ID: 31118
Updated by: [EMAIL PROTECTED]
Reported By: dennis at inmarket dot lviv dot ua
-Status: Analyzed
+Status: Wont fix
Bug Type: Zend Engine 2 problem
Operating System: Win
PHP Version: 5.0.2
Assigned To: andi
Previous Comments:
------------------------------------------------------------------------
[2004-12-23 23:48:39] [EMAIL PROTECTED]
I looked into this problem. It's actually not a bug but just "weird"
behavior as a result of PHP blocks not having scope.
Basically the first foreach() statement leaves the value variable ($v)
as a reference. When the second loop runs, it "assigns" the current
array's position to $v. Because $v was a reference it'll actually
overwrite the previously pointed to value.
Now we can't go and unset($v) at the end of the foreach() statement as
I bet there are many applications out there that take advantage of the
last value staying in the $v variable after the foreach() finishes.
The only thing I have in mind is possible emitting an E_STRICT during
the foreach() loop if the loop value variable is a reference. However,
just from looking at make test this might potentially break many
scripts which are using E_STRICT and/or confuse their authors. Not sure
how to weight that, and as we haven't had many complaints about this
behavior I'm not sure it's worth it.
Taking this to internals@ but most likely, it'll remain this way.
------------------------------------------------------------------------
[2004-12-16 16:08:01] dennis at inmamrket dot lviv dot ua
Sorry for opening another ticket but this bug took me 2 weeks to
shuffle the code and I got really nervous about it. This is abnormal
behaviuor, and the bug you forwarded me to is different - there is
array modification inside the loop.
------------------------------------------------------------------------
[2004-12-16 16:05:33] dennis at inmarket dot lviv dot ua
No, it is NOT related no those bugs: here is a test case that proves
that with no array modification two consecutive foreach loops give
different results
$a = array('key1'=>'value1', 'key2'=>'value2', 'key3'=>'value3');
foreach($a as $k=>&$v) {
echo $k . '=' . $v . "\r\n";
}
foreach($a as $k=>$v) {
echo $k . '=' . $v . "\r\n";
}
This produces this:
key1=value1
key2=value2
key3=value3
key1=value1
key2=value2
key3=value2 <- must be 3
------------------------------------------------------------------------
[2004-12-16 12:43:59] [EMAIL PROTECTED]
Please do not submit the same bug more than once. An existing
bug report already describes this very problem. Even if you feel
that your issue is somewhat different, the resolution is likely
to be the same.
Thank you for your interest in PHP.
See #29992.
------------------------------------------------------------------------
[2004-12-16 12:26:02] dennis at inmarket dot lviv dot ua
Description:
------------
If you foreach an array with a reference (foreach $a as $x=>&$y),
modifying $y, and then without it (foreach $a as $x=>$y), on the second
time it will return incorrect results.
The sample code has two functions - each iterates over array with a
reference to value and modifies it and then they foreach that array -
first function without a reference, and the second - with a reference.
The first function fails to iterate to the end of array. However, the
print_r shows the array is ok.
Reproduce code:
---------------
function test1() {
$a = array('key1'=>'value1', 'key2'=>'value2', 'key3'=>'value3');
foreach($a as $k=>&$v) {
$v .= '0';
}
print_r($a);
foreach($a as $k=>$v) {
echo $k .'=' . $v . "\r\n";
}
}
function test2() {
$a = array('key1'=>'value1', 'key2'=>'value2', 'key3'=>'value3');
foreach($a as $k=>&$v) {
$v .= '0';
}
print_r($a);
foreach($a as $k=>&$v) {
echo $k .'=' . $v . "\r\n";
}
}
test1();
test2();
Expected result:
----------------
Array
(
[key1] => value10
[key2] => value20
[key3] => value30
)
key1=value10
key2=value20 <- all values properly changed
key3=value30
Array
(
[key1] => value10
[key2] => value20
[key3] => value30
)
key1=value10
key2=value20 <- all values properly changed
key3=value30
Actual result:
--------------
Array
(
[key1] => value10
[key2] => value20
[key3] => value30
)
key1=value10
key2=value20
key3=value20 <- SHOULD BE '30'
Array
(
[key1] => value10
[key2] => value20
[key3] => value30
)
key1=value10
key2=value20
key3=value30
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=31118&edit=1
