Schroedinger Objects

Yep, the default for an instantiated object should be true (i.e. it's
not null).

Andi

At 12:14 AM 8/25/2005, Marcus Boerger wrote:

Hello Andi,

in that case we are providing a default conversion, maybe like the old
one? Or just always return 1 like we do in 5.0 ?

marcus

Thursday, August 25, 2005, 1:31:08 AM, you wrote:

Yep I think that's a good point.
Checking for cast is the right thing IMO.

At 02:45 PM 8/24/2005, Rasmus Lerdorf wrote:

As per bug #34199 and as Rob points out, if($obj) and if(!$obj) are
handled by different opcodes and these two opcodes are inconsistent in
whether they call an object's cast_object handler.

if($obj) results in a ZEND_JMPZ_SPEC_CV_HANDLER which calls
i_zend_is_true() which always return true for objects, no matter what
(ignore compatibility mode here) because of this code in zend_execute.h:

    case IS_OBJECT:
        if(IS_ZEND_STD_OBJECT(*op)) {
            TSRMLS_FETCH();
            if(EG(ze1_compatibility_mode)) {
                result =

(zend_hash_num_elements(Z_OBJPROP_P(op))?1:0);
} else {
result = 1;
}
} else {
result = 1;
}
break;

if(!$obj) results in a which calls convert_to_boolean() which in turn
calls convert_object_to_type() which has:

if (Z_OBJ_HT_P(op)->cast_object) {

if (Z_OBJ_HT_P(op)->cast_object(op, op, ctype, 1 TSRMLS_CC) ==

SUCCESS) {
op->type = ctype;

}

This means that any object which actually implements a cast_object
handler that returns false under some condition will be broken. The
simple example is:

$a = simplexml_load_string('<a></a>');
if($a && !$a) echo "BUG!";

I think we need to fix i_zend_is_true's IS_OBJECT case to check to see
if the object has a cast_object handler and call it or just call
convert_to_boolean() there. Or we need to clean this up and not have
such different codepaths for these two cases.