Missing named arguments in formatting call¶
ID: py/str-format/missing-named-argument
Kind: problem
Security severity:
Severity: error
Precision: high
Tags:
- reliability
- correctness
Query suites:
- python-security-and-quality.qls
Click to see the query in the CodeQL repository
A formatting expression, that is an expression of the form the_format.format(args) or format(the_format, args), can use named fields. If it does, then keyword arguments must be supplied for all named fields. If any of the keyword arguments are missing then a KeyError will be raised.
Recommendation¶
Change the format to match the arguments and ensure that the arguments have the correct names.
Example¶
In the following example, if unlikely_condition() is true, then a KeyError will be raised as the keyword parameter eggs is missing. Adding a keyword parameter named eggs would fix this.
def unsafe_named_format():
the_format = "{spam} {eggs}"
if unlikely_condition():
return the_format.format(spam="spam", completely_different="eggs")
else:
return the_format.format(spam="spam", eggs="eggs")
References¶
Python Library Reference: String Formatting.