Problem with "use" namespace keyword.

[trq]

I have here what I would refer to as doozy. I'm not sure anyone is going to be able to help as there is allot involved.

 

The issue could be in a number of locations, I am using PHPUnit as a test suite (and this is how I have found the issue) and PHP5.4rc5. The problem could be in either, or it could be in my code.

 

I am also using a cascading filesystem (explained here) and while I'm confident this isn't the issue. It has the potential to be involved I guess. If you need to see how this is implemented it is see here: https://github.com/proem/proem/blob/develop/lib/Proem/Api/Autoloader.php#L108

 

I have narrowed the problem down to two classes:

 

https://github.com/proem/proem/blob/develop/lib/Proem/Api/Chain.php & https://github.com/proem/proem/blob/develop/lib/Proem/Api/Proem.php

 

The tests that test these classes are:

 

https://github.com/proem/proem/blob/develop/tests/lib/Proem/Tests/ChainTest.php & https://github.com/proem/proem/blob/develop/tests/lib/Proem/Tests/ProemTest.php

 

As the code stands right now, everything is fine and all tests pass. However, I am about to start some more work on the Proem\Api\Proem class and it needs access to the Proem\Api\Chain class.

 

To do this, I add the line "use Proem\Chain;", the code becomes:

 

<?php

/**
* @namespace Proem\Api
*/
namespace Proem\Api;

use Proem\Chain;

/**
* Proem\Api\Proem
*
* The Proem boostrap wrapper (eventually)
*/
class Proem
{
    const VERSION = '0.1.0';
}

 

As soon as I do this the tests fail with:

 

Fatal error: Cannot use Proem\Chain as Chain because the name is already in use in /home/thorpe/src/proem/lib/Proem/Api/Proem.php on line 32

 

If I alias the namespace ( "use Proem\Chain as C;" ) the tests pass again. The issue is I shouldn't have to use an alias here.

 

from the manual:

Note:

 

Importing rules are per file basis, meaning included files will NOT inherit the parent file's importing rules.

 

Writing this post I have come to realise that the issue is likely that both the Chain class and the Proem class are in the same namespace yet I am trying to force the Chain class to be loaded from Proem\Chain instead of Proem\Api\Chain (this is part of the cascading filesystem setup).

 

Anyway, if anyone has some ideas I would be grateful if you could take a look. Otherwise, it looks like I might need to do some re-shuffling.

 

Iv'e created a ticket for this bug if anyone wan't to chip in. See here

[Andy-H]

use \Proem\Chain;

 

 

Does that work if you use \ before Proem to use it starting from the global namespace?

 

// EDIT:

 

or are you intending for it to use

\Proem\Api\Proem\Chain

namespace?

[trq]

Hi Andy-H, I did try pulling it from the global \Proem but it shouldn't need to and that doesn't work either.

 

One thing (and probably the most important thing) I forgot to mention is that if I remove the ChainTest from the test suite all tests pass. So the issue isn't in Proem.php alone, it is only introduced when the ChainTest is also run.

[trq]

 

// EDIT:

 

or are you intending for it to use

\Proem\Api\Proem\Chain

namespace?

 

Oh, and using Proem\Chain should (under the hood) end up calling Proem\Api\Chain. This cascades down into Proem\Chain.

[Andy-H]

Surely if you're already in the namespace \Proem\Api, and you want to call \Proem\Api\Chain, you should just need

 

 

use Chain;

 

 

Or does use only call from absolute paths?

[teynon]

I haven't really used namespaces in PHP, but I did a bunch in C++.

 

What happens if you encapsulate those namespaces? (namespace blah { // code })

[trq]

Surely if you're already in the namespace \Proem\Api, and you want to call \Proem\Api\Chain, you should just need

 

 

use Chain;

 

 

Or does use only call from absolute paths?

 

Generally you wouldn't even need to call "use Chain" because Chain is in the same namespace so you can just go ahead and use it.

 

As the link to the "cascading filesystem" stuff points out however, it's not so simple in this case.

 

All classes within Proem are actually created in the Proem\Api\ namespace. However, when you go to use one you must always use it from Proem\

 

Lets use Foo as an example:

 

use Proem\Foo;{/php]

This searches the Proem namespace for Foo, when not found, it will then search Proem\Api. Once located it will alias the class to Proem\Foo and give you access to it. 

Interanally all classes are declared in Proem\Api\ yet used from Proem\

This means that a user can override the functionality of Foo throughout the entire framework without needing to hack the framework itself. You would simply create a file within the Proem namespace and extend Proem\Api\Foo

[code=php:0]

namespace Proem;

class Foo extends \Proem\Api\Foo {}

 

Now, anywhere (including within the framework itself) that access Proem\Foo will get your new class instead of the original one declared within Proem\Api\Foo which it would normally get.

 

I understand that there is a bit going on here, but this functionality allows great flexability and for the most part it is working.

 

I'm at work at the moment but will be investigating this issue tonight when I get home as it is blocking progress. I'll let you guys know if I find a solotion.

 

I already had an idea of moving all components into there own namespace anyway (not because of this issue), so this might be the raod I end up travelling down.

 

Thanks for taking a look.

[KevinM1]

Can you do any kind of stack trace both with and without the alias?  At the very least, you can verify what you think is happening.

[trq]

Yeah, I'mg going to have to do something like that when I get home. I'll let you know what I discover.

[trq]

Actually, that is probably going to be more difficult than it seems as PHPUnit swallow most of the output.

 

I might have to mock up some tests outside of PHPUnit. What a fucking waste of time.