qdiff: NameError when pygments not installed

[Daniel Clemente]

qdiff crashes at each diff, both calling it from qlog and directly through bzr qdiff.
I'm using latest bzr.dev and qbzr from right now.

 ~/.bazaar/plugins/qbzr $ bzr qdiff
bzr: ERROR: exceptions.NameError: global name 'get_style_by_name' is not defined

Traceback (most recent call last):
  File "/home/dc/.mirp/.bazaar/plugins/qbzr/lib/commands.py", line 165, in run
    ret_code = self._qbzr_run(*args, **kwargs)
  File "/home/dc/.mirp/.bazaar/plugins/qbzr/lib/commands.py", line 466, in _qbzr_run
    ui_mode=ui_mode)
  File "/w/bzr/oficial/bzrlib/lazy_import.py", line 125, in __call__
    return obj(*args, **kwargs)
  File "/home/dc/.mirp/.bazaar/plugins/qbzr/lib/diffwindow.py", line 143, in __init__
    self.diffview = SidebySideDiffView(self)
  File "/home/dc/.mirp/.bazaar/plugins/qbzr/lib/diffview.py", line 213, in __init__
    QtGui.QTextCharFormat(self.monospacedFormat))
  File "/home/dc/.mirp/.bazaar/plugins/qbzr/lib/syntaxhighlighter.py", line 175, in __init__
    self.style = get_style_by_name("default")
NameError: global name 'get_style_by_name' is not defined

bzr 2.2.0dev1 on python 2.5.5 (Linux-2.6.32-3-amd64-x86_64-with-debian-squeeze-sid)
arguments: ['/w/bzr/oficial/bzr', 'qdiff']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'ca_ES.UTF-8'
plugins:
  bzrtools /home/dc/.mirp/.bazaar/plugins/bzrtools [2.1.0]
  etckeeper /usr/lib/python2.5/site-packages/bzrlib/plugins/etckeeper [unknown]
  explorer /home/dc/.mirp/.bazaar/plugins/explorer [1.1.0dev]
  fastimport /home/dc/.mirp/.bazaar/plugins/fastimport [0.9.0dev]
  git /home/dc/.mirp/.bazaar/plugins/git [0.5.0]
  gtk /home/dc/.mirp/.bazaar/plugins/gtk [0.99.0dev1]
  launchpad /home/w/bzr/oficial/bzrlib/plugins/launchpad [2.2.0dev1]
  netrc_credential_store /home/w/bzr/oficial/bzrlib/plugins/netrc_credential_store [2.2.0dev1]
  news_merge /home/w/bzr/oficial/bzrlib/plugins/news_merge [2.2.0dev1]
  push_and_update /home/dc/.mirp/.bazaar/plugins/push_and_update [0.2.0dev]
  qbzr /home/dc/.mirp/.bazaar/plugins/qbzr [0.19.0dev1]

*** Bazaar has encountered an internal error. This probably indicates a
    bug in Bazaar. You can help us fix it by filing a bug report at
        https://bugs.launchpad.net/bzr/+filebug
    including this traceback and a description of the problem.

Via bisect I tracked down the change at which this crash appeared:

On revision 1227.1.6 (<email address hidden>):
Better custom lazy import for pygments.

And from: bzr diff -c 1227.1.6
…
         try:
- import pygments
+ from pygments.util import ClassNotFound
+ from pygments.styles import get_style_by_name
+ from pygments import lex
+ from pygments.lexers import get_lexer_for_filename
         except ImportError:
             _have_pygments = False
         else:

Maybe it's necessary to add an "except NameError"?