Refactor/vendorize typings

[tony]

In re: #1305

I'm having difficulty with if making switches that work between ASGIREF_33/ASGIREF_34. Apparently type annotations can't handle that since it's more of a runtime thing?

@Kludex Is this possible to do without watering the typings down too much?

• What's done _types.py being backported to 3.3.2 and removed asgiref as a dependency
• version checking without needing distutils/packaging

It can do branching like a _compat.py module would, but mypy considers things like:

if ASGIREF_33:

    class HTTPScope(TypedDict):
        type: Literal["http"]
        asgi: ASGISpecInfo
        http_version: str
        method: str
        scheme: str
        path: str
        raw_path: bytes
        query_string: bytes
        root_path: str
        headers: Iterable[Tuple[bytes, bytes]]
        client: Optional[Tuple[str, int]]
        server: Optional[Tuple[str, Optional[int]]]
        extensions: Dict[str, Dict[object, object]]


elif ASGIREF_34:

    class HTTPScope(TypedDict):
        type: Literal["http"]
        asgi: ASGISpecInfo
        http_version: str
        method: str
        scheme: str
        path: str
        raw_path: bytes
        query_string: bytes
        root_path: str
        headers: Iterable[Tuple[bytes, bytes]]
        client: Optional[Tuple[str, int]]
        server: Optional[Tuple[str, Optional[int]]]
        extensions: Optional[Dict[str, Dict[object, object]]]

to be duplication.

And it's also not possible to override or extend:

  class HTTPScope(TypedDict):
      type: Literal["http"]
      asgi: ASGISpecInfo
      http_version: str
      method: str
      scheme: str
      path: str
      raw_path: bytes
      query_string: bytes
      root_path: str
      headers: Iterable[Tuple[bytes, bytes]]
      client: Optional[Tuple[str, int]]
      server: Optional[Tuple[str, Optional[int]]]
      extensions: Dict[str, Dict[object, object]]

if ASGIREF_34:

    class HTTPScope(HTTPScope):
        extensions: Optional[Dict[str, Dict[object, object]]]

I suppose it's because that requires runtime that mypy isn't meant to analyze

Thoughts on this? I've allowed edits and you're welcome to fork my branch refactor/vendorize-typings

[Kludex]

I was thinking more about ignoring the asgiref version, vendoring the current asgiref.typing, and testing comparing the types from the latest asigref.typing to the vendored file.

EDIT: Remember to include the copyright notice.

[tony]

Some asgiref.typing history (for posterity):

• 2.3.10 and 3.3.0 - 3.3.1 don't have this
• 3.3.2 added
• 3.4.1 - clarification of {HTTP,Websocket}Scope's extension attribute, Websocket -> WebSocket` (I didn't realize today you actually made those contributions, nice!)

testing comparing the types from the latest asigref.typing to the vendored file.

Sorry, not 100% sure what this would look like. Can you clarify?

P.S. If we were to vendorize the typings, they wouldn't necessarily hold true for 3.2.10 as asgiref.typing doesn't exist. In 3.3.4 the are different but perhaps this can be worked around for ones where the class name is different (Websocket* -> WebSocket*) Would the typings only be expected to work with the latest asgiref release?

I should also clarify: Is the use of the typing purely internal, or is it also intended to be used by people implementing the package/using it as a library in some fashion?

EDIT: Remember to include the copyright notice.

For asgiref right? In the pydoc for the file?

[Kludex]

Thanks for the efforts here @tony! 🙇

Sorry for taking so long to act.

I'll be taking this over on #1476.