict module

[mdickinson]

Thanks, @rahulporuri

There's an easy part and a hard part for the fix.

For the easy part, if we're already defining stubs for a function or class but not exposing those stubs in api.pyi, then we should do that.

The harder part is creating stubs where they don't already exist.

[mdickinson]

Bumping; it would still be good to fix this, but it's not a priority for the current release.