Another way to manipulate and print a backtrace, without using output buffering:<?php// print backtrace, getting rid of repeated absolute path on each file$e = new Exception();print_r(str_replace('/path/to/code/', '', $e->getTraceAsString()));?>
(PHP 5, PHP 7, PHP 8)
debug_print_backtrace — Prints a backtrace
debug_print_backtrace() prints a PHP backtrace. It prints the function calls, included/required files and eval()ed stuff.
optionsThis parameter is a bitmask for the following options:
| DEBUG_BACKTRACE_IGNORE_ARGS | Whether or not to omit the "args" index, and thus all the function/method arguments, to save memory. |
limit
This parameter can be used to limit the number of stack frames printed.
By default (limit=0) it prints all stack frames.
No value is returned.
Example #1 debug_print_backtrace() example
<?php
// include.php file
function a() {
b();
}
function b() {
c();
}
function c(){
debug_print_backtrace();
}
a();
?><?php
// test.php file
// this is the file you should run
include 'include.php';
?>The above example will output something similar to:
#0 c() called at [/tmp/include.php:10] #1 b() called at [/tmp/include.php:6] #2 a() called at [/tmp/include.php:17] #3 include(/tmp/include.php) called at [/tmp/test.php:3]
Another way to manipulate and print a backtrace, without using output buffering:<?php// print backtrace, getting rid of repeated absolute path on each file$e = new Exception();print_r(str_replace('/path/to/code/', '', $e->getTraceAsString()));?>If you see string arguments and parameters getting cut off like this:#0 hook.php(324): output_notice('checkout_before...')#1 hook.php(348): invoke_hook('checkout_before...', Array)You can increase the maximum length of arguments and parameters in the printed trace through an PHP INI setting:<?phpini_set('zend.exception_string_param_max_len', 100);debug_print_backtrace();?>…so you can read the full arguments:#0 hook.php(324): output_notice('checkout_before_payment')#1 hook.php(348): invoke_hook('checkout_before_payment', Array)In edge cases, it might even uncover nested traces that you didn't notice before.I like the output of debug_print_backtrace() but I sometimes want it as a string.
bortuzar's solution to use output buffering is great, but I'd like to factorize that into a function. Doing that however always results in whatever function name I use appearing at the top of the stack which is redundant.
Below is my noddy (simple) solution. If you don't care for renumbering the call stack, omit the second preg_replace().
<?php
function debug_string_backtrace() {
ob_start();
debug_print_backtrace();
$trace = ob_get_contents();
ob_end_clean();
// Remove first item from backtrace as it's this function which
// is redundant.
$trace = preg_replace ('/^#0\s+' . __FUNCTION__ . "[^\n]*\n/", '', $trace, 1);
// Renumber backtrace items.
$trace = preg_replace ('/^#(\d+)/me', '\'#\' . ($1 - 1)', $trace);
return $trace;
}
?>This is for latest php versionfunction debugStringBacktrace() { ob_start(); debug_print_backtrace(); $trace = ob_get_contents(); ob_end_clean(); $trace = preg_replace('/^#0\s+' . __FUNCTION__ . "[^\n]*\n/", '', $trace, 1); $trace = preg_replace_callback('/^#(\d+)/m', function ($matches) { return '#' . ($matches[1] - 1); }, $trace); return $trace; }If your show your error messages in HTML (with suitable safety using entities), this function won't work nicely because it uses newlines for formatting.Here is a function that works similarly, but using <BR> tags. Insert it near the beginning of your program to add a stack to Warning output only, or modify it as you like:// Here is code for error stack output in HTML:function error_handler_callback($errno,$message,$file,$line,$context) { if ($errno === E_WARNING) echo "Stack, innermost first:<br>".nl2br((new Exception())->getTraceAsString()); return false; // to execute the regular error handler }set_error_handler("error_handler_callback");