Remove generic type from BaseApiClient

[llucax]

The BaseApiClient class is not generic anymore, and doesn't take a function to create the stub. Instead, subclasses should create their own stub right after calling the parent constructor. This enables subclasses to cast the stub to the generated XxxAsyncStub class, which have proper async type hints.

[daniel-zullo-frequenz]

Just a few minor comments to check for

[daniel-zullo-frequenz]

Suggested change

	even parametrized using the async class, so the instantiation of the stub can't
	even parameterized using the async class, so the instantiation of the stub can't

[llucax]

🤔

[daniel-zullo-frequenz]

I found it confusing :D
I seems I was wrong 👼

[shsms]

it is an irregular language.

[llucax]

I just noticed that it says parametrized when defining past tense and past participle, but uses parameterized in the example 🤣

[llucax]

Rebased to resolve release notes conflicts too.

[llucax]

Enabled auto-merge.

[shsms]

Can't we just ask them to pass cast(MyServiceAsyncStub, MyServiceStub(service.channel)) as an argument, and make the base client generic over MyServiceAsyncStub instead?

[llucax]

No, because __init__ can't have MyServiceAsyncStub as a type hint, to do that we need to take the type as a generic, and we can't use an async stub as a generic because it is parsed by the interpreter, and it can't find it because it is not present in the .py file, only the .pyi file.

This is how great grpio is handling asyncio and type-hinting 😬 (there is a new experimental interface in the cooking, let's see how that turns out).

[shsms]

It won't parse them with from __future__ import annotations right?

[shsms]

never mind, it will parse them

[llucax]

Yes, because it is not an annotation in this case, is is a proper object for the interpreter. You can give it a go if you want, I already tried many different attempts and nothing seemed to work.

$ head -n 100 t.py* t2.py 
==> t.py <==
class IDoExist:
    pass

==> t.pyi <==
class IDoExist:
    pass

class IDontExist:
    pass

==> t2.py <==
from __future__ import annotations

from typing import Generic, TypeVar

from t import IDoExist, IDontExist

T = TypeVar("T")


class G(Generic[T]):
    def __init__(self, x: T):
        self.x = x


class Sub(G[IDoExist]):
    pass


class Sub2(G[IDontExist]):
    pass
$ python t2.py 
Traceback (most recent call last):
  File "/home/luca/devel/client-base/t2.py", line 5, in <module>
    from t import IDoExist, IDontExist
ImportError: cannot import name 'IDontExist' from 't' (/home/luca/devel/client-base/t.py)

[llucax]

Put another way, with TYPE_CHECKING:

from t import IDoExist

if TYPE_CHECKING:
    from t import IDontExist

Then the error becomes:

$ python t2.py 
Traceback (most recent call last):
  File "/home/luca/devel/client-base/t2.py", line 22, in <module>
    class Sub2(G[IDontExist]):
                 ^^^^^^^^^^
NameError: name 'IDontExist' is not defined. Did you mean: 'IDoExist'?

Maybe it is more clear to see this way. Only stuff after a : (or used in special constructs, like cast), are type hints, the rest is just code.

[llucax]

I just added back the commit in #86 adding the channels defaults to the examples too.

[daniel-zullo-frequenz]

I've removed it from the queue because Sahas had some comments

Dismissing only to be able to enable auto-merge again, and let Sahas make the final approval that triggers the merging