Re: Timestamps in ...-autoloads.el files

[Ludovic Courtès]

Hi!

Alex Kost <address@hidden> skribis:

> To recap: we use "gnu/packages/patches/emacs-source-date-epoch.patch" to
> modify 'autoload-insert-section-header' function, and it should work,
> but it doesn't.  IIUC this happens because "autoload.elc" file was
> compiled using the unpatched "autoload.el", but first things first.  Try
> the following recipe in Emacs (installed with Guix):
>
> 1. M-: (setenv "SOURCE_DATE_EPOCH" "1")
>
> 2. Generate autoloads for any file with autoload cookies.  If you don't
>    have such a file at hand, make "/tmp/f1.el" file with this single
>    line:
>
>    ;;;###autoload(defun f1 nil)
>
>    Then: "M-x update-file-autoloads </tmp/f1.el> </tmp/auto1.el>"
>
> Now open "/tmp/auto1.el" and you'll see a "bad" timestamp like this one:
> (22323 17532 313464 85000).
>
> But!  If you reevaluate 'autoload-insert-section-header' and try again
> the timestamp will be "good":
>
> 3. M-x find-function autoload-insert-section-header
>
> 4. Reevaluate it: C-M-x
>
> 5. M-x update-file-autoloads </tmp/f1.el> </tmp/auto2.el>
>
> Now look at "/tmp/auto2.el": it contains (0 1 0 0) timestamp as
> expected.

Weird!

> I looked at the compiled "autoload.elc" file and if I understood it
> correctly, it was compiled using the unpatched version of "autoload.el"
> (because there is no mention of SOURCE_DATE_EPOCH there).

Indeed.

> But I don't understand how it could happen since patching is performed
> before building.  Any ideas?

I think I have one:

--8<---------------cut here---------------start------------->8---
$ git describe 
v0.10.0-798-g8a7680a
$ tar tvf $(./pre-inst-env guix build -S emacs) |grep 'autoload\.el'
-rw-r--r-- root/root     37292 1970-01-01 01:00 
emacs-24.5/lisp/emacs-lisp/autoload.el
-rw-r--r-- root/root     37127 1970-01-01 01:00 
emacs-24.5/lisp/emacs-lisp/autoload.el.orig
-rw-r--r-- root/root     22624 1970-01-01 01:00 
emacs-24.5/lisp/emacs-lisp/autoload.elc
--8<---------------cut here---------------end--------------->8---

Upstream’s tarball already includes those three files.  Ideally, we
should remove all the .elc files and rebuild them, but maybe there are
bootstrapping issues.

Would you be willing to give it a try?  :-)

Thanks,
Ludo’.