Chatty Init signature with mypy when using help magic

[ocehugo]

Originally posted at python/mypy#5713. The init signature is too long, and should be shorter. Please advise if this is not the correct location for reporting this.

• Please insert below the code you are checking with mypy,

from typing import Union

from mypy_extensions import TypedDict


class Orequest(TypedDict):
    origin: str


class Drequest(TypedDict):
    dest: str


Urequest = Union[Orequest, Drequest]


class Server(object):
    def __init__(self, adict: Urequest) -> None:
        pass

• What is the actual behavior/output?

In [1]: from test import Server
In [2]: Server?
Init signature: Server(adict:Union[importlib._bootstrap.Orequest, importlib._bootstrap.Drequest]) -> None
Docstring:      <no docstring>
...

• What is the behavior/output you expect?

In [2]: Server?
Init signature: Server(adict:Union[Orequest,Drequest]) -> None
Docstring:      <no docstring>
...

• What are the versions of mypy and Python you are using?
  python 3.6.5
  ipython 6.4.0
  mypy 0.6

• Do you see the same issue after installing mypy from Git master?
  Yes

• What are the mypy flags you are using? (For example --strict-optional)
  None

I would expect a clean init signature, without the importlib._bootstrap.

The code works as expected if using the "help" function, but not with the "help magic".

[Carreau]

Thanks, but that seem to be a Python issue, it is not limited to IPython:

$ python
Python 3.6.5 | packaged by conda-forge | (default, Apr  6 2018, 13:44:09)
[GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from foo import Server
>>> import inspect
>>> inspect.signature(Server)
<Signature (adict:Union[importlib._bootstrap.Orequest, importlib._bootstrap.Drequest]) -> None>

So my guess is to move that to CPython.

Sorry for the bump across many projects, and thanks for the report, we can try to have a workaround here, but it would be nice to have a fix Upstream.