kruskal_minimum_spanning_tree not working on filtered graph with weight map as named property

[AlvoDa]

Hi everyone,

i cant use kruskal's alg on a filtered graph with a weight_map as named property.

#include <boost/graph/adjacency_list.hpp>
#include "boost/graph/graph_utility.hpp"
#include <boost/graph/filtered_graph.hpp>
#include <boost/property_map/function_property_map.hpp>
#include <boost/graph/kruskal_min_spanning_tree.hpp>

using Graph  = boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS>;
using Vertex = boost::graph_traits<Graph>::vertex_descriptor;
using Edge   = boost::graph_traits<Graph>::edge_descriptor;

int main()
{
  Graph G;
  
  // create a complete graph with 4 nodes.
  for (int i = 0; i < 5 ; ++i)
  {
    for (int j = i+1; j< 5; ++j)
      boost::add_edge(i, j, G);
  }
  boost::print_graph(G);
  /*  0 <--> 1 2 3 4
      1 <--> 0 2 3 4
      2 <--> 0 1 3 4
      3 <--> 0 1 2 4
      4 <--> 0 1 2 3  */

  struct Filter
  {
    bool operator()(Vertex const & v) const
    {
      if (v != 0 && v != 2)
        return true;
      return false;
    }
  };
  boost::filtered_graph G_f(G, boost::keep_all(), Filter());
  boost::print_graph(G_f);
  /* 1 <--> 3 4
     3 <--> 1 4
     4 <--> 1 3  */

  auto wmap = boost::make_function_property_map<Edge, double>([](Edge const & e){ return 1.0; });
  std::vector<Edge> mst;

  // Works:
  kruskal_minimum_spanning_tree(G, std::back_inserter(mst), boost::weight_map(wmap));
  
  // Does not compile:
  kruskal_minimum_spanning_tree(G_f, std::back_inserter(mst), boost::weight_map(wmap));
  
  double result = 0;
  for (auto const & e : mst)
    result += wmap[e];
  std::cout << result << "\n";  // prints 4
}

Gives following errors:

error C2039: 'type': is not a member of 'boost::vertex_property_type<Graph>'
error C2039:         [
error C2039:         with
error C2039:             Graph=boost::filtered_graph<Graph,boost::keep_all,main::Filter>
error C2039:         ]
error C3203: 'type': unspecialized class template can't be used as a template argument for template parameter 'Property', expected a real type

Workaround:
kruskal_minimum_spanning_tree(G_f, std::back_inserter(mst), boost::weight_map(wmap).vertex_index_map(get(boost::vertex_index, G_f)));

More details on stackoverflow (Thanks to user sehe who helped me out):
https://stackoverflow.com/questions/78612600/boost-graph-using-kruskal-algorithm-on-filtered-graph-doesnt-compile