Lösen Sie das Problem, dass die Isset-Methode nach dem Upgrade auf PHP7 immer falsch ist

 'foobar']; public function __get($key) { if (isset($this->attributes[$key])) { return $this->attributes[$key]; } } } $post = new Post(); echo isset($post->content); // false

 'foobar']; public function __get($key) { if (isset($this->attributes[$key])) { return $this->attributes[$key]; } } public function __isset($key) { if (isset($this->attributes[$key])) { return true; } return false; } } $post = new Post(); echo isset($post->content); //true

class Model { // 存放属性 protected $attributes = []; // 存放关系 protected $relations = []; public function __get($key) { if( isset($this->attributes[$key]) ) { return $this->attributes[$key]; } // 找到关联的对象，放在关系里面 if (method_exists($this, $key)) { $relation = $this->$method(); return $this->relations[$method] = $relation; } } public function __set($k, $v) { $this->attributes[$k] = $v; } public function __isset($key) { if (isset($this->attributes[$key]) || isset($this->relations[$key])) { return true; } return false; } }

class Post extends Model { protected function user() { $user = new User(); $user->name = 'user name'; return $user; } } class User extends Model { }

$post = new Post(); echo 'isset 发帖用户：'; echo isset($post->user) ? 'true' : 'false'; // false echo PHP_EOL; echo 'isset 发帖用户的名字：'; echo isset($post->user->name) ? 'true' : 'false'; // false echo PHP_EOL; echo '发帖用户的名字：'; echo $post->user->name; // user name echo PHP_EOL; echo '再次判断 isset 发帖用户的名字：'; echo isset($post->user->name) ? 'true' : 'false'; // true echo PHP_EOL;

PHP 7 has fixed a bug with __isset which affects both the native isset and empty methods. This causes specific issues with checking isset or empty on relations in Eloquent. In PHP 7 checking if a property exists on an unloaded relation, for example isset($this->relation->id) is always returning false because unlike PHP 5.6, PHP 7 is now checking the offset of each attribute before chaining to the next one. In PHP 5.6 it would eager load the relation without checking the offset. This change brings back the intended behavior of the core Eloquent model __isset method for PHP 7 so it works like it did in PHP 5.6. For reference, please check the following link, specifically Nikita Popov's comment (core PHP dev) - https://bugs.php.net/bug.php?id=69659