Using native-compile for borg-compile-function doesn't seem to work as advertised

[league]

Hello! I just bootstrapped from the emacs.g seed, and updated borg drone to the latest, cd1fbd6. When I run make, it will generate the .elc files in all the lib/DRONE locations, and when they are first loaded emacs 28.1 will native-compile them. But I'd like to do the native-compile ahead of time.

I tried this setting in etc/borg/config.el, as suggested in the borg manual:

(when (native-comp-available-p)
  (setq borg-compile-function #'native-compile))

With that, make says it's (re-)building everything (and maybe it is?), but afterward, there are no more .elc files in the lib/DRONE locations. I think that when the .elc is missing, Emacs doesn't bother to load the native .eln either!

When I restart emacs, I try these to verify – loading one function provided with emacs and one from a drone:

(describe-function 'font-lock-refresh-defaults)
;; ⇒ font-lock-refresh-defaults is a native compiled Lisp function in ‘font-lock.el’
(describe-function 'epkg-describe-package)
;; ⇒ epkg-describe-package is an autoloaded interactive Lisp closure in ‘epkg-desc.el’

The epkg function is not reported as compiled at all, even byte-compiled.

One hacky way I've found to resolve this is to set borg-compile-function so it explicitly does both:

(when (native-comp-available-p)
  (setq borg-compile-function
	(defun cl/my-compile (filename)
	  (and (byte-compile-file filename)
	       (native-compile filename)))))

Now after a make the .elc files stick around, and the native files seem to be ready ahead of time and load properly:

(describe-function 'epkg-describe-package)
;; ⇒ epkg-describe-package is an interactive native compiled Lisp function in ‘epkg-desc.el’.

So maybe this is a documentation bug about that config.el setting, or borg itself needs to ensure the .elc is also created when it's native-compile, or maybe there's something strange about my setup (or my interpretation of it)? Thanks!

[Eason0210]

@tarsius

I can reproduce this issue.

The workaround also works for me

(when (native-comp-available-p)
  (setq borg-compile-function
	(defun cl/my-compile (filename)
	  (and (byte-compile-file filename)
	       (native-compile filename)))))

And the issue on building packages with compat.el also fixed.
magit/magit#4665

[tarsius]

Using native-compile for borg-compile-function doesn't seem to work as advertised

I don't think I advertised it. I always said you use it at your own risk. I only added support because people insisted it was a good idea and it looked like it more or less would just worked (but now I think it never really worked). But I guess now I am on the hook and have to implement it properly.

See the native branch. Still needs more testing, tweaking, foot-gun removal and documentation; but otherwise is ready.

• Use make clean build-native to wait a long time,
• or use make clean all; emacs; make native-compile to start using emacs as soon as the byte-code is ready.
• Use (setq borg-compile-function #'borg-byte+native-compile) to make the borg-compile command slower,
• or don't do that and let Emacs continue to perform the native compilation asynchronously.

[tarsius]

Still not done, but seems usable. This is in the work branch now.

[Eason0210]

👍 Thanks for your great work on it.
I tried the work branch with make native, It works well as expected.
And I aslo tried to set the /.emacs.d/etc/borg/config.el as below:

(when (native-comp-available-p)
  (setq borg-compile-function #'native-compile))

Then M-x borg-assimilate <package-name>, It also works well.

Tested on macOS with Emacs 29.0.50