bug#24802: emacs -Q -nw loads cl-lib

bug#24802: emacs -Q -nw loads cl-lib

[Glenn Morris]

Package: emacs
Version: 26.0.50

Current trunk on GNU/Linux in an xterm:

emacs -Q -nw
(featurep 'cl-lib)  -> t

I believe this is because term/xterm.el now requires cl-lib at run-time.

You might want to consider:

i) Preload cl-lib - see previous discussions in list archives.

ii) Make term/*.el subject to same rules as files that are explicitly
listed in loadup.el - ie no requirements beyond those of loadup.

bug#24802: emacs -Q -nw loads cl-lib

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Date: Wed, 26 Oct 2016 12:40:16 -0400
> 
> emacs -Q -nw
> (featurep 'cl-lib)  -> t
> 
> I believe this is because term/xterm.el now requires cl-lib at run-time.
> 
> You might want to consider:
> 
> i) Preload cl-lib - see previous discussions in list archives.
> 
> ii) Make term/*.el subject to same rules as files that are explicitly
> listed in loadup.el - ie no requirements beyond those of loadup.

But why is it bad that a specific file loaded only by some sessions
needs to load cl-lib?  Maybe I'm missing something, but I don't see
anything wrong here that needs to be fixed.  E.g., how is it different
from, say, starting to compose email, which then causes message.el to
load half a dozen of additional packages?

bug#24802: emacs -Q -nw loads cl-lib

[Glenn Morris]

I'm saying that simply starting Emacs (and no more) should not load
any extra libraries beyond those of loadup [1].
This is obviously not comparable to starting Emacs and then
doing some arbitrary operation, like composing a mail.

As you said in

http://lists.gnu.org/archive/html/emacs-devel/2015-10/msg00095.html

    Up until now, the rules for pre-loading package X were that either
    (a) some preloaded package requires X, or (b) X will be
    auto-loaded at the beginning of every session by some very
    frequent operation, like visiting the first file or creating a
    window or a frame.

Here we have case b), without needing any operation at all.

OK, it's not "every session", it's "every -nw session in an
xterm-like terminal", but IMO the same should apply.

[1] I don't count the actual term/*.el files themselves in this,
because those that aren't preloaded have traditionally been trivial.
Perhaps xterm.el has become so large, and is used (I guess) in such a
large fraction of without-x builds, that it should be preloaded in
such builds, as x-win.el is in with-x builds. I think that's a
separate issue though. It would however make the issue in this report
obvious.

bug#24802: emacs -Q -nw loads cl-lib

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Cc: 24802@debbugs.gnu.org
> Date: Sun, 30 Oct 2016 19:49:26 -0400
> 
> As you said in
> 
> http://lists.gnu.org/archive/html/emacs-devel/2015-10/msg00095.html
> 
>     Up until now, the rules for pre-loading package X were that either
>     (a) some preloaded package requires X, or (b) X will be
>     auto-loaded at the beginning of every session by some very
>     frequent operation, like visiting the first file or creating a
>     window or a frame.
> 
> Here we have case b), without needing any operation at all.
> 
> OK, it's not "every session", it's "every -nw session in an
> xterm-like terminal", but IMO the same should apply.
> 
> [1] I don't count the actual term/*.el files themselves in this,
> because those that aren't preloaded have traditionally been trivial.
> Perhaps xterm.el has become so large, and is used (I guess) in such a
> large fraction of without-x builds, that it should be preloaded in
> such builds, as x-win.el is in with-x builds. I think that's a
> separate issue though. It would however make the issue in this report
> obvious.

That's exactly my line of reasoning: as long as we don't preload
xterm.el, we shouldn't regard its loading of other files a problem.

bug#24802: emacs -Q -nw loads cl-lib

[Eli Zaretskii]

> Date: Mon, 31 Oct 2016 17:45:16 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 24802@debbugs.gnu.org
> 
> > From: Glenn Morris <rgm@gnu.org>
> > Cc: 24802@debbugs.gnu.org
> > Date: Sun, 30 Oct 2016 19:49:26 -0400
> > 
> > As you said in
> > 
> > http://lists.gnu.org/archive/html/emacs-devel/2015-10/msg00095.html
> > 
> >     Up until now, the rules for pre-loading package X were that either
> >     (a) some preloaded package requires X, or (b) X will be
> >     auto-loaded at the beginning of every session by some very
> >     frequent operation, like visiting the first file or creating a
> >     window or a frame.
> > 
> > Here we have case b), without needing any operation at all.
> > 
> > OK, it's not "every session", it's "every -nw session in an
> > xterm-like terminal", but IMO the same should apply.
> > 
> > [1] I don't count the actual term/*.el files themselves in this,
> > because those that aren't preloaded have traditionally been trivial.
> > Perhaps xterm.el has become so large, and is used (I guess) in such a
> > large fraction of without-x builds, that it should be preloaded in
> > such builds, as x-win.el is in with-x builds. I think that's a
> > separate issue though. It would however make the issue in this report
> > obvious.
> 
> That's exactly my line of reasoning: as long as we don't preload
> xterm.el, we shouldn't regard its loading of other files a problem.

In any case, your recipe yields nil with the current master, so even
if you disagree with the above reasoning, the original problem is now
gone, and I'm therefore closing this bug report.

Thanks.