Deleted a project, now getting Error 500 on GitLab dashboard page

Hi there,

I deleted a project as I normally do from the GitLab project settings page and now get an Error 500 page come up when I go to the dashboard of my self-hosted GitLab installation. This is from my production.log file:

Started DELETE "/myorg/37323" for 127.0.0.1 at 2015-07-03 15:48:06 +0100
Processing by ProjectsController#destroy as HTML
  Parameters: {"utf8"=>"āœ“", "authenticity_token"=>"[FILTERED]", "namespace_id"=>"myorg", "id"=>"37323"}
Redirected to https://git.myorg.local/dashboard
Completed 302 Found in 2001ms (ActiveRecord: 119.0ms)
Started GET "/dashboard" for 127.0.0.1 at 2015-07-03 15:48:08 +0100
Processing by DashboardController#show as HTML
Completed 500 Internal Server Error in 44ms (ActiveRecord: 6.2ms)

ActionView::Template::Error (undefined method 'default_branch' for nil:NilClass):
    1: - if show_last_push_widget?(event)
    2:   .event-last-push
    3:     .event-last-push-text
    4:       %span You pushed to
  app/models/event.rb:264:in 'last_push_to_non_root?'
  app/helpers/application_helper.rb:157:in 'show_last_push_widget?'
  app/views/events/_event_last_push.html.haml:1:in '_app_views_events__event_last_push_html_haml__1824484147939618157_107362180'
  app/views/dashboard/_activities.html.haml:2:in '_app_views_dashboard__activities_html_haml__436365269611238158_39773360'
  app/views/dashboard/show.html.haml:10:in '_app_views_dashboard_show_html_haml___4414829035350156518_56194540'
  app/controllers/dashboard_controller.rb:11:in 'show'

Oddly enough, I can still get to the Admin area and project pages (project, files, commits, network, graphs, etc), but not the GitLab dashboard.

Does anyone know what it causing it and how I can fix it?

Iā€™m using Ubuntu Server 14.04.2 LTS and GitLab CE 7.12.1 [f6fb946].

Many thanks for your help in advance.

Maybe try to search & find over here: https://gitlab.com/gitlab-org/gitlab-ce/issues/605

Just guessing