[logging-too-few-args] Raise for format strings with no interpolation at all

[Pierre-Sassoulas]

Type of Changes

	Type
✓	🐛 Bug fix
✓	🔨 Refactoring

Description

The original decision was taken in db8b3a4 during implementation with a different rational ("If no args were supplied, then all format strings are valid don't check any further.") and was not discussed again when the comment was updated in #2713. I think the new behavior make sense especially considering that the primer shows 4 false negative in home-assistant.

Taken from the initial implementation in #10108 based on indication from #9999

Closes #9999

[Copilot]

Pull Request Overview

This PR fixes a bug in the logging checker by ensuring that format strings with insufficient interpolation arguments are flagged, and it refactors the logic to handle such cases consistently.

• Added new test files for both old and new-style logging usage to demonstrate and verify the improved behavior.
• Removed an early exit in the logging checker to enforce proper argument checking even when no arguments are supplied.

Reviewed Changes

Copilot reviewed 4 out of 9 changed files in this pull request and generated no comments.

File	Description
tests/functional/l/logging/logging_too_few_args_old_style.py	Added tests for old style logging calls with too few arguments
tests/functional/l/logging/logging_too_few_args_new_style.py	Added tests for new style logging calls with too few arguments
pylint/checkers/logging.py	Removed the early return to update the logic for format string checks

Files not reviewed (5)

• doc/whatsnew/fragments/9999.false_negative: Language not supported
• tests/functional/l/logging/logging_too_few_args.txt: Language not supported
• tests/functional/l/logging/logging_too_few_args_new_style.txt: Language not supported
• tests/functional/l/logging/logging_too_few_args_old_style.rc: Language not supported
• tests/functional/l/logging/logging_too_few_args_old_style.txt: Language not supported

Comments suppressed due to low confidence (3)

tests/functional/l/logging/logging_too_few_args_old_style.py:5

• [nitpick] Consider adding assertions or expected warning message verification to ensure that this logging call produces the expected warning, instead of relying solely on the function call.

logging.error("%s, %s", 1)  # [logging-too-few-args]

tests/functional/l/logging/logging_too_few_args_new_style.py:7

• [nitpick] Consider adding explicit assertions to verify that this logging call triggers the expected warning, which would improve the robustness of the test coverage.

logging.error("{}")  # [logging-too-few-args]

pylint/checkers/logging.py:328

• Ensure that the removal of this early return does not lead to unexpected behavior when no logging arguments are supplied; verify that subsequent logic handles these cases appropriately.

if not num_args:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.89%. Comparing base (3b9e2d2) to head (f7200cf).
Report is 97 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10321      +/-   ##
==========================================
- Coverage   95.89%   95.89%   -0.01%     
==========================================
  Files         175      175              
  Lines       19082    19080       -2     
==========================================
- Hits        18299    18297       -2     
  Misses        783      783              

Files with missing lines	Coverage Δ
pylint/checkers/logging.py	94.66% <ø> (-0.08%)	⬇️

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[github-actions]

🤖 Effect of this PR on checked open source code: 🤖

Effect on home-assistant:
The following messages are now emitted:

1. logging-too-few-args:
   Not enough arguments for logging format string
   https://github.com/home-assistant/core/blob/09f6246d1b7693393332535866e02fb203fb689d/homeassistant/components/homeworks/config_flow.py#L175
2. logging-too-few-args:
   Not enough arguments for logging format string
   https://github.com/home-assistant/core/blob/09f6246d1b7693393332535866e02fb203fb689d/homeassistant/components/shopping_list/__init__.py#L242
3. logging-too-few-args:
   Not enough arguments for logging format string
   https://github.com/home-assistant/core/blob/09f6246d1b7693393332535866e02fb203fb689d/homeassistant/components/snoo/config_flow.py#L53
4. logging-too-few-args:
   Not enough arguments for logging format string
   https://github.com/home-assistant/core/blob/09f6246d1b7693393332535866e02fb203fb689d/homeassistant/components/sisyphus/light.py#L88
5. logging-too-few-args:
   Not enough arguments for logging format string
   https://github.com/home-assistant/core/blob/09f6246d1b7693393332535866e02fb203fb689d/homeassistant/components/sisyphus/light.py#L94

This comment was generated for commit f7200cf