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* Issue using Ruby1.9 (instance_eval in /lib/rack/builder.rb)
@ 2009-09-15 11:50 Iñaki Baz Castillo
  2009-09-15 11:59 ` Magnus Holm
  0 siblings, 1 reply; 4+ messages in thread
From: Iñaki Baz Castillo @ 2009-09-15 11:50 UTC (permalink / raw)
  To: rack-devel


Using Ruby1.9 there is an issue related to instance_eval() method
which behaves different than in 1.8. Let me show this example:

--------myapp.rb------------------------
class MyRack

    MY_VAR = "helloooo"

    def self.create
        Rack::Builder.new do
            map "/" do
                puts "[1] MY_VAR = #{MY_VAR}"   <----- [1]  (line 20)
                run Proc.new { |env|
                    puts "[2] MY_VAR = #{MY_VAR}"   <----- [2]  (line 22)
                    [ 200, {"Content-Type" => "text/plain"}, ["Yeah"] ]
                }
            end
        end
    end

end


rack_core = MyRack.create

Rack::Handler::Thin.run rack_core
----------------------------------------


This works great in Ruby1.8.

However, in Ruby1.9 I get this error:


/myapp.rb:20:in `block (2 levels) in core': uninitialized constant
Rack::Builder::MY_VAR (NameError)
        from /usr/local/lib/ruby1.9/gems/1.9.1/gems/rack-1.0.0/lib/rack/builder.rb:29:in
`instance_eval'
        from /usr/local/lib/ruby1.9/gems/1.9.1/gems/rack-1.0.0/lib/rack/builder.rb:29:in
`initialize'
        from /usr/local/lib/ruby1.9/gems/1.9.1/gems/rack-1.0.0/lib/rack/builder.rb:46:in
`new'
        from /usr/local/lib/ruby1.9/gems/1.9.1/gems/rack-1.0.0/lib/rack/builder.rb:46:in
`map'
        from /root/svn_local_copies/OpenXDMS/trunk/lib/rack/core.rb:41:in
`block in core'
        from /usr/local/lib/ruby1.9/gems/1.9.1/gems/rack-1.0.0/lib/rack/builder.rb:29:in
`instance_eval'
        from /usr/local/lib/ruby1.9/gems/1.9.1/gems/rack-1.0.0/lib/rack/builder.rb:29:in
`initialize'



If I remove line 20, then it would in runtime in line 22 (when "run"
is invoked for a incoming request).


The only solution for it to work in 1.9 is to add ALL the Module/Class
namespace for ALL the modules/classes:

        Rack::Builder.new do
            map "/" do
                puts "[1] MY_VAR = #{::MyRack::MY_VAR}"   <----- [1]  (line 20)
                run Proc.new { |env|
                    puts "[2] MY_VAR = #{::MyRack::MY_VAR}"   <-----
[2]  (line 22)
                    [ 200, {"Content-Type" => "text/plain"}, ["Yeah"] ]
                }
            end
        end


It's VERY important to note that if I use "MyRack::MY_VAR" instead of
"::MyRack::MY_VAR" then it would *also* fail in Ruby1.9:

    `block (2 levels) in core': uninitialized constant
Rack::Builder::MyRack (NameError)


It seems that using instance_eval in Ruby1.9 a class/module is just
looked for into the class/module executing the instance_eval and
doesn't look on top of it.


Regards.


-- 
Iñaki Baz Castillo
<ibc@aliax.net>

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2009-09-15 16:04 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2009-09-15 11:50 Issue using Ruby1.9 (instance_eval in /lib/rack/builder.rb) Iñaki Baz Castillo
2009-09-15 11:59 ` Magnus Holm
2009-09-15 12:46   ` Iñaki Baz Castillo
2009-09-15 16:03     ` Yehuda Katz

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