class_exists returns true but still getting a Class not found error

if (class_exists('PhpThumb')) {
  $pt = PhpThumb::getInstance();
开发者_如何学C  $pt->registerPlugin('GdReflectionLib', 'gd');
}


if (in_array('PhpThumb', get_declared_classes())) {
  $pt = PhpThumb::getInstance();
  $pt->registerPlugin('GdReflectionLib', 'gd');
}

Either of these codes blocks throw the following error: "PHP Fatal error: Class 'PhpThumb' not found"

Can anyone explain why? Is this a bug in PHP?

I've encountered the same bug. In my case problem was due to mixed Russian and English letters in class name which looks similar.

I had a legacy code running under a newer version of PHP (5.3.10). I had some require_once() statements that was not doing their job. As I could change, I changed them do include() and it worked again.

I guess it have something to do with the PHP version, because running under a previous version the website was ok.

This happened for me when I was requiring a file not needed by a phpunit class I was running. The file was there, but I got the error.

Yet for a test that does need that class, the same include call works.

My work around was to have 2 config files, where 1 requires that class file and the 2nd file doesn't. So when not needed, I use the latter.

A little clunky with 1 extra small file (that I shouldn't have to create .. cse' la vie), but unblocks the issue here

After spending few hours on practicing with this mistakefullish fatal error...I've admitted that this function doesn't work with SPL autoload! And I've finally found a solution : I replace 'class_exists()' by 'file_exists()' with a little bit more process to find out the real path of the class file (my classes have the same name as their filename). Hope it helps.