Question

在使用 symfony-flex 将symfony3.4项目迁移到Symfony4的过程中...

在调整目录结构并进行少量调整后，我现在面临的是在应用程序服务容器引导阶段出现的循环依赖错误。点击应用程序（无论是从控制台还是从前端）引发了一些与 Xdebug 相关的异常，说«嵌套函数调用限制已达到（'256'）»。

查看回溯，揭示了一种重复自身的模式，并得出结论 Xdebug 不是应该责备但是两种服务间接依赖于彼此相反。

涉及的服务包括：

日志管理器是一项公共服务，可帮助将用户操作保存到数据库：

log_manager:
    class: Service\Log\LogManager
    public: true
    arguments:
        - "@doctrine.orm.entity_manager"
        - "@?security.token_storage"

LoggableSubscriber 使用 LogManager 服务，以便在某些应用程序对象状态发生变化时创建新记录：

Doctrine\Behavior\ORM\Loggable\LoggableSubscriber:
    public: false
    arguments:
        - "@log_manager"
        - "@event_dispatcher"
    tags:
        - { name: doctrine.event_subscriber }

Backtrace （请自下而上阅读）：

==== ↑↑ PATTERN REPEATS ON AND ON ↑↑ ====
==== ONCE AGAIN DOCTRINE LOOKS FOR SUBSCRIBERS ====
at boDevDebugProjectContainer->load('…/var/cache/bo/dev/ContainerTv5AUyL/getLoggableSubscriberService.php')
    in getDoctrine_Dbal_ApiacmeConnectionService.php (line 34)
at require('…/var/cache/bo/dev/ContainerTv5AUyL/getDoctrine_Dbal_ApiacmeConnectionService.php')
    in boDevDebugProjectContainer.php (line 446)
at boDevDebugProjectContainer->load('…/var/cache/bo/dev/ContainerTv5AUyL/getDoctrine_Dbal_ApiacmeConnectionService.php')
    in getDoctrine_Orm_ApiacmeEntityManagerService.php (line 74)
at require('…/var/cache/bo/dev/ContainerTv5AUyL/getDoctrine_Orm_ApiacmeEntityManagerService.php')
    in boDevDebugProjectContainer.php (line 446)
==== "LOGMANAGER" NATURALLY REQUIRES DOCTRINE ENTITY MANAGER SERVICE ====
at boDevDebugProjectContainer->load('…/var/cache/bo/dev/ContainerTv5AUyL/getDoctrine_Orm_ApiacmeEntityManagerService.php')
    in getLogManagerService.php (line 10)
at require('…/var/cache/bo/dev/ContainerTv5AUyL/getLogManagerService.php')
    in boDevDebugProjectContainer.php (line 446)
at boDevDebugProjectContainer->load('…/var/cache/bo/dev/ContainerTv5AUyL/getLogManagerService.php')
    in getLoggableSubscriberService.php (line 11)

==== BUT OUR "LOGGABLESUBSCRIBER" IN TURN NEEDS THE "LOGMANAGER" SERVICE ====
at require('…/var/cache/bo/dev/ContainerTv5AUyL/getLoggableSubscriberService.php')
    in boDevDebugProjectContainer.php (line 446)

==== DOCTRINE LOADS SUBSCRIBERS (ATTACHED VIA "TAG" PROPERTY) ====
at boDevDebugProjectContainer->load('…/var/cache/bo/dev/ContainerTv5AUyL/getLoggableSubscriberService.php')
    in getDoctrine_Dbal_ApiacmeConnectionService.php (line 34)
==== ↑↑ PATTERN STARTS HERE ↑↑ ====

at require('…/var/cache/bo/dev/ContainerTv5AUyL/getDoctrine_Dbal_ApiacmeConnectionService.php')
    in boDevDebugProjectContainer.php (line 446)
at boDevDebugProjectContainer->load('…/var/cache/bo/dev/ContainerTv5AUyL/getDoctrine_Dbal_ApiacmeConnectionService.php')
    in getDoctrine_Orm_ApiacmeEntityManagerService.php (line 74)
at require('…/var/cache/bo/dev/ContainerTv5AUyL/getDoctrine_Orm_ApiacmeEntityManagerService.php')
    in boDevDebugProjectContainer.php (line 446)

==== FIRST, OUR "LOGMANAGER" SERVICE DEPENDS ON DOCTRINE MAIN ENTITYMANAGER ====
at boDevDebugProjectContainer->load('…/var/cache/bo/dev/ContainerTv5AUyL/getDoctrine_Orm_ApiacmeEntityManagerService.php')
    in getLogManagerService.php (line 10)
at require('…/var/cache/bo/dev/ContainerTv5AUyL/getLogManagerService.php')
    in boDevDebugProjectContainer.php (line 446)
↑↑ ↑↑ ↑↑
…

这纯粹是一个误解问题吗？或者有没有办法通过在配置中的某处设置一些属性/标志来使服务容器意识到这种情况，这样它就不会生气？我看到了几个与此主题相关的问题，但答案是特定于他们的问题的背景。

我打算破坏 LogManager 服务对doctrine实体管理器的依赖，使 LogManager 类无法再将其底层实体对象自身持久化到数据库中，结果通过返回要保留的实例来将该作业委托给调用上下文。我不相信这是理想的解决方案。

非常感谢建议的方法谢谢。

Answer 1

用方法调用替换依赖注入参数确实解决了这个问题。我的log_manager服务定义现在看起来像这样：

log_manager:
    class: Service\Log\LogManager
    public: true
    arguments:
        - "@?security.token_storage"
    calls:
        - ['setEntityManager', ["@doctrine.orm.entity_manager"]]

如果有更好的方法可以解决问题，请发表评论/回答。

Symfony4服务容器循环依赖

1 个答案: