php - 如果发生弃用警告，为什么要在带有(@)符号的trigger_error前面加上前缀？

Question

This question already has answers here:

What is the purpose of '@' (silence operator, at sign) before trigger_error?

(3个答案)


2年前关闭。




我看到人们在这里和那里都在前缀不赞成使用警告。看起来像这样:

@trigger_error('This method is deprecated', E_USER_DEPRECATED);

同时知道 @运算符 will basically make any error messages go away。因此，似乎这些警告无济于事，而 indeed they cause no output。

@trigger_error('No one ever sees this', E_USER_DEPRECATED);
trigger_error('Visible deprecation warning', E_USER_DEPRECATED);

因此，考虑到相当广泛的用途( 1， 2， 3， 4， 5 ...)，为什么有人要这样做？我为什么要这么做？是否应该对任何弃用使用相同的方法？

更重要的是，我还没有在Google中找到解释。似乎与 Symfony's error handling有关，并且有 this extensive discussion on that subject，但到目前为止我还没有找到确切的答案。

最佳答案

引用Symfony 4 PHPUnit Bridge documentation:

Deprecation notices can be triggered by using:

@trigger_error('Your deprecation message', E_USER_DEPRECATED);

Without the @-silencing operator, users would need to opt-out from deprecation notices. Silencing by default swaps this behavior and allows users to opt-in when they are ready to cope with them (by adding a custom error handler like the one provided by this bridge). When not silenced, deprecation notices will appear in the Unsilenced section of the deprecation report.

归结为 the following example:

set_error_handler(function ($errno, $errstr) {
    var_dump($errstr);
}, E_USER_DEPRECATED);

@trigger_error('Will only be seen from a custom error handler', E_USER_DEPRECATED);

否则，如果需要，仍可以从自定义错误处理程序中听到静音的弃用通知，而不会同时污染常规日志。

关于php - 如果发生弃用警告，为什么要在带有(@)符号的trigger_error前面加上前缀？ ，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/52489730/

上一篇：json - 一次JSON多个查询

下一篇：error-handling - 为什么TCL CATCH命令不返回错误？

Answer 1

引用Symfony 4 PHPUnit Bridge documentation:

Deprecation notices can be triggered by using:

@trigger_error('Your deprecation message', E_USER_DEPRECATED);

Without the @-silencing operator, users would need to opt-out from deprecation notices. Silencing by default swaps this behavior and allows users to opt-in when they are ready to cope with them (by adding a custom error handler like the one provided by this bridge). When not silenced, deprecation notices will appear in the Unsilenced section of the deprecation report.

归结为 the following example:

set_error_handler(function ($errno, $errstr) {
    var_dump($errstr);
}, E_USER_DEPRECATED);

@trigger_error('Will only be seen from a custom error handler', E_USER_DEPRECATED);

否则，如果需要，仍可以从自定义错误处理程序中听到静音的弃用通知，而不会同时污染常规日志。