E721: type comparison is partially working

[pmeier]

Related to the discussion in #882 if type equality or identity comparisons should be allowed.

Consider the following snippet run with pycodestyle==2.6.0 on python==3.6:

def foo():
    return 0


def bar():
    return 1


assert type(foo()) == type(bar())
assert type(foo()) is type(bar())

foz = foo()
baz = bar()

assert type(foz) == type(baz)
assert type(foz) is type(baz)

foobar.py:9:20: E721 do not compare types, use 'isinstance()'
foobar.py:10:20: E721 do not compare types, use 'isinstance()'

It complains only for the first two assertions. If I'm not mistaken this means that either:

• type comparisons are allowed, but are not registered properly if one does not compare variables or
• type comparisons should still be not allowed, but are by accident.

[sigmavirus24]

In the future, please search closed and open issues before creating new ones that are duplicates. The issue right below you on the issue list is literally a duplicate of this: #945

[pmeier]

@sigmavirus24

In the future, please search closed and open issues before creating new ones that are duplicates.

I did and this is how I discovered #882. As far as I understand the discussion there, only workarounds exist for this problem. Thus, I was even more surprised to find that one "style" above checks fine while the other fails.

The issue right below you on the issue list is literally a duplicate of this: #945

Maybe it is related, but from my perspective its definitively not a duplicate. #945 is specifically about how to handle None for E721, which is not part of the problem I described.