Zend: refactor zend_parse_arg_class() so that it can be reused

[Girgias]

And stop throwing the exceptions directly, fixing quiet mode handling at the same time.

Based on: #23052

[arnaud-lb]

Can we avoid saving this in the non-error case? This increases code size and the load adds overhead.

We could change zend_parse_arg_class() so that it returns a zend_class_entry* or NULL. This way we don't need to take the address of dest, which is inline with previous refactorings:

zend_class_entry *ce = dest;
dest = zend_parse_arg_class(_arg, ce, _i, check_null);
if (UNEXPECTED(!dest)) {
    _error = ce ? ZSTR_VAL(ce->name) : NULL;
    ...
}

[Girgias]

That should work yeah. Those semantics will be quite weird.

I do think we should get rid of the "derived from" behaviour and introduce a custom FastZPP specifier for it that takes the CE explicitly rather than re-using the pointer for two different things. But that'll need to wait for PHP next I think as this affects extensions in non obvious ways.

[arnaud-lb]

That's what zend_parse_arg_class() does in my code snippet :) (no re-use, ce is explicit). The semantics of Z_PARAM_CLASS_EX() doesn't change however.