[5.6] Fix for HasManyThrough returning incorrect results with cursor() (

#22144)

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

@@ -425,6 +425,16 @@ public function chunk($count, callable $callback)
         return $this->prepareQueryBuilder()->chunk($count, $callback);
     }
 
+    /**
+     * Get a generator for the given query.
+     *
+     * @return \Generator
+     */
+    public function cursor()
+    {
+        return $this->prepareQueryBuilder()->cursor();
+    }
+
     /**
      * Execute a callback over each item while chunking.
      *

tests/Database/DatabaseEloquentHasManyThroughIntegrationTest.php

@@ -199,6 +199,27 @@ public function testChunkReturnsCorrectModels()
         });
     }
 
+    public function testCursorReturnsCorrectModels()
+    {
+        $this->seedData();
+        $this->seedDataExtended();
+        $country = HasManyThroughTestCountry::find(2);
+
+        $posts = $country->posts()->cursor();
+
+        foreach ($posts as $post) {
+            $this->assertEquals([
+                'id',
+                'user_id',
+                'title',
+                'body',
+                'email',
+                'created_at',
+                'updated_at',
+                'country_id', ], array_keys($post->getAttributes()));
+        }
+    }
+
     public function testEachReturnsCorrectModels()
     {
         $this->seedData();