python/mypy

WE'VE MOVED! See you at https://gitter.im/python/typing

Anvar

@arpanetus

why doesn't mypy take body of conditional statements as a different scope?

if some_bool:
     this_var: TypeOfVar =  TypeOfVar()
else:
    this_var: DifferenTypeOfVar = DifferenTypeOfVar()

Omry Yadan

@omry

Is there as config flag to make --strict the default?

Brian Mboya

@asheux

is there a way I could potentially get rid of this error. Apparently mypy has a file called types and python thinks it's the same file and trying to get BuiltinFunctionType from it.

Traceback (most recent call last):
  File "main.py", line 3, in <module>
    import argparse
  File "/usr/lib/python3.8/argparse.py", line 88, in <module>
    import re as _re
  File "/usr/lib/python3.8/re.py", line 124, in <module>
    import enum
  File "/usr/lib/python3.8/enum.py", line 2, in <module>
    from types import MappingProxyType, DynamicClassAttribute
  File "/home/kreebz/Projects/opensource/mypy/mypy/types.py", line 3, in <module>
    import copy
  File "/usr/lib/python3.8/copy.py", line 111, in <module>
    types.BuiltinFunctionType, type(Ellipsis), type(NotImplemented),
AttributeError: partially initialized module 'types' has no attribute 'BuiltinFunctionType' (most likely due to a circular import)

Vincent

@vsiles

Hi ! I'm playing with mypy and I see some "starred" types, like X* (see https://gist.github.com/70d59f208548878654505b0b9c89f0a2 line 45 vs 54). What's the difference between X and X* ?

oups, you moved :)

Axel Mousset

@PymZoR

This message was deleted

Jacob

@Jacob25585268_twitter

Hi! I'm trying to extract type infomation of python files. Is that possible to be done by mypy? I have found the api.py file of mypy, but can't find a deeper api that about type infomation. Thanks for any ideas!

Alexander Ivanov

@alehander92

please use https://gitter.im/python/typing

Jason R. Coombs

@jaraco

Am I the first person to try to install mypy on pypy? When I do, it fails with an installation error on typed_ast, which is closed without resolution.

python/typed_ast#111

Jason R. Coombs

@jaraco

Does the resolution there imply that mypy is perpetually not supported on pypy?

I didn’t see anything in the readme about pypy. Would the project consider a PR that advertises that pypy isn’t supported?

Alexander Ivanov

@alehander92

please use

another channel https://gitter.im/python/typing

this channel is not suported

Jason R. Coombs

@jaraco

Got it. Thanks. I did follow the link from the project, but because that opened in a browser, it wasn’t authenticated so I had to try to find the channel manually and found this with a search. I see the message above now also.

Bart

@louwers

Hi, is there a function to convert a Optional value to a non-Optional value?

47: def unopt(x: Optional[X]) -> X:
48:     # similar to https://doc.rust-lang.org/std/option/enum.Option.html#method.unwrap
49:     assert x is not None
50:     return x

I came across this, is it part of a library?

Bart

@louwers

I found this :)
https://returns.readthedocs.io/en/latest/pages/maybe.html

max w

@wwiimmaaxx_twitter

Hi folks! Had a quick mypy question.

In my venv I have a third-party library, chalice, in my site-packages.
The library has inline types. It does not have a py.typed file.
However, when trying to consume it, mypy seems to think it does not have types

A quick repro is attached as a thread:

4 replies

max w

@wwiimmaaxx_twitter

(update: yeah, i think i just needed to make chalice PEP 561 compatible)

Alexander Ivanov

@alehander92

sorry

https://gitter.im/python/typing

use this channel only

QiuJiangkun

@qiujiangkun

Implicit return in function which does not return for "NoReturn" hint

Does anyone meet this situational?

Is it a bug?

Deepti Sharma

@dsdeeptisharma

Hi Everyone

I ama begineer with BeautifulSoup library and I am using it to extract row and column data from a website. But in the code, I am getting "Undefined name row_td"

I am stuck. Can anyone help?

from typing import Any

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import seaborn as sns
import bs4

from urllib.request import urlopen
from bs4 import BeautifulSoup

url = "https://mcs.ciena.com/InetReports/AssemblyHistory/ResultsByAO.asp?SN=NNTMRT112ND8&PN=NTK540BC-820&R=008"
html = urlopen(url)
soup = BeautifulSoup(html, 'lxml')
type(soup)
bs4.BeautifulSoup
title = soup.title
print(title)

text = soup.get_text()

print(text)

rows = soup.find_all('tr')
print(rows[7:10])
for row in rows:
row_td = row.find_all('td')
print(row_td)
type(row_td)
str_cells = str(row_td)
cleantext = BeautifulSoup(str_cells, "lxml").get_text()
print(cleantext)

Its here:

for row in rows:
row_td = row.find_all('td')
print(row_td)

caseydm

@caseydm_gitlab

Hi all. Anybody know how to run mypy on a directory, but NOT inspect files in the folders above it? For example, I have a folder src that then contains two modules myapp.fonts. When I run mypy src/myapp/fonts it is inspecting every app in my django directory.

Yang Bo

@Bryant-Yang

Hi guys, how to make sub class method return value compatible with it's base class?

error: Incompatible return value type (got "AbstractUnitOfWork", expected "SqlAlchemyUnitOfWork")

Yang Bo

@Bryant-Yang

class AbstractUnitOfWork(abc.ABC):
    def __enter__(self) -> AbstractUnitOfWork:
        return self

class SqlAlchemyUnitOfWork(AbstractUnitOfWork):
    # True: when in pytest, don't persist db changes
    # False: when in pytest, persist db changes
    is_pytest_non_persistence = True

    def __init__(self, session: scoped_session) -> None:
        super().__init__()
        self._session = session

    def __enter__(self) -> SqlAlchemyUnitOfWork:
        return super().__enter__()

got this: https://stackoverflow.com/questions/55441612/does-mypy-have-a-subclass-acceptable-return-type

Yang Bo

@Bryant-Yang

and this: https://stackoverflow.com/questions/44640479/mypy-annotation-for-classmethod-returning-instance/44644576

Yang Bo

@Bryant-Yang

ok, subclass of type annotation
for class:

def func(sub_cls: Type[Base]):
    ...

for instance

Uow  = TypeVar("Uow", bound=AbstractUnitOfWork)
def func(instance: Uow):
    ...

Loris Zinsou

@Hellzed

Hi! In one of my projects, there's a specific dataclass I reuse a lot that's semantically an ordered an frozen dataclass, ediclass = partial(dataclass, order=True, frozen=True). I noticed this completely prevents mypy from treating it as a dataclass, which is 99% of mypy errors in this project.

To my surprise, the decorators for dataclasses are actually hardcoded: https://github.com/python/mypy/blob/master/mypy/plugins/dataclasses.py#L19

Any idea how I could register a custom dataclass_maker to mypy?

Eugene

@Eugene-1984

Does anybody knows anything about the import and\or import order side-effects for mypy? I have working code that mypy comlains abouth with Unexpected keyword argument error. And yet I am unable to reproduce it outside of a big project. I have a hierarchy of dataclassed and if it is all in a single file - mypy agrees and yet once its get distributed across several packages, error emerges.

Marti Raudsepp

@intgr

@Eugene-1984 Have you tried deleting .mypy_cache? Has helped me on rare occasions.

Eugene

@Eugene-1984

@intgr No, but this situation reproduces within CI so.. I'll try that regardless, thanks! Now I am trying make the whole project pass with mypy --strictand now metting lots of reexport errors. It is tiresome not to be able to imports to propagate implicitly via all to the top :(

Eugene

@Eugene-1984

@intgr removing cache wont help, now I am thinking that the cyclic imports under TYPE_CHECKING hack may be the problem

Massimo Redaelli

@mredaelli

Suppose I have a complicated Protocol for a callback. I would like to avoid typing all the parameters and return types in every callback definition. Is there a way to say something like @my_protocol def callback(a, b) and have mypy figure out the rest?

Robot Wei

@wyl8899

Hi! In one of my projects, there's a specific dataclass I reuse a lot that's semantically an ordered an frozen dataclass, ediclass = partial(dataclass, order=True, frozen=True). I noticed this completely prevents mypy from treating it as a dataclass, which is 99% of mypy errors in this project.

@Hellzed Have you found a solution? From the dataclass_makers constant you provided, I found its usage https://github.com/python/mypy/blob/ec76ccafa757c6d8fbb2c83195170bf75e0ff324/mypy/plugins/default.py#L92, which is get_class_decorator_hook(). IMO chances are a custom plugin providing get_class_decorator_hook() would work.

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text = soup.get_text()

print(text)