isset() indeed, mea culpa. I'll try to abstain from posting when I'm sleepy
Secondly, can you provide more information by empty() may introduce security holes.
No, I didn't mean that, I mean that
security fixes may introduce new holes
. This follows from the "age barrier" between time-tested mature code and "young" new code. It's happened a lot before (to me as to many others) and is definitely a thing to watch out for when you're a newbie developer. And it's not just about security holes but about generic "old-skool" bugs/bugfixes as well.
To answer the question (with "regular bug" substituted for "security hole"), a value of 0 will return true for isset() and false for !empty(), buf of course you're well aware of that. As for how
boss01 fixed the code - we can't tell without seeing it, that's why I ask him to post the new version again. Might be fixed, might have forgotten to plug a hole, might have introduced a new one. As I said, I've seen it happen before, it's just in the nature of the programming process.