Description:
------------
I've been hit several times by what looks like a bug in the the scripting engine, or maybe an over-active post-parsing optimizer.

What I see are error messages in my httpd log that make no sense when I inspect the program to check the offending code.

Isolating the code in a small script does not replicate these problems: they only occur in the environment of the application I'm working on.


Example:
	# make sure that $n is a numeric scalar
	if (!isset($n) || !is_numeric($n)) {
		return $this;
	}
	# some code omitted, no changes to $n here
	if (!isset($testvalue) || !is_array($testvalue) || !array_key_exists($n, $testvalue)) { return $this; } # line 174

And PHP complains thusly in the error log:

array_key_exists(): The first argument should be either a string or an integer in [FILENAME.php] on line 174


As you can see: the first argument of array_key_exists() in line 174 is certainly a scalar, so why complain?


Another one:

	$i = $first; # $first is an integer
	# some code omitted, no changes to $i here
	while ($i <= $last) {
		# some code omitted, no changes to $i here
		$displayName_utf8 = (is_array($displayNames) && array_key_exists($i, $displayNames) && isset($displayNames[$i])) ? bc_utf8($displayNames[$i]) : $i;
		# some code omitted, no changes to $i here			
		$i ++;
	}

produces this error message:

array_key_exists(): The first argument should be either a string or an integer in ...

Again this makes no sense: $i is an integer all the way.


I've also had problems with code like this

if (is_array($a) && is_scalar($k) && array_key_exists($k, $a)) {

And PHP complains that the second argument to array_key_exists() must be an array, or in other cases that the first argument should be a string or int, which it is!

I've changed code like that to 
if (isset($a[$k])) {
AFAIK, that is almost the same thing, except when $a is an object or $k is set, but not a scalar.


Last example:

	$res = sendMailToUser(); # returns -1, 0 or 1
	if ($res == -1) {
		$errorMessage = 'Action not allowed';
	}
	else if ($res == 0) {
		$errorMessage = 'Mail could not be sent';
	}
	else {
		$errorMessage = 'Mail has been sent';
	}
	echo $res.'<br />';
	echo $errorMessage.'<br />';

Expected result:
any of the three $res values with the corresponding $errorMessage

Actual result:
1
Action not allowed

Those two values do not belong together. [I'm not making this up.]

I've been able to work around most of these issue by changing the code a little bit. Like in the last example, I wrote 

	$res = 0 + sendMailToUser();

and that solved the problem.

All of the other issues could also be solved by making this type of ridiculous changes to the code. But that does not solve the underlying issue. And new issues might popup anywhere.


My setup: [from phpinfo()]

Apache/2.2.16 (Debian)

PHP Version 5.3.3-7+squeeze7 [ = 5.3.10]

Suhosin Patch 0.9.9.1, with Suhosin v0.9.32.1
Zend Engine v2.3.0


System 	Linux 2.6.32-5-686 #1 SMP Mon Jan 16 16:04:25 UTC 2012 i686
Build Date 	Feb 2 2012 18:20:23 
Additional .ini files parsed 	/etc/php5/apache2/conf.d/gd.ini, /etc/php5/apache2/conf.d/imap.ini, /etc/php5/apache2/conf.d/mcrypt.ini, /etc/php5/apache2/conf.d/mysql.ini, /etc/php5/apache2/conf.d/mysqli.ini, /etc/php5/apache2/conf.d/pdo.ini, /etc/php5/apache2/conf.d/pdo_mysql.ini, /etc/php5/apache2/conf.d/suhosin.ini 
PHP API 	20090626
PHP Extension 	20090626
Zend Extension 	220090626
Zend Extension Build 	API220090626,NTS
PHP Extension Build 	API20090626,NTS
Debug Build 	no
Thread Safety 	disabled
Zend Memory Manager 	enabled
Zend Multibyte Support 	disabled
IPv6 Support 	enabled
Registered PHP Streams 	https, ftps, compress.zlib, compress.bzip2, php, file, glob, data, http, ftp, phar, zip
Registered Stream Socket Transports 	tcp, udp, unix, udg, ssl, sslv3, sslv2, tls
Registered Stream Filters 	zlib.*, bzip2.*, convert.iconv.*, string.rot13, string.toupper, string.tolower, string.strip_tags, convert.*, consumed, dechunk, mcrypt.*, mdecrypt.*