Recursive inspect for Data gives StackOverflowError

[eregon]

From ruby/net-imap#470 (comment)

[nevans]

For what it's worth, it looks like the error in the net-imap tests is not with the builtin core Data, but only with the Net::IMAP::Data polyfill. I based the Net::IMAP implementation on the inspect recursion guard methods in pp. But it's not a direct copy, so TruffleRuby might work fine with pp's recursion guard and not with Net::IMAP::Data#inspect's.

(But the builtin Data fails for other more important reasons that weren't captured directly by the Net::IMAP::DataLite tests. I don't expect Net::IMAP::Data to be used for recursive objects, so we don't need this feature to work... I just copied it because it was in CRuby.)

[nevans]

Ah, never mind about that last comment. I confused myself at some point, while going back and forth between different versions of the code and different ruby engines. There's definitely a StackOverflowError there!