为什么 (probe-file #P"/") return nil？

Question

这似乎是 ECL 实现中的错误——或者由于标准中的一些细节：

    > (probe-file #P"/usr")

    #P"/usr/"
    > (probe-file #P"/usr/")

    #P"/usr/"
    > (probe-file #P"/")

    NIL
    > (probe-file #P"//")

    NIL

还有一个案例：

    > (probe-file #P"/.")

    #P"/"

更新，FWIW，SBCL 符合我的预期：

    * (probe-file #P"/")

    #P"/"

Answer 1

这是我正在测试的修复程序的提交消息（希望这能回答问题——这确实是一个错误）：

unixfsys: remove coerce_to_posix_filename

This was a workaround around bugs in cygwin and mingw (which are already fixed), when the directory name ended with '/'. This fix introduced extra bug with probe-file called on the root directory (it returned nil on all platforms).

Original comment:

This converts a pathname designator into a namestring, with the particularity that directories do not end with a slash '/', because this is not supported on all POSIX platforms (most notably Windows).

Bug reference:

https://sourceforge.net/p/mingw-w64/patches/34/

Fixes #351.

为什么 (probe-file #P"/") return nil？

Why does (probe-file #P"/") return nil?

common-lisp

ecl