Laravel backpack select_multiple | select2_multple breaks while updating/editing with one to many relation

Question

I've encountered a strange bug/issue in my opinion while updating a (goal) model using the BackpackCrudController.

First let me give you some information about my database structure and models. (i've left out useless relations and functions)

quick grasp from my composer.json

        "php": "^7.2",
        "backpack/crud": "4.0.*",
        "backpack/logmanager": "^3.0",
        "backpack/pagemanager": "^2.0",
        "backpack/permissionmanager": "^5.0",
        "fideloper/proxy": "^4.0",
        "laravel/framework": "^6.2",
        "laravel/tinker": "^2.0"

recipes table:

        Schema::create('recipes', function (Blueprint $table) {
            $table->increments('id');
            $table->string('title');
            $table->string('slug');
            $table->string('image');
            $table->text('content');
            $table->text('preparation');
            $table->json('ingredients');
            $table->integer( 'goal_id')->unsigned()->nullable();
            $table->integer( 'category_id')->unsigned()->nullable();
            $table->unsignedBigInteger( 'user_id');
            $table->timestamps();
        });

        Schema::table('recipes', function(Blueprint $table) {
            $table->foreign( 'goal_id')->references( 'id')->on('goals');
            $table->foreign( 'category_id')->references( 'id')->on('categories');
            $table->foreign( 'user_id')->references( 'id')->on('users');
        });

goals table:

       Schema::create('goals', function (Blueprint $table) {
            $table->increments('id');
            $table->string('title');
            $table->string('slug');
            $table->string('image');
            $table->text( 'content');
            $table->string('workbook')->nullable();
            $table->tinyInteger('duration')->nullable();
            $table->timestamps();
        });

Recipe model:

class Recipe extends Model
{
    use CrudTrait;
    use Sluggable;
    use SluggableScopeHelpers;

    /*
    |--------------------------------------------------------------------------
    | GLOBAL VARIABLES
    |--------------------------------------------------------------------------
    */

    protected $table = 'recipes';
    protected $guarded = ['id'];
    protected $fillable = ['title', 'slug', 'image', 'content', 'preparation', 'ingredients', 'goal_id', 'category_id', 'user_id'];


    /*
    |--------------------------------------------------------------------------
    | RELATIONS
    |--------------------------------------------------------------------------
    */
    public function goal(  ) {
        return $this->belongsTo( Goal::class);
    }
}

Goal model:

class Goal extends Model
{
    use CrudTrait;
    use Sluggable;
    use SluggableScopeHelpers;

    /*
    |--------------------------------------------------------------------------
    | GLOBAL VARIABLES
    |--------------------------------------------------------------------------
    */

    protected $table = 'goals';
    protected $guarded = ['id'];
    protected $fillable = ['title', 'slug', 'image', 'content', 'workbook', 'duration'];


    /*
    |--------------------------------------------------------------------------
    | RELATIONS
    |--------------------------------------------------------------------------
    */
    public function recipes(  ) {
        return $this->hasMany( Recipe::class,'goal_id', 'id');
    }
}

The problem exists while updating a goal, so here's my GoalCrudController:

class GoalCrudController extends CrudController
{
    use \Backpack\CRUD\app\Http\Controllers\Operations\ListOperation;
    use \Backpack\CRUD\app\Http\Controllers\Operations\CreateOperation;
    use \Backpack\CRUD\app\Http\Controllers\Operations\UpdateOperation;
    use \Backpack\CRUD\app\Http\Controllers\Operations\DeleteOperation;
    use \Backpack\CRUD\app\Http\Controllers\Operations\ShowOperation;

    public function setup()
    {
        $this->crud->setModel('App\Models\Goal');
        $this->crud->setRoute(config('backpack.base.route_prefix') . '/goal');
        $this->crud->setEntityNameStrings('goal', 'goals');
    }

    protected function setupCreateOperation()
    {
        $this->crud->setValidation(GoalRequest::class);
        $this->crud->addField([
            'label'     => 'Articles',
            'type'      => 'select2_multiple',
            'name'      => 'articles',
            'entity'    => 'articles',
            'attribute' => 'title',
        ]);
        $this->crud->addField([
            'label'     => 'Recipes',
            'type'      => 'select2_multiple',
            'name'      => 'recipes',
            'entity'    => 'recipes',
            'attribute' => 'title',
        ]);
    }

    protected function setupUpdateOperation()
    {
        $this->setupCreateOperation();
        $this->crud->removeField('image');
        $this->crud->addField([
            'name'      => 'image',
            'label'     => 'Image',
            'type'      => 'image',
            'upload'    => true,
            'prefix'    => 'uploads/',
        ])->afterField('title');
    }
}

Again, i left out functions that are not for this issue.

Now, the problem is when i create a goal, i can attach a recipe (from the select2_multiple field) and the relation between a goal and a recipe will be created. Though, when i want to edit/update the goal i just created, to add a new recipe for example, i get the following Exception:

Exception
Property [recipes] does not exist on this collection instance.

I've tried to edit the field in the setupUpdateOperation() to the following:

        $this->crud->removeField('recipes');
        $this->crud->addField([
            'label'     => 'Recipes',
            'type'      => 'select2_multiple',
            'name'      => 'recipes',
            'entity'    => 'recipes',
            'attribute' => 'title',
            'value'     => Recipe::where('goal_id', $this->crud->getCurrentEntryId()), // <-- added this
        ]);

But then i get the following Exception:

Call to a member function pluck() on string (View: /Users/name/Docker/sitename/vendor/backpack/crud/src/resources/views/crud/fields/select_multiple.blade.php) // <-- at line 27

My questions now are actually:

• How will i be able to let the user update an existing goal to add new recipes?
• Also, how it is possible that it works when creating, but not when i want to update?
• Am i using select_multiple | select2_multiple incorrect in this case?
• Are my relations incorrect?
• Am i unable to save the relation in this way? And do i need to do it from the Recipe end?
• Should i use a different select field for the update operation or a model_function?

If i need to provide more information, please let me know and i'll be happy to provide it for you. Thanks in advance!

PS. The issue is the same when using select_multiple.

Answer 1

After fiddling around a bit, i managed to find a solution.

In the setupUpdateOperation function i added the following:

$this->crud->removeField('recipes'); // remove the original field
$this->crud->addField([
            'label'     => 'Recipes',
            'type'      => 'select2_multiple',
            'name'      => 'recipes',
            'entity'    => 'recipes',
            'attribute' => 'title',
            'value'     => $this->crud->getCurrentEntry()->recipes,
        ]);

With this i managed to get the currently related recipes in the update view and actually update the related recipes.