Cannot redefine class on 'require_once'

Question

UPDATE:

I've abandoned CodeIgniter, and the desire to build a web interface around my database application from PHP, as there was no way of getting rid of this bug...

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The Exception

I get this exception:

Fatal error: require_once(): Cannot redeclare class doctrine\orm\abstractquery in Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php on line 190

Call Stack:
    0.0007     330016   1. {main}() Q:\Digest\index.php:0
    0.0058     330800   2. require_once('Q:\Digest\lib\CodeIgniter\core\CodeIgniter.php') Q:\Digest\index.php:163
    0.2207     935856   3. call_user_func_array() Q:\Digest\lib\CodeIgniter\core\CodeIgniter.php:297
    0.2207     935904   4. Crud->index() Q:\Digest\lib\CodeIgniter\core\CodeIgniter.php:0
    0.2574    1065064   5. Crud->__getEntities() Q:\Digest\Application\controllers\crud.php:19
    0.2649    1121824   6. Doctrine\ORM\AbstractQuery->getResult() Q:\Digest\Application\controllers\crud.php:49
    0.2649    1121976   7. Doctrine\ORM\AbstractQuery->execute() Q:\Digest\lib\Doctrine\ORM\AbstractQuery.php:366
    0.2651    1121976   8. Doctrine\ORM\Query->_doExecute() Q:\Digest\lib\Doctrine\ORM\AbstractQuery.php:528
    0.2651    1121976   9. Doctrine\ORM\Query->_parse() Q:\Digest\lib\Doctrine\ORM\Query.php:223
    0.2848    1185896  10. Doctrine\ORM\Query\Parser->parse() Q:\Digest\lib\Doctrine\ORM\Query.php:203
    0.3089    1238704  11. Doctrine\ORM\Query\SqlWalker->getExecutor() Q:\Digest\lib\Doctrine\ORM\Query\Parser.php:311
    0.3090    1239104  12. Symfony\Component\HttpFoundation\UniversalClassLoader->loadClass() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:0
    0.3107    1241104  13. require_once('Q:\Digest\lib\Doctrine\ORM\Query\Exec\SingleSelectExecutor.php') Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:190
    0.3108    1241440  14. Symfony\Component\HttpFoundation\UniversalClassLoader->loadClass() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:0

I am using Doctrine 2.0, with the Symfony UniversalClassLoader, as can be seen above, to implement a data-analysis script. To view the results, I have set up a CodeIgniter project.

Here's what has me baffled with this exception: I have eliminated almost all reasonably causes, and found nothing. Tell me if I did something wrong in the elemination rounds here.

If anyone has any clue whatsoever about what might be going wrong here, please help. Should you think there is any information I've left out, also, please tell me.

Thank you.

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Eliminating duplicate declarations

It tells me I cannot redefine a class. I have grepped all my files, and this class is defined only in its specific file "Doctrine/ORM/AbstractQuery.php".

Note that initially the error was reported at the call to require at line 190 of the Symfony UniversalClassLoader.php, and I have changed this to require_once to make sure the file isn't loaded twice.

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Eliminating the case-sensitive filesystem

Because of the note I found here, I think it's I should share that I'm running PHP 5.3.5 on Windows 7. This should mean the bug/feature described below is of no influence.

This behaviour changed in PHP 5, so for example with Windows the path is normalized first so that C:\PROGRA~1\A.php is realized the same as C:\Program Files\a.php and the file is included just once.

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Eliminating require duplication

I've now gone so far as to replace every single call in every library (and my own code) to the function require to one to require_once, and the error persists unchanged. This means that I can now safely say that no call to require is responsible. My question remains: what is?

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Debugger Output

Running a debugger brings me absolutely nothing:

    ...
    0.4658    1274904                       -> Doctrine\ORM\Query\SqlWalker->getExecutor() Q:\Digest\lib\Doctrine\ORM\Query\Parser.php:311
    0.4660    1275304                         -> Logger::autoload() Q:\Digest\lib\Log4PHP\Logger.php:0
    0.4662    1275304                         -> Symfony\Component\HttpFoundation\UniversalClassLoader->loadClass() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:0
    0.4663    1275384                           -> strripos() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:183
    0.4665    1275400                           -> substr() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:185
    0.4666    1275488                           -> strpos() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:187
    0.4667    1275520                           -> substr() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:188
    0.4668    1275672                           -> str_replace() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:189
    0.4669    1275696                           -> str_replace() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:189
    0.4671    1275656                           -> file_exists() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:190
    0.4700    1277304                           -> require_once(Q:\Digest\lib\Doctrine\ORM\Query\Exec\SingleSelectExecutor.php) Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:192
    0.4702    1277640                             -> Logger::autoload() Q:\Digest\lib\Log4PHP\Logger.php:0
    0.4703    1277640                             -> Symfony\Component\HttpFoundation\UniversalClassLoader->loadClass() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:0
    0.4704    1277720                               -> strripos() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:183
    0.4706    1277736                               -> substr() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:185
    0.4707    1278280                               -> strpos() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:187
    0.4708    1278312                               -> substr() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:188
    0.4709    1278464                               -> str_replace() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:189
    0.4711    1278488                               -> str_replace() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:189
    0.4712    1278448                               -> file_exists() Q:\Digest\lib\Symfony\Component\HttpFoundation\UniversalClassLoader.php:190
    0.5259 zu
TRACE END   [2011-03-28 11:28:00]

Some additional inspection tells me that the file it's loading while it crashes is lib\Doctrine\ORM\Query\Exec\AbstractSqlExecutor.php, or the AbstractSqlExecutor class... thus, something completely unrelated.

Answer 1

The other possibilities I can think of (after skimming the answers proposed so far) are:

1. Maybe there is a symlink somewhere in your source tree? (I've found that require_once() isn't smart enough to know that you're importing the same file if the path looks different).

2. Maybe there's a cycle somewhere in your inclusion dependencies? (if A includes B which includes C which includes A, I've found that require_once() isn't smart enough to break the cycle).

Answer 2

Too bad you gave up. The simple way to fix it would be to put:

if (!class_exists('ClassName')) {


}

around the file. This doesn't fix the bug, just makes the symptom go away. Codeigniter is unfortunately not too smart about PHP5 object instantiation, and may be loading your code twice.