Unknown When Mongoid is asked to load a configuration file which happens to be empty, it produces a message that references an internal error:
irb(main):018:0> Mongoid.load!("empty.yml") Traceback (most recent call last): 16: from /home/w/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bundler-2.2.15/lib/bundler/cli.rb:30:in `dispatch' 15: from /home/w/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bundler-2.2.15/lib/bundler/vendor/thor/lib/thor.rb:392:in `dispatch' 14: from /home/w/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bundler-2.2.15/lib/bundler/vendor/thor/lib/thor/invocation.rb:127:in `invoke_command' 13: from /home/w/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bundler-2.2.15/lib/bundler/vendor/thor/lib/thor/command.rb:27:in `run' 12: from /home/w/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bundler-2.2.15/lib/bundler/cli.rb:494:in `exec' 11: from /home/w/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bundler-2.2.15/lib/bundler/cli/exec.rb:28:in `run' 10: from /home/w/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bundler-2.2.15/lib/bundler/cli/exec.rb:63:in `kernel_load' 9: from /home/w/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/bundler-2.2.15/lib/bundler/cli/exec.rb:63:in `load' 8: from /home/w/.rbenv/versions/2.7/bin/irb:23:in `<top (required)>' 7: from /home/w/.rbenv/versions/2.7/bin/irb:23:in `load' 6: from /home/w/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/irb-1.2.6/exe/irb:11:in `<top (required)>' 5: from (irb):17 4: from (irb):18:in `rescue in irb_binding' 3: from /home/w/.rbenv/versions/2.7.2/lib/ruby/2.7.0/forwardable.rb:235:in `load!' 2: from /home/w/apps/mongoid/lib/mongoid/config.rb:133:in `load!' 1: from /home/w/apps/mongoid/lib/mongoid/config/environment.rb:55:in `load_yaml' NoMethodError (undefined method `[]' for false:FalseClass) The error message should reflect the error condition (i.e. the configuration file is empty or doesn't contain a configuration for the active environment).