西山和広です。

fgに引数を指定しなかったりjobsにない数値を指定すると
「Maybe IRB bug!!」になります。

「Maybe IRB bug!!」の前に改行がないのも変な気がします。

% irb-trunk -r irb/completion --simple-prompt
>> RUBY_DESCRIPTION
=> "ruby 1.9.0 (2008-06-12 revision 17105) [i686-linux]"
>> fg
ArgumentError: wrong number of arguments (0 for 1)
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/cmd/nop.rb:19:in `execute'
        from (eval):3:in `irb_fg'
        from (eval):9:in `irb_fg'
        from (irb):2:in `irb_binding'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/workspace.rb:80:in `ev
al'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/workspace.rb:80:in `evaluate'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/context.rb:218:in `evaluate'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:149:in `block (2 levels) in eval_input'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:263:in `signal_status'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:146:in `block in eval_input'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/ruby-lex.rb:243:in `block (2 levels) in each_top_level_statement'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/ruby-lex.rb:230:in `loop'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/ruby-lex.rb:230:in `block in each_top_level_statement'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/ruby-lex.rb:229:in `catch'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/ruby-lex.rb:229:in `each_top_level_statement'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:145:in `eval_input'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:69:in `block in start'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:68:in `catch'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:68:in `start'
        from /home/kazu/opt/ruby-trunk/bin/irb-trunk:12:in `<main>'Maybe IRB bug!!
>> jobs
=> #0->irb on main (#<Thread:0x805c1cc>: running)
>> fg 1
NoMethodError: undefined method `alive?' for nil:NilClass
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/ext/multi-irb.rb:55:in `switch'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/cmd/subirb.rb:32:in `execute'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/cmd/nop.rb:19:in `execute'
        from (eval):3:in `irb_fg'
        from (eval):9:in `irb_fg'
        from (irb):4:in `irb_binding'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/workspace.rb:80:in `eval'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/workspace.rb:80:in `evaluate'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/context.rb:218:in `evaluate'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:149:in `block (2 levels) in eval_input'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:263:in `signal_status'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:146:in `block in eval_input'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/ruby-lex.rb:243:in `block (2 levels) in each_top_level_statement'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/ruby-lex.rb:230:in `loop'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/ruby-lex.rb:230:in `block in each_top_level_statement'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/ruby-lex.rb:229:in `catch'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb/ruby-lex.rb:229:in `each_top_level_statement'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:145:in `eval_input'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:69:in `block in start'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:68:in `catch'
        from /home/kazu/opt/ruby-trunk/lib/ruby/1.9.0/irb.rb:68:in `start'
        from /home/kazu/opt/ruby-trunk/bin/irb-trunk:12:in `<main>'Maybe IRB bug!!
>>


-- 
|ZnZ(ゼット エヌ ゼット)
|西山和広(Kazuhiro NISHIYAMA)