Boost C++ Libraries: Ticket #10987: bug in any_xxx_node_traits, returning by reference

anonymous — Sun, 01 Feb 2015 01:56:10 GMT

After fixing this I still have infinite loops and crashes in intrusive sets. Rolled back to 1.55 where everything is stable for me...

Ion Gaztañaga — Sun, 01 Feb 2015 18:20:43 GMT

I can't see any problem with the code, the temporary is valid until the function ends. Any chance to have a test program that reproduces your crash?

attachment set

anonymous — Sun, 01 Feb 2015 21:51:18 GMT

attachment → ConsoleApplication1.cpp

anonymous — Sun, 01 Feb 2015 21:56:53 GMT

Yes, memory block is valid. But this is not temporary, this is any hook's member. In case of non-any hook (normal set_base_hook) this IS actually a temporary.

Program above can be fixed by making parameter p_parent not ref but value. But there are more bugs and I currently not able to find out, ma application still crashing or has infinite loops but only after some time.

anonymous — Sun, 01 Feb 2015 22:10:22 GMT

To be even more specific: &p_parent == &p.node_ptr_1 in case of any_hook. So when rotate_left calls rotate_left_no_parent_fix(p,...) &p_parent starts p_right, while with set_base_hook it remains the same.

status, summary changed; resolution set

Ion Gaztañaga — Mon, 02 Feb 2015 16:27:19 GMT

status new → closed
resolution → fixed
summary bstree_algo::rotate_left bug → bug in any_xxx_node_traits, returning by reference

Ok, I see. The problem is in the any hook member, it should not return by reference. This was changed in all other node_traits and it seems I forgot to do the same with any_xxx_node_traits classes.

Fixed in:

https://github.com/boostorg/intrusive/commit/b9aa032d981ad65fce5ea99179e22c25e35f03e8

Thanks for the report.

anonymous — Mon, 02 Feb 2015 22:22:03 GMT

Happy to help!

PS: TBH strange function argument requirement to be temporary, at least static assertion in rbtree_algorithms could verify that hook trait returns value.