[ruby-core:39297] [Ruby 1.9 - Bug #5280][Open] irb crash "begin;retry unless false; end" (plus suggested fix)

Issue #5280 has been reported by Chris Phoenix.

----------------------------------------
Bug #5280: irb crash "begin;retry unless false; end" (plus suggested fix)
http://redmine.ruby-lang.org/issues/5280

Author: Chris Phoenix
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 1.9.2
ruby -v: ruby 1.9.2p180 (2011-02-18 revision 30909) [i386-darwin9.8.0] 


If you type "begin;retry unless false; end" into irb 1.9.2, the program prints a nice long error stack (copied below) and exits.

The problem seems to be on line 100 of ~/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb/workspace.rb
in the filter_backtrace function: the backtrace strings are frozen, and line 100 tries to sub! the string:
        bt.sub!(/:\s*in `irb_binding'/, '') 

But all it does is return the string (or nil) so it shouldn't need to sub in-place.

It looks like simply replacing that line with 
        bt = bt.sub(/:\s*in `irb_binding'/, '') 
would fix the problem. 

Here's the trace:

Hobbes-8:cptest cphoenix$ irb
ruby-1.9.2-p180 :001 > begin ; retry unless false; end
SyntaxError: (irb):1: Invalid retry
/Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb/workspace.rb:100:in `sub!': can't modify frozen string (RuntimeError)
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb/workspace.rb:100:in `filter_backtrace'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb.rb:180:in `block (3 levels) in eval_input'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb.rb:179:in `each'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb.rb:179:in `block (2 levels) in eval_input'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb.rb:273:in `signal_status'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb.rb:156:in `block in eval_input'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb/ruby-lex.rb:243:in `block (2 levels) in each_top_level_statement'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb/ruby-lex.rb:229:in `loop'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb/ruby-lex.rb:229:in `block in each_top_level_statement'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb/ruby-lex.rb:228:in `catch'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb/ruby-lex.rb:228:in `each_top_level_statement'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb.rb:155:in `eval_input'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb.rb:70:in `block in start'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb.rb:69:in `catch'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/irb.rb:69:in `start'
	from /Users/cphoenix/.rvm/rubies/ruby-1.9.2-p180/bin/irb:16:in `<main>'
Hobbes-8:cptest cphoenix$ 

And here's the trace after my suggested fix:

Hobbes-8:cptest cphoenix$ irb
ruby-1.9.2-p180 :001 > begin ; retry unless false; end
SyntaxError: (irb):1: Invalid retry
	from (irb)
ruby-1.9.2-p180 :002 > 




-- 
http://redmine.ruby-lang.org