Chef WebUI 0.9.16 (and all previous versions tested > 0.9.12) incompatible with haml 3.1.0

When haml 3.1.0 is installed, the webui will throw a 500 error as soon as it is accessed in a browser. from server-webui.log:

merb : chef-server-webui : worker (port 4040) ~ Started request handling: Mon Apr 25 14:49:46 -0400 2011
merb : chef-server-webui : worker (port 4040) ~ Routed to: {"action"=>"index", "controller"=>"nodes"}
merb : chef-server-webui : worker (port 4040) ~ Params: {"action"=>"index", "controller"=>"nodes"}
merb : chef-server-webui : worker (port 4040) ~ Redirecting to: /users/login?_message=BAh7BjoKZXJyb3IiMVlvdSBkb24ndCBoYXZlIGFjY2VzcyB0byB0aGF0LCBw%0AbGVhc2UgbG9naW4u%0A (302)
merb : chef-server-webui : worker (port 4040) ~ {:dispatch_time=>0.002827, :action_time=>0.001689, :after_filters_time=>1.6e-05}
merb : chef-server-webui : worker (port 4040) ~

merb : chef-server-webui : worker (port 4040) ~ Started request handling: Mon Apr 25 14:49:46 -0400 2011
merb : chef-server-webui : worker (port 4040) ~ Routed to: {"action"=>"login", "controller"=>"users", "_message"=>"BAh7BjoKZXJyb3IiMVlvdSBkb24ndCBoYXZlIGFjY2VzcyB0byB0aGF0LCBw\nbGVhc2UgbG9naW4u\n"}
merb : chef-server-webui : worker (port 4040) ~ Params: {"action"=>"login", "controller"=>"users", "_message"=>"BAh7BjoKZXJyb3IiMVlvdSBkb24ndCBoYXZlIGFjY2VzcyB0byB0aGF0LCBwnbGVhc2UgbG9naW4un"}"}
merb : chef-server-webui : worker (port 4040) ~ odd number of arguments for Hash - (ArgumentError)
/usr/lib64/ruby/gems/1.8/gems/haml-3.1.0/lib/haml/util.rb:40:in `[]'
/usr/lib64/ruby/gems/1.8/gems/haml-3.1.0/lib/haml/util.rb:40:in `to_hash'
/usr/lib64/ruby/gems/1.8/gems/haml-3.1.0/lib/haml/buffer.rb:193:in `attributes'
/usr/lib64/ruby/gems/1.8/gems/haml-3.1.0/lib/haml/buffer.rb:192:in `each'
/usr/lib64/ruby/gems/1.8/gems/haml-3.1.0/lib/haml/buffer.rb:192:in `attributes'
/usr/lib64/ruby/gems/1.8/gems/chef-server-webui-0.9.16/app/views/layout/login.html.haml:26:in `_usrlib64rubygems_1_8_gemschefserverwebui_0_9_16_appviewslayout_login_html_haml'
/usr/lib64/ruby/gems/1.8/gems/chef-server-webui-0.9.16/app/views/layout/login.html.haml:25:in `each'
/usr/lib64/ruby/gems/1.8/gems/chef-server-webui-0.9.16/app/views/layout/login.html.haml:25:in `_usrlib64rubygems_1_8_gemschefserverwebui_0_9_16_appviewslayout_login_html_haml'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/controller/mixins/render.rb:147:in `send'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/controller/mixins/render.rb:147:in `render'
/usr/lib64/ruby/gems/1.8/gems/chef-server-webui-0.9.16/app/controllers/users.rb:124:in `login'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/controller/abstract_controller.rb:321:in `send'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/controller/abstract_controller.rb:321:in `_call_action'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/controller/abstract_controller.rb:289:in `_dispatch'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/controller/abstract_controller.rb:284:in `catch'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/controller/abstract_controller.rb:284:in `_dispatch'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/controller/merb_controller.rb:285:in `_dispatch'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/controller/merb_controller.rb:262:in `_call'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/controller/merb_controller.rb:252:in `call'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/dispatch/dispatcher.rb:91:in `dispatch_action'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/dispatch/dispatcher.rb:69:in `handle'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/dispatch/dispatcher.rb:29:in `handle'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/rack/application.rb:17:in `call'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/rack/middleware/static.rb:28:in `call'
/usr/lib64/ruby/gems/1.8/gems/rack-1.2.0/lib/rack/content_length.rb:13:in `call'
/usr/lib64/ruby/gems/1.8/gems/thin-1.2.7/lib/thin/connection.rb:76:in `pre_process'
/usr/lib64/ruby/gems/1.8/gems/thin-1.2.7/lib/thin/connection.rb:74:in `catch'
/usr/lib64/ruby/gems/1.8/gems/thin-1.2.7/lib/thin/connection.rb:74:in `pre_process'
/usr/lib64/ruby/gems/1.8/gems/thin-1.2.7/lib/thin/connection.rb:57:in `process'
/usr/lib64/ruby/gems/1.8/gems/thin-1.2.7/lib/thin/connection.rb:42:in `receive_data'
/usr/lib64/ruby/gems/1.8/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in `run_machine'
/usr/lib64/ruby/gems/1.8/gems/eventmachine-0.12.10/lib/eventmachine.rb:256:in `run'
/usr/lib64/ruby/gems/1.8/gems/thin-1.2.7/lib/thin/backends/base.rb:57:in `start'
/usr/lib64/ruby/gems/1.8/gems/thin-1.2.7/lib/thin/server.rb:156:in `start'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/rack/adapter/thin.rb:30:in `start_server'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/rack/adapter/abstract.rb:305:in `start_at_port'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/rack/adapter/abstract.rb:138:in `start'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/server.rb:174:in `bootup'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/server.rb:159:in `daemonize'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/server.rb:143:in `fork'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/server.rb:143:in `daemonize'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core/server.rb:35:in `start'
/usr/lib64/ruby/gems/1.8/gems/merb-core-1.1.3/lib/merb-core.rb:165:in `start'
/usr/lib64/ruby/gems/1.8/gems/chef-server-webui-0.9.16/bin/chef-server-webui:70
/usr/bin/chef-server-webui:19:in `load'
/usr/bin/chef-server-webui:19
merb : chef-server-webui : worker (port 4040) ~ Params: {"action"=>"login", "controller"=>"users", "_message"=>"BAh7BjoKZXJyb3IiMVlvdSBkb24ndCBoYXZlIGFjY2VzcyB0byB0aGF0LCBw\nbGVhc2UgbG9naW4u\n"}
merb : chef-server-webui : worker (port 4040) ~ {:before_filters_time=>0.000131, :dispatch_time=>0.018261, :action_time=>0.001138, :after_filters_time=>2.2e-05}
merb : chef-server-webui : worker (port 4040) ~

After downgrading to haml 3.0.24 the webui started working as expected.