Re: [PATCH] editor: use canonicalized absolute path

> By improving the relative_path() algorithm, e02ca72 (path.c: refactor
> relative_path(), not only strip prefix, 2013-06-25) uncovered a latent
> bug.  While most editor applications like cat and vim handle
> non-canonicalized relative paths fine, emacs does not.  This is due to a
> long-standing bug in emacs, where it refuses to resolve symlinks in the
> supplied path:
>
>   #!/bin/sh
>   mkdir z z/a z/b
>   echo moodle >z/a/file
>   ln -s z/b
>   cd b
>   emacs ../a/file # fail: opens /tmp/a/file
>
> Even if emacs were to be patched to fix this bug now, we still need to
> support users running older versions.

> Co-authored-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
> Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
> ---
>  Urgent candidate for maint.  I wrote to emacs-devel, but nobody seems
>  to be interested; the sources are horrendously unmaintainable, and
>  the project should die soon.

> diff --git a/editor.c b/editor.c
> index 27bdecd..0abbd8d 100644
> --- a/editor.c
> +++ b/editor.c
> @@ -37,7 +37,7 @@ int launch_editor(const char *path, struct strbuf *buffer, const char *const *en
>                 return error("Terminal is dumb, but EDITOR unset");
>
>         if (strcmp(editor, ":")) {
> -               const char *args[] = { editor, path, NULL };
> +               const char *args[] = { editor, real_path(path), NULL };
>                 struct child_process p;
>                 int ret, sig;