trac uses python eggs as plugin containers. To use these eggs, dev-python/setuptools is needed. If it is missing, trac will simply ignore all plugins without further notice. Reproducible: Always Steps to Reproduce: 1. emerge and setup trac (make sure, setuptools aren't installed) 2. add a plugin egg to /var/lib/trac/yourtracinstance/plugins 3. restart apache if necessary Actual Results: The plugin egg won't be registered or activated. Expected Results: The plugin egg should be found, extracted and activated for that trac instance. This egg mechanism is the only supported way of installing trac plugins.
setuptools is not needed for trac-0.10.x to work. If you need third-party packages, such as trac plugins, it is your responsability to emerge the required dependencies. You might also want to create your own ebuilds in a local overlay for the plugins you need, and declare the setuptools dependency for them. Also note that www-apps/trac-webadmin pulls setuptools in.
Thanks for the clarification.