Detect missing arguments in logging format strings

[sam-s]

Current problem

The following error should be easily detectable:

import logging
logging.info("foo %s")  # missing format arg

the missing arguments should be easily detectable, like we already get too-many-format-args on

logging.warning("foo",1,2,3) # extra format args

Desired solution

I want pylint to issue the too-few-format-args error on the above code.

Additional context

No response

[zenlyj]

thanks for the report, you may be referring to logging-too-many-args and logging-too-few-args here.

seems that the checker is skipping these checks if no arguments are provided:

pylint/pylint/checkers/logging.py

Lines 329 to 332 in 0687c85

	if not num_args:
	# If no args were supplied the string is not interpolated and can contain
	# formatting characters - it's used verbatim. Don't check any further.
	return

i agree that we should probably raise logging-too-few-args when the logging message contains placeholders but no arguments are provided. such cases are more likely to be oversights rather than intentional verbatim messages.

[Pierre-Sassoulas]

Closed in #10321