False positive py/uninitialized-local-variable

[woodywuuu]

Description of the false positive

Code samples or links to source code

class Foo:
    def foo(self, a, b, c=0):
        start = 0
        visible = not (a == b and c)
        end = start if visible else None
        return end

CodeQL Version: 2.18.3

Alert : Local variable 'visible' may be used before it is initialized.

I suspect that the issue is caused by EssaVariable being unable to locate the assignment statement for the variable visible, but I'm not sure how to modify the ql statement.

[woodywuuu]

If you modify it to be written like this, it will not be able to detect any issues.

class Foo:
    def foo(self, a, b, c=0):
        start = 0
        # visible = not (a == b and c)
        end = start if visible else None
        return end

[RasmusWL]

Thanks for reporting this, I agree that's a FP. We'll take a closer look, but can't make any promises on when we have a fix.

I think I've seen issues with inline if-then-else before, so we might have some context on this already (found it in #10998)