Recently I had some trouble with a Trac instance running on fastcgi that had been moved from one server to another, the latter running a slightly newer Debian.

The Trac used the TracGit plugin for Git integration, running with trac-0.12. On the new server it got upgraded to Trac-1.0. I soon discovered strange errors being displayed from time to time when trying to access big images from the repo via browser:

ValueError: too many values to unpack


ValueError: need more than 1 value to unpack

The Trac log contained entries like this one:

2014-06-17 22:09:43,999 Trac[main] ERROR: Internal Server Error:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/trac/web/", line 497, in _dispatch_request
  File "/usr/lib/python2.7/dist-packages/trac/web/", line 214, in dispatch
    resp = chosen_handler.process_request(req)
  File "/usr/lib/python2.7/dist-packages/trac/versioncontrol/web_ui/", line 397, in process_request
    file_data = self._render_file(req, context, repos, node, rev)
  File "/usr/lib/python2.7/dist-packages/trac/versioncontrol/web_ui/", line 629, in _render_file
    content = node.get_content()
  File "/usr/lib/python2.7/dist-packages/tracext/git/", line 527, in get_content
    return self.repos.git.get_file(self.fs_sha)
  File "/usr/lib/python2.7/dist-packages/tracext/git/", line 660, in get_file
    return cStringIO.StringIO(self.cat_file("blob", str(sha)))
  File "/usr/lib/python2.7/dist-packages/tracext/git/", line 500, in cat_file
    _sha, _type, _size = self.__cat_file_pipe.stdout.readline().split()
ValueError: need more than 1 value to unpack

Searching the net I found many solutions, but none that had anything to do with the TracGit plugin.

Then I saw a news entry stating that Git support had been integrated into Trac as of version 1.0, so here's the solution: removing the TracGit plugin!

Seems like the plugin got priority over the new internal mechanism but at the same time was not compatible with Trac interna anymore.