Issue #7009 has been updated by shyouhei (Shyouhei Urabe).

Priority changed from Normal to Low

This is a known issue, hard to fix.  Patches are welcomed very much.
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Bug #7009: Crash in method_missing
https://bugs.ruby-lang.org/issues/7009#change-29255

Author: alexcoplan (Alex Coplan)
Status: Open
Priority: Low
Assignee: 
Category: 
Target version: 
ruby -v: ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-darwin11.4.0]


Given the following code:

(({def method_missing(sym, *args)
  foo(sym, *args)
end

bar}))

When (({bar})) is called, it triggers method_missing (because bar is undefined). Inside method_missing, it calls (({foo})) (another undefined method), and that in turn calls method_missing, but this time the method name and the rest of the arguments are passed back to method missing. This results in an ever-increasing number of arguments. If I add a debug line like so:

(({def method_missing(sym, *args)
  print "#{sym} #{args}\n"
  foo(sym, *args)
end

bar # undefined method}))

then this is the first few lines of output:

bar []
foo [:bar]
foo [:foo, :bar]
foo [:foo, :foo, :bar]
foo [:foo, :foo, :foo, :bar]

The expected result is that it should report a SystemStackError

mm.rb:2: stack level too deep (SystemStackError)

The actual result is this:

 mm.rb:2: [BUG] Segmentation fault
 ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-darwin11.4.0]
 
 -- Control frame information -----------------------------------------------
 c:2695 p:0037 s:10775 b:9428 l:009427 d:009427 METHOD thing.rb:3
 c:2694 p:---- s:9423 b:9423 l:009422 d:009422 FINISH
 c:2693 p:0037 s:9421 b:9421 l:009420 d:009420 METHOD thing.rb:3
 c:2692 p:---- s:9416 b:9416 l:009415 d:009415 FINISH

That crash log goes on a lot longer and I will attach both the ruby crash log and the system crash log.


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