Perl 安装模块的文件夹中存在文件 .exists 是什么原因?

What for there is file .exists in Perl installed modules' folders?

我前段时间安装了 CPAN 模块。打开模块Catalyst-Plugin-Browser的文件夹后,有一个文件.exists。它在那里干什么?

ExtUtils::MM_Anydir_target 目标的文档是这样说的:

Because depending on a directory to just ensure it exists doesn't work too well (the modified time changes too often) dir_target() creates a .exists file in the created directory. It is this you should depend on.

所以它是 CPAN 模块安装工具链使用的机制的一部分。