I did as instructed.

Here is a couple of instances of what I saw in *Messages* right after I was
able to trigger the problem.

case 1:

DBus-Event (dbus-event :post-blank 0 :post-affiliated 1455145 :mode nil
:granularity element :cached t :parent (section (:begin 1179957 :end
1609350 :contents-begin 1179957 :contents-end 1609349 :robust-begin 1179957
:robust-end 1609347 :post-blank 1 :post-affiliated 1179957 :mode section
:granularity element :cached t :parent (headline (:raw-value Old stuff
:begin 1179945 :end 1609350 :pre-blank 0 :contents-begin 1179957
:contents-end 1609349 :robust-begin 1180109 :robust-end 1609347 :level 1
:priority nil :tags nil :todo-keyword nil :todo-type nil :post-blank 1
:footnote-section-p nil :archivedp nil :commentedp nil :post-affiliated
1179945 :ARCHIVE_TIME 2020-10-17 Sat 15:00 :ARCHIVE_FILE ~/work/worklog.org
:ARCHIVE_OLPATH Scratch :ARCHIVE_CATEGORY worklog :title Old stuff :mode
nil :granularity element :cached t :parent (org-data (:begin 1
:contents-begin 1 :contents-end 15432855 :end 15432856 :robust-begin 3
:robust-end 15432853 :post-blank 1 :post-affiliated 1 :path
/home/kun/work/worklog.org_archive :mode org-data :CATEGORY worklog :cached
t :org-element--cache-sync-key nil)) :org-element--cache-sync-key nil))
:org-element--cache-sync-key nil)) :org-element--cache-sync-key nil) [2
times]
Entering debugger...
DBus-Event (dbus-event x . make4ht)
funcall-interactively: Wrong type argument: listp, "make4ht"

case 2:

DBus-Event (dbus-event :post-blank 0 :post-affiliated 1455145 :mode nil
:granularity element :cached t :parent (section (:begin 1179957 :end
1609350 :contents-begin 1179957 :contents-end 1609349 :robust-begin 1179957
:robust-end 1609347 :post-blank 1 :post-affiliated 1179957 :mode section
:granularity element :cached t :parent (headline (:raw-value Old stuff
:begin 1179945 :end 1609350 :pre-blank 0 :contents-begin 1179957
:contents-end 1609349 :robust-begin 1180109 :robust-end 1609347 :level 1
:priority nil :tags nil :todo-keyword nil :todo-type nil :post-blank 1
:footnote-section-p nil :archivedp nil :commentedp nil :post-affiliated
1179945 :ARCHIVE_TIME 2020-10-17 Sat 15:00 :ARCHIVE_FILE ~/work/worklog.org
:ARCHIVE_OLPATH Scratch :ARCHIVE_CATEGORY worklog :title Old stuff :mode
nil :granularity element :cached t :parent (org-data (:begin 1
:contents-begin 1 :contents-end 15432855 :end 15432856 :robust-begin 3
:robust-end 15432853 :post-blank 1 :post-affiliated 1 :path
/home/kun/work/worklog.org_archive :mode org-data :CATEGORY worklog :cached
t :org-element--cache-sync-key nil)) :org-element--cache-sync-key nil))
:org-element--cache-sync-key nil)) :org-element--cache-sync-key nil) [2
times]
dbus-event-bus-name: D-Bus error: "Not a valid D-Bus event", (dbus-event
:post-blank 0 :post-affiliated 1455145 :mode nil :granularity element
:cached ...)


On Wed, May 15, 2024 at 3:35 AM Michael Albinus <michael.albinus@gmx.de>
wrote:

> Eli Zaretskii <eliz@gnu.org> writes:
>
> Hi,
>
> > We have already established that some invalid D-Bus events cause these
> > problems.  What we need now is to find out what kind of D-Bus events
> > are those, and what does VirtualBox mean to happen when it emits these
> > D-Bus events?
> >
> > Looking at dbus-check-event, I see that event of the form
> >
> >   (dbus-event 10 14)
> >
> > is invalid because the first member of the list after 'dbus-event'
> > should be either a keyword (a symbol, AFAIU) or a string, but here we
> > have a number.
> >
> > The event
> >
> >   (dbus-event "[ \11]*$")
> >
> > from your previous message is also invalid, since it has only one
> > member after 'dbus-event'.
> >
> > IOW, VirtualBox is emitting invalid D-Bus events, at least as far as
> > our support for D-Bus is concerned.
> >
> > Michael, are these events invalid according to the D-Bus spec, or we
> > just lack support for them in Emacs?  If the former, I don't see how
> > this can be an Emacs problem; you should ask the VirtualBox folks what
> > to do to avoid this.
>
> These aren't valid D-Bus events according to the spec, and I doubt that
> they come from D-Bus itself. But let's instrument Emacs in order to see
> which D-Bus events flow around. The following recipe:
>
> --8<---------------cut here---------------start------------->8---
> # rm src/dbusbind.o
> # make MYCPPFLAGS='-DDBUS_DEBUG'
> # src/emacs --eval '(setq dbus-debug t message-log-max t)'
> --8<---------------cut here---------------end--------------->8---
>
> Then trigger the problem, and send us the *Messages* buffer afterwards.
> Recompile Emacs w/o the MYCPPFLAGS arg.
>
> > Maybe we can make Emacs more tolerant to these issues, e.g., make the
> > error a warning or a message?
>
> Maybe. But my gut feeling tells me there is an error in Emacs handling
> incoming event. And this isn't related to D-Bus, necessarily.
>
> > All in all, I feel like this is not an Emacs issue at all, and should
> > not be brought to us.
>
> Maybe. But I'd like to see the D-Bus events first.
>
> Best regards, Michael.
>