`bzr commit` throws an exception when bzr-dbus is installed, and commit is via SSH

[Craig Mason]

Running `bzr commit` when logged into a machine via SSH causes a crash. Speaking with somebody in the #bzr IRC channel, it was discovered that the variable $DBUS_SESSION_BUS_ADDRESS is blank when connecting via SSH.

Running `dbus-launch bzr commit` works without crashing.

Committing to: /tmp/bzr/
added testfile
bzr: ERROR: dbus.exceptions.DBusException: org.freedesktop.DBus.Error.Spawn.ExecFailed: dbus-launch failed to autolaunch D-Bus session: Autolaunch error: X11 initialization failed.

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 857, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 797, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 499, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.5/site-packages/bzrlib/builtins.py", line 2290, in run
    exclude=safe_relpath_files(tree, exclude))
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 192, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/workingtree_4.py", line 242, in commit
    result = WorkingTree3.commit(self, message, revprops, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 192, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/mutabletree.py", line 197, in commit
    revprops=revprops, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/commit.py", line 407, in commit
    self.branch.set_last_revision_info(new_revno, self.rev_id)
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 192, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 2096, in set_last_revision_info
    self._run_post_change_branch_tip_hooks(old_revno, old_revid)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 1634, in _run_post_change_branch_tip_hooks
    hook(params)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/dbus/hook.py", line 46, in on_post_change_branch_tip
    activity.Activity().advertise_branch(params.branch)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/dbus/activity.py", line 71, in __init__
    self.bus = _get_bus(bus)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/dbus/activity.py", line 49, in _get_bus
    return dbus.SessionBus()
  File "/var/lib/python-support/python2.5/dbus/_dbus.py", line 217, in __new__
    mainloop=mainloop)
  File "/var/lib/python-support/python2.5/dbus/_dbus.py", line 106, in __new__
    bus = BusConnection.__new__(subclass, bus_type, mainloop=mainloop)
  File "/var/lib/python-support/python2.5/dbus/bus.py", line 125, in __new__
    bus = cls._new_for_bus(address_or_type, mainloop=mainloop)
DBusException: org.freedesktop.DBus.Error.Spawn.ExecFailed: dbus-launch failed to autolaunch D-Bus session: Autolaunch error: X11 initialization failed.

bzr 1.6.1 on python 2.5.2 (linux2)
arguments: ['/usr/bin/bzr', 'commit']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_GB.UTF-8'
plugins:
  avahi /usr/lib/python2.5/site-packages/bzrlib/plugins/avahi [0.3.0dev0]
  bzrtools /usr/lib/python2.5/site-packages/bzrlib/plugins/bzrtools [1.6.0]
  dbus /usr/lib/python2.5/site-packages/bzrlib/plugins/dbus [unknown]
  gtk /usr/lib/python2.5/site-packages/bzrlib/plugins/gtk [0.95.0]
  launchpad /usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad [unknown]
*** Bazaar has encountered an internal error.
    Please report a bug at https://bugs.launchpad.net/bzr/+filebug
    including this traceback, and a description of what you
    were doing when the error occurred.

[Craig Mason (craig-mason-stasismedia)]

Running `bzr commit` when logged into a machine via SSH causes a crash. Speaking with somebody in the #bzr IRC channel, it was discovered that the variable $DBUS_SESSION_BUS_ADDRESS is blank when connecting via SSH.

Running `dbus-launch bzr commit` works without crashing.

Committing to: /tmp/bzr/
added testfile
bzr: ERROR: dbus.exceptions.DBusException: org.freedesktop.DBus.Error.Spawn.ExecFailed: dbus-launch failed to autolaunch D-Bus session: Autolaunch error: X11 initialization failed.

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 857, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 797, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 499, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.5/site-packages/bzrlib/builtins.py", line 2290, in run
    exclude=safe_relpath_files(tree, exclude))
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 192, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/workingtree_4.py", line 242, in commit
    result = WorkingTree3.commit(self, message, revprops, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 192, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/mutabletree.py", line 197, in commit
    revprops=revprops, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/commit.py", line 407, in commit
    self.branch.set_last_revision_info(new_revno, self.rev_id)
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 192, in write_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 2096, in set_last_revision_info
    self._run_post_change_branch_tip_hooks(old_revno, old_revid)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 1634, in _run_post_change_branch_tip_hooks
    hook(params)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/dbus/hook.py", line 46, in on_post_change_branch_tip
    activity.Activity().advertise_branch(params.branch)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/dbus/activity.py", line 71, in __init__
    self.bus = _get_bus(bus)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/dbus/activity.py", line 49, in _get_bus
    return dbus.SessionBus()
  File "/var/lib/python-support/python2.5/dbus/_dbus.py", line 217, in __new__
    mainloop=mainloop)
  File "/var/lib/python-support/python2.5/dbus/_dbus.py", line 106, in __new__
    bus = BusConnection.__new__(subclass, bus_type, mainloop=mainloop)
  File "/var/lib/python-support/python2.5/dbus/bus.py", line 125, in __new__
    bus = cls._new_for_bus(address_or_type, mainloop=mainloop)
DBusException: org.freedesktop.DBus.Error.Spawn.ExecFailed: dbus-launch failed to autolaunch D-Bus session: Autolaunch error: X11 initialization failed.

bzr 1.6.1 on python 2.5.2 (linux2)
arguments: ['/usr/bin/bzr', 'commit']
encoding: 'UTF-8', fsenc: 'UT...

[Charles Duffy (M1) (cduffy-messageone)]

Per discussion with Colin Walters in #dbus -- the immediate workaround is probably to short-circuit if DBUS_SESSION_BUS_ADDRESS is unset; the proper fix is probably for libdbus to avoid auto-spawning behavior if no DISPLAY variable is set.

<nDuff> Is it appropriate for an application with an optional dependency on dbus to not make any calls at all if DBUS_SESSION_BUS_ADDRESS is unset?
<walters> well...ug. You want to avoid the auto-spawning session bus?
<nDuff> there's a report in #bzr of commit operations crashing with the bzr-dbus plugin installed but without a session active
<walters> actually it looks like DBUS_SESSION_BUS_ADDRESS is in the specification (for better or worse)
<walters> so yeah, that's a reasonable thing to do
<walters> the reason i'm a little ambivalent about it is that we'd like to make the session bus per-uid which would involve some kernel tricks most likely
<nDuff> ...yar, I can see how something like an API call to check for a valid session might be more futureproof, then.
<walters> but if we do that i think we'll need to keep some compatibility with the environment variable for various reasons; so go ahead and depend on it
<walters> though i do wonder why bzr would be crashing
<nDuff> http://pastebin.com/d30394fa1
<walters> crashing as in python traceback, or crash as in native segv?
<nDuff> a Python exception
<nDuff> DBusException: org.freedesktop.DBus.Error.Spawn.ExecFailed: dbus-launch failed to autolaunch D-Bus session: Autolaunch error: X11 initialization failed.
<walters> oh...hm.
<nDuff> ...I suppose just catching and logging the exception might be a saner approach than the environment variable, actually...
<walters> so in this situation there's no X server (i.e. no DISPLAY?)
<nDuff> correct; it's being used over a non-X-forwarding ssh session.
<walters> i'm thinking this is really a libdbus bug; we shouldn't try to auto-spawn a bus in this situation
<walters> the reason this crazy autospawning got added was for people ssh -X into their server and running an X app like firefox
<walters> we didn't want to just break firefox trying to talk to the session bus when none exists

[Charles Duffy (M1) (cduffy-messageone)]

See also https://bugs.freedesktop.org/show_bug.cgi?id=19997

[Jelmer Vernooij (jelmer)]

This bug has already been fixed in upstream bzr-dbus as well as in
Debian. A new version should be synced into Ubuntu.

  affects bzr-dbus
  status fixreleased

  affects ubuntu/bzr-dbus
  status confirmed

On Fri, 2009-02-06 at 19:59 +0000, Craig Mason wrote:
> Public bug reported:
>
> Running `bzr commit` when logged into a machine via SSH causes a crash.
> Speaking with somebody in the #bzr IRC channel, it was discovered that
> the variable $DBUS_SESSION_BUS_ADDRESS is blank when connecting via SSH.
>
> Running `dbus-launch bzr commit` works without crashing.
>
> Committing to: /tmp/bzr/
> added testfile
> bzr: ERROR: dbus.exceptions.DBusException: org.freedesktop.DBus.Error.Spawn.ExecFailed: dbus-launch failed to autolaunch D-Bus session: Autolaunch error: X11 initialization failed.
>
>
> Traceback (most recent call last):
> File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 857, in run_bzr_catch_errors
> return run_bzr(argv)
> File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 797, in run_bzr
> ret = run(*run_argv)
> File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 499, in run_argv_aliases
> return self.run(**all_cmd_args)
> File "/usr/lib/python2.5/site-packages/bzrlib/builtins.py", line 2290, in run
> exclude=safe_relpath_files(tree, exclude))
> File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 192, in write_locked
> result = unbound(self, *args, **kwargs)
> File "/usr/lib/python2.5/site-packages/bzrlib/workingtree_4.py", line 242, in commit
> result = WorkingTree3.commit(self, message, revprops, *args, **kwargs)
> File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 192, in write_locked
> result = unbound(self, *args, **kwargs)
> File "/usr/lib/python2.5/site-packages/bzrlib/mutabletree.py", line 197, in commit
> revprops=revprops, *args, **kwargs)
> File "/usr/lib/python2.5/site-packages/bzrlib/commit.py", line 407, in commit
> self.branch.set_last_revision_info(new_revno, self.rev_id)
> File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 192, in write_locked
> result = unbound(self, *args, **kwargs)
> File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 2096, in set_last_revision_info
> self._run_post_change_branch_tip_hooks(old_revno, old_revid)
> File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 1634, in _run_post_change_branch_tip_hooks
> hook(params)
> File "/usr/lib/python2.5/site-packages/bzrlib/plugins/dbus/hook.py", line 46, in on_post_change_branch_tip
> activity.Activity().advertise_branch(params.branch)
> File "/usr/lib/python2.5/site-packages/bzrlib/plugins/dbus/activity.py", line 71, in __init__
> self.bus = _get_bus(bus)
> File "/usr/lib/python2.5/site-packages/bzrlib/plugins/dbus/activity.py", line 49, in _get_bus
> return dbus.SessionBus()
> File "/var/lib/python-support/python2.5/dbus/_dbus.py", line 217, in __new__
> mainloop=mainloop)
> File "/var/lib/python-support/python2.5/dbus/_dbus.py", line 106, in __new__
> bus = BusConnection.__new__(subclass, bus_type, mainloop=mainloop)
> File "/var/lib...

[Hp-pobox (hp-pobox)]

Makes sense.