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[2009-11-25 21:10 UTC] shepik at yandex dot ru
Description:
------------
I tried this in php 5.3.2-dev (snapshot from 2009-11-19, latest php for windows available) and in php 5.3.0 on linux.
I tried to do something like 'lazy object instantiation', and found this strange behaviour of php.
Method "valid" declared in "lazyNew" class is called in context of instance of "ArrayIterator" class.
Reproduce code:
---------------
<?php
class lazyNew implements Iterator {
private $obj = null;
private $func ;
public function __construct($func) {
$this->func = $func;
}
public function init() {
if ($this->obj === null) {
$func = $this->func;
$this->obj = $func();
}
return $this->obj;
}
public function current() {
return $this->init()->current();
}
public function valid() {
echo "valid on ".get_class($this)."\n";
//also try var_dump($this)
return $this->init()->valid();
}
public function next() {
return $this->init()->next();
}
public function key() {
return $this->init()->key();
}
public function rewind() {
echo "rewind on ".get_class($this)."\n";
return $this->init()->rewind();
}
}
$P = new lazyNew(function() use (&$P) {
return $P = new ArrayIterator(array(1,2,3,4,5));
});
foreach ($P as $val) echo($val);
?>
Expected result:
----------------
rewind on lazyNew
valid on lazyNew
12345
Actual result:
--------------
rewind on lazyNew
valid on ArrayIterator
Fatal error: Call to undefined method ArrayIterator::init() in /storage1/www/htdocs/evectio/scripts/test.php on line 20
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Last updated: Sat Jul 12 20:01:32 2025 UTC |
And if change code to $P = new lazyNew(function() use (&$P) { $v = new ArrayIterator(array(1,2,3,4,5)); $P = null; return $v; }); instead of fatal error, or "12345", or something else, i get segmentation fault.shepik@samoval ~/php-5.3-200911260930 $ gdb sapi/cli/php GNU gdb 6.8 [..] This GDB was configured as "i686-pc-linux-gnu"... (gdb) run test_variant2.php Starting program: /home/shepik/php-5.3-200911260930/sapi/cli/php test_variant2.php rewind on Foo Program received signal SIGSEGV, Segmentation fault. 0x083a67d7 in zend_get_class_entry (zobject=0x8e536c0) at /home/shepik/php-5.3-200911260930/Zend/zend_API.c:230 230 if (Z_OBJ_HT_P(zobject)->get_class_entry) { (gdb) bt #0 0x083a67d7 in zend_get_class_entry (zobject=0x8e536c0) at /home/shepik/php-5.3-200911260930/Zend/zend_API.c:230 #1 0x083bef20 in zend_call_method (object_pp=0xbfc6b3cc, obj_ce=0x8e50038, fn_proxy=0x8e50170, function_name=0x87194c5 "valid", function_name_len=5, retval_ptr_ptr=0xbfc6b3c8, param_count=0, arg1=0x0, arg2=0x0) at /home/shepik/php-5.3-200911260930/Zend/zend_interfaces.c:88 #2 0x083bf1d9 in zend_user_it_valid (_iter=0x8e53754) at /home/shepik/php-5.3-200911260930/Zend/zend_interfaces.c:163 #3 0x08446999 in ZEND_FE_RESET_SPEC_CV_HANDLER (execute_data=0x8e7dba0) at /home/shepik/php-5.3-200911260930/Zend/zend_vm_execute.h:22653 #4 0x083d0b7e in execute (op_array=0x8e51a84) at /home/shepik/php-5.3-200911260930/Zend/zend_vm_execute.h:104 #5 0x083a605e in zend_execute_scripts (type=8, retval=0x0, file_count=3) at /home/shepik/php-5.3-200911260930/Zend/zend.c:1194 #6 0x0833df90 in php_execute_script (primary_file=0xbfc6d8cc) at /home/shepik/php-5.3-200911260930/main/main.c:2231 #7 0x0846b874 in main (argc=2, argv=0xbfc6da24) at /home/shepik/php-5.3-200911260930/sapi/cli/php_cli.c:1190it seems that "rewind" and "valid" are called on $P variable and not on the contents of $P variable at the moment "foreach" was called. #3 0x08397fe1 in zend_call_function (fci=0xbfdeeaf4, fci_cache=0xbfdeeac4) at /home/shepik/php-5.3-200911260930/Zend/zend_execute_API.c:942 #4 0x083bef94 in zend_call_method (object_pp=0xbfdeeb60, obj_ce=0x8f20038, fn_proxy=0x8f20180, function_name=0x871959d "rewind", function_name_len=6, retval_ptr_ptr=0x0, param_count=0, arg1=0x0, arg2=0x0) at /home/shepik/php-5.3-200911260930/Zend/zend_interfaces.c:97 #5 0x083bf735 in zend_user_it_rewind (_iter=0x8f23754) at /home/shepik/php-5.3-200911260930/Zend/zend_interfaces.c:261 *(zval*)iter->it.data = {value = {lval = 1, dval = 5.6472996106671002e-268, str = {val = 0x1 <Address 0x1 out of bounds>, len = 141731200}, ht = 0x1, obj = {handle = 1, handlers = 0x872a580}}, refcount__gc = 3, type = 5 '\005', is_ref__gc = 1 '\001'} now callind "valid": #1 0x083bef20 in zend_call_method (object_pp=0xbfdeeb5c, obj_ce=0x8f20038, fn_proxy=0x8f20170, function_name=0x87194c5 "valid", function_name_len=5, retval_ptr_ptr=0xbfdeeb58, param_count=0, arg1=0x0, arg2=0x0) at /home/shepik/php-5.3-200911260930/Zend/zend_interfaces.c:88 #2 0x083bf1d9 in zend_user_it_valid (_iter=0x8f23754) at /home/shepik/php-5.3-200911260930/Zend/zend_interfaces.c:163 *(zval*)iter->it.data = {value = {lval = 0, dval = 8.4879831638610893e-314, str = {val = 0x0, len = 4}, ht = 0x0, obj = {handle = 0, handlers = 0x4}}, refcount__gc = 2, type = 0 '\0', is_ref__gc = 1 '\001'} (i don't know if this information is useful at all, but hope it is)