Use of the return value of a procedure¶
ID: py/procedure-return-value-used
Kind: problem
Security severity:
Severity: warning
Precision: high
Tags:
- maintainability
Query suites:
- python-security-and-quality.qls
Click to see the query in the CodeQL repository
All functions in Python return a value. If a function has no return statements or none of the return statements return a value then the function will return None. However, this value has no meaning and should be ignored.
Using the return value of such a ‘procedure’ is confusing to the reader as it suggests that the value is significant.
Recommendation¶
Do not use the return value of a procedure; replace x = proc() with proc() and replace any use of the value with None.
Example¶
In this example, the my_print function is a procedure as it returns no value of any meaning. Using the return value is misleading in subsequent code.
import sys
def my_print(*args):
print (args)
def main():
err = my_print(sys.argv)
if err:
sys.exit(err)
#FIXED VERSION
def main():
my_print(sys.argv)
#The rest of the code can be removed as None as always false
References¶
Python Library Reference: None.