Fixed Inappropriate Logical Expression

[asifhaider]

Details

While triaging your project, our bug-fixing tool generated the following message(s)-

In file: _core.py, method: process_args_into_dataframe, a logical expression uses the identity operator. A new object is created inside the identity check operation and then used for matching identity. Since this is a distinct, new object, it will not match with anything else. As a result, the identity check will have a logical short circuit and the program may have unintended behavior. iCR suggested that the logical operation should be reviewed for correctness.

In this specific case, the line 1134 of the file _core.py is as follows:

if argument_list is None or argument_list is [None]:

In python, the is operator checks for identity, not equality. This means that the is operator checks whether the two operands refer to the same object or not. In this case, [None] is a list with None element. However, the [None] is a new object and is not the same as the argument_list variable being compared with. In the mentioned case, the is operator will always evaluate to False. We can test this scenerio by running the following code in python:

a = [None]
print(a is [None]) # This will print False
print(a == [None]) # This will print True

Here, the is operator evaluates the expression to return False. However, it should have returned True in this case.

Changes

• To ensure logical correctness, in the line 1134 the is operator is replaced with == operator.

if argument_list is None or argument_list == [None]:

Suggestions related to these changes are welcomed.

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This work is done by the security researchers from OpenRefactory and is supported by the Open Source Security Foundation (OpenSSF): Project Alpha-Omega. Alpha-Omega is a project partnering with open source software project maintainers to systematically find new, as-yet-undiscovered vulnerabilities in open source code - and get them fixed – to improve global software supply chain security.

The bug is found by running the Intelligent Code Repair (iCR) tool by OpenRefactory and then manually triaging the results.

[alexcjohnson]

Thanks @asifhaider! You're absolutely right, that condition can never be true... (cc @nicolaskruchten, it's not clear to me what we're trying to catch with this condition anyway?)

However your fix breaks a bunch of tests, looks like because == with a numpy array or some derivative of it throws an error. So perhaps instead of argument_list == [None] we need to do (len(argument_list) == 1 and argument_list[0] is None) or some such?