I had a problem using one of my own frameworks in MacRuby. gen_bridge_metadata was giving me the following: Received exception: can't convert nil into String: /usr/bin/gen_bridge_metadata:573:in `+' /usr/bin/gen_bridge_metadata:573:in `encode_includes' /usr/bin/gen_bridge_metadata:2091:in `handle_framework' /usr/bin/gen_bridge_metadata:882:in `prepare' /usr/bin/gen_bridge_metadata:882:in `each' /usr/bin/gen_bridge_metadata:882:in `prepare' /usr/bin/gen_bridge_metadata:721:in `parse' /usr/bin/gen_bridge_metadata:2321 /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/optparse.rb:791:in `initialize' /usr/bin/gen_bridge_metadata:2252:in `new' /usr/bin/gen_bridge_metadata:2252 can't convert nil into String After some debugging, I found out it was because my framework was named "audio-utilities" and the code in handle_framework expects the framework name to match the regular expression (\w+) which doesn't support the dash character. Xcode doesn't complain about that name. Are frameworks supposed to conform to a particular naming convention or is gen_bridge_metadata being too restrictive? Thanks