bug#64325: ACL error

bug#64325: ACL error

[Charles Millar via Bug reports for GNU Emacs, the Swiss army knife of text editors]

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Please see the attached debug on error which is generated when I attempt 
to save a modified buffer/file, regardless of mode.

Emacs version - GNU Emacs 30.0.50 (build 36, x86_64-pc-linux-gnu, GTK+ 
Version 3.24.36, cairo version 1.16.0) of 2023-06-28

Charlie Millar

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\Debugger entered--Lisp error: (file-error "Setting ACL" "Operation not permitted" "/mnt/Data/ActiveFiles/thuis~")
  set-file-acl("/mnt/Data/ActiveFiles/thuis~" "user::rwx\ngroup::rwx\nother::rwx\n")
  set-file-extended-attributes("/mnt/Data/ActiveFiles/thuis~" ((acl . "user::rwx\ngroup::rwx\nother::rwx\n") (selinux-context nil nil nil nil)))
  backup-buffer-copy("/mnt/Data/ActiveFiles/thuis" "/mnt/Data/ActiveFiles/thuis~" 511 ((acl . "user::rwx\ngroup::rwx\nother::rwx\n") (selinux-context nil nil nil nil)))
  backup-buffer()
  basic-save-buffer-2()
  basic-save-buffer-1()
  basic-save-buffer(t)
  save-buffer(1)
  funcall-interactively(save-buffer 1)
  call-interactively(save-buffer nil nil)
  command-execute(save-buffer)

bug#64325: ACL error

[Eli Zaretskii]

> Date: Wed, 28 Jun 2023 09:15:16 -0400
> From:  Charles Millar via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> Please see the attached debug on error which is generated when I attempt 
> to save a modified buffer/file, regardless of mode.

If, as I understand, you set debug-on-error non-nil when saving the
buffer, then this is normal: it means that the volume you have mounted
in /mnt/ doesn't support ACLs.  Emacs normally hides the ACL-related
errors and silently falls back on using set-file-modes, but setting
debug-on-error non-nil disables that.

So I don't think there's a bug here if you set debug-on-error.

If this happens even if you do not set debug-on-error, then I'd ask
you to step in Edebug through the code in backup-buffer-copy and tell
how come the with-demoted-errors form there doesn't do its job of
catching errors.

Thanks.

bug#64325: ACL error

[Eli Zaretskii]

> Cc: 64325@debbugs.gnu.org
> Date: Thu, 29 Jun 2023 08:47:29 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> 
> > Date: Wed, 28 Jun 2023 09:15:16 -0400
> > From:  Charles Millar via "Bug reports for GNU Emacs,
> >  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> > 
> > Please see the attached debug on error which is generated when I attempt 
> > to save a modified buffer/file, regardless of mode.
> 
> If, as I understand, you set debug-on-error non-nil when saving the
> buffer, then this is normal: it means that the volume you have mounted
> in /mnt/ doesn't support ACLs.  Emacs normally hides the ACL-related
> errors and silently falls back on using set-file-modes, but setting
> debug-on-error non-nil disables that.
> 
> So I don't think there's a bug here if you set debug-on-error.
> 
> If this happens even if you do not set debug-on-error, then I'd ask
> you to step in Edebug through the code in backup-buffer-copy and tell
> how come the with-demoted-errors form there doesn't do its job of
> catching errors.

No further comments, so I presume the issue can be closed now.