Re: master 9dc306b1: Improve reporting of I/O, access errors

[Eli Zaretskii <eliz@gnu.org>]

> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Thu, 19 Sep 2019 17:21:09 -0700
> Cc: emacs-devel@gnu.org
> 
> Although the jury might still be out on the 
> ancestor-directory-permissions aspect of the change (certainly on 
> MS-Windows, which reports EACCES for missing directories), surely Emacs 
> should not simply ignore I/O errors and the like.

I think the jury is still out on the latter part as well.  I, for one,
am not convinced.  Emacs is not a file- or directory-management
utility, it's an editor, so its file I/O aspects are secondary to the
primary goal of modifying files' contents.  IMO, we need to closely
watch the results of these changes, which from my POV are still
experimental, and carefully draw conclusions from the user reports.
(What's worse, these changes might significantly delay the release of
Emacs 27.1, but that ship has sailed.)

> And the permissions change has been helpful for testing

That could mean these changes should be only activated by some
build-time option, or maybe a run-time option, by default off.  It
isn't an evidence in favor of the changes being active by default, at
least not a significant evidence.