blackbox: do not assume self._bb{vfs,repo,fp} are set in blackboxui.__init__

It's possible for the blackboxui code to do a "del self._bbvfs", then ui.copy()
or similar attempt will fail. It will also fail when constructing a blackboxui
from a non-blackbox ui.
This patch fixes the issue by not assuming any _bb* attr is set.

hgext/blackbox.py

@@ -1,250 +1,250 b''
 # blackbox.py - log repository events to a file for post-mortem debugging
 #
 # Copyright 2010 Nicolas Dumazet
 # Copyright 2013 Facebook, Inc.
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 """log repository events to a blackbox for debugging
 
 Logs event information to .hg/blackbox.log to help debug and diagnose problems.
 The events that get logged can be configured via the blackbox.track config key.
 
 Examples::
 
   [blackbox]
   track = *
   # dirty is *EXPENSIVE* (slow);
   # each log entry indicates `+` if the repository is dirty, like :hg:`id`.
   dirty = True
   # record the source of log messages
   logsource = True
 
   [blackbox]
   track = command, commandfinish, commandexception, exthook, pythonhook
 
   [blackbox]
   track = incoming
 
   [blackbox]
   # limit the size of a log file
   maxsize = 1.5 MB
   # rotate up to N log files when the current one gets too big
   maxfiles = 3
 
 """
 
 from __future__ import absolute_import
 
 import errno
 import re
 
 from mercurial.i18n import _
 from mercurial.node import hex
 
 from mercurial import (
     cmdutil,
     ui as uimod,
     util,
 )
 
 cmdtable = {}
 command = cmdutil.command(cmdtable)
 # Note for extension authors: ONLY specify testedwith = 'internal' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = 'internal'
 lastui = None
 
 filehandles = {}
 
 def _openlog(vfs):
     path = vfs.join('blackbox.log')
     if path in filehandles:
         return filehandles[path]
     filehandles[path] = fp = vfs('blackbox.log', 'a')
     return fp
 
 def _closelog(vfs):
     path = vfs.join('blackbox.log')
     fp = filehandles[path]
     del filehandles[path]
     fp.close()
 
 def wrapui(ui):
     class blackboxui(ui.__class__):
         def __init__(self, src=None):
             super(blackboxui, self).__init__(src)
             if src is None:
                 self._partialinit()
             else:
-                self._bbfp = src._bbfp
+                self._bbfp = getattr(src, '_bbfp', None)
                 self._bbinlog = False
-                self._bbrepo = src._bbrepo
-                self._bbvfs = src._bbvfs
+                self._bbrepo = getattr(src, '_bbrepo', None)
+                self._bbvfs = getattr(src, '_bbvfs', None)
 
         def _partialinit(self):
             if util.safehasattr(self, '_bbvfs'):
                 return
             self._bbfp = None
             self._bbinlog = False
             self._bbrepo = None
             self._bbvfs = None
 
         def copy(self):
             self._partialinit()
             return self.__class__(self)
 
         @util.propertycache
         def track(self):
             return self.configlist('blackbox', 'track', ['*'])
 
         def _openlogfile(self):
             def rotate(oldpath, newpath):
                 try:
                     self._bbvfs.unlink(newpath)
                 except OSError as err:
                     if err.errno != errno.ENOENT:
                         self.debug("warning: cannot remove '%s': %s\n" %
                                    (newpath, err.strerror))
                 try:
                     if newpath:
                         self._bbvfs.rename(oldpath, newpath)
                 except OSError as err:
                     if err.errno != errno.ENOENT:
                         self.debug("warning: cannot rename '%s' to '%s': %s\n" %
                                    (newpath, oldpath, err.strerror))
 
             fp = _openlog(self._bbvfs)
             maxsize = self.configbytes('blackbox', 'maxsize', 1048576)
             if maxsize > 0:
                 st = self._bbvfs.fstat(fp)
                 if st.st_size >= maxsize:
                     path = fp.name
                     _closelog(self._bbvfs)
                     maxfiles = self.configint('blackbox', 'maxfiles', 7)
                     for i in xrange(maxfiles - 1, 1, -1):
                         rotate(oldpath='%s.%d' % (path, i - 1),
                                newpath='%s.%d' % (path, i))
                     rotate(oldpath=path,
                            newpath=maxfiles > 0 and path + '.1')
                     fp = _openlog(self._bbvfs)
             return fp
 
         def _bbwrite(self, fmt, *args):
             self._bbfp.write(fmt % args)
             self._bbfp.flush()
 
         def log(self, event, *msg, **opts):
             global lastui
             super(blackboxui, self).log(event, *msg, **opts)
             self._partialinit()
 
             if not '*' in self.track and not event in self.track:
                 return
 
             if self._bbfp:
                 ui = self
             elif self._bbvfs:
                 try:
                     self._bbfp = self._openlogfile()
                 except (IOError, OSError) as err:
                     self.debug('warning: cannot write to blackbox.log: %s\n' %
                                err.strerror)
                     del self._bbvfs
                     self._bbfp = None
                 ui = self
             else:
                 # certain ui instances exist outside the context of
                 # a repo, so just default to the last blackbox that
                 # was seen.
                 ui = lastui
 
             if not ui or not ui._bbfp:
                 return
             if not lastui or ui._bbrepo:
                 lastui = ui
             if ui._bbinlog:
                 # recursion guard
                 return
             try:
                 ui._bbinlog = True
                 date = util.datestr(None, '%Y/%m/%d %H:%M:%S')
                 user = util.getuser()
                 pid = str(util.getpid())
                 formattedmsg = msg[0] % msg[1:]
                 rev = '(unknown)'
                 changed = ''
                 if ui._bbrepo:
                     ctx = ui._bbrepo[None]
                     parents = ctx.parents()
                     rev = ('+'.join([hex(p.node()) for p in parents]))
                     if (ui.configbool('blackbox', 'dirty', False) and (
                         any(ui._bbrepo.status()) or
                         any(ctx.sub(s).dirty() for s in ctx.substate)
                     )):
                         changed = '+'
                 if ui.configbool('blackbox', 'logsource', False):
                     src = ' [%s]' % event
                 else:
                     src = ''
                 try:
                     ui._bbwrite('%s %s @%s%s (%s)%s> %s',
                         date, user, rev, changed, pid, src, formattedmsg)
                 except IOError as err:
                     self.debug('warning: cannot write to blackbox.log: %s\n' %
                                err.strerror)
             finally:
                 ui._bbinlog = False
 
         def setrepo(self, repo):
             self._bbfp = None
             self._bbinlog = False
             self._bbrepo = repo
             self._bbvfs = repo.vfs
 
     ui.__class__ = blackboxui
     uimod.ui = blackboxui
 
 def uisetup(ui):
     wrapui(ui)
 
 def reposetup(ui, repo):
     # During 'hg pull' a httppeer repo is created to represent the remote repo.
     # It doesn't have a .hg directory to put a blackbox in, so we don't do
     # the blackbox setup for it.
     if not repo.local():
         return
 
     if util.safehasattr(ui, 'setrepo'):
         ui.setrepo(repo)
 
 @command('^blackbox',
     [('l', 'limit', 10, _('the number of events to show')),
     ],
     _('hg blackbox [OPTION]...'))
 def blackbox(ui, repo, *revs, **opts):
     '''view the recent repository events
     '''
 
     if not repo.vfs.exists('blackbox.log'):
         return
 
     limit = opts.get('limit')
     fp = repo.vfs('blackbox.log', 'r')
     lines = fp.read().split('\n')
 
     count = 0
     output = []
     for line in reversed(lines):
         if count >= limit:
             break
 
         # count the commands by matching lines like: 2013/01/23 19:13:36 root>
         if re.match('^\d{4}/\d{2}/\d{2} \d{2}:\d{2}:\d{2} .*> .*', line):
             count += 1
         output.append(line)
 
     ui.status('\n'.join(reversed(output)))