[ruby-core:46662] [ruby-trunk - Bug #6783] Infinite loop in inspect, not overriding inspect, to_s, and no known circular references. Stepping into inspect in debugger locks it up with 100% CPU.

Issue #6783 has been updated by garysweaver (Gary Weaver).


Note: unfortunately this is an internal script that depends on a local DB so can't share, but can duplicate bug each time.
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Bug #6783: Infinite loop in inspect, not overriding inspect, to_s, and no known circular references. Stepping into inspect in debugger locks it up with 100% CPU.
https://bugs.ruby-lang.org/issues/6783#change-28327

Author: garysweaver (Gary Weaver)
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-darwin11.4.0]


In Ruby 1.9.3p194 in Rails 3.2.6 in rails console, in my script I'm calling inspect on a Ruby object and even though I'm not overriding inspect, to_s, and there are no known circular references, inspect is going into an infinite loop locking Ruby up with 100% CPU usage.

At first, I would think this problem is probably outside of Ruby and either in my code or in a gem that I'm using, however the problem is that using the Debugger gem, if I set a breakpoint above the issue and use "s" (by itself) to step into the line where it calls inspect, it locks up there, so I can't debug the issue. When I do that I hit ctrl-c, I'm in .../.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/irb.rb:

       64      trap("SIGINT") do
    => 65        irb.signal_handle
       66      end

and breaking out of that, or if I don't step into it and I break out of it, I see:

	path_to_script/script_name.rb:739:in `call'
	path_to_script/script_name.rb:739:in `inspect'
	path_to_script/script_name.rb:739:in `inspect'
	...
        (~100 times)
        path_to_script/script_name.rb:739:in `block (2 levels) in my_method_name'

In a situation like this, how can I debug the issue? Is there anything in the inspect method that could causing this behavior?

I think the most likely culprit is some bad code on my part in the script, but unfortunately I can't debug it when the debugger can't step into inspect.

Thanks for any help you can provide.


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