Fix ambiguous py::str(kwargs) overload on GCC

include/pybind11/pytypes.h

@@ -1641,6 +1641,9 @@ class str : public object {
 #    endif
 
 #endif
+    // Avoid ambiguity when converting from kwargs (GCC)
+    template <typename T, detail::enable_if_t<std::is_same<T, kwargs>::value, int> = 0>
+    explicit str(const T &k) : str(static_cast<handle>(k)) {}
 
     explicit str(const bytes &b);
 

tests/test_pytypes.cpp

@@ -1212,3 +1212,7 @@ TEST_SUBMODULE(pytypes, m) {
         return py::isinstance<RealNumber>(x);
     });
 }
+
+TEST_SUBMODULE(pytypes, kwargs_str) {
+    m.def("kwargs_to_str", [](py::kwargs kwargs) { return py::str(kwargs); });
+}