Re: master 10a7615b5d4: Separate filename-deletion mechanism from policy.

[Eli Zaretskii <eliz@gnu.org>]

> From: Po Lu <luangruo@yahoo.com>
> Cc: "Eric S. Raymond" <esr@thyrsus.com>
> Date: Sun, 06 Aug 2023 21:37:21 +0800
> 
> "Eric S. Raymond" <esr@thyrsus.com> writes:
> 
> >     This is a pure refactoring step, delete-file's behavior is
> >     unchanged. But the C core is a little simpler now.
> > ---
> >  lisp/files.el | 20 ++++++++++++++++++++
> >  src/fileio.c  | 40 +++++++++-------------------------------
> >  2 files changed, 29 insertions(+), 31 deletions(-)
> >
> > diff --git a/lisp/files.el b/lisp/files.el
> > index f8867432000..84a8c308b09 100644
> > --- a/lisp/files.el
> > +++ b/lisp/files.el
> > @@ -6352,6 +6352,26 @@ non-nil and if FN fails due to a missing file or directory."
> >        (apply fn args)
> >      (file-missing (or no-such (signal (car err) (cdr err))))))
> >  
> > +(defun delete-file (filename &optional trash)
> > +  "Delete file named FILENAME.  If it is a symlink, remove the symlink.
> > +If file has multiple names, it continues to exist with the other names.q
>                                                                           ^
> Typo alert!
> 
> Thanks.  While I'm not enthusiastic about moving functions from C to
> Lisp, others seem to appreciate the gesture, so I won't mention this
> subject now.

This kind of changes should have been discussed before it was
installed.  There are several issues I can see here:

  . delete-file-internal must call expand-file-name on its argument,
    as all primitives that interface to the filesystem must; I fixed
    that;
  . Emacs will now be unable to call delete-file or rename-file during
    loadup, until files.el is loaded -- not sure if this is a problem,
    but I guess we will see;
  . the changeset failed to adjust internal_delete_file, which still
    called Fdelete_file; I fixed that (I hope, see below)

Andrea, please take a look at the last bullet above: I made
internal_delete_file call Fdelete_file_internal, which means it no
longer supports remote files.  If that is a problem, we should call
Qdelete_file there, but then I wonder whether calling Lisp at that
place, even though delete-file is preloaded, can cause any trouble?
If there's any doubt this will work, I'd rather revert this whole
changeset, as this is a delicate place in Emacs, and I'd hate to break
it.

> However,
> 
> > branch: master
> > commit 10a7615b5d45bcd909bb03d67423b337dfe93b1e
> > Author: Eric S. Raymond <esr@thyrsus.com>
> > Commit: Eric S. Raymond <esr@thyrsus.com>
> >
> >     Separate filename-deletion mechanism from policy.
> >     
> >     src/fileio.c: (delete-file-internal) Renamed from delete-file,
> >                   parallel to delete-directory-internal; policy
> >                   code moved to Lisp.
> >     src/files.el: (delete-file) New function, holds policy logic.
> >                   calls delete-file-internal.
> 
> is incorrect, since our ChangeLog generator expects the entries to be
> formatted like so:

That's water under the bridge, as this is Git.  Whoever prepares the
Emacs 30.1 tarball will have to deal with this.