--- Begin Message ---
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Subject: |
24.0.50; dbus-unregister-object fails if service is nil |
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Date: |
Fri, 23 Sep 2011 01:01:17 +0200 |
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User-agent: |
Gnus/5.110018 (No Gnus v0.18) Emacs/24.0.50 (gnu/linux) |
If you use `dbus-register-signal' with a nil SERVICE value, like:
(dbus-register-signal :session nil
"/org/gtk/Private/RemoteVolumeMonitor"
"org.gtk.Private.RemoteVolumeMonitor" "VolumeAdded"
'identity)
This is valid and works fine. However, on unregister it fails:
Debugger entered--Lisp error: (dbus-error "Call to ReleaseName has wrong args
(b, expected s)")
dbus-call-method(:session "org.freedesktop.DBus" "/org/freedesktop/DBus"
"org.freedesktop.DBus" "ReleaseName" nil)
dbus-unregister-object(((:session "org.gtk.Private.RemoteVolumeMonitor"
"VolumeAdded") (nil "/org/gtk/Private/RemoteVolumeMonitor" identity)))
Why does it fail? Because of the following code in
`dbus-unregister-object':
#+begin_src emacs-lisp
(unless found
(dbus-call-method
bus dbus-service-dbus dbus-path-dbus dbus-interface-dbus
"ReleaseName" service))))
+end_src
And here service is… nil. Which is translated to a boolean (b) but
should be a string (s).
But honestly, I'm not sure what the good fix is. To me, this code is
totally wrong in such a case.
When using `dbus-register-signal', this happens:
1. the dbus_bus_add_match() function is called to add a match on the bus
2. the (match callback) pair is recorded into
`dbus-registered-objets-table'
This makes things work. When a signal happens, something is looking into
`dbus-registered-objets-table' and call the callback function.
But to stop listening for a signal, the function to use is
`dbus-unregister-object', and it is doing this:
1. remove the (match callback) pair from `dbus-registered-objets-table'
2. call ReleaseName on the service we were listening
While I agree on point 1., the point 2. is totally irrelevant in such a
case. There's no need to do such a thing, the name has never been
requested with RequestName before.
I think that:
- step 2 should be removed or another function should be created which
does not send a ReleaseName
- dbus_bus_remove_match() should be used to remove the watch from the
bus, which would be a lot cleaner.
--
Julien Danjou
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--- Begin Message ---
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Subject: |
Re: bug#9581: 24.0.50; dbus-unregister-object fails if service is nil |
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Date: |
Mon, 26 Sep 2011 15:57:57 +0200 |
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User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.0.50 (gnu/linux) |
Julien Danjou <address@hidden> writes:
> I think you can close this bug, and maybe reopen one if you want to
> track the other changes you want to do after the pretest. You call. :)
OK, closed.
I don't believe we need another bug report just to remind myself ... I
tend to forget everything (ask my wife!), but this patch is already
prepared in my local repo. I should find it after the release.
Thanks for your patient testing, and best regards, Michael.
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