Trait collision: Conflict with other traits overriding newCollection method

[yusrashahina]

When using HasRecursiveRelationships alongside traits that override newCollection (e.g., Mediable from plank/mediable), a fatal error occurs due to method collision:
Trait method 'newCollection' will not be applied because it collides with another trait method.

Steps to Reproduce:

composer require plank/mediable staudenmeir/laravel-adjacency-list

Create a model using both traits:

use Plank\Mediable\Mediable;  
use Staudenmeir\LaravelAdjacencyList\Eloquent\HasRecursiveRelationships;  

class Category extends Model {  
    use Mediable, HasRecursiveRelationships;  
} 

Attempt to use the model (e.g., fetch records).

Trait method 'newCollection' has not been applied because there are collisions with other trait methods on App\Models\Category

Temporary Workaround:
A custom collection class can be created to combine both traits’ collection logic, but this requires manual delegation (example below). However, this may not cover all edge cases.

Request:
Could the package provide a way to avoid overriding newCollection or make it compatible with other traits that modify collections? For example:

• Allow configuration to disable the newCollection override.
• Use a trait without the newCollection method (e.g., split HasAdjacencyList into subtraits).
• Use composition instead of inheritance for collections.

Example Workaround Code:

// Custom collection  
class HybridCollection extends MediableCollection {  
    use \Staudenmeir\LaravelAdjacencyList\Eloquent\Concerns\HasCollection;  
}  

// Model  
class Category extends Model {  
    use Mediable, HasRecursiveRelationships;  

    public function newCollection(array $models = []) {  
        return new HybridCollection($models);  
    }  
}  

• Environment:
• Laravel: 11.x
• PHP: 8.2
• Package version: staudenmeir/laravel-adjacency-list:^1.7

Thank you for this excellent package! Any guidance or updates to resolve this would be appreciated.

[staudenmeir]

Hi @yusrashahina,

Are you using the collection's methods toTree() or loadTreeRelationships()? If not, you can use newCollection() from the other package:

use Plank\Mediable\Mediable;  
use Staudenmeir\LaravelAdjacencyList\Eloquent\HasRecursiveRelationships;  

class Category extends Model {  
    use Mediable, HasRecursiveRelationships {
        Mediable::newCollection insteadof HasRecursiveRelationships;
    }
} 

[yusrashahina]

Hi @staudenmeir,

I do use toTree() and other adjacency list features that depend on the package’s custom collection. Using Mediable::newCollection insteadof HasRecursiveRelationships breaks these features (e.g., toTree() is unavailable).

Is there a way to retain both MediableCollection and adjacency list functionality?

Our current workaround (custom HybridCollection) works partially but may miss edge cases. Any guidance would be appreciated!

[staudenmeir]

In this case, you do need to merge both Collection classes into a single one.

Our current workaround (custom HybridCollection) works partially but may miss edge cases. Any guidance would be appreciated!

What does your current HybridCollection class look like?

[yusrashahina]

Here’s our current HybridCollection:

namespace App\Collections;  

use Plank\Mediable\MediableCollection;  
use Staudenmeir\LaravelAdjacencyList\Eloquent\Collection as AdjacencyCollection;  

class HybridCollection extends MediableCollection  
{  
    public function __construct(array $models = [])  
    {  
        parent::__construct($models);  
        // Proxy adjacency list methods  
        $this->adjacencyProxy = new AdjacencyCollection($models);  
    }  

    public function __call($method, $parameters)  
    {  
        if (method_exists($this->adjacencyProxy, $method)) {  
            return $this->adjacencyProxy->{$method}(...$parameters);  
        }  

        return parent::__call($method, $parameters);  
    }  

    // Basic adjacency list method (example)  
    public function toTree()  
    {  
        return $this->adjacencyProxy->toTree();  
    }  
}

Methods like map() or filter() return a MediableCollection instead of HybridCollection, breaking adjacency list functionality in subsequent calls. Is there a way to ensure all collection methods return the merged collection type?

[staudenmeir]

Have you tried this approach?

namespace App\Collections;  

use Plank\Mediable\MediableCollection;

class HybridCollection extends MediableCollection  
{
    public function toTree()  
    {  
        // TODO: Copy code from Staudenmeir\LaravelAdjacencyList\Eloquent\Collection
    }  
}