Fix issue with generator bindings.

Author: Holt59

src/mobase/wrappers/pyfiletree.cpp

@@ -49,7 +49,7 @@ namespace mo2::detail {
             return std::make_shared<PyFileTree>(parent, name, m_Callback);
         }
 
-        bool doPopulate(std::shared_ptr<const IFileTree> parent,
+        bool doPopulate([[maybe_unused]] std::shared_ptr<const IFileTree> parent,
                         std::vector<std::shared_ptr<FileTreeEntry>>&) const override
         {
             return true;
@@ -83,10 +83,6 @@ namespace mo2::python {
 
     void add_ifiletree_bindings(pybind11::module_& m)
     {
-
-        // register generator for walk and glob
-        register_generator_type<std::shared_ptr<const FileTreeEntry>>(m);
-
         // FileTreeEntry class:
         auto fileTreeEntryClass =
             py::class_<FileTreeEntry, std::shared_ptr<FileTreeEntry>>(m,
@@ -191,10 +187,17 @@ namespace mo2::python {
                 QString>(&IFileTree::walk, py::const_),
             py::arg("callback"), py::arg("sep") = "\\");
 
-        iFileTreeClass.def("walk", py::overload_cast<>(&IFileTree::walk, py::const_));
+        iFileTreeClass.def("walk", [](IFileTree const* tree) {
+            return make_generator(tree->walk());
+        });
 
-        iFileTreeClass.def("glob", &IFileTree::glob, py::arg("pattern"),
-                           py::arg("type") = IFileTree::GlobPatternType::GLOB);
+        iFileTreeClass.def(
+            "glob",  // &IFileTree::glob,
+            [](IFileTree const* tree, QString pattern,
+               IFileTree::GlobPatternType patternType) {
+                return make_generator(tree->glob(pattern, patternType));
+            },
+            py::arg("pattern"), py::arg("type") = IFileTree::GlobPatternType::GLOB);
 
         // Kind-of-static operations:
         iFileTreeClass.def("createOrphanTree", &IFileTree::createOrphanTree,

src/pybind11-utils/include/pybind11_utils/generator.h

@@ -7,28 +7,46 @@
 
 namespace mo2::python {
 
+    // the code here is mostly taken from pybind11 itself, and relies on some pybind11
+    // internals so might be subject to change when upgrading pybind11 versions
+
+    namespace detail {
+        template <typename T>
+        struct generator_state {
+            std::generator<T> g;
+            decltype(g.begin()) it;
+
+            generator_state(std::generator<T> gen) : g(std::move(gen)), it(g.begin()) {}
+        };
+    }  // namespace detail
+
     // create a Python generator from a C++ generator
     //
     template <typename T>
-    auto register_generator_type(pybind11::handle scope,
-                                 const char* name = "_mo2_generator")
+    auto make_generator(std::generator<T> g)
     {
+        using state = detail::generator_state<T>;
+
         namespace py = pybind11;
+        if (!py::detail::get_type_info(typeid(state), false)) {
+            py::class_<state>(py::handle(), "iterator", pybind11::module_local())
+                .def("__iter__",
+                     [](state& s) -> state& {
+                         return s;
+                     })
+                .def("__next__", [](state& s) {
+                    if (s.it != s.g.end()) {
+                        const auto v = *s.it;
+                        s.it++;
+                        return v;
+                    }
+                    else {
+                        throw py::stop_iteration();
+                    }
+                });
+        }
 
-        return py::class_<std::generator<T>>(scope, name, py::module_local())
-            .def("__iter__",
-                 [](std::generator<T>& gen) -> std::generator<T>& {
-                     return gen;
-                 })
-            .def("__next__", [](std::generator<T>& gen) {
-                auto it = gen.begin();
-                if (it != gen.end()) {
-                    return *it;
-                }
-                else {
-                    throw py::stop_iteration();
-                }
-            });
+        return py::cast(state{std::move(g)});
     }
 
 }  // namespace mo2::python

tests/python/CMakeLists.txt

@@ -53,7 +53,7 @@ foreach (test_file ${test_files})
 	pybind11_add_module(${target} EXCLUDE_FROM_ALL THIN_LTO ${test_file})
 	set_target_properties(${target}
 		PROPERTIES
-		CXX_STANDARD 20
+		CXX_STANDARD 23
 		OUTPUT_NAME ${pymodule}
 		FOLDER tests/python
 		LIBRARY_OUTPUT_DIRECTORY "${PYLIB_DIR}/mobase_tests")