mercurial-plugin does not work on Windows due to svn error

[blokeley@…]

When using a fresh install of Python and trac I get the following traceback:

2011-03-04 20:01:46,540 Trac[main] DEBUG: Dispatching <Request "GET '/'">
2011-03-04 20:01:46,555 Trac[svn_fs] INFO: Failed to load Subversion bindings
Traceback (most recent call last):
  File "C:\Python26\lib\site-packages\trac\versioncontrol\svn_fs.py", line 267, in __init__
    _import_svn()
  File "C:\Python26\lib\site-packages\trac\versioncontrol\svn_fs.py", line 68, in _import_svn
    from svn import fs, repos, core, delta
ImportError: No module named svn

Surely if the repository type is hg then svn should not be required.

Steps to replicate on Windows XP Pro SP3:

1. Install ​Python 2.6.6
2. Install ​setuptools 0.6c11
3. easy_install genshi (0.6)
4. Install ​trac 0.12.2
5. Install ​mercurial 1.8 Python 2.6.2 bindings (Python 2.6.6 bindings are not available)
6. Edit trac.ini.
7. Run tracd from the command line.

Relevant parts of trac.ini:

[components]
acct_mgr.admin.* = enabled
acct_mgr.api.* = enabled
acct_mgr.db.* = enabled
acct_mgr.htfile.* = enabled
acct_mgr.http.* = enabled
acct_mgr.notification.* = enabled
acct_mgr.pwhash.* = enabled
acct_mgr.web_ui.* = enabled
tracext.hg.* = enabled

[trac]
authz_file = 
authz_module_name = 
auto_reload = False
base_url = 
check_auth_ip = true
database = sqlite:db/trac.db
default_charset = iso-8859-15
htdocs_location = 
ignore_auth_case = false
mainnav = wiki,timeline,roadmap,browser,tickets,newticket,search
metanav = login,logout,prefs,help,about
permission_policies = DefaultPermissionPolicy, LegacyAttachmentPolicy
permission_store = DefaultPermissionStore
repository_dir = C:/mercurial_repositories
repository_type = hg
show_email_addresses = false
timeout = 20
use_base_url_for_redirect = False

Please don't say, "Just install svn". Doing that throws an ImportError: No module named _fs which cannot be fixed.

[Remy Blank]

The traceback in the log is ugly, but as I explained on trac-dev, it's really only a warning (INFO even) that you can skip if you don't use SVN. We put the traceback in to facilitate debugging for people having trouble with their SVN bindings. If you want to avoid the traceback, simply add the following line to your [components] section in trac.ini:

trac.versioncontrol.svn_fs.* = disabled

Does the Mercurial plugin really not work? Then it's due to something else, and not this traceback. You should look for other messages in the log mentioning "hg". That should give you a clue.

Anyway, closing as an InstallationIssue.