From: Justin Collins <collinsj@...>
Date: 2006-08-03T02:57:10+09:00
Subject: Re: irb: Segmentation fault

Pavel Smerk wrote:
>     Hello folks,
>
> in the following two cases irb fails (I've removed spaces from the 
> =~/^irb/ lines to prevent line breaks):
>
> $ irb
> irb(main):001:0>"ahoj".split(//).join('|')
> => "a|h|o|j"
> irb(main):002:0>"ahoj".split(/(?<=(?![Cc][Hh]).)/).join('|')
> SyntaxError: compile error
> (irb):2: undefined (?...) sequence: /(?<=(?![Cc][Hh]).)/
>         from (irb):2
> irb(main):003:0>"ahoj".split(/(?!ch)/).join('|')
> => "a|h|o|j"
> irb(main):004:0>"achoj".split(/(?!ch)/).join('|')
> => "ac|h|o|j"
> irb(main):005:0>"achoj".gsub(/([Cc])([Hh])/,'$1_$2').split(/(?!_[Hh])/).join('|') 
>
> => "a|$|1|_|$|2|o|j"
> irb(main):006:0>"achoj".gsub(/([Cc])([Hh])/,'\1_\2').split(/(?!_[Hh])/).join('|') 
>
> /usr/lib/ruby/1.8/irb/ruby-lex.rb:979: [BUG] Segmentation fault
> ruby 1.8.2 (2005-04-11) [i386-linux]
>
> Ne�sp��n� ukon�en (SIGABRT)
> $
>
Works for me:

$ irb -v
irb 0.9(02/07/03)
$ ruby -v
ruby 1.8.2 (2004-12-25) [i586-linux-gnu]
$ irb
irb(main):001:0> "ahoj".split(//).join('|')
=> "a|h|o|j"
irb(main):002:0> "ahoj".split(/(?<=(?![Cc][Hh]).)/).join('|')
SyntaxError: compile error
(irb):2: undefined (?...) sequence: /(?<=(?![Cc][Hh]).)/
        from (irb):2
irb(main):003:0> "ahoj".split(/(?!ch)/).join('|')
=> "a|h|o|j"
irb(main):004:0> "achoj".split(/(?!ch)/).join('|')
=> "ac|h|o|j"
irb(main):005:0> 
"achoj".gsub(/([Cc])([Hh])/,'$1_$2').split(/(?!_[Hh])/).join('|')
=> "a|$|1|_|$|2|o|j"
irb(main):006:0> 
"achoj".gsub(/([Cc])([Hh])/,'\1_\2').split(/(?!_[Hh])/).join('|')
=> "a|c_|h|o|j"
irb(main):007:0> quit

> $ irb
> irb(main):001:0>"ahoj".split(//).join('|')
> => "a|h|o|j"
> irb(main):002:0>"ahoj".split(/(?<=(?![Cc][Hh]).)/).join('|')
> SyntaxError: compile error
> (irb):2: undefined (?...) sequence: /(?<=(?![Cc][Hh]).)/
>         from (irb):2
> irb(main):003:0>"ahoj".split(/(?!ch)/).join('|')
> => "a|h|o|j"
> irb(main):004:0>"achoj".gsub(/([Cc])([Hh])/,'$1_$2').split(/(?!_[Hh])/).join('|') 
>
> => "a|$|1|_|$|2|o|j"
> irb(main):005:0>"achoj".gsub(/([Cc])([Hh])/,'\1_\2').split(/(?!_[Hh])/).join('|') 
>
> => "a|c_|h|o|j"
> /usr/lib/ruby/1.8/irb.rb:265: [BUG] Segmentation fault
> ruby 1.8.2 (2005-04-11) [i386-linux]
>
> Ne�sp��n� ukon�en (SIGABRT)
> $
>
Works for me:
$ irb
irb(main):001:0> "ahoj".split(//).join('|')
=> "a|h|o|j"
irb(main):002:0> "ahoj".split(/(?<=(?![Cc][Hh]).)/).join('|')
SyntaxError: compile error
(irb):2: undefined (?...) sequence: /(?<=(?![Cc][Hh]).)/
        from (irb):2
irb(main):003:0> "ahoj".split(/(?!ch)/).join('|')
=> "a|h|o|j"
irb(main):004:0> 
"achoj".gsub(/([Cc])([Hh])/,'$1_$2').split(/(?!_[Hh])/).join('|')
=> "a|$|1|_|$|2|o|j"
irb(main):005:0> 
"achoj".gsub(/([Cc])([Hh])/,'\1_\2').split(/(?!_[Hh])/).join('|')
=> "a|c_|h|o|j"
irb(main):006:0>

> ["Ne�sp��n� ukon�en" is perhaps some Czech translation of SIGABRT]
>
> If I repeat it exactly as shown, irb fails. I've tried to skip some 
> statements, but only the fourth could be skipped to get Segmentation 
> fault --- and even in this case the error message differed (and return 
> value was got compared to the first case). Skipping whichever else 
> does not lead to failure. I haven't tried simplifying of the 
> statements too much (only a bit, but unsuccessfully with respect to 
> retain the irb failure).
>
> Please, could someone test it with current version of ruby/irb?
>
> Where should one post such bugreports?
>
> Regards,
>
> P.
>

Maybe you just need a slightly newer version?

-Justin