id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
2649	iterator_range's assignment fires an assert when rhs is singular	eyal.farago@…	Neil Groves	"the following code will raise an assertion in debug builds:


{{{
typedef boost::iterator_range<std::string> str_range_t;

std::string eyal(""eyal"");
str_range_t eyal_range( eyal ), empty_range;

//here it is...
eyal_range = empty_range;
}}}


the reason for the assert is an assert in iterator_range's begin/end methods, the assignment operator is doing something like 
{{{
this->m_begin = rhs.begin()
}}}
which fails for debug builds when rhs is singular.

a lot has been said about the decision to remove the singular member/concept from the library code, but I believe that assigning a singular range '''should not''' raise an assert.

ps. I stumbled upon this bug after upgrading from 1.34 to 1.36, ""I think this is a really nasty one because: [[BR]]
1. it denies me from using a very standard use case.[[BR]]
2. it simply crashes in release builds.[[BR]]
3. a massive behavior change for singular ranges which used to behave like empty ranges. while I agree that using iterators of a singular range is a bad idea, querying for its length is not.[[BR]]

eyal.
"	Bugs	closed	Boost 1.43.0	range	Boost 1.36.0	Regression	fixed	iterator_range	eyal.farago@…