id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
7357,copy constructor of mutable_heap does not copy Compare base class,Alex Hagen-Zanker <ahh34@…>,timblechmann,"The copy constructor of priority_queue_mutable_wrapper only copies over the elements in the queue and it default constructs the Compare base class.

Therefore the third assertion in the code below fails. This is a severe problem when an indirect comparison is applied.

#include <boost/heap/d_ary_heap.hpp>
#include <assert.h>
struct multiplied_compare
{
  multiplied_compare(int m = 1) : m(m)
  {}

  bool operator()(const int& a, const int& b) const
  {
    return m*a < m*b;
  }
  int m;
};

int main()
{
  typedef boost::heap::d_ary_heap<
    int, boost::heap::mutable_<true>, 
    boost::heap::compare<multiplied_compare>, 
    boost::heap::arity<4> > heap_type;
  
  heap_type plus(1);
  plus.push(100);
  plus.push(200);
  assert(plus.top() == 200);

  heap_type minus(-1);
  minus.push(100);
  minus.push(200);
  assert(minus.top() == 100);

  heap_type copy = minus;
  copy.clear();
  copy.push(100);
  copy.push(200);
  assert(copy.top() == 100);

  return 0;
}",Bugs,closed,To Be Determined,heap,Boost 1.52.0,Problem,fixed,"indirect compare, mutable heap",