[MacRuby] #1435: GC crashing when trying to free a regex currently in use

[MacRuby]

#1435: GC crashing when trying to free a regex currently in use
------------------------------------+---------------------------------------
 Reporter:  mrada@…                 |       Owner:  lsansonetti@…        
     Type:  defect                  |      Status:  new                  
 Priority:  blocker                 |   Milestone:                       
Component:  MacRuby                 |    Keywords:                       
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 I have scores of crash reports now where the problem originates from the
 GC thread. The top of the backtrace always looks the same:

 ```
 Thread 1 Crashed:: Dispatch queue: Garbage Collection Work Queue
 0   ???                            0x00007fff7b51f930 typeinfo for
 icu::UVector + 0
 1   libicucore.A.dylib             0x00007fff8cad159c
 icu::RegexPattern::~RegexPattern() + 30
 2   libicucore.A.dylib             0x00007fff8cb10632 0x7fff8c9c0000 +
 1377842
 3   libicucore.A.dylib             0x00007fff8cb10779 uregex_close + 40
 4   libmacruby.dylib               0x00000001000baf44
 rb_char_to_icu_option + 564
 5   libobjc.A.dylib                0x00007fff959fb57c finalizeOneObject +
 53
 6   libauto.dylib                  0x00007fff946de07e
 Auto::foreach_block_do(auto_zone_cursor*, void (*)(void*, void*), void*) +
 94
 7   libobjc.A.dylib                0x00007fff959fb4ac batchFinalize + 53
 8   libauto.dylib                  0x00007fff946de019
 Auto::Zone::invalidate_garbage(unsigned long, void**) + 73
 9   libauto.dylib                  0x00007fff946f19db
 __finalize_local_garbage_later_block_invoke_0 + 59
 10  libdispatch.dylib              0x00007fff8fbc48ba
 _dispatch_call_block_and_release + 18
 11  libdispatch.dylib              0x00007fff8fbc610a
 _dispatch_queue_drain + 264
 12  libdispatch.dylib              0x00007fff8fbc5f66
 _dispatch_queue_invoke + 54
 13  libdispatch.dylib              0x00007fff8fbc5760
 _dispatch_worker_thread2 + 198
 14  libsystem_c.dylib              0x00007fff8e6bc3da _pthread_wqthread +
 316
 15  libsystem_c.dylib              0x00007fff8e6bdb85 start_wqthread + 13
 ```

 This happens when I build myself or when I use a nightly build. It has
 been happening for a while now, I'm not sure exactly how long since I only
 started using MacRuby regularly a again recently.

 I get this crash when running my AXElements gem, but seems to happen a lot
 more often if I also run Rspec (2.6, the latest version doesn't run on
 MacRuby). I'm not sure of any other way to cause the bug.

 If you want full crash reports, just ask.

-- 
Ticket URL: <http://www.macruby.org/trac/ticket/1435>
MacRuby <http://macruby.org/>