example28_networking uninitialized constant IO::WaitReadable + possible fix

[flipcoder]

I get an error when I try to run example28_networking (error occurs in chingu/lib/chingu/game_states/network_server.rb line 208). I'm not too familiar with ruby yet but it looks like an exception had an invalid type or something.

By changing line 208 to:

rescue Errno::EAGAIN, Errno::EINTR

It works. Should I commit this or am I missing something?

The full error is here:

$ ruby example28_networking.rb 
/home/flipcoder/Projects/School/ChicoTeam/chingu/lib/chingu/game_states/network_server.rb:208:in `handle_incoming_connections': uninitialized constant IO::WaitReadable (NameError)
    from /home/flipcoder/Projects/School/ChicoTeam/chingu/lib/chingu/game_states/network_server.rb:176:in `update'
    from example28_networking.rb:32:in `update'
    from example28_networking.rb:80

[flipcoder]

Decided to commit the change. We can always go back if necessary.

[cqcallaw]

The relevant bit from the stack trace seems to be "uninitialized constant IO::WaitReadable".

IO::WaitReadable is documented here: http://www.ruby-doc.org/core-1.9/classes/IO/WaitReadable.html. Certainly doesn't seem like an exception type.

However, searching for "rescue IO::WaitReadable" yields results such as http://stackoverflow.com/questions/7127603/why-is-iowaitreadable-being-raised-differently-for-stdout-than-stderr-ruby-1 and http://ruby-doc.org/stdlib/libdoc/socket/rdoc/classes/TCPServer.html, so it seems like a valid construct. The second hit, http://lists.macosforge.org/pipermail/macruby-devel/2010-May/005127.html, is also interesting because it seems like a very similar bug report.

I'd also hesitate to say Errno::EAGAIN is the correct fix until you've figured out what exceptions could possibly be raised by the begin block...

References for Ruby exception handling (based on a quick search, not extensive study):
http://ruby-doc.org/docs/ProgrammingRuby/html/tut_exceptions.html
http://www.ruby-doc.org/docs/ProgrammingRuby/html/ref_m_errno.html

[flipcoder]

Thanks for the info. I wasn't clear in my post about the reason I added Errno::EAGAIN. That was another unhandled exception I received after removing the IO::WaitReadable. I agree with your suggestion and am still unsure about this being the final solution, but wanted to commit these changes so we could see if it was a problem with something on my machine or not. I'll reopen the issue.