ID: 42641
User updated by: robin_fernandes at uk dot ibm dot com
-Summary: ob_start(): inconsistent behaviour with undefined
callbacks
Reported By: robin_fernandes at uk dot ibm dot com
-Status: Feedback
+Status: Open
Bug Type: Output Control
Operating System: Windows
PHP Version: 5CVS-2007-09-12 (snap)
New Comment:
Hi,
Thanks for your reply. As documentation isn't always complete/up to
date, I looked at the implementation of ob_start() to understand its
behaviour.
The code in the 5.2 version of php_ob_init() in output.c splits strings
on ',' and attempts to process each part seaparately (line 485). For
arrays, if a pair does not represent a method, a comment explicitly
states "init all array elements recursively" (line 516).
The prototype in the 5.2 code currently looks like this:
bool ob_start([ string|array user_function [, int chunk_size [, bool
erase]]])
The following testcase shows this behaviour in action:
http://pastebin.com/f4f15a025
Regarding tuning up the error message display params, I'm currently
using: error_reporting = E_ALL | E_STRICT / display_errors = 1 . Would
you expect see warnings/notices with my testcase?
I'll happily raise a documentation bug to ensure this is covered.
Alternatively, perhaps the fact that this behaviour is available is
itself a bug? Note that this is raised against php5 (not 6 where the
output buffering implementation seems to be a bit different).
Previous Comments:
------------------------------------------------------------------------
[2007-09-12 11:17:04] [EMAIL PROTECTED]
Let's start with the prototype for this function:
bool ob_start ( [callback $output_callback [, int $chunk_size [, bool
$erase]]] )
The first parameter is "callback" type, so it expects either a string
(function name) or array (object, method).
More information about "callback" pseudo-type:
http://www.php.net/callback
I don't know where you got the idea that you can pass multiple
callbacks in there. It's not said to work like that anywhere in the
manual at least. :)
Please fix your example script accordingly (and tune up your
display_errors / error_reporting levels..).
------------------------------------------------------------------------
[2007-09-12 09:15:35] robin_fernandes at uk dot ibm dot com
Description:
------------
ob_start() can initialize multiple output buffers in a single call
using a comma delimited list of output callbacks, as follows:
ob_start('f,f,f');
where function f() is a defined function.
However, behaviour when passing an undefined callback is inconsistent:
ob_start('non_existent,f');
returns false and initializes no output buffers, whereas
ob_start('non_existent,f,f');
returns true and initializes 2 output buffers with f as a callback.
Using arrays, the behaviour is consistent. The following both return
false and initialize no output buffers:
ob_start(array('non_existent', 'f'));
ob_start(array('non_existent', 'f', 'f'));
Tested on Windows XP on PHP 5.2.5-dev (cli) (built: Sep 12 2007
04:04:36).
Reproduce code:
---------------
<?php
function f($str) {
return $str;
}
function checkAndClean() {
print_r(ob_list_handlers());
while (ob_get_level()>0) {
ob_end_flush();
}
}
var_dump(ob_start(array('non_existent', 'f')));
checkAndClean();
var_dump(ob_start(array('non_existent', 'f', 'f')));
checkAndClean();
var_dump(ob_start('non_existent,f'));
checkAndClean();
var_dump(ob_start('non_existent,f,f')); //bug: expecting false with no
output buffers. Actually returns true and initialises 2 output buffers.
checkAndClean();
?>
Expected result:
----------------
bool(false)
Array
(
)
bool(false)
Array
(
)
bool(false)
Array
(
)
bool(false)
Array
(
)
Actual result:
--------------
bool(false)
Array
(
)
bool(false)
Array
(
)
bool(false)
Array
(
)
bool(true)
Array
(
[0] => f
[1] => f
)
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=42641&edit=1
