Re: [RFC] Transform exit() from a language construct into a standard function

On Mon, 27 May 2024, Ilija Tovilo wrote: > On Sun, May 26, 2024 at 11:47 PM Gina P. Banyard <internals@gpb.moe> > wrote: > > > > On Wednesday, 8 May 2024 at 14:40, Gina P. Banyard > > <internals@gpb.moe> wrote: > > > > > I would like to formally propose my idea for exit() as a function > > > brought up to the list on 2024-02-24 [1] with the following RFC: > > > https://wiki.php.net/rfc/exit-as-function > > > > As there haven't been any comments for nearly two weeks, I'm > > planning on opening the vote for the RFC on Tuesday. Right now, I am not going to be in favour of this. Specfically because the Backward Incompatible Changes don't list some of the backward breaking changes, and no mitigations are provided. See below. I also don't see the benefit from doing this in the first place. exit/die has always meant "bail straight out", without any function semantics (from https://www.php.net/exit): exit — Output a message and terminate the current script exit is a language construct and it can be called without parentheses if no status is passed. It's not that this a particularly new or novel behaviour. I saw somewhere else in the thread that the exit construct could already throw a catchable exception. I consider that a bug. > As mentioned early on in private, I don't see a convincing reason to > remove tokenizer/parser support for exit/die. I'd rather see this > handled in the parser directly, by converting the standalone keywords > to function calls. This avoids any backwards incompatibility, and > avoids special handling in zend_compile_const. > > Another thing that's probably not too important: The PR likely breaks > dead code elimination for exit() and die(). I have just checked this for Xdebug, and you're definitely right with that. With the removal of the ZEND_EXIT opcode, it can not now detect a scope/function exit now. It also breaks my "do tasks on ZEND_EXIT" with the profiler. It is used to always write the closing profiling footer to the files. Without me being able to overload thati opcode, data would not be complete. I even have two bugs (with tests) for this: - https://bugs.xdebug.org/68 - https://bugs.xdebug.org/631 Xdebug has been overloading ZEND_EXIT for nearly 20 years now. > This could be re-added by checking for the never return type instead. I can't quite see a way on how to do that? The EXIT is replaced by an INIT_FCALL/DO_ICALL: 4 0 E > EXT_STMT 1 ECHO '55' 5 2 EXT_STMT - 3 > EXIT - 6 4* EXT_STMT - 5* ECHO '675' - 7 6* EXT_STMT - 7* > RETURN null + 3 INIT_FCALL 'exit' + 4 DO_ICALL + 6 5 EXT_STMT + 6 ECHO '675' + 7 7 EXT_STMT + 8 > RETURN null The opcodes don't have direct access to the type mask structure as far as I know. cheers, Derick