python3.9: forbid anything, but dotted names inside decorators

Rule request

Thesis

After python3.9 we would be able to use this as a decorator:

@decorator_generator[start[5]:end_generator(start[5], end[-1])](gen=DecEnum.generate, **options).build() / overloaded_operator()
def some(): 
    ...

WHAT?! WHY?!

We need to add a rule that forbids it. Only names, attributes, and calls should be allowed after @

Reasoning

This is an extra complexity that is totally not required. I don’t have any valid use-cases for this. Use variables, functions, attributes. It is not that hard!

Related: https://www.python.org/dev/peps/pep-0614/

[sobolevn]

Nope, sorry. python3.9 is not even released. Let’s wait 🙂

[lewisacidic]

I agree it is not a fantastic example, the variable name button_0 is bad, and button[0].anything smells. But what if you have a dictionary of buttons:

@buttons["registration"].clicked.connect
def spam():
     ...

I do think index notation is more succinct and doesn’t compromise readability in some contexts.

In any case, thanks for clarifying the reasoning behind this issue: it’s a matter of enforcing explicit variable naming, rather than avoiding messy expressions as decorators which was my interpretation from the initial comment. I’ll respectfully probably disable this rule as and when it lands.

Off topic, but thanks for your work on this library!