Add a checker for superfluous `import a` statements when there is already `import a.b`

[e-gebes]

Current problem

I was reading the documentation for ungrouped-imports:

https://pylint.readthedocs.io/en/stable/user_guide/messages/convention/ungrouped-imports.html

Under "Correct code" it says:

import logging
import logging.config

But for me this is not "correct", but bad style because import logging is superfluous anyway. logging is implicitly imported with import logging.config.

See also:

https://docs.python.org/3/reference/simple_stmts.html#the-import-statement ("Examples")
https://docs.python.org/3/reference/import.html#the-module-cache

Desired solution

I suggest to change the example in the documentation to use logging.config and logging.handlers.

I also suggest to introduce a checker to warn about such superfluous import statements.

Additional context

No response

[akamat10]

I think that example can be improved. What you are suggesting is covered under reimported check.

[e-gebes]

I think that example can be improved. What you are suggesting is covered under reimported check.

I tried it out with Pylint 2.17.7 and with 3.3.0, neither one trigger a message on the following piece of code:

import logging
import logging.config

[akamat10]

Hmm. Need to check it out. I have seen it work recently for a different case. Will investigate.

[akamat10]

You are right. I made a mistake. It is not supported. It sounds like a nice feature and is not too difficult to add for the following case:

import logging
import logging.config

It may potentially need extra work for the reverse order ie.

import logging.config
import logging

One thing that will need some thought is whether it should fit into an existing warning or whether it should be a new message like say implicit-reimport