convert: move svn config initializer out of the module level

The svn_config_get_config config call was being called at the module level, but
had the potential to throw permission denied errors if ~/.subversion/servers was
not readable. This could happen in certain test environments where the user
permissions were very particular.

This prevented the remotenames extension from loading, since it imports
convert's hg module, which imports convert's subversion module, which calls
this. The config is only ever used from this one constructor, so let's just move
it in to there.

hgext/convert/transport.py

@@ -1,135 +1,137 b''
 # -*- coding: utf-8 -*-
 
 # Copyright (C) 2007 Daniel Holth <[e-mail]>
 # This is a stripped-down version of the original bzr-svn transport.py,
 # Copyright (C) 2006 Jelmer Vernooij <[e-mail]>
 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 2 of the License, or
 # (at your option) any later version.
 
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, see <http://www.gnu.org/licenses/>.
 from __future__ import absolute_import
 
 import svn.client
 import svn.core
 import svn.ra
 
 Pool = svn.core.Pool
 SubversionException = svn.core.SubversionException
 
 from mercurial import (
     util,
 )
 
 # Some older versions of the Python bindings need to be
 # explicitly initialized. But what we want to do probably
 # won't work worth a darn against those libraries anyway!
 svn.ra.initialize()
 
-svn_config = svn.core.svn_config_get_config(None)
-
+svn_config = None
 
 def _create_auth_baton(pool):
     """Create a Subversion authentication baton. """
     import svn.client
     # Give the client context baton a suite of authentication
     # providers.h
     providers = [
         svn.client.get_simple_provider(pool),
         svn.client.get_username_provider(pool),
         svn.client.get_ssl_client_cert_file_provider(pool),
         svn.client.get_ssl_client_cert_pw_file_provider(pool),
         svn.client.get_ssl_server_trust_file_provider(pool),
         ]
     # Platform-dependent authentication methods
     getprovider = getattr(svn.core, 'svn_auth_get_platform_specific_provider',
                           None)
     if getprovider:
         # Available in svn >= 1.6
         for name in ('gnome_keyring', 'keychain', 'kwallet', 'windows'):
             for type in ('simple', 'ssl_client_cert_pw', 'ssl_server_trust'):
                 p = getprovider(name, type, pool)
                 if p:
                     providers.append(p)
     else:
         if util.safehasattr(svn.client, 'get_windows_simple_provider'):
             providers.append(svn.client.get_windows_simple_provider(pool))
 
     return svn.core.svn_auth_open(providers, pool)
 
 class NotBranchError(SubversionException):
     pass
 
 class SvnRaTransport(object):
     """
     Open an ra connection to a Subversion repository.
     """
     def __init__(self, url="", ra=None):
         self.pool = Pool()
         self.svn_url = url
         self.username = ''
         self.password = ''
 
         # Only Subversion 1.4 has reparent()
         if ra is None or not util.safehasattr(svn.ra, 'reparent'):
             self.client = svn.client.create_context(self.pool)
             ab = _create_auth_baton(self.pool)
             if False:
                 svn.core.svn_auth_set_parameter(
                     ab, svn.core.SVN_AUTH_PARAM_DEFAULT_USERNAME, self.username)
                 svn.core.svn_auth_set_parameter(
                     ab, svn.core.SVN_AUTH_PARAM_DEFAULT_PASSWORD, self.password)
             self.client.auth_baton = ab
+            global svn_config
+            if svn_config is None:
+                svn_config = svn.core.svn_config_get_config(None)
             self.client.config = svn_config
             try:
                 self.ra = svn.client.open_ra_session(
                     self.svn_url,
                     self.client, self.pool)
             except SubversionException as xxx_todo_changeme:
                 (inst, num) = xxx_todo_changeme.args
                 if num in (svn.core.SVN_ERR_RA_ILLEGAL_URL,
                            svn.core.SVN_ERR_RA_LOCAL_REPOS_OPEN_FAILED,
                            svn.core.SVN_ERR_BAD_URL):
                     raise NotBranchError(url)
                 raise
         else:
             self.ra = ra
             svn.ra.reparent(self.ra, self.svn_url.encode('utf8'))
 
     class Reporter(object):
         def __init__(self, reporter_data):
             self._reporter, self._baton = reporter_data
 
         def set_path(self, path, revnum, start_empty, lock_token, pool=None):
             svn.ra.reporter2_invoke_set_path(self._reporter, self._baton,
                         path, revnum, start_empty, lock_token, pool)
 
         def delete_path(self, path, pool=None):
             svn.ra.reporter2_invoke_delete_path(self._reporter, self._baton,
                     path, pool)
 
         def link_path(self, path, url, revision, start_empty, lock_token,
                       pool=None):
             svn.ra.reporter2_invoke_link_path(self._reporter, self._baton,
                     path, url, revision, start_empty, lock_token,
                     pool)
 
         def finish_report(self, pool=None):
             svn.ra.reporter2_invoke_finish_report(self._reporter,
                     self._baton, pool)
 
         def abort_report(self, pool=None):
             svn.ra.reporter2_invoke_abort_report(self._reporter,
                     self._baton, pool)
 
     def do_update(self, revnum, path, *args, **kwargs):
         return self.Reporter(svn.ra.do_update(self.ra, revnum, path,
                                               *args, **kwargs))