[Boost-bugs] [Boost C++ Libraries] #10895: graph - copy_component is broken

Subject: [Boost-bugs] [Boost C++ Libraries] #10895: graph - copy_component is broken
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2014-12-23 21:13:48

#10895: graph - copy_component is broken
----------------------------------+----------------------
 Reporter:  erdem@…               |      Owner:  jewillco
     Type:  Bugs                  |     Status:  new
Milestone:  To Be Determined      |  Component:  graph
  Version:  Boost 1.57.0          |   Severity:  Problem
 Keywords:  graph copy_component  |
----------------------------------+----------------------
 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

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/10895>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.