redefined-outer-name no longer emitted in nested loops

[bolducfr]

Bug description

The following Python code contains a redefined variable (instrument) in the inner loop:

def conflate(book):
    result = {}
    for instrument, trades in book.items():
        total = 0
        for qty, side1, side2, instrument in trades:
            if side1 != side2:
                total += qty
        result[instrument] = total
    return result

Pylint 2.13 correctly detects the error with the following message:

************* Module test
test.py:5:8: W0621: Redefining name 'instrument' from outer scope (line 3) (redefined-outer-name)

However, Pylint 2.14 fails to detect it.

Configuration

No response

Command used

pytlint test.py

Pylint output

Outputs nothing.

Expected behavior

Output:
************* Module test
test.py:5:8: W0621: Redefining name 'instrument' from outer scope (line 3) (redefined-outer-name)

Pylint version

2.14

OS / Environment

No response

Additional dependencies

No response

[jacobtylerwalls]

Thanks for the report. This was an intentional design decision, because there were inconsistencies with how pylint treated overwriting loop variables. (We were special casing nested loops only.) To retain this check you need to enable the optional redefined-loop-name message. Ref #5649

[bolducfr]

How do I re-enable the check?

I tried adding:

--enable=redefined-loop-name

as well as:

--load-plugin==pylint.extensions.redefined_loop_name

and even:

--load-plugin==pylint.extensions.redefined_loop_name --enable=redefined-loop-name

but none of these work.

[Pierre-Sassoulas]

The doc got better this release too : https://pylint.pycqa.org/en/latest/user_guide/messages/warning/redefined-loop-name.html?highlight=redefined-loop-name 😄

[Pierre-Sassoulas]

I think the issue is that you're using load-plugin instead of --load-plugins. Don't you get a warning for this ?

[jacobtylerwalls]

Yes, that's the issue. This command works:

pylint b.py --load-plugins=pylint.extensions.redefined_loop_name

************* Module b
b.py:5:8: W2901: Redefining 'instrument' from loop (line 3) (redefined-loop-name)

------------------------------------------------------------------
Your code has been rated at 8.89/10 (previous run: 0.00/10, +8.89)

@Pierre-Sassoulas @DanielNoord , no I don't see an error with --load-plugin. Is it an old name?

[Pierre-Sassoulas]

Opened #6810 to address this

[bolducfr]

I confirm I can again get the warning with the suggestion above. Thank you!