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Debug vanilla

Submitted by fgm on Fri, 2009-12-11 13:14

Most of the time, when working on some piece of code, I'll resort to the configured debugger in my current Zend Studio configuration. And you probably do too :-)

However, I often have to access debug-type information on live sites where installing a debugger is out of the question, and I find myself often resorting to parameter dumps like the following:

<?php
// lazy version for simple cases
function foo_bar($x, $y, $z) {
  dsm(func_get_args());
  // [...]

// less lazy version for more hairy cases
function foo_baz($x, $y, $z) {
  dsm(array('in foo_baz, x' => $x, 'y' => $y, 'z' => $z));
  // ...
?>

You've probably being using it too and, of course, after the first few dozen times, it becomes a bit used. So here's a tiny snippet that makes such dumps simpler to type and use :

<?php
function foo_quux($x, $y, $z) {
  dsm(func_get_args_hash());
  // [...]

/**
* Provide a better func_get_args()
*
* @return array
*   Hash of parameters, keyed by parameter name
*/
function func_get_args_hash() {
  $stack = debug_backtrace();
  $stack = $stack[1];
  $rf = new ReflectionFunction($stack['function']);
  $params = $rf->getParameters();
  $ret = array();
  foreach ($params as $index => $param) {
    $ret[$param->name] = $stack['args'][$index];
  }
  return $ret;
}
?>

Knowing next to nothing about

Submitted by dalin (not verified) on Sun, 2009-12-13 11:27.

Knowing next to nothing about reflection, I can't see what makes this better than vanila dsm() or dpm(). What does the output look like?

Parameter names and default values

Submitted by fgm on Sun, 2009-12-13 12:42.

When using dsm(func_get_args_hash()) instead of dsm(func_get_args()), you get:

  1. the names of the parameters along with their values, which you don't get with a normal dsm(func_get_args()).
  2. the values taken by default parameters (those not passed in by the caller, which you don't get from func_get_args

When you're bug-hunting, it's often useful (to me at least) to know which parameter is being represented by a value in the args dump, and which values all the parameters have, default or explicit.

Sample use on _locale_import_one_string_db() below.

Difference between func_get_args() and func_get_args_hash()