Linting error: account.inbox.filter(...)

[DeflateAwning]

Describe the bug
The following code gives a linting error:

from exchangelib import Credentials, Account

# from README for completeness
credentials = Credentials("[email protected]", "topsecret")
account = Account("[email protected]", credentials=credentials, autodiscover=True)

# part with linting problem:
email_message = account.inbox.filter(subject__contains='the', sender__contains='example.com').order_by('-datetime_received')[0]

This code runs fine, but the .filter part of account.inbox.filter(...) gets the following linting error in Pyright:

Cannot access member "filter" for type "threaded_cached_property"
  Member "filter" is unknown

Additional context
Python 3.9, exchangelib 5.1.0

[ecederstrand]

I think this is just Pyright not being able to understand the code properly. I don't see anything wrong.

[DeflateAwning]

Just opened an issue at Pyright: microsoft/pyright#7378

[DeflateAwning]

Welp, pyright is blaming this repo for the error. Looking myself, it looks like it is perhaps an issue here. I think maybe we just need to export the list of attributes in an __all__ = [...] list. I'd have to look at it harder though.

[hmc-cs-mdrissi]

pydanny/cached-property#172 is probably real issue. threaded_cached_property doesn't play well with static analysis tools in general.

The easiest trick,

if TYPE_CHECKING:
  my_prop = property
else:
  my_prop = threaded_cached_property

[ecederstrand]

Most of exchangelib was written long before type annotations became a Python feature. Adding full annotations is a huge effort that I will not undertake myself, at least.

[DeflateAwning]

I wasn't suggesting that we need full annotations; I do however thing that it makes sense to add hints on parts that are being labelled as errors

[ecederstrand]

In this case, it looks like the real issue lies in the cached-property package. I think the issue should be solved there.

There are other places where static type checkers have a hard time reasoning about exchangelib code. I haven't seen any cases where there were actual errors, and refactoring turned out to be a lot of work for very little gain.

I'm closing this issue because exchangelib doesn't use Pyright. I'm not generally opposed to doing so, but please work on adding support in a PR instead.

[DeflateAwning]

@ecederstrand, would you be willing to help me write an issue for this in the cached-property package? Or at least point me to the part where that issue needs to be referenced as an example of the issue?

[hmc-cs-mdrissi]

The issue already exists. pydanny/cached-property#172 is the correct issue. Fixing that will fix the problem here.