Redmine

The git repository indexing worked great for quite a while, until it suddenly stopped. Manually executing

ruby script/rails runner "Repository.fetch_changesets" -e production

shows

/var/lib/gems/1.9.1/gems/railties-3.2.13/lib/rails/commands/runner.rb:53:in `eval': undefined method `merge!' for #<String:0x000000053fec60> (NoMethodError)
    from /home/server/services/redmine-2.3.4/app/models/repository/git.rb:143:in `fetch_changesets'
    from /home/server/services/redmine-2.3.4/app/models/repository.rb:333:in `block (2 levels) in fetch_changesets'
    from /var/lib/gems/1.9.1/gems/activerecord-3.2.13/lib/active_record/associations/collection_proxy.rb:89:in `each'
    from /var/lib/gems/1.9.1/gems/activerecord-3.2.13/lib/active_record/associations/collection_proxy.rb:89:in `method_missing'
    from /home/server/services/redmine-2.3.4/app/models/repository.rb:331:in `block in fetch_changesets'
    from /home/server/services/redmine-2.3.4/app/models/repository.rb:330:in `each'
    from /home/server/services/redmine-2.3.4/app/models/repository.rb:330:in `fetch_changesets'
    from (eval):1:in `<top (required)>'
    from /var/lib/gems/1.9.1/gems/railties-3.2.13/lib/rails/commands/runner.rb:53:in `eval'
    from /var/lib/gems/1.9.1/gems/railties-3.2.13/lib/rails/commands/runner.rb:53:in `<top (required)>'
    from /var/lib/gems/1.9.1/gems/railties-3.2.13/lib/rails/commands.rb:64:in `require'
    from /var/lib/gems/1.9.1/gems/railties-3.2.13/lib/rails/commands.rb:64:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'