id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
11609	circular_buffer erroneously invalidates reverse_iterator at pop_back in debug mode	christian.stimming@…	Jan Gaspar	"The circular_buffer container offers reverse iterators. Using one so that it points to the second-to-last element would in theory allow to pop_back() the last element without causing problems with that iterator. However, apparently pop_back() invalidates those reverse iterators even though they wouldn't cause problems, as if the debug_iterator_registry in boost/circular_buffer/debug.hpp is working correctly only for forward iterators but not for backward iterators.

Example code that works fine without debug mode, but will run into a failed assertion in debug mode:


{{{
#define BOOST_CB_ENABLE_DEBUG
#include <boost/circular_buffer.hpp>
#include <iostream>
int main(int /*argc*/, char** /*argv*/) {
	typedef boost::circular_buffer<int> CircBuffer;
	CircBuffer testBuffer(2);
	testBuffer.push_back(4);
	testBuffer.push_back(8);

	CircBuffer::const_reverse_iterator bufIter = testBuffer.rbegin();
	std::cout << ""element at rbegin="" << *bufIter << std::endl; // prints ""=8"" correctly
	++bufIter;
	std::cout << ""element after ++="" << *bufIter << std::endl; // prints ""=4"" correctly
	testBuffer.pop_back();
	std::cout << ""elem="" << *bufIter << std::endl; // ERROR: Causes ""Assertion `is_valid(m_buff)' failed.""
}
}}}

"	Bugs	new	To Be Determined	circular_buffer	Boost 1.57.0	Problem