* Allow covariants of __enter__, __aenter__, and @classmethod
The problem we currently have is the return type of classes such as
Client does not allow covariants when subclassing or context manager.
In other words:
```python
class Base:
def __enter__(self) -> Base: # XXX
return self
class Derived(Base):
...
with Derived() as derived:
# The type of derived is Base but not Derived. It is WRONG
...
```
There are three approaches to improve type annotations.
1. Just do not type-annotate and let the type checker infer
`return self`.
2. Use a generic type with a covariant bound
`_AsyncClient = TypeVar('_AsyncClient', bound=AsyncClient)`
3. Use a generic type `T = TypeVar('T')` or `Self = TypeVar('Self')`
They have pros and cons.
1. It just works and is not friendly to developers as there is no type
annotation at the first sight. A developer has to reveal its type via
a type checker. Aslo, documentation tools that rely on type
annotations lack the type. I haven't found any python docuementation
tools that rely on type inference to infer `return self`. There are
some tools simply check annotations.
2. This approach is correct and has a nice covariant bound that adds
type safety. It is also nice to documentation tools and _somewhat_
friendly to developers. Type checkers, pyright that I use, always
shows the the bounded type '_AsyncClient' rather than the subtype.
Aslo, it requires more key strokes. Not good, not good.
It is used by `BaseException.with_traceback`
See https://github.com/python/typeshed/pull/4298/files
3. This approach always type checks, and I believe it _will_ be the
official solution in the future. Fun fact, Rust has a Self type
keyword. It is slightly unfriendly to documentation, but is simple to
implement and easy to understand for developers. Most importantly,
type checkers love it.
See https://github.com/python/mypy/issues/1212
But, we can have 2 and 3 combined:
```python
_Base = typing.TypeVar('_Base', bound=Base)
class Base:
def __enter__(self: _Base) -> _Base:
return self
class Derive(Base): ...
with Derived() as derived:
... # type of derived is Derived and it's a subtype of Base
```
* revert back type of of SteamContextManager to Response
* Remove unused type definitions
* Add comment and link to PEP484 for clarification
* Switch to `T = TypeVar("T", covariant=True)`
* fixup! Switch to `T = TypeVar("T", covariant=True)`
* Add back bound=xxx in TypeVar
Co-authored-by: Florimond Manca <florimond.manca@gmail.com>
* Support header comparisons with dict or list.
* Add check for no headers item
* Fixup testcases affected by headers comparison using dict or list
* Update test_responses.py
Co-authored-by: Tom Christie <tom@tomchristie.com>
* url.userinfo should be URL encoded bytes
* Neater copy_with implementation
* Finesse API around URL properties and copy_with
* Docstring for URL, and drop url.authority
* Support url.copy_with(raw_path=...)
* Docstrings on URL methods
* Tweak docstring
