Bug #70188 [Nab]: debug_backtrace + register_tick_function do not always work

Edit report at https://bugs.php.net/bug.php?id=70188&edit=1 ID: 70188 User updated by: emilio dot pinn at gmail dot com Reported by: emilio dot pinn at gmail dot com Summary: debug_backtrace + register_tick_function do not always work Status: Not a bug Type: Bug Package: *General Issues Operating System: Ubuntu PHP Version: Irrelevant Assigned To: cmb Block user comment: N Private report: N New Comment: 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. Previous Comments: ------------------------------------------------------------------------ [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) ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=70188&edit=1