Re: 900276502f..: Paul Eggert 2018-11-13 Act like POSIX sh if $HOME is relative

[João Távora]

Hi,

I've only now caught up with the discussion of bug#33255.  Are the
consequences of interpreting the string "c:" on Windows as a relative
file name understood?

With HOME="z:", it used to be that (expand-file-name "~/blabla")
returned "z:/blabla" but now it returns
"z:/source/emacs/emacs/src/z:/blabla", which is not a valid Windows
pathname.

With HOME set thusly, this breaks a recent master build immediately (and
misteriously), since it can't find/create user-emacs-directory.

Notice however that (expand-file-name "z:") does return "z:/".  So I
think there is an inconsistency here, even if it is true that
(file-name-absolute-p "z:") has always returned nil.

All of this can be fixed by me by setting HOME to "z:/", but
unfortunately I am breaking other applications that expected it
slash-less.

An alternative would be:

* for this part of the change to be reverted in Emacs;

* for me to set the correct environment var from the Windows shortcut
  that points to runemacs.exe. Can it be done easily?

Anyway, maybe a tiny edit to the NEWS to mention this particular (and
presumably common) case could be worth it.

João Távora