Bug #70188 [Nab->Fbk]: debug_backtrace + register_tick_function do not always work
Edit report at https://bugs.php.net/bug.php?id=70188&edit=1
ID: 70188
Updated by: cmb@php.net
Reported by: emilio dot pinn at gmail dot com
Summary: debug_backtrace + register_tick_function do not
always work
-Status: Not a bug
+Status: Feedback
Type: Bug
Package: *General Issues
Operating System: Ubuntu
PHP Version: Irrelevant
Assigned To: cmb
Block user comment: N
Private report: N
New Comment:
On further consideration the behavior is somewhat strange. Anyhow,
to properly diagnose the problem, we need a short but complete
example script to be able to reproduce this bug ourselves.
A proper reproducing script starts with <?php, is max. 10-20 lines
long and does not require any external resources such as
databases, etc. If the script requires a database to demonstrate
the issue, please make sure it creates all necessary tables,
stored procedures etc.
Please avoid embedding huge scripts into the report.
Previous Comments:
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[2015-08-03 12:57:58] emilio dot pinn at gmail dot com
Hi, thanks for your prompt response.
The very strange behaviour is that in the conditions I described, debug_backtrace() returns just a
single element backtrace, instead of the complete backtrace of any invoked functions. I can't
understand why this strange behaviour.
------------------------------------------------------------------------
[2015-08-03 12:51:55] cmb@php.net
Sorry, but your problem does not imply a bug in PHP itself. For a
list of more appropriate places to ask for help using PHP, please
visit http://www.php.net/support.php as this bug system
is not the
appropriate forum for asking support questions. Due to the volume
of reports we can not explain in detail here why your report is not
a bug. The support channels will be able to provide an explanation
for you.
Thank you for your interest in PHP.
If there is only a single stack frame, debug_backtrace() is
supposed to return an array with a single element. Change
count($bt) <= 1 to count($bt) < 1 or empty($bt).
------------------------------------------------------------------------
[2015-08-03 12:11:36] emilio dot pinn at gmail dot com
Description:
------------
The following simple profiling script does not work on certain codes, e.g. with the vanilla
installation of Joomla v3.4.2. It works with other complex CMS e.g. with WordPress.
To easily prepend the profiling PHP script to the application, I used
php_value auto_prepend_file "/tmp/instrumentation.php"
In the .htaccess in the web root. Then, paste the test script in
"/tmp/instrumentation.php". The output you can see in
"/var/log/apache2/error.log" is just a series of "NO BACKTRACE" strings.
PHP version; PHP 5.5.9-1ubuntu4.11 (cli) (built: Jul 2 2015 15:23:08)
Test script:
---------------
<?php
function printname() {
$bt = debug_backtrace();
if (count($bt) <= 1) {
error_log('NO BACKTRACE: ' . print_r($bt, true));
}
else {
error_log('FUNCTION NAME: ' . $bt[1]['function']);
}
}
declare(ticks=1);
register_tick_function('printname');
?>
Expected result:
----------------
I expect a result like the following when I open the "/var/log/apache2/error.log"
[:error] [pid 9091] [client 127.0.0.1:55726] FUNCTION NAME: function1
[:error] [pid 9091] [client 127.0.0.1:55726] FUNCTION NAME: function2
[:error] [pid 9091] [client 127.0.0.1:55726] FUNCTION NAME: function3
[:error] [pid 9091] [client 127.0.0.1:55726] FUNCTION NAME: function4
...
As this happens using the same test script with other code.
Actual result:
--------------
[:error] [pid 7555] [client 127.0.0.1:55742] NO BACKTRACE: Array\n(\n [0] => Array\n
(\n [file] => /tmp/instrumentation.php\n [line] => 14\n
[function] => printname\n [args] => Array\n (\n )\n\n
)\n\n)
[:error] [pid 7555] [client 127.0.0.1:55742] NO BACKTRACE: Array\n(\n [0] => Array\n
(\n [file] => /tmp/instrumentation.php\n [line] => 16\n
[function] => printname\n [args] => Array\n (\n )\n\n
)\n\n)
------------------------------------------------------------------------
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