warnings during blackbox test cleanup cause flush errors

[Jelmer Vernooij]

  affects bzr
  status confirmed
  importance medium

If the test directory gets removed as part of the test the test runner
will attempt to print a warning. This fails:

------------
Text attachment: traceback
------------
Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/testtools/testcase.py", line
153, in _runCleanups
    function(*arguments, **keywordArguments)
  File "/home/jelmer/src/bzr/bzr.dev/bzrlib/tests/__init__.py", line
1471, in _finishLogFile
    bzrlib.trace.pop_log_file(self._log_memento)
  File "/home/jelmer/src/bzr/bzr.dev/bzrlib/trace.py", line 384, in
pop_log_file
    new_trace_file.flush()
ValueError: I/O operation on closed file
------------

The following patch makes the error go away and gets me a proper
warning:

--- bzrlib/trace.py 2010-06-28 02:41:22 +0000
+++ bzrlib/trace.py 2010-07-26 00:59:43 +0000
@@ -380,8 +380,6 @@
     # file will likely already be closed underneath.
     new_handler.close()
     bzr_logger.handlers = old_handlers
- if new_trace_file is not None:
- new_trace_file.flush()