Edit report at https://bugs.php.net/bug.php?id=53710&edit=1
ID: 53710
Updated by: col...@php.net
Reported by: weierophin...@php.net
Summary: Data registered with equal priority not returned in
expected order
-Status: Assigned
+Status: Wont fix
Type: Bug
Package: SPL related
Operating System: Linux 32-bit
PHP Version: 5.3.5
Assigned To: colder
Block user comment: N
Private report: N
New Comment:
There is no such guarantee. The only guarantee that you'll get from
SplPriorityQueue is that you won't get an element out of order. Elements with
the
same priority are extracted in arbitrary order, the rest is implementation
dependant.
Previous Comments:
------------------------------------------------------------------------
[2011-01-17 19:44:44] daniel at berste dot in
Reproduced on OSX (PHP compiled from MacPorts):
$ php --version
PHP 5.3.5 (cli) (built: Jan 9 2011 20:15:19)
Copyright (c) 1997-2010 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies
with Xdebug v2.1.0, Copyright (c) 2002-2010, by Derick Rethans
$ cat test.php
<?php
$queue = new SplPriorityQueue();
$queue->insert('foo', 100);
$queue->insert('bar', 100);
$queue->insert('baz', 100);
$queue->insert('bat', 100);
foreach ($queue as $data) {
echo $data, "\n";
}
$ php test.php
foo
bat
baz
bar
------------------------------------------------------------------------
[2011-01-10 22:23:46] weierophin...@php.net
Description:
------------
SplPriorityQueue does not behave as expected when data is registered with equal
priority. One would expect one of the following situations:
* The data retain the same order as how they were registered
* The data are ordered based on value
Neither of these are the case, however. From empirical analysis, it appears
that
the following happens:
* The first item registered at that priority will always be the first returned
* The remaining items are returned in the reverse order in which they were
enqueued.
Test script:
---------------
$queue = new SplPriorityQueue();
$queue->insert('foo', 100);
$queue->insert('bar', 100);
$queue->insert('baz', 100);
$queue->insert('bat', 100);
foreach ($queue as $data) {
echo $data, "\n";
}
Expected result:
----------------
// IDEALLY order in which they are registered:
foo
bar
baz
bat
// OR following same rules as priority queue -- higher values == higher priority
foo
baz
bat
bar
Actual result:
--------------
foo
bat
baz
bar
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=53710&edit=1
