Php – How to get xdebug var_dump to show full object/array

PHPxdebug

I am using xdebug (php_xdebug-2.1.2-5.3-vc9.dll) on WAMP. When I use var_dump on a large object or variable it does not show the full variable.

array
'node' => 
  array
    'my_form' => 
      array
        'form' => 
          array
            ...

Without xdebug it shows as should be expected. I looked at the documentation but did not see a solution. Does anyone know how I can fix this so xdebug var_dump shows the full object?

Best Answer

These are configurable variables in php.ini:

; with sane limits
xdebug.var_display_max_depth = 10
xdebug.var_display_max_children = 256
xdebug.var_display_max_data = 1024 


; with no limits
; (maximum nesting is 1023)
xdebug.var_display_max_depth = -1 
xdebug.var_display_max_children = -1
xdebug.var_display_max_data = -1

Of course, these may also be set at runtime via ini_set(), useful if you don't want to modify php.ini and restart your web server but need to quickly inspect something more deeply.

ini_set('xdebug.var_display_max_depth', 10);
ini_set('xdebug.var_display_max_children', 256);
ini_set('xdebug.var_display_max_data', 1024);

Xdebug settings are explained in the official documentation.

Try `var_export`

You may want to check out var_export — while it doesn't provide the same output as var_dump it does provide a second $return parameter which will cause it to return its output rather than print it:

$debug = var_export($my_var, true);

Why?

I prefer this one-liner to using ob_start and ob_get_clean(). I also find that the output is a little easier to read, since it's just PHP code.

The difference between var_dump and var_export is that var_export returns a "parsable string representation of a variable" while var_dump simply dumps information about a variable. What this means in practice is that var_export gives you valid PHP code (but may not give you quite as much information about the variable, especially if you're working with resources).

Demo:

$demo = array(
    "bool" => false,
    "int" => 1,
    "float" => 3.14,
    "string" => "hello world",
    "array" => array(),
    "object" => new stdClass(),
    "resource" => tmpfile(),
    "null" => null,
);

// var_export -- nice, one-liner
$debug_export = var_export($demo, true);

// var_dump
ob_start();
var_dump($demo);
$debug_dump = ob_get_clean();

// print_r -- included for completeness, though not recommended
$debug_printr = print_r($demo, true);

The difference in output:

var_export (`$debug_export` in above example):

 array (
  'bool' => false,
  'int' => 1,
  'float' => 3.1400000000000001,
  'string' => 'hello world',
  'array' => 
  array (
  ),
  'object' => 
  stdClass::__set_state(array(
  )),
  'resource' => NULL, // Note that this resource pointer is now NULL
  'null' => NULL,
)

var_dump (`$debug_dump` in above example):

 array(8) {
  ["bool"]=>
  bool(false)
  ["int"]=>
  int(1)
  ["float"]=>
  float(3.14)
  ["string"]=>
  string(11) "hello world"
  ["array"]=>
  array(0) {
  }
  ["object"]=>
  object(stdClass)#1 (0) {
  }
  ["resource"]=>
  resource(4) of type (stream)
  ["null"]=>
  NULL
}

print_r (`$debug_printr` in above example):

Array
(
    [bool] => 
    [int] => 1
    [float] => 3.14
    [string] => hello world
    [array] => Array
        (
        )

    [object] => stdClass Object
        (
        )

    [resource] => Resource id #4
    [null] => 
)

Caveat: `var_export` does not handle circular references

If you're trying to dump a variable with circular references, calling var_export will result in a PHP warning:

 $circular = array();
 $circular['self'] =& $circular;
 var_export($circular);

Results in:

 Warning: var_export does not handle circular references in example.php on line 3
 array (
   'self' => 
   array (
     'self' => NULL,
   ),
 )

Both var_dump and print_r, on the other hand, will output the string *RECURSION* when encountering circular references.

Php – How to get PHP errors to display

This always works for me:

ini_set('display_errors', '1');
ini_set('display_startup_errors', '1');
error_reporting(E_ALL);

However, this doesn't make PHP to show parse errors - the only way to show those errors is to modify your php.ini with this line:

display_errors = on

(if you don't have access to php.ini, then putting this line in .htaccess might work too):

php_flag display_errors 1

Best Answer

Related Solutions

Php – How to capture the result of var_dump to a string

Try var_export

Why?

Demo:

The difference in output:

var_export ($debug_export in above example):

var_dump ($debug_dump in above example):

print_r ($debug_printr in above example):

Caveat: var_export does not handle circular references