id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
12555,Graph headers are not self-contained,gromer@…,Jeremiah Willcock,"Many BGL header files are not self-contained, meaning that they will not compile if `#include`d into a translation unit that doesn't `#include` anything else. For example, `boost/graph/bandwidth.hpp` refers to `vertex_index`, but does not `#include boost/graph/properties.hpp`, the header which declares `vertex_index`.

Among other things, this prevents BGL from being adapted to take advantage of C++ modules (see http://clang.llvm.org/docs/Modules.html), because modules require headers to be self-contained.

Attached is a patch (against 1.60.0) to correct these problems, usually by adding missing `#include`s. The change to `howard_cycle_ratio.hpp` is slightly more subtle: the problem there is that the code refers to `boost::num_edges(g)`, but doesn't `#include` a header that declares that function. However, the choice of the right header to `#include` depends on the type `Graph` of `g`, which is a template parameter. This points to the real problem: this code should be calling `num_edges(g)` unqualified, so that it uses argument-dependent lookup to find the `num_edges()` overload in the namespace of `Graph`, rather than restricting itself to the overloads defined in namespace `boost`.",Bugs,new,To Be Determined,graph,Boost 1.60.0,Problem,,,