wrong-type-argument consp :int64 when using emms-mpris.el

[Sheng Wang]

Without the attached patch mpris integration doesn't work on my setup.
Actions like "Next" and "Previous" doesn't work, showing
"wrong-type-argument consp :int64" in minibuffer.

Does this happen to you too?

mpris.patch
Description: Text Data

Tried on both Emacs 28 and the latest master branch, on nixos-unstable KDE 
5.26.5.
dbus-daemon --version shows 1.14.4

Steps to reproduce:

(toggle-debug-on-error)
(emms-mpris-enable)

Debugger entered--Lisp error: (wrong-type-argument consp :int64)
  dbus-message-internal(2 :session ":1.53" 16780 :variant :int64 0)
  dbus-method-return-internal(:session ":1.53" 16780 :variant :int64 0)
  apply(dbus-method-return-internal :session ":1.53" 16780 (:variant :int64 0))
  dbus-handle-event((dbus-event :session 1 16780 ":1.53" 
"org.mpris.MediaPlayer2.emms" "/org/mpris/MediaPlayer2" 
"org.freedesktop.DBus.Properties" "Get" emms-mpris-get-property-handler 
(:string "org.mpris.MediaPlayer2.Player") (:string "Position")))
  funcall-interactively(dbus-handle-event (dbus-event :session 1 16780 ":1.53" 
"org.mpris.MediaPlayer2.emms" "/org/mpris/MediaPlayer2" 
"org.freedesktop.DBus.Properties" "Get" emms-mpris-get-property-handler 
(:string "org.mpris.MediaPlayer2.Player") (:string "Position")))
  command-execute(dbus-handle-event nil [(dbus-event :session 1 16780 ":1.53" 
"org.mpris.MediaPlayer2.emms" "/org/mpris/MediaPlayer2" 
"org.freedesktop.DBus.Properties" "Get" emms-mpris-get-property-handler 
(:string "org.mpris.MediaPlayer2.Player") (:string "Position"))] t)

publickey - sheng@a64.work - e0b3e13f.asc
Description: application/pgp-keys

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Description: OpenPGP digital signature