Added deprecated decorators check

[matusvalo]

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  doc/whatsnew/<current release.rst>.
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Description

This PR introduces new check for deprecated decorators:

$ cat test.py
from abc import abstractproperty

@abstractproperty
def foo():
        pass

$ pylint test.py
************* Module test
test.py:41:0: C0104: Disallowed name "foo" (disallowed-name)
test.py:40:0: W1513: Using deprecated decorator abc.abstractproperty() (deprecated-decorator)

------------------------------------------------------------------
Your code has been rated at 3.33/10 (previous run: 3.33/10, +0.00)

Type of Changes

	Type
	🐛 Bug fix
✓	✨ New feature
	🔨 Refactoring
	📜 Docs

Related Issue

Closes #4429

[matusvalo]

Hm checks are failing. I need to investigate. For now I will put MR as draft...

[Pierre-Sassoulas]

Thank you for this ! I nitpicked a little about typing and formatting. Maybe you could add a little functional tests with an @abc.abstractclassmethod too. But mostly worry about your work environment :) So many deprecations to take care of ! Are you okay with the legacy code 😉 ?

[cdce8p]

Thanks for working on that! I did look at the pytest errors. Most fail because they use abc.abstractproperty 😄 In two cases the decorator is uninferable which cause an error.

class Foo:
    def __init__(self):
        self._baz = 84

    def method(self):
        return self._baz

    @method.setter  # Invalid decorator
    def method(self, value):
        self._baz = value

This isn't valid python as method doesn't have a setter (it would require the @property decorator), but I think that we shouldn't raise an unexpected error for it never the less.

I would appreciate if you could add this as a test case as well.

[cdce8p]

I'm not sure you can be certain that the result will always have a qname() method here.

[cdce8p]

Instead of .infer() try safe_infer from the pylint/checkers/utils.py module.

[coveralls]

Coverage increased (+0.006%) to 91.847% when pulling 8f2173a on matusvalo:deprecated_decorators into 5805a73 on PyCQA:master.

[Pierre-Sassoulas]

Thank you for this checker ! It will be available in 2.9.0 which should release shortly.

[Pierre-Sassoulas]

Merging as @cdce8p comments were taken into account.

[matusvalo]

Thank you @Pierre-Sassoulas !