Bug#882607: libdbus-1-3: steam crashes at start with latest libdbus update

[Simon McVittie]

Control: reassign -1 steam
Control: forwarded -1 https://github.com/ValveSoftware/steam-for-linux/issues/5201

On Fri, 24 Nov 2017 at 18:45:10 +0100, Axel R. wrote:
> Updating libdbus-1-3:i386 (1.12.0-1, 1.12.2-1) led to steam client crashes with:
> dbus[4877]: arguments to dbus_message_new_method_call() were incorrect, assertion "path != NULL" failed in file ../../../dbus/dbus-message.c line 1362.
> This is normally a bug in some application using the D-Bus library.
> D-Bus not built with -rdynamic so unable to print a backtrace

This is a bug in Steam, which I think is specifically in the bundled
copy of SDL 2.0.6 that it uses. It will crash in this way on everything
that isn't a Debian derivative.

On Debian derivatives, until recently a Debian-specific patch downgraded
the response to failing the precondition check to a warning (this was
done "temporarily" 11 years ago). "export DBUS_FATAL_WARNINGS=0" before
running Steam would do the same thing as that patch. This will avoid the
crash and just spam warnings instead, unless you are unlucky with the
contents of uninitialized memory, in which case it might still crash.

Workarounds:

* don't have or use ibus ("unset XMODIFIERS" before launching Steam
  is said to work)
* or, export DBUS_FATAL_WARNINGS=0

I think this would be better worked around in /usr/games/steam than in
libdbus, unless the same failure mode is very widespread (but hopefully
it isn't, because if it was, the same code would crash on non-Debian).

Steam will hopefully pick up SDL 2.0.7 soon, which is believed to fix
the crash.

Regards,
    smcv