When executing ZEND_FETCH_OBJ_IS on a non-object, the handler dispatches to
zend_fetch_property_address_read_helper with type==BP_VAR_IS and ends up
generating an error (isset() is supposed to be quiet) here:
if (Z_TYPE_P(container) != IS_OBJECT ||
!Z_OBJ_HT_P(container)->read_property) {
zend_error(E_NOTICE, "Trying to get property of non-object");
*retval = EG(uninitialized_zval_ptr);
SELECTIVE_PZVAL_LOCK(*retval, &opline->result);
AI_USE_PTR(EX_T(opline->result.u.var).var);
It's cousin ZEND_FETCH_DIM_IS winds up at zend_fetch_dimension_address() where
the non-arrayness of op1 is handled via these case statements:
case IS_NULL: {
/* for read-mode only */
if (result) {
result->var.ptr_ptr = &EG(uninitialized_zval_ptr);
PZVAL_LOCK(*result->var.ptr_ptr);
}
if (type==BP_VAR_W || type==BP_VAR_RW) {
zend_error(E_WARNING, "Cannot use a NULL value as an array");
}
break;
}
default: {
switch (type) {
case BP_VAR_UNSET:
zend_error(E_WARNING, "Cannot unset offset in a
non-array variable");
/* break missing intentionally */
case BP_VAR_R:
case BP_VAR_IS:
retval = &EG(uninitialized_zval_ptr);
break;
default:
retval = &EG(error_zval_ptr);
break;
}
if (result) {
result->var.ptr_ptr = retval;
PZVAL_LOCK(*result->var.ptr_ptr);
}
if (type==BP_VAR_W || type==BP_VAR_RW) {
zend_error(E_WARNING, "Cannot use a scalar value as an
array");
}
}
Which indicate the expected behavior of silent failure. It's probably gone
undetected till now as it requires fetching a property or dimension offset from
a property in a third (non-object) variable within an isset() statement:
$foo = NULL;
isset($foo->bar->baz);
Unless someone can suggest why Objects should be noisy inside isset(), I'd like
to suggest the following fix:
Index: Zend/zend_vm_def.h
===================================================================
RCS file: /repository/ZendEngine2/zend_vm_def.h,v
retrieving revision 1.120
diff -u -r1.120 zend_vm_def.h
--- Zend/zend_vm_def.h 13 Jun 2006 12:56:20 -0000 1.120
+++ Zend/zend_vm_def.h 5 Jul 2006 20:52:41 -0000
@@ -1176,7 +1176,9 @@
if (Z_TYPE_P(container) != IS_OBJECT ||
!Z_OBJ_HT_P(container)->read_property) {
- zend_error(E_NOTICE, "Trying to get property of non-object");
+ if (type != BP_VAR_IS) {
+ zend_error(E_NOTICE, "Trying to get property of
non-object");
+ }
*retval = EG(uninitialized_zval_ptr);
SELECTIVE_PZVAL_LOCK(*retval, &opline->result);
AI_USE_PTR(EX_T(opline->result.u.var).var);
I suggest only excluding BP_VAR_IS since the matching behavior for unset()/DIM
is to throw a notice. I could potentially see excluding BP_VAR_R in order to
match read/DIM, but personally I never liked that behavior :)
-Sara
