[evanphx]

Neither Rubinius nor JRuby (and probably IronRuby too) have this issue because they all use accurate garbage collection rather than conservative. Accurate requires much more bookkeeping since all pointers must always be properly identified, but if you start writing a system with accurate GC, it's pretty easy. Bugs like this are a direct result of a conservative GC strategy (and these bugs, as I'm sure you got reading Joe's post, really really suck to find).

[pmjordan]

This class of subtle bugs exists whether or not your GC is accurate as soon as you take the red pill and leave the VM environment. If you forget to add your C pointer to the accurate GC's root set, you're just as dead. Related story: http://news.ycombinator.com/item?id=217189

[evanphx]

But that is by definition a tractable problem because the source will show that the root set isn't being used properly. (additionally, in practice this proves to be a rare and easy to fix bug)