<?php
// Dear Php developers/users,
//
// *-> Background
// I'm re-posting this bug (http://bugs.php.net/bug.php?id=17959)
// since the original one has been its status changed to
// 'Analyzed' and even after providing a new example that needs
// new analysis there are no means for me to change its status to
// 'Open' or anything else other than 'Closed'.
//
// I have sent email to hholzgra@php.net (person assigned to bug)
// asking him about it but never have heard back from him
// (neither by email nor update on the bug's comment page).
//
// Therefore, it seems that if I don't re-post this bug it will
// NEVER get any attention and possibly never get fixed.
//
// *-> Bug report
// Php fails to change/update a globally defined reference's
// value from within a user defined function using either of the
// following methods of accessing the reference variable:
//
//    global $ptr;     // where $ptr is the reference variable
//    $GLOBALS['ptr']
//
// hholzgra@php.net explained (in original bug #17959) that I
// should not expect the first method to work as it is a "short
// hand" for "$ptr = &$GLOBALS['ptr'];" and a new assignment to
// local-to-function $ptr only changes the local reference and
// not the intended global one.  Btw, I find this a counter
// intuitive behavior on the Php's part.  I think "global $var"
// should act more like a C++ reference rather than a C pointer.
//
// After considering explanation of what exactly 'global $ptr'
// is i changed my code to strictly use $GLOBALS['ptr'].  However,
// after doing so my program still didn't function properly!
//
// I had to work a bit harder to come up with a simplified example
// for you.  I believe i have done so below.
//
// Please pay close attention to the notes w/in comments explaining
// strange conditions that would make this sample code to work as
// expected.  Now I'm certain there EXISTS a serious problem with
// the Php engine when processing this code.
//
// Thanks,
// --patrick
//
// *-> Sample code
// define array we plan to navigate.
$top =
array
  (
  'name' => 'top',
  'A' => array
          (
          'name' => 'A',
          'A_a' => array
                    (
                    'name' => 'A_a',
                    'fn_1' => 'Aa_fn_1',
                    'fn_2' => 'Aa_fn_2',
                    'fn_3' => 'Aa_fn_3',
                    'A_a_1' => array
                                (
                                'name' => 'A_a_1',
                                'fn_1' => 'Aa1_fn_1',
                                'fn_2' => 'Aa1_fn_2',
                                ),
                    'A_a_2' => array
                                (
                                'name' => 'A_a_2',
                                'fn_1' => 'Aa2_fn_1',
                                'fn_2' => 'Aa2_fn_2',
                                ),
                    ),
          ),
  );

// setup "parent references" for each of the nodes.
$top['parent']              = null;
$top['A']['parent']         = &$top;
$top['A']['A_a']['parent']  = &$top['A'];
$top['A']['A_a']['A_a_1']['parent']  = &$top['A']['A_a'];
$top['A']['A_a']['A_a_2']['parent']  = &$top['A']['A_a'];
//$top['A']['A_a']['A_a_1']['parent']  = &$top['A']['A_a'];
  //
  // Note!
  // Here if we uncomment the above line the sample code will
  // magically WORK!
  //
  // Why does the order of initialization matter!?  And will the
  // code now break elsewhere?

// setup our reference to $top.  $ptr is what should change
// on every call to change_ptr(name).
$ptr  = &$top;

// change_ptr( name ) does the following w/some verbose
// messages to display the state of variables in question.
//
//    if ( ptr[name] )
//      ptr = ptr[name];
//
function change_ptr( $name )
{
  printf( "  change_ptr($name) " );

  if ( $GLOBALS['ptr'][$name] ) {
    // Setting up string for later printing.
    $before_change =
    sprintf( "before: \$GLOBALS['ptr']['name'] = %s",
                       $GLOBALS['ptr']['name'] );

    $GLOBALS['ptr'] = &$GLOBALS['ptr'][$name];

    $after_change =
    sprintf( "after: \$GLOBALS['ptr']['name'] = %s",
                      $GLOBALS['ptr']['name'] );

    printf( "<font color=\"green\"><b>CHANGED</b></font>:\n" );
    printf( "    %s\n     %s", $before_change, $after_change );
  }
  else
    printf( "<font color=\"red\"><b>NO CHANGE!</b></font>" );

  printf( "<br>\n" );
}
?>
<pre>
<?
// All of the following calls should succeed and print
// 'CHANGED'.  However, you will notice that the last call
// will fail to change $ptr to point to the 'parent' of
// $top['A']['A_a']['A_a_2'].
//
change_ptr('A');
change_ptr('A_a');
change_ptr('A_a_1');
change_ptr('parent');
change_ptr('A_a_2');
change_ptr('parent');
?>
</pre>
?>