--- Begin Message ---
|
Subject: |
29.0.50; Help-mode bookmarks not loading with native compilation |
|
Date: |
Tue, 19 Jul 2022 13:45:19 +0000 |
Overview:
With native compilation enabled, adding a bookmark in a help buffer seems to
work normally for the duration of the Emacs session, but when Emacs is
restarted an "Invalid read syntax: '#'" error is thrown and the entire bookmark
list fails to load. This appears to be caused by a compiled lambda being
serialized to the bookmark file in a way that is unreadable to the reader.
Emacs version:
29.0.5, compiled from latest master branch on 7-18-2022, and started with emacs
-Q for both scenarios below.
Steps to reproduce:
1. Ensure that native compilation is enabled by running M-x
native-comp-available-p
2. Run M-x describe-function {{any-function}} and move to the resulting *Help*
buffer
3. Create a bookmark with C-x r m
4. Without quitting Emacs, kill the *Help* buffer, then run C-x r b to jump
back to the bookmark (this works as expected)
5. Quit Emacs (C-x C-c), and restart
6. Attempt to jump to the same bookmark again (running C-x r b), and observe
that the bookmark list fails to load and throws an "Invalid read syntax: '#'"
error
Here is an example of a help bookmark as it was serialized to the bookmarks
file (note the "help-fn" value):
("native-comp-bookmark"
(position . 1)
(last-modified 25301 49750 590832 312000)
(help-fn . #<subr F616e6f6e796d6f75732d6c616d626461_anonymous_lambda_9>)
(help-args switch-to-buffer "*scratch*")
(position . 1)
(handler . help-bookmark-jump))
For comparison, I compiled Emacs without the native compilation flag (and
verified that native-comp-available-p returned nil), and went through the same
steps above, creating a new bookmark. Jumping back to the bookmark after
restarting works as expected, and here is an example of that bookmark
serialized without native comp:
("vanilla-bookmark"
(position . 1)
(last-modified 25301 49238 861856 736000)
(help-fn .
#[514 "\301!\205\0\211\302!)\207"
[describe-function-orig-buffer buffer-live-p describe-function]
4 "\n\n(fn FUNCTION BUFFER)"])
(help-args switch-to-buffer "*scratch*")
(position . 1)
(handler . help-bookmark-jump))
I did find an older similar bug (#24573
https://lists.gnu.org/archive/html/bug-gnu-emacs/2016-09/msg00971.html) which
was causing the same error due to a buffer object being serialized. This was
fixed by saving just the buffer name, but I'm not sure there's any comparable
way to save a reference to a compiled lambda. Any advice would be much
appreciated though!
--- End Message ---
--- Begin Message ---
|
Subject: |
Re: bug#56643: 29.0.50; Help-mode bookmarks not loading with native compilation |
|
Date: |
Sat, 23 Jul 2022 12:57:49 +0300 |
> Cc: michael_heerdegen@web.de, defun.foo@proton.me, 56643@debbugs.gnu.org
> Date: Fri, 22 Jul 2022 17:40:48 +0300
> From: Eli Zaretskii <eliz@gnu.org>
>
> > > Thanks. If Andrea confirms that this won't have any problems with
> > > native-compilation, I will install such changes on the release branch
> > > (since AFAIU this issue is a regression in Emacs 28).
> >
> > I confirm it should just work.
>
> Thanks, so I will make those changes on the release branch.
Done.
> > BTW, I mention this for other similar cases, another fix would be to add
> > (declare (speed -1)) to `describe-function'.
>
> Thanks, good to know. I guess we should document that in the ELisp
> manual.
Also done.
Closing.
--- End Message ---