bug#69606: [PATCH] Ensure default-directory exists when generating diff

[Michael Albinus via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Philip Kaludercic <philipk@posteo.net> writes:

Hi Philip,

> The reason I was thinking about a more general solution, is that
> something like
>
> (let ((default-directory "/this/does/not/exists"))
>   (make-process :command '("true")))
>
> will always fail, even though "true" doesn't use the current working
> directory.  I think it would be useful to have some :fallback option for
> these situations, to ensure that if `default-directory' doesn't exist,
> any other directory should be used instead.

This is a more general request than just make it work for "diff".

Well, there is a reason that `default-directory' isn't set to something
else behind your back, if it doesn't exist. Processes can use relative
file names as arguments, and it is always better to fail with an error
message instead of doing something unexpected you even don't know about.

Best regards, Michael.