[8.x] Eager load pivot relations

src/Illuminate/Database/Eloquent/Relations/BelongsToMany.php

@@ -1013,10 +1013,17 @@ protected function hydratePivotRelation(array $models)
         // To hydrate the pivot relationship, we will just gather the pivot attributes
         // and create a new Pivot model, which is basically a dynamic model that we
         // will set the attributes, table, and connections on it so it will work.
+        $pivots = [];
         foreach ($models as $model) {
-            $model->setRelation($this->accessor, $this->newExistingPivot(
+            $pivots[] = $pivot = $this->newExistingPivot(
                 $this->migratePivotAttributes($model)
-            ));
+            );
+            $model->setRelation($this->accessor, $pivot);
+        }
+
+        if (count($pivots) > 0) {
+            $query = $pivots[0]->newQuery();
+            $query->eagerLoadRelations($pivots);
         }
     }
 

tests/Database/DatabaseEloquentIntegrationTest.php

@@ -1364,6 +1364,20 @@ public function testBelongsToManyCustomPivot()
         $this->assertSame('Jule Doe', $johnWithFriends->friends->find(4)->pivot->friend->name);
     }
 
+    public function testBelongsToManyCustomPivotUsingWithAttribute()
+    {
+        $john = EloquentTestUserWithCustomFriendPivotUsingWithAttribute::create(['id' => 1, 'name' => 'John Doe', 'email' => 'johndoe@example.com']);
+        $jane = EloquentTestUserWithCustomFriendPivotUsingWithAttribute::create(['id' => 2, 'name' => 'Jane Doe', 'email' => 'janedoe@example.com']);
+
+        EloquentTestFriendLevel::create(['id' => 1, 'level' => 'acquaintance']);
+
+        $john->friends()->attach($jane, ['friend_level_id' => 1]);
+
+        $johnWithFriends = EloquentTestUserWithCustomFriendPivotUsingWithAttribute::with('friends')->find(1);
+
+        $this->assertTrue($johnWithFriends->friends->first()->pivot->relationLoaded('level'));
+    }
+
     public function testIsAfterRetrievingTheSameModel()
     {
         $saved = EloquentTestUser::create(['id' => 1, 'email' => 'taylorotwell@gmail.com']);
@@ -1987,6 +2001,15 @@ public function friends()
     }
 }
 
+class EloquentTestUserWithCustomFriendPivotUsingWithAttribute extends EloquentTestUser
+{
+    public function friends()
+    {
+        return $this->belongsToMany(EloquentTestUser::class, 'friends', 'user_id', 'friend_id')
+                        ->using(EloquentTestFriendPivotUsingWithAttribute::class)->withPivot('user_id', 'friend_id', 'friend_level_id');
+    }
+}
+
 class EloquentTestUserWithSpaceInColumnName extends EloquentTestUser
 {
     protected $table = 'users_with_space_in_colum_name';
@@ -2166,6 +2189,11 @@ public function level()
     }
 }
 
+class EloquentTestFriendPivotUsingWithAttribute extends EloquentTestFriendPivot
+{
+    protected $with = ['level'];
+}
+
 class EloquentTouchingUser extends Eloquent
 {
     protected $table = 'users';