I have GitLab 8.0.4 installed from Omnibus packages on an Ubuntu 14.04 server. Suddenly I can't create new projects anymore. The last significant thing I did was creating a new group (but I don't feel this should be part of the problem). The last new project is 27 days old, so it may be that there has been a GitLab update in between (but I don't really know that).
When clicking on the "New Project" menu item the system responds with the `500` error page, and the respective entry in `production.log` is
Started GET "/projects/new" for 88.66.154.89 at 2015-10-19 11:55:13 +0200
Processing by ProjectsController#new as HTML
Completed 500 Internal Server Error in 61ms (ActiveRecord: 7.9ms)
ActionView::Template::Error (undefined method `empty?' for #<ActiveRecord::AttributeMethods::Serialization::Attribute:0x0000000da0f5e8>):
22: .col-sm-10
23: = f.select :namespace_id, namespaces_options(params[:namespace_id] || :current_user), {}, {class: 'select2', tabindex: 2}
24:
25: - if import_sources_enabled?
26: %hr
27:
28: .project-import.js-toggle-container
app/controllers/application_controller.rb:303:in `import_sources_enabled?'
app/views/projects/new.html.haml:25:in `block in _app_views_projects_new_html_haml___3279847372260590402_70154110845080'
app/views/projects/new.html.haml:8:in `_app_views_projects_new_html_haml___3279847372260590402_70154110845080'
I did update GitLab through APT, and I did `gitlab-cfg reconfigure`, both without any improvement.
Somehow this error message (`ActionView::Template::Error ...`) looks like indicating a bug, but I don't know. Any help greatly appreciated.