PHP foreach loop odd references behaviour

Question

I have a weird issue with a foreach loop and references. Here is my code:

  $authors = array(                                                                                                                                                            
       new Author(array('first_name'=>'Name 1','last_name'=>'last name 1')),                                                                                                         
       new Author(array('first_name'=>'name 1','last_name'=>'last name 2')),                                                                                                   
  );                                                                                                                                                                           

  foreach($authors as $key => $author){                                                                                                                                                
    $authors[$key] = Author::manager()->getOrCreate($author);                                                                                                                       
    print $author->id."-".$authors[0]->id."<br>";                                                                                                                                                                                                                                                               
  }

So if we assume that both of those objects are created in the database, then the output shown is :

1-1
2-2

As you guess my question is: why does $authors[0]->id refers to $author->id ?? I suppose that it is a problem with reference but since I don't use reference in the foreach loop, I have no idea where it comes from!

Any suggestion will be welcome. Thanks

Are you sure the output isn't 1-1, 2-1? Looks like that'd be what it'd output. Just wanted to confirm? — Ben Swinburne
– Ben Swinburne, Commented Mar 13, 2012 at 19:06
Since you don't store any id's when you create the $authors array they will be set to 0, 1, .... So $authors[0] would be the same as $author in the first iteration. — Bjørne Malmanger
– Bjørne Malmanger, Commented Mar 13, 2012 at 19:08

webbiedave · Accepted Answer · 2012-03-13 19:04:58Z

why does $authors[0]->id refers to $author->id ??

It doesn't (after the first iteration).

There's something wrong elsewhere (perhaps in Author::__construct or Author::manager):

class Author
{
    public $id;

    function __construct($params)
    {
        $this->id = substr($params['last_name'], -1);
    }
}


$authors = array(                                                                                                                                                            
    new Author(array('first_name'=>'Name 1','last_name'=>'last name 1')),                                                                                                         
    new Author(array('first_name'=>'name 1','last_name'=>'last name 2')),                                                                                                   
);                                                                                                                                                                           

foreach($authors as $key => $author){                                                                                                                                                                                                                                                                      
    print $author->id."-".$authors[0]->id."<br>";                                                                                                                                                                                                                                                               
}

/* 
output:

1-1
2-1

*/

Indeed, there is an ORM layer which execute the queries to create or get the data. Then I retrieved the PHP object model fed with the shadow data such as the id attribute.

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