PMP hole filling not working

[myociss]

Hi, I am trying to use the Polygon Mesh Processing library for hole filling and it doesn't seem to be working for me. The code below prints that for the border halfedge found, patch_facets and patch_vertices have size 0, and the mesh is not closed. My mesh does not contain non-manifold vertices; what are some other reasons that hole filling might fail? Does this code contain an obvious bug? I am using CGAL version 5.4.1. Thank you!

std::vector<halfedge_descriptor> border_cycles;
PMP::extract_boundary_cycles(high_priority_mesh, std::back_inserter(border_cycles));

std::cout << border_cycles.size() << std::endl;

for(halfedge_descriptor h : border_cycles){
    std::vector<face_descriptor>  patch_facets;
    std::vector<vertex_descriptor> patch_vertices;
    
    //PMP::triangulate_hole(high_priority_mesh, h, std::back_inserter(patch_facets));
    PMP::triangulate_and_refine_hole(high_priority_mesh, h, std::back_inserter(patch_facets), std::back_inserter(patch_vertices));

    std::cout << patch_facets.size() << std::endl;
    std::cout << patch_vertices.size() << std::endl;
}

std::cout << CGAL::is_closed(high_priority_mesh) << std::endl;

[myociss]

It turns out the hole vertices were collinear and this is why it isn't working.