Redmine

At source:tags/4.0.4/Gemfile#L28, openid gems are stated as optional.

# Optional gem for OpenID authentication
group :openid do
  gem "ruby-openid", "~> 2.3.0", :require => "openid" 
  gem "rack-openid" 
end

However, but Redmine fails to start with the error "LoadError: cannot load such file -- openid" if you skipped installing openid gems.

Steps to reproduce:

$ svn co https://svn.redmine.org/redmine/trunk redmine
$ cd redmine
$ vim config/database.yml  # configure config/database.yml
$ bundle install --without openid
$ bin/rake db:migrate
rake aborted!
LoadError: cannot load such file -- openid
/private/tmp/redmine/vendor/bundle/ruby/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `require'
/private/tmp/redmine/vendor/bundle/ruby/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `block in require'
/private/tmp/redmine/vendor/bundle/ruby/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:257:in `load_dependency'
/private/tmp/redmine/vendor/bundle/ruby/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `require'
/private/tmp/redmine/lib/plugins/open_id_authentication/lib/open_id_authentication.rb:2:in `<top (required)>'
/private/tmp/redmine/vendor/bundle/ruby/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `require'
/private/tmp/redmine/vendor/bundle/ruby/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `block in require'
/private/tmp/redmine/vendor/bundle/ruby/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:257:in `load_dependency'
/private/tmp/redmine/vendor/bundle/ruby/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `require'
/private/tmp/redmine/lib/plugins/open_id_authentication/init.rb:7:in `block in <top (required)>'
/private/tmp/redmine/config/initializers/00-core_plugins.rb:14:in `eval'
/private/tmp/redmine/config/initializers/00-core_plugins.rb:14:in `block in <top (required)>'
/private/tmp/redmine/config/initializers/00-core_plugins.rb:4:in `each'
/private/tmp/redmine/config/initializers/00-core_plugins.rb:4:in `<top (required)>'
.
.
.