Fix cursor pagination with HasManyThrough (#40300)

Author: driesvints

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

@@ -431,6 +431,22 @@ public function simplePaginate($perPage = null, $columns = ['*'], $pageName = 'p
         return $this->query->simplePaginate($perPage, $columns, $pageName, $page);
     }
 
+    /**
+     * Paginate the given query into a cursor paginator.
+     *
+     * @param  int|null  $perPage
+     * @param  array  $columns
+     * @param  string  $cursorName
+     * @param  string|null  $cursor
+     * @return \Illuminate\Contracts\Pagination\CursorPaginator
+     */
+    public function cursorPaginate($perPage = null, $columns = ['*'], $cursorName = 'cursor', $cursor = null)
+    {
+        $this->query->addSelect($this->shouldSelect($columns));
+
+        return $this->query->cursorPaginate($perPage, $columns, $cursorName, $cursor);
+    }
+
     /**
      * Set the select clause for the relation query.
      *