Re: The “//” fix confuses cygwin-mount

[Andy Moreton]

On Fri 28 Sep 2018, Michael Albinus wrote:

> On an MS Windows machine, I have installed
>
> GNU Emacs 26.1 (build 1, x86_64-unknown-cygwin)
>  of 2018-05-28
>
> (That's the version distributed by Cygwin.). And I have also installed
> recent Tramp
>
> tramp-version
> => "2.4.1-pre"
>
> When I run your example, I get
>
> (substitute-in-file-name "/method:host:/foo")
> => "/method:host:/foo"
>
> Everything looks normal. What do I miss?

Here you are running a cygwin build of emacs, but the problem occurs
when running a native Windows version of emacs (Mingw,org or MSYS2).

cygwin-mount.el allows a native Windows emacs to understand the mapping
between POSIX paths used in cgywin and the equivalent Windows native
paths (found by parsing the output from the Cygwin 'mount' executable).

This allows the emacs user to type Cygwin POSIX paths in a native
Windows emacs, and have those paths automatically translated into the
equivalent Windows native paths.

For example, on a 64bit native Windows build from master, using built-in
Tramp and the cygwin-mount.el package):

(version)
"GNU Emacs 27.0.50 (build 22, x86_64-w64-mingw32)
 of 2018-09-28"

emacs-repository-version
"06e2814e1f3a80d247675319d3c438989592fb06"

(substitute-in-file-name "/method:host:/foo")
#("/method:address@hidden:c:/cygwin/foo" 8 11 (tramp-default t))