improper STL list sort iterator invalidation

[Andy Sloane]

Hi there,

I'm not sure if this address is still valid, but we've found a bug, or what
we believe to be a bug, in the libg++ standard template library involving
list<T>::sort().

Test code:

#include <stdio.h>
#include <list>

int main()
{
        list<int> x;
        list<int>::iterator i;
        x.push_back(5);
        x.push_back(1);
        x.push_back(3);
        x.push_back(2);
        i = x.end();
        x.sort();
        if(i == x.end()) printf("i is at the end()\n");
        else printf("i is not at the end()\n");
}

Proper output is "i is at the end()", but on Red Hat Linux gcc 2.96, and
Mac OS X gcc 1151 ("based on version 3.1"), i is not at the end() after the
sort().

The problem is that sort() invalidates an iterator pointing to the end,
when the STL spec, or at least SGI's STL documentation, says it won't
invalidate any of them.

I have no idea whether this was fixed in the recent gcc 3.2.1 release, but
I just wanted to be sure someone was aware of it.

-Andy