[11.x] Fix attribute mutator access in loadMissing

src/Illuminate/Database/Eloquent/Collection.php

@@ -271,7 +271,7 @@ protected function loadMissingRelation(self $models, array $path)
             return;
         }
 
-        $models = $models->pluck($name)->whereNotNull();
+        $models = $models->pluck($name)->filter();
 
         if ($models->first() instanceof BaseCollection) {
             $models = $models->collapse();

tests/Integration/Database/EloquentModelLoadMissingTest.php

@@ -3,6 +3,7 @@
 namespace Illuminate\Tests\Integration\Database\EloquentModelLoadMissingTest;
 
 use DB;
+use Illuminate\Database\Eloquent\Casts\Attribute;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Support\Facades\Schema;
@@ -12,20 +13,40 @@ class EloquentModelLoadMissingTest extends DatabaseTestCase
 {
     protected function afterRefreshingDatabase()
     {
+        Schema::create('users', function (Blueprint $table) {
+            $table->increments('id');
+            $table->string('name');
+        });
+
+        Schema::create('comment_mentions_users', function (Blueprint $table) {
+            $table->unsignedInteger('comment_id');
+            $table->unsignedInteger('user_id');
+        });
+
         Schema::create('posts', function (Blueprint $table) {
             $table->increments('id');
+            $table->unsignedInteger('first_comment_id')->nullable();
+            $table->string('content')->nullable();
         });
 
         Schema::create('comments', function (Blueprint $table) {
             $table->increments('id');
             $table->unsignedInteger('parent_id')->nullable();
             $table->unsignedInteger('post_id');
+            $table->string('content')->nullable();
         });
 
         Post::create();
 
-        Comment::create(['parent_id' => null, 'post_id' => 1]);
+        Comment::create(['parent_id' => null, 'post_id' => 1, 'content' => 'Hello <u:1> <u:2>']);
         Comment::create(['parent_id' => 1, 'post_id' => 1]);
+
+        User::create(['name' => 'Taylor']);
+        User::create(['name' => 'Otwell']);
+
+        Comment::first()->mentionsUsers()->attach([1, 2]);
+
+        Post::first()->update(['first_comment_id' => 1]);
     }
 
     public function testLoadMissing()
@@ -39,6 +60,17 @@ public function testLoadMissing()
         $this->assertCount(1, DB::getQueryLog());
         $this->assertTrue($post->comments[0]->relationLoaded('parent'));
     }
+
+    public function testLoadMissingNoUnnecessaryAttributeMutatorAccess()
+    {
+        $posts = Post::all();
+
+        DB::enableQueryLog();
+
+        $posts->loadMissing('firstComment.parent');
+
+        $this->assertCount(1, DB::getQueryLog());
+    }
 }
 
 class Comment extends Model
@@ -51,14 +83,42 @@ public function parent()
     {
         return $this->belongsTo(self::class);
     }
+
+    public function mentionsUsers()
+    {
+        return $this->belongsToMany(User::class, 'comment_mentions_users');
+    }
+
+    public function content(): Attribute
+    {
+        return new Attribute(function (?string $value) {
+            return preg_replace_callback('/<u:(\d+)>/', function ($matches) {
+                return '@'.$this->mentionsUsers->find($matches[1])?->name;
+            }, $value);
+        });
+    }
 }
 
 class Post extends Model
 {
     public $timestamps = false;
 
+    protected $guarded = [];
+
     public function comments()
     {
         return $this->hasMany(Comment::class);
     }
+
+    public function firstComment()
+    {
+        return $this->belongsTo(Comment::class, 'first_comment_id');
+    }
+}
+
+class User extends Model
+{
+    public $timestamps = false;
+
+    protected $guarded = [];
 }