Re: msys2 build path problems + copy-paste english results in chinese characters

[Eli Zaretskii <eliz@gnu.org>]

> From: Óscar Fuentes <ofv@wanadoo.es>
> Date: Thu, 02 Dec 2021 10:42:49 +0100
> 
> >> (let ((dir (file-name-directory (car command-line-args))))
> >>   (setenv "PATH" (concat (getenv "PATH") path-separator dir))
> >>   (setq exec-path (append exec-path (list dir))))
> >
> > Changing PATH from within Emacs is not recommended, it will bite you
> > down the road when you least expect it.
> 
> I'm using that since many years ago without problems.

Sheer luck.

> If you know a better approach

Yes, change PATH outside of Emacs.  Then live happily ever after.

> and/or wish to describe a failure mode for the above code...

One failure is that you put directories with forward slashes into the
environment of the programs you invoke, and not all of them like that
(although most do cope with that).

Another problem is that after this, PATH used by Emacs and PATH used
by sub-processes is different.

Yet another problem, specific to invoking MSYS2 commands, is that the
directory might be incorrectly encoded (if it includes non-ASCII
characters), since MSYS2 programs expect UTF-8 encoding AFAIK, whereas
Emacs encodes it using the system codepage.

There might be other problems, I'm not sure I remember all of them.  I
just learned long ago not to do that.