[dbus-cplusplus-devel] Problem with Introspectable

[dorphell <dor...@gm...>]

Hello all,

I'm having problems getting a dbus-c++ based app, Youki Media Player, to
run properly -- and I was hoping someone here would have some ideas of
what could be wrong.

Specifically, the problem is that the app won't register Introspectable
for some reason, when it absolutely should and does on the developer's
system (Milosz) with the same exact version of the app and dbus-c++ (we
both compiled from the same source package).

With the 'echo' example in the dbus-c++ source tree, it works:
----------------
$ export DBUSXX_VERBOSE=1
$ ./echo-server
dbus-c++: registering stubs for connection 0xf1ec40
dbus-c++: added watch 0xf207e0 (off) fd=3 flags=2
dbus-c++: added watch 0xf20870 (on) fd=3 flags=1
dbus-c++: :1.31: registering bus name org.freedesktop.DBus.Examples.Echo
dbus-c++: added timeout 0xf1f1f0 (on) interval=25000
dbus-c++: removed timeout 0xf1f1f0
dbus-c++: added timeout 0xf1eff0 (on) interval=25000
dbus-c++: removed timeout 0xf1eff0
dbus-c++: :1.31: added match rule
destination='org.freedesktop.DBus.Examples.Echo'
dbus-c++: adding interface org.freedesktop.DBus.EchoDemo
dbus-c++: adding interface org.freedesktop.DBus.Introspectable
dbus-c++: Introspectable
dbus-c++: registering local object /org/freedesktop/DBus/Examples/Echo
dbus-c++: entering dispatcher 0x616bc0
dbus-c++: dispatching on 0xf1ec40
dbus-c++: dispatching on 0xf1ec40
dbus-c++: all dispatching done on 0xf1ec40
----------------

But when I run the app, for some reason I can't get the Introspectable
even though it's in the app code and Milosz is certain there is no problem
in Youki's code.
I mean... it "just works" for him and the point at which it fails seems
too trivial, it's such a basic fundamental constructor call, that we
cannot find any way it can be wrong in the application itself... Almost
like a hello-world program failing ;-)
----------------
$ /usr/libexec/youki-mlibman-bin
...
... [normal application startup output]
...
dbus-c++: registering stubs for connection 0xb58a70
dbus-c++: glib: added watch 0xa21cf0 (off) fd=10 flags=2
dbus-c++: glib: added watch 0xa21d20 (on) fd=10 flags=1
dbus-c++: :1.42: registering bus name info.backtrace.Youki.MLibMan
dbus-c++: glib: added timeout 0xa21c10 (on)
dbus-c++: glib: removed timeout 0xa21c10
dbus-c++: glib: added timeout 0xa21c10 (on)
dbus-c++: glib: removed timeout 0xa21c10
dbus-c++: :1.42: added match rule
destination='info.backtrace.Youki.MLibMan'
...
... [more application startup output]
...
dbus-c++: dispatching on 0xb58a70
dbus-c++: dispatching on 0xb58a70
dbus-c++: all dispatching done on 0xb58a70
----------------

==> No "adding interface org.freedesktop.DBus.Introspectable"

We tried running it in gdb as well, trying to break out at the
introspection.cpp line in the IntrospectableAdaptor constructor, but it
didn't break out, as if it's not being called at all.

And as you can see, the dbus session is created. I can see the active
info.backtrace.Youki.MLibMan in dbus-browser, but I can't introspec it
(i.e. the browser pane shows empty).

And the app doesn't crash/exit. It keeps running (though the overall
application can't function since the dbus communication with its GUI
doesn't work)

If you would like to take a look at where in Youki
DBus::IntrospectableAdaptor is called, here it is:

mlibmanager.hh ==>  http://pastebin.ca/1534526
mlibmanager.cc ==>  http://pastebin.ca/1534528

We debugged this for many hours trying to narrow it down but have run out
of ideas. If anyone has any suggestions, I'm willing to try anything.

Thanks in advance,
dorphell