1 files changed, 8 insertions, 0 deletions
diff --git a/lib/yaml.rb b/lib/yaml.rb
index 9b5a9b2787..dd89a30e3f 100644
--- a/lib/yaml.rb
+++ b/lib/yaml.rb
@@ -30,6 +30,14 @@ module YAML
   ENGINE = YAML::EngineManager.new
 end
 
+begin
+  require 'psych'
+rescue LoadError
+  warn "#{caller[0]}:"
+  warn "It seems your ruby installation is missing psych (for YAML output)."
+  warn "To eliminate this warning, please install libyaml and reinstall your ruby."
+end
+
 engine = (!defined?(Syck) && defined?(Psych) ? 'psych' : 'syck')
 
 module Syck