id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
10895	graph - copy_component is broken	erdem@…	Jeremiah Willcock	"I noticed two issues with copy_component in graph/copy.hpp.

1. The non-named parameter version gives compiler error due to failing look up:

{{{
    return detail::copy_component_impl
      (g_in, src, g_out,
       make_vertex_copier(g_in, g_out), 
       make_edge_copier(g_in, g_out), 
       make_iterator_property_map(orig2copy.begin(), 
                                  get(vertex_index, g_in), orig2copy[0]),
       bgl_named_params<char,char>('x') // dummy param object
       );
}}}


error: 'make_vertex_copier' was not declared in this scope.

Prefixing them with '''detail::''' solves this issue. This change makes it similar to copy_graph which also refers to the detail namespace for these functions.

Fixed version:

{{{
    return detail::copy_component_impl
      (g_in, src, g_out,
       detail::make_vertex_copier(g_in, g_out), 
       detail::make_edge_copier(g_in, g_out), 
       make_iterator_property_map(orig2copy.begin(), 
                                  get(vertex_index, g_in), orig2copy[0]),
       bgl_named_params<char,char>('x') // dummy param object
       );
}}}


2. In graph_copy_visitor struct's '''copy_one_vertex''' member function, the template arguments include '''class Graph''' but it is not used (neither in the function arguments nor inside the func. body). 


{{{
      template <class Vertex, class Graph>
      typename graph_traits<NewGraph>::vertex_descriptor copy_one_vertex(Vertex u) const { ... }

}}}

So the compiler complains about the failing deduction.

error: template argument deduction/substitution failed: note:   couldn't deduce template parameter 'Graph'

Fix: Removing the template argument class Graph fixes the issue.


{{{
      template <class Vertex>
      typename graph_traits<NewGraph>::vertex_descriptor copy_one_vertex(Vertex u) const { ... }

}}}

Note: Tried with GCC 4.7.2 and 4.8.3 "	Bugs	new	To Be Determined	graph	Boost 1.57.0	Problem		graph copy_component	erdem.cilingir@…