Fix a false positive for 'missing-parentheses-for-call-in-test' and add doc example

[Pierre-Sassoulas]

Type of Changes

	Type
✓	📜 Docs

Description

Part of #5953 Actual conversation with ChatGPT that led to this MR:

Pierre Sassoulas: Could you give me an example of bad code raising a 'missing-parentheses-for-call-in-test' message in pylint

Sure, here's an example of code that would raise the "missing-parentheses-for-call-in-test" message in Pylint:

def example_func():
    return "example return value"

if example_func:
    print("example_func is defined")

In this code, the line if example_func: raises the "missing-parentheses-for-call-in-test" message, because Pylint is expecting to see a function call in the test expression of an if statement, but there are no parentheses after example_func. To correct this, you can add parentheses to make it a function call:

if example_func():
    print("example_func is defined")

Pierre Sassoulas
Could you make it more lively, the name is very generic ?

Sure, here's a more lively example that also includes a more descriptive function name:

def say_hello():
    return "Hello, world!"

if say_hello:
    print("say_hello is defined")

In this code, the line if say_hello: raises the "missing-parentheses-for-test-call-in-if" message, because Pylint is expecting to see a function call in the test expression of an if statement, but there are no parentheses after say_hello. To correct this, you can add parentheses to make it a function call:

if say_hello():
    print("say_hello is defined")

Pierre Sassoulas
That's kinda expected and boring, could you be more imaginative ? Also I don't think it should return a string, it's supposed to return a boolean.

Sure, here's a more imaginative example with a function that returns a boolean:

def is_it_a_good_day():
    import random
    return random.choice([True, False])

if is_it_a_good_day:
    print("Today is a good day!")

In this code, the line if is_it_a_good_day: raises the "missing-parentheses-for-call-in-test" message, because Pylint is expecting to see a function call in the test expression of an if statement, but there are no parentheses after is_it_a_good_day. To correct this, you can add parentheses to make it a function call:

if is_it_a_good_day():
    print("Today is a good day!")

Pierre Sassoulas
You need to add a # [missing-parentheses-for-call-in-test] on the line the actual message would be raised, could you update the bad example, please ?

Of course! Here's the updated bad example with a comment indicating the location of the "missing-parentheses-for-call-in-test" message:

def is_it_a_good_day():
    import random
    return random.choice([True, False])

if is_it_a_good_day:  # [missing-parentheses-for-call-in-test]
    print("Today is a good day!")

In this code, the line if is_it_a_good_day: would raise the "missing-parentheses-for-call-in-test" message, because Pylint is expecting to see a function call in the test expression of an if statement, but there are no parentheses after is_it_a_good_day. To correct this, you can add parentheses to make it a function call, as shown in the corrected code in my previous answer.

[codecov]

Codecov Report

Merging #8185 (69e76de) into main (8d13dbe) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8185      +/-   ##
==========================================
- Coverage   95.53%   95.53%   -0.01%     
==========================================
  Files         177      177              
  Lines       18622    18616       -6     
==========================================
- Hits        17791    17785       -6     
  Misses        831      831              

Impacted Files	Coverage Δ
pylint/checkers/base/basic_checker.py	97.87% <100.00%> (-0.03%)	⬇️

[Pierre-Sassoulas]

This started as a fun chat GPT fueled adventure and then I did not manage to make it raise like it should and went on another more painful adventure.

[DanielNoord]

Two nits! Love this adventure 😄

[DanielNoord]

This is a nit, but can't we do the unpacking above where we are already catching InferenceError?

[Pierre-Sassoulas]

Sure, that not a nit that's an optimization 😄

[github-actions]

🤖 According to the primer, this change has no effect on the checked open source code. 🤖🎉

This comment was generated for commit 69e76de