RFC: remove traceback from "newer branch format than your bzr"

[Emma Jane]

This evening I tried to grab a copy of Ian's new documentation. I'm using the 
Bazaar that comes with Ubuntu (1.13) which happens to use the old formats. I 
was a greeted with a fairly scary message. It's at the bottom of this message.

While I appreciate the usefulness of tracebacks, I'm not sure it's entirely 
necessary or appropriate in this case. More specifically:

1. The first line of the error pretty much says everything I need to know:
	bzr: ERROR: exceptions.KeyError: 'Bazaar repository format 2a 
	(needs bzr 1.16 or later)\n'
With the exception of the \n, I think this message does a pretty good job of 
telling me what the problem is. The rest of the message (all traceback?) could 
be omitted.

2. At the end of the message, which is what my terminal window scrolls after 
dumping a lot of garbage, I'm told to report a bug. I don't think it's a "bug" 
that I'm using an old version. Perhaps a new type of error message is needed?

3. Generally I find tracebacks really scary. I don't do anything in Bazaar that 
*should* generate errors (I typically work with fewer than 30 files and fewer 
than 500 revisions per project; I rarely do merges and use BzrUpload for most 
projects). I would prefer if the tracebacks were turned off by default with a 
message on how to enable them, but there's no way that I can see to turn them 
off.


regards,
emma

PS I'm now using the PPA at Robert's recommendation and it's working well. 
Thanks!




emmajane at hum:~/websites/bazaar-vcs.org$ bzr branch lp:bzr-alldocs
bzr: ERROR: exceptions.KeyError: 'Bazaar repository format 2a (needs bzr 1.16 
or later)\n'

Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 716, in 
exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 911, in 
run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 547, in 
run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.6/dist-packages/bzrlib/builtins.py", line 1100, in 
run
    source_branch=br_from)
  File "/usr/lib/python2.6/dist-packages/bzrlib/bzrdir.py", line 1098, in 
sprout
    cloning_format = self.cloning_metadir(stacked)
  File "/usr/lib/python2.6/dist-packages/bzrlib/remote.py", line 165, in 
cloning_metadir
    repo_name)
  File "/usr/lib/python2.6/dist-packages/bzrlib/registry.py", line 255, in get
    r = Registry.get(self, format_string)
  File "/usr/lib/python2.6/dist-packages/bzrlib/registry.py", line 168, in get
    return self._dict[self._get_key_or_default(key)].get_obj()
KeyError: 'Bazaar repository format 2a (needs bzr 1.16 or later)\n'

bzr 1.13.1 on python 2.6.2 (linux2)
arguments: ['/usr/bin/bzr', 'branch', 'lp:bzr-alldocs']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_CA.UTF-8'
plugins:
  bzrtools             /usr/lib/python2.6/dist-
packages/bzrlib/plugins/bzrtools [1.13]
  etckeeper            /usr/lib/python2.6/dist-
packages/bzrlib/plugins/etckeeper [unknown]
  launchpad            /usr/lib/python2.6/dist-
packages/bzrlib/plugins/launchpad [unknown]
  netrc_credential_store /usr/lib/python2.6/dist-
packages/bzrlib/plugins/netrc_credential_store [unknown]
  upload               /home/emmajane/.bazaar/plugins/upload [1.0dev]
*** 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.