Go语言的创造者写道:
Go doesn't provide assertions. They are undeniably convenient, but our experience has been that programmers use them as a crutch to avoid thinking about proper error handling and reporting. Proper error handling means that servers continue operation after non-fatal errors instead of crashing. Proper error reporting means that errors are direct and to the point, saving the programmer from interpreting a large crash trace. Precise errors are particularly important when the programmer seeing the errors is not familiar with the code.
你对此有什么看法?
如果您所谈论的断言意味着程序抛出然后存在,那么断言可能非常糟糕。这并不是说它们总是错误的使用,它们是一种很容易被误用的结构。他们也有很多更好的选择。这样的事情很容易被称为邪恶。
例如,第三方模块(或任何模块)几乎不应该退出调用程序。这并没有给调用程序的程序员任何控制程序此时应该承担的风险。在许多情况下,数据是如此重要,即使保存损坏的数据也比丢失数据要好。断言可能会迫使您丢失数据。
断言的一些替代方法:
使用调试器,
控制台/数据库/其他日志
异常
其他类型的错误处理
参考:
http://ftp.gnu.org/old-gnu/Manuals/nana-1.14/html_node/nana_3.html
http://www.lenholgate.com/blog/2005/09/assert-is-evil.html
Go不提供断言,并且有很好的理由:http://golang.org/doc/faq#assertions
http://c2.com/cgi/wiki?DoNotUseAssertions
甚至主张assert的人也认为它们应该只用于开发而不是生产:
http://codebetter.com/gregyoung/2007/12/12/asserts-are-not-evil/
http://www.codeproject.com/Articles/6404/Assert-is-your-friend
http://parabellumgames.wordpress.com/using-asserts-for-debugging/
This person says that asserts should be used when the module has potentially corrupted data that persists after an exception is thrown: http://www.advogato.org/article/949.html . This is certainly a reasonable point, however, an external module should never prescribe how important corrupted data is to the calling program (by exiting "for" them). The proper way to handle this is by throwing an exception that makes it clear that the program may now be in an inconsistent state. And since good programs mostly consist of modules (with a little glue code in the main executable), asserts are almost always the wrong thing to do.