Djblets provides a few useful property classes for marshalling data or

ensuring strict typing at runtime. These have been updated to support

type hints, in order to help developers provide the right typing

information when working with these classes.
There are a couple caveats in the implementation:


Due to the current lack of widespread support for PEP 696 (Type

   defaults for TypeVarLikes), we can't add any defaults for any of the

   types, meaning that get/set types must be specified.


Pyright and MyPy behave differently when it comes to determining the

   correct type during assignment. MyPy implicitly uses the type of the

   assignment, while Pyright will happily allow other assignments to

   override that type. This means that conusmers need to explicitly type

   the descriptors.


Examples are now present in the docs to help define these correctly.

Best practices here will evolve after PEP 696 is landed, and hopefully

once Pyright and MyPy come closer on implementations.
Some other modernization is present:


Properties now define a __set_name__() in order to know their attribute

   name, rather than having to scan for it. This is safer and faster than the

   old method.


Most arguments to these properties are now keyword-only arguments.


The old behavior/methods are now deprecated, scheduled to be removed in

Djblets 5.0.

Unit tests pass.
Made use of this with some upcoming changes in Review Board for better type

safety.