#20548 [Com]: Decrement ("$x[$y]--") doesn't work on uninitiated variable

From: Date: Sat, 27 Sep 2003 18:36:59 +0000
Subject: #20548 [Com]: Decrement ("$x[$y]--") doesn't work on uninitiated variable
References: 1  Groups: php.bugs 
Request: Send a blank email to php-bugs+get-48187@lists.php.net to get a copy of this message 
 ID:               20548
 Comment by:       lew at mailduct dot com
 Reported By:      prgallier at yahoo dot com
 Status:           Wont fix
 Bug Type:         Scripting Engine problem
 Operating System: Linux 2.4
 PHP Version:      4.3.2-dev
 New Comment:

This is a GROSS inconsistency in how the increment/decrement operators
work, and one that coders are likely to stumble upon the hard way.
Please study the effect of fixing this, at the expense of breaking a
long-time quirk in BC. Breaking a quirk, and documenting it on the BC
page, is better than maintaining a GROSS inconsistency in one of the
basic language construct operators!  Please fix this!


Previous Comments:
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[2003-08-03 12:57:49] iliaa@php.net

This is a valid bug, however a fix would be a BC break that would
result in a beahviour change that was in place since 3.0 days.

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[2003-02-14 17:14:59] bulletbait at yahoo dot com

I just stumbled across this bug recently with an older version (4.1.1)
of PHP on Win32 -- verified that it still exists in 4.3.0.  This one
had me going in circles trying to debug.  Work-arounds:

  $score[$num] -= 1;

or
  $score[$num] = $score[$num] - 1;

------------------------------------------------------------------------

[2002-11-21 12:42:11] prgallier at yahoo dot com

The following:
  $score[$num]--;
does not affect $score[$num] if $score[$num] is uninitiated.
Using $score[$num]++ does work, however.
This is inconsistent.


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