Scary indeed.

This one could be helped by always using this pattern whenever you write a function that returns a value, in any language, along with no early returns:

int func(...) {
    int result = -1;
    ...
    return result;
}

I always start with writing my result default value, ideally indicating failure, and the return line. Then I implement the rest. We often don’t have the luxury of choosing the language we work with that has the features we like, but consistently enforced code style can help with a lot of problems. Anyone can make mistakes like the one in this bug regardless of experience so every little bit helps.