[PATCH] [ZE] (critical?) object comparison recursion bug

Here's a patch for the ZE which shortcuts the recursive comparisions if the object properties hash tables are at the same address (therefore, the objects are the same object). This should save a few cycles for non-recursive objects too. Additionally, when comparing hash tables, this patch changes the recursion protection to return indicating that the tables are not the same rather than raising a fatal error. I'd feel happier if we could control this behaviour via a flag, as it is not always the best thing to do. (Perhaps we should only enable this when checking for identity for objects?). --Wez. On 09/29/02, "Wez Furlong" <wez@thebrainroom.com> wrote: > The code below produces: > > Fatal error: Nesting level too deep - recursive dependency? > in test.php on line 24 > > This is should not happen since the objects being compared are > the same object, so there should be no need to recusively compare the > objects. > Additionally, I think the comparison should bail out (without a fatal > error) when the objects are not the same and when a recursive dependency > is found. > > IMHO, this is a critical problem that should be fixed for 4.3, since it > prevents anyone from using OO with references in a reasonable way. > > > <?php > class A { > var $b; > > function A() > { > $this->b =& new B($this); > } > } > > class B { > var $a; > > function B(&$a) > { > $this->a =& $a; > } > } > > $one =& new A; > $two =& $one; > > if ($one == $two) { // <-- fatal error here > echo "Same object\n"; > } else { > echo "not the same object\n"; > } > ?> > > -- > Wez Furlong > The Brain Room Ltd. > > > -- > PHP Development Mailing List <http://www.php.net/> > To unsubscribe, visit: http://www.php.net/unsub.php

Index: zend_operators.c =================================================================== RCS file: /repository/Zend/zend_operators.c,v retrieving revision 1.125 diff -u -r1.125 zend_operators.c --- zend_operators.c 26 Sep 2002 18:39:28 -0000 1.125 +++ zend_operators.c 29 Sep 2002 11:34:19 -0000 @@ -1245,7 +1245,7 @@ if (Z_OBJCE_P(op1) != Z_OBJCE_P(op2)) { result->value.lval = 0; } else { - if (zend_hash_compare(Z_OBJPROP_P(op1), Z_OBJPROP_P(op2), (compare_func_t) hash_zval_identical_function, 1 TSRMLS_CC)==0) { + if (Z_OBJPROP_P(op1) == Z_OBJPROP_P(op2) || zend_hash_compare(Z_OBJPROP_P(op1), Z_OBJPROP_P(op2), (compare_func_t) hash_zval_identical_function, 1 TSRMLS_CC)==0) { result->value.lval = 1; } else { result->value.lval = 0; @@ -1725,7 +1725,11 @@ ZEND_API void zend_compare_symbol_tables(zval *result, HashTable *ht1, HashTable *ht2 TSRMLS_DC) { result->type = IS_LONG; - result->value.lval = zend_hash_compare(ht1, ht2, (compare_func_t) hash_zval_compare_function, 0 TSRMLS_CC); + if (ht1 == ht2) { + result->value.lval = 0; + } else { + result->value.lval = zend_hash_compare(ht1, ht2, (compare_func_t) hash_zval_compare_function, 0 TSRMLS_CC); + } }