Fix assertion failure for unions (#1685) (#1709)
In def_readonly and def_readwrite, there is an assertion that the member comes
from the class or a base class:
static_assert(std::is_base_of<C, type>::value, "...");
However, if C and type are the same type, is_base_of will still only be true
if they are the same _non-union_ type. This means we can't define accessors
for the members of a union type because of this assertion.
Update the assertion to test
std::is_same<C, type>::value || std::is_base_of<C, type>::value
which will allow union types, or members of base classes.
Also add a basic unit test for accessing unions.diff --git a/tests/test_union.cpp b/tests/test_union.cpp
new file mode 100644
index 0000000..7b98ea2
--- /dev/null
+++ b/tests/test_union.cpp
@@ -0,0 +1,22 @@
+/*
+ tests/test_class.cpp -- test py::class_ definitions and basic functionality
+
+ Copyright (c) 2019 Roland Dreier <roland.dreier@gmail.com>
+
+ All rights reserved. Use of this source code is governed by a
+ BSD-style license that can be found in the LICENSE file.
+*/
+
+#include "pybind11_tests.h"
+
+TEST_SUBMODULE(union_, m) {
+ union TestUnion {
+ int value_int;
+ unsigned value_uint;
+ };
+
+ py::class_<TestUnion>(m, "TestUnion")
+ .def(py::init<>())
+ .def_readonly("as_int", &TestUnion::value_int)
+ .def_readwrite("as_uint", &TestUnion::value_uint);
+}