bug#23692: 25.1.50; Package.el gets confused if file has no autoloads (could be a bug in update-directory-autoloads)

[Eli Zaretskii]

> From: Stefan Monnier <monnier@IRO.UMontreal.CA>
> Date: Mon, 13 Jun 2016 20:40:24 -0400
> Cc: Clément Pit--Claudel <clement.pitclaudel@live.com>,
>  23692@debbugs.gnu.org
> 
> > i) I guess now autoload will sometimes not create any output file.
> 
> I think this shouldn't happen.  Both in the sense that it would be
> a bug, and that my understanding of the code makes me think it
> won't happen.  We create the file before we even try to update it.
> 
> > ii) I wonder what this means for reproducibility of the loaddefs file.
> 
> Good question.
> 
> > iii) Would applying a move-if-change style logic be better?
> 
> Could be, indeed.  My only motivation for the original patch was to
> avoid repeatedly re-dumping Emacs even when no significant change had
> happened.  I wrote the patch years ago, and at that point the
> time-stamps were always different, so the buffer's content was
> definitely changed, tho in ways which had no impact on the dump, so
> "move-if-changed" was not an option.
> Now that we avoid time-stamps maybe we can actually compare the buffer's
> content with the file and skip saving if it's identical.

Stefan, you didn't commit your patch, please do (it should go to the
master branch).

TIA