From: Shugo Maeda <shugo@...>
Date: 2009-12-14T17:06:37+09:00
Subject: [ruby-core:27165] Re: [Bug #2476] instance_eval ArgumentError

Hi,

2009/12/14 Lourens Naud� <redmine@ruby-lang.org>:
> I believe I've found an edge case referencing the recent (Dec 4) changes of instance_eval etc. compatibility with current MRI 1.8 behavior.
>
> Ruby backtrace and context :
> https://gist.github.com/1be3d65c1ff8c23ce964 ( from sinatra trunk )
>
> C function call :
> http://github.com/methodmissing/ruby/blob/trunk/vm_insnhelper.c#L716

I don't know sinatra well, but it passes a Proc object created by
lambda which doesn't take any arguments to instance_eval, doesn't it?
If so, please use Proc.new or proc instead of lambda.

instance_eval yields the receiver in both 1.8 and 1.9.
Unfortunately, a Proc object created by lambda raises ArgumentError
when extra arguments are yielded in 1.9.

defiant:~$ ruby-1_8 -ve 'lambda {}.call("foo")'
ruby 1.8.8dev (2009-12-05 revision 26022) [i686-linux]
defiant:~$ ruby-trunk -ve 'lambda {}.call("foo")'
ruby 1.9.2dev (2009-12-09 trunk 26052) [i686-linux]
-e:1:in `call': wrong number of arguments (1 for 0) (ArgumentError)
	from -e:1:in `<main>'

You should use Proc.new or proc instead of lambda if you don't want
checks for the number of arguments.

-- 
Shugo Maeda