commit a83d69e78ffe58bbd410aa7503384a312e08963b
author Sebastian Gsänger <8004308+sgsaenger@users.noreply.github.com> Thu Oct 31 12:38:24 2019 +0100
committer Wenzel Jakob <wenzel.jakob@epfl.ch> Thu Oct 31 12:38:24 2019 +0100
tree dd788aaf6bd33082c555549f533ce585d243e781
parent bdf6a5e8708abe87d42e0e4c8bef51db0f0957ff

test pair-copyability on C++17 upwards (#1886)

* test pair-copyability on C++17 upwards

The stdlib falsely detects containers like M=std::map<T, U>
as copyable, even when one of T and U is not copyable.
Therefore we cannot rely on the stdlib dismissing std::pair<T, M>
by itself, even on C++17.

* fix is_copy_assignable

bind_map used std::is_copy_assignable which suffers from the same problems
as std::is_copy_constructible, therefore the same fix has been applied.

* created tests for copyability

tests/test_stl_binders.cpp

diff --git a/tests/test_stl_binders.cpp b/tests/test_stl_binders.cpp
index a88b589..8688874 100644
--- a/tests/test_stl_binders.cpp
+++ b/tests/test_stl_binders.cpp
@@ -54,6 +54,14 @@
     return m;
 }
 
+template <class NestMap> NestMap *times_hundred(int n) {
+    auto m = new NestMap();
+    for (int i = 1; i <= n; i++)
+        for (int j = 1; j <= n; j++)
+            (*m)[i].emplace(int(j*10), E_nc(100*j));
+    return m;
+}
+
 TEST_SUBMODULE(stl_binders, m) {
     // test_vector_int
     py::bind_vector<std::vector<unsigned int>>(m, "VectorInt", py::buffer_protocol());
@@ -85,6 +93,20 @@
     m.def("get_mnc", &times_ten<std::map<int, E_nc>>, py::return_value_policy::reference);
     py::bind_map<std::unordered_map<int, E_nc>>(m, "UmapENC");
     m.def("get_umnc", &times_ten<std::unordered_map<int, E_nc>>, py::return_value_policy::reference);
+    // Issue #1885: binding nested std::map<X, Container<E>> with E non-copyable
+    py::bind_map<std::map<int, std::vector<E_nc>>>(m, "MapVecENC");
+    m.def("get_nvnc", [](int n)
+        {
+            auto m = new std::map<int, std::vector<E_nc>>();
+            for (int i = 1; i <= n; i++)
+                for (int j = 1; j <= n; j++)
+                    (*m)[i].emplace_back(j);
+            return m;
+        }, py::return_value_policy::reference);
+    py::bind_map<std::map<int, std::map<int, E_nc>>>(m, "MapMapENC");
+    m.def("get_nmnc", &times_hundred<std::map<int, std::map<int, E_nc>>>, py::return_value_policy::reference);
+    py::bind_map<std::unordered_map<int, std::unordered_map<int, E_nc>>>(m, "UmapUmapENC");
+    m.def("get_numnc", &times_hundred<std::unordered_map<int, std::unordered_map<int, E_nc>>>, py::return_value_policy::reference);
 
     // test_vector_buffer
     py::bind_vector<std::vector<unsigned char>>(m, "VectorUChar", py::buffer_protocol());