From: Ian Duggan <ian@...>
Date: 2009-05-29T02:52:35+09:00
Subject: [ruby-core:23594] [1].cycle.to_a causes very tight loop

I'm not sure if this goes into the category of "just don't do that"
but the following goes into a very tight loop that requires a "kill
-9" to terminate.

  % ruby1.9 --version
  ruby 1.9.1p0 (2009-01-30 revision 21907) [i486-linux]

  % irb1.9
  irb --> [1].cycle.to_a
  ^C^C^C^C^C
  zsh: suspended  irb1.9

  % kill 4554

  % kill -9 4554
  [1]  + killed     irb1.9

Perhaps it would be helpful if the object could be somehow tagged as
being an infinite cycle so that things like to_a could warn rather
than sink the process, at least in the simple cases like this?

--Ian



















^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^C^Z

zsh: suspended  irb1.9

:( [09-05-28 10:38:47] ijcd@bearcat:lib/nokogiri/xml (1032) % ps aux | grep irb

ijcd      4554 44.9 13.3 281216 276860 pts/4   Tl   10:38   0:09
irb1.9

ijcd      4559  0.0  0.0   3180   724 pts/4    S+   10:38   0:00 grep irb

ijcd     11106  0.0  0.4  13196  8888 pts/3    S+   May27   0:00 irb

:) [09-05-28 10:38:49] ijcd@bearcat:lib/nokogiri/xml (1033) % kill 4554

:) [09-05-28 10:38:54] ijcd@bearcat:lib/nokogiri/xml (1034) % fg

[3] 4560

[3]  - done       jobs ${2:-%%} 2> /dev/null

[1]  - continued  irb1.9







^C^C^C^C^Z

zsh: suspended  irb1.9


:) [09-05-28 10:39:02] ijcd@bearcat:lib/nokogiri/xml (1036) %

[1]  + killed     irb1.9

:) [09-05-28 10:39:02] ijcd@bearcat:lib/nokogiri/xml (1036) % :)
[09-05-28 10:39:02] ijcd@bearcat:lib/nokogiri/xml (1036) %

:) [09-05-28 10:39:03] ijcd@bearcat:lib/nokogiri/xml (1036) %

:) [09-05-28 10:39:03] ijcd@bearcat:lib/nokogiri/xml (1036) % fg

[2] 4563

[2]  + exit 1     jobs ${2:-%%} 2> /dev/null

fg: no current job

:( [09-05-28 10:39:04] ijcd@bearcat:lib/nokogiri/xml (1037) % ruby --version

ruby 1.8.7 (2008-08-11 patchlevel 72) [i486-linux]