Merge branch 'iamgergo/7.x' into 7.x

Author: taylorotwell

src/Illuminate/Database/Eloquent/Concerns/HasAttributes.php

@@ -415,7 +415,8 @@ public function getRelationValue($key)
         // If the "attribute" exists as a method on the model, we will just assume
         // it is a relationship and will load and return results from the query
         // and hydrate the relationship's value on the "relationships" array.
-        if (method_exists($this, $key)) {
+        if (method_exists($this, $key) ||
+            (static::$relationResolvers[get_class($this)][$key] ?? null)) {
             return $this->getRelationshipFromMethod($key);
         }
     }

src/Illuminate/Database/Eloquent/Concerns/HasRelationships.php

@@ -2,6 +2,7 @@
 
 namespace Illuminate\Database\Eloquent\Concerns;
 
+use Closure;
 use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Model;
@@ -44,6 +45,28 @@ trait HasRelationships
         'belongsToMany', 'morphToMany', 'morphedByMany',
     ];
 
+    /**
+     * The relation resolver callbacks.
+     *
+     * @var array
+     */
+    protected static $relationResolvers = [];
+
+    /**
+     * Define a dynamic relation resolver.
+     *
+     * @param  string  $name
+     * @param  \Closure  $callback
+     * @return void
+     */
+    public static function resolveRelationUsing($name, Closure $callback)
+    {
+        static::$relationResolvers = array_replace_recursive(
+            static::$relationResolvers,
+            [static::class => [$name => $callback]]
+        );
+    }
+
     /**
      * Define a one-to-one relationship.
      *

src/Illuminate/Database/Eloquent/Model.php

@@ -1725,6 +1725,10 @@ public function __call($method, $parameters)
             return $this->$method(...$parameters);
         }
 
+        if ($resolver = (static::$relationResolvers[get_class($this)][$method] ?? null)) {
+            return $resolver($this);
+        }
+
         return $this->forwardCallTo($this->newQuery(), $method, $parameters);
     }
 

tests/Database/DatabaseEloquentRelationTest.php

@@ -267,6 +267,20 @@ public function testMacroable()
         $result = $relation->foo();
         $this->assertSame('foo', $result);
     }
+
+    public function testRelationResolvers()
+    {
+        $model = new EloquentRelationResetModelStub;
+        $builder = m::mock(Builder::class);
+        $builder->shouldReceive('getModel')->andReturn($model);
+
+        EloquentRelationResetModelStub::resolveRelationUsing('customer', function ($model) use ($builder) {
+            return new EloquentResolverRelationStub($builder, $model);
+        });
+
+        $this->assertInstanceOf(EloquentResolverRelationStub::class, $model->customer());
+        $this->assertSame(['key' => 'value'], $model->customer);
+    }
 }
 
 class EloquentRelationResetModelStub extends Model
@@ -329,3 +343,11 @@ class EloquentNoTouchingAnotherModelStub extends Model
         'id' => 2,
     ];
 }
+
+class EloquentResolverRelationStub extends EloquentRelationStub
+{
+    public function getResults()
+    {
+        return ['key' => 'value'];
+    }
+}