Doesn't really matter if ARC is in use or not; any setjmp
/longjmp
that jumps over any frame of code from the system frameworks will yield undefined behavior (for the same reason that exceptions cannot be used for recoverable error handling).
So, yes, that code might leak. Might because it depends on whether the compiler emits a retain
/release
in that block and where. Might also because whether the compiler emits retain
/release
will be impacted by the optimization level and, over time, the version of the compiler.
longjmp
only unwinds to Lua internals, and never crosses any system code, except for Lua source (which is aware), and my entry points (which I hope are aware).
That is helpful. As long as you structure your entry points such that they never intermingle system scope with Lua jumpable scopes, you should be OK. I would recommend turning off ARC in the source files where you have to manage this (and, of course, put the ObjC->Lua interface into a nicely encapsulated bit of implementation so the rest of your code can be ARC clean).
Consider, though, that there is non-obvious risk:
for(id x in anArray) {
... lua call that causes longjmp ...
}
The above would cause lua to "jump over" system code. Same goes for enumerateWithBlock:
, KVO, Notification handlers, etc...
You're going to have to think very very carefully about every potential stack trigger by a call from Lua into your code. If that call triggers any kind of automated behavior on the part of the system that could then call Lua API that could trigger a longjmp
, all bets are off.