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To: internals@lists.php.net
Date: Wed, 1 Sep 2004 14:37:55 +0200
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Subject: Very weird behaviour with a neverending recursive function
From: r.korving@xit.nl ("Ron Korving")

Hi,

I've been experiencing very weird behaviour (which I can't seem to
reproduce). Nonetheless, I can tell you what happens, and you can decide if
this is a PHP5 bug or feature. I wish I could give more information on this,
but I can't seem to create a clean situation where this happens. I just hope
somebody reads this and goes "Eureka!" or something.

I post some text fields to a PHP page. These variables are entered into a
function, which calls itself (so it's a recursive function). The idea is
that it deletes information from a table, and the records link to eachother
(records are child/parent of eachother). I made the mysql query wrong, so
that the function ended up calling itself recursively for infinity. The
weird thing though, is that my script did not crash, it just stopped
functioning when I called this function for the first time (and thereby
creating the infinite loop).

Now I figure that the infinity is somehow detected so the function won't
stall the system until apache is stopped. This isn't the weird thing. The
weird thing is, that when this occured, none of the submitted information
existed anymore, not even at the start of my script.

The idea:

submit.php:
<?
  var_dump($_POST);

  $obj->recursiveFunction($_POST["foo"]);
?>

var_dump printed "NULL".

submit.php:
<?
  var_dump($_POST);

  // $obj->recursiveFunction($_POST["info"]);
?>

var_dump printed array information as it normally would.

I can't explain this situation and it just doesn't seem to be preferred
behaviour.
I hope anyone can do anything with the above information. I can't offer you
a perfect example to reproduce this (and I don't have a clue why I can't).

Thanks for reading,

Ron