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Bug #7659 Class variables get confused
Submitted: 2000-11-06 06:14 UTC Modified: 2000-11-06 06:25 UTC
From: awilkins at hmc dot edu Assigned:
Status: Closed Package: Scripting Engine problem
PHP Version: 4.0 Latest CVS (06/11/2000) OS: RedHat Linux 6.2
Private report: No CVE-ID: None
 [2000-11-06 06:14 UTC] awilkins at hmc dot edu
When this script is run:

<?php
  class Three {
    var $one, $two;

    function Three($a, $b) {
      echo "a is $a; b is $b<br>\n";

      $this->$one = $a;

      echo "one is " . $this->$one . "; two is " . $this->$two . "<br>\n";

      $this->$two = $b;

      echo "one is " . $this->$one . "; two is " . $this->$two . "<br>\n";
    }
  }

  $three = new Three(1, 2);
?>

the results it produces are:

a is 1; b is 2
one is 1; two is 1
one is 2; two is 2

For some reason, it appears as if the two separate variables $one and $two are pointing at the same thing.  This doesn't appear to be a problem that is specific to the constructor, as it happens even if the function involved is only a normal function.  It also occurs if the variables are modified outside of the class.

I also found this bug in 4.0.3pl1, but have not tried any earlier version.  The only module I compiled PHP with was pgsql, if it matters.

Alex Wilkins

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 [2000-11-06 06:25 UTC] stas@php.net
Please read the manual. Syntax is $obj->var, not $obj->$var.
 
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