ortools-clone/patches/pybind11-v2.13.6.patch

diff --git a/include/pybind11/stl.h b/include/pybind11/stl.h
index 71bc5902..6a148e74 100644
--- a/include/pybind11/stl.h
+++ b/include/pybind11/stl.h
@@ -11,10 +11,14 @@
 
 #include "pybind11.h"
 #include "detail/common.h"
+#include "detail/descr.h"
+#include "detail/type_caster_base.h"
 
 #include <deque>
+#include <initializer_list>
 #include <list>
 #include <map>
+#include <memory>
 #include <ostream>
 #include <set>
 #include <unordered_map>
@@ -35,6 +39,89 @@
 PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 PYBIND11_NAMESPACE_BEGIN(detail)
 
+//
+// Begin: Equivalent of
+//        https://github.com/google/clif/blob/ae4eee1de07cdf115c0c9bf9fec9ff28efce6f6c/clif/python/runtime.cc#L388-L438
+/*
+The three `PyObjectTypeIsConvertibleTo*()` functions below are
+the result of converging the behaviors of pybind11 and PyCLIF
+(http://github.com/google/clif).
+
+Originally PyCLIF was extremely far on the permissive side of the spectrum,
+while pybind11 was very far on the strict side. Originally PyCLIF accepted any
+Python iterable as input for a C++ `vector`/`set`/`map` argument, as long as
+the elements were convertible. The obvious (in hindsight) problem was that
+any empty Python iterable could be passed to any of these C++ types, e.g. `{}`
+was accepted for C++ `vector`/`set` arguments, or `[]` for C++ `map` arguments.
+
+The functions below strike a practical permissive-vs-strict compromise,
+informed by tens of thousands of use cases in the wild. A main objective is
+to prevent accidents and improve readability:
+
+- Python literals must match the C++ types.
+
+- For C++ `set`: The potentially reducing conversion from a Python sequence
+  (e.g. Python `list` or `tuple`) to a C++ `set` must be explicit, by going
+  through a Python `set`.
+
+- However, a Python `set` can still be passed to a C++ `vector`. The rationale
+  is that this conversion is not reducing. Implicit conversions of this kind
+  are also fairly commonly used, therefore enforcing explicit conversions
+  would have an unfavorable cost : benefit ratio; more sloppily speaking,
+  such an enforcement would be more annoying than helpful.
+*/
+
+inline bool PyObjectIsInstanceWithOneOfTpNames(PyObject *obj,
+                                               std::initializer_list<const char *> tp_names) {
+    if (PyType_Check(obj)) {
+        return false;
+    }
+    const char *obj_tp_name = Py_TYPE(obj)->tp_name;
+    for (const auto *tp_name : tp_names) {
+        if (std::strcmp(obj_tp_name, tp_name) == 0) {
+            return true;
+        }
+    }
+    return false;
+}
+
+inline bool PyObjectTypeIsConvertibleToStdVector(PyObject *obj) {
+    if (PySequence_Check(obj) != 0) {
+        return !PyUnicode_Check(obj) && !PyBytes_Check(obj);
+    }
+    return (PyGen_Check(obj) != 0) || (PyAnySet_Check(obj) != 0)
+           || PyObjectIsInstanceWithOneOfTpNames(
+               obj, {"dict_keys", "dict_values", "dict_items", "map", "zip"});
+}
+
+inline bool PyObjectTypeIsConvertibleToStdSet(PyObject *obj) {
+    return (PyAnySet_Check(obj) != 0) || PyObjectIsInstanceWithOneOfTpNames(obj, {"dict_keys"});
+}
+
+inline bool PyObjectTypeIsConvertibleToStdMap(PyObject *obj) {
+    if (PyDict_Check(obj)) {
+        return true;
+    }
+    // Implicit requirement in the conditions below:
+    // A type with `.__getitem__()` & `.items()` methods must implement these
+    // to be compatible with https://docs.python.org/3/c-api/mapping.html
+    if (PyMapping_Check(obj) == 0) {
+        return false;
+    }
+    PyObject *items = PyObject_GetAttrString(obj, "items");
+    if (items == nullptr) {
+        PyErr_Clear();
+        return false;
+    }
+    bool is_convertible = (PyCallable_Check(items) != 0);
+    Py_DECREF(items);
+    return is_convertible;
+}
+
+//
+// End: Equivalent of clif/python/runtime.cc
+//
+
 /// Extracts an const lvalue reference or rvalue reference for U based on the type of T (e.g. for
 /// forwarding a container element).  Typically used indirect via forwarded_type(), below.
 template <typename T, typename U>
@@ -66,17 +153,10 @@ private:
     }
     void reserve_maybe(const anyset &, void *) {}
 
-public:
-    bool load(handle src, bool convert) {
-        if (!isinstance<anyset>(src)) {
-            return false;
-        }
-        auto s = reinterpret_borrow<anyset>(src);
-        value.clear();
-        reserve_maybe(s, &value);
-        for (auto entry : s) {
+    bool convert_iterable(const iterable &itbl, bool convert) {
+        for (const auto &it : itbl) {
             key_conv conv;
-            if (!conv.load(entry, convert)) {
+            if (!conv.load(it, convert)) {
                 return false;
             }
             value.insert(cast_op<Key &&>(std::move(conv)));
@@ -84,6 +164,29 @@ public:
         return true;
     }
 
+    bool convert_anyset(anyset s, bool convert) {
+        value.clear();
+        reserve_maybe(s, &value);
+        return convert_iterable(s, convert);
+    }
+
+public:
+    bool load(handle src, bool convert) {
+        if (!PyObjectTypeIsConvertibleToStdSet(src.ptr())) {
+            return false;
+        }
+        if (isinstance<anyset>(src)) {
+            value.clear();
+            return convert_anyset(reinterpret_borrow<anyset>(src), convert);
+        }
+        if (!convert) {
+            return false;
+        }
+        assert(isinstance<iterable>(src));
+        value.clear();
+        return convert_iterable(reinterpret_borrow<iterable>(src), convert);
+    }
+
     template <typename T>
     static handle cast(T &&src, return_value_policy policy, handle parent) {
         if (!std::is_lvalue_reference<T>::value) {
@@ -115,15 +218,10 @@ private:
     }
     void reserve_maybe(const dict &, void *) {}
 
-public:
-    bool load(handle src, bool convert) {
-        if (!isinstance<dict>(src)) {
-            return false;
-        }
-        auto d = reinterpret_borrow<dict>(src);
+    bool convert_elements(const dict &d, bool convert) {
         value.clear();
         reserve_maybe(d, &value);
-        for (auto it : d) {
+        for (const auto &it : d) {
             key_conv kconv;
             value_conv vconv;
             if (!kconv.load(it.first.ptr(), convert) || !vconv.load(it.second.ptr(), convert)) {
@@ -134,6 +232,25 @@ public:
         return true;
     }
 
+public:
+    bool load(handle src, bool convert) {
+        if (!PyObjectTypeIsConvertibleToStdMap(src.ptr())) {
+            return false;
+        }
+        if (isinstance<dict>(src)) {
+            return convert_elements(reinterpret_borrow<dict>(src), convert);
+        }
+        if (!convert) {
+            return false;
+        }
+        auto items = reinterpret_steal<object>(PyMapping_Items(src.ptr()));
+        if (!items) {
+            throw error_already_set();
+        }
+        assert(isinstance<iterable>(items));
+        return convert_elements(dict(reinterpret_borrow<iterable>(items)), convert);
+    }
+
     template <typename T>
     static handle cast(T &&src, return_value_policy policy, handle parent) {
         dict d;
@@ -166,13 +283,35 @@ struct list_caster {
     using value_conv = make_caster<Value>;
 
     bool load(handle src, bool convert) {
-        if (!isinstance<sequence>(src) || isinstance<bytes>(src) || isinstance<str>(src)) {
+        if (!PyObjectTypeIsConvertibleToStdVector(src.ptr())) {
             return false;
         }
-        auto s = reinterpret_borrow<sequence>(src);
+        if (isinstance<sequence>(src)) {
+            return convert_elements(src, convert);
+        }
+        if (!convert) {
+            return false;
+        }
+        // Designed to be behavior-equivalent to passing tuple(src) from Python:
+        // The conversion to a tuple will first exhaust the generator object, to ensure that
+        // the generator is not left in an unpredictable (to the caller) partially-consumed
+        // state.
+        assert(isinstance<iterable>(src));
+        return convert_elements(tuple(reinterpret_borrow<iterable>(src)), convert);
+    }
+
+private:
+    template <typename T = Type, enable_if_t<has_reserve_method<T>::value, int> = 0>
+    void reserve_maybe(const sequence &s, Type *) {
+        value.reserve(s.size());
+    }
+    void reserve_maybe(const sequence &, void *) {}
+
+    bool convert_elements(handle seq, bool convert) {
+        auto s = reinterpret_borrow<sequence>(seq);
         value.clear();
         reserve_maybe(s, &value);
-        for (const auto &it : s) {
+        for (const auto &it : seq) {
             value_conv conv;
             if (!conv.load(it, convert)) {
                 return false;
@@ -182,13 +321,6 @@ struct list_caster {
         return true;
     }
 
-private:
-    template <typename T = Type, enable_if_t<has_reserve_method<T>::value, int> = 0>
-    void reserve_maybe(const sequence &s, Type *) {
-        value.reserve(s.size());
-    }
-    void reserve_maybe(const sequence &, void *) {}
-
 public:
     template <typename T>
     static handle cast(T &&src, return_value_policy policy, handle parent) {
@@ -220,43 +352,87 @@ struct type_caster<std::deque<Type, Alloc>> : list_caster<std::deque<Type, Alloc
 template <typename Type, typename Alloc>
 struct type_caster<std::list<Type, Alloc>> : list_caster<std::list<Type, Alloc>, Type> {};
 
+template <typename ArrayType, typename V, size_t... I>
+ArrayType vector_to_array_impl(V &&v, index_sequence<I...>) {
+    return {{std::move(v[I])...}};
+}
+
+// Based on https://en.cppreference.com/w/cpp/container/array/to_array
+template <typename ArrayType, size_t N, typename V>
+ArrayType vector_to_array(V &&v) {
+    return vector_to_array_impl<ArrayType, V>(std::forward<V>(v), make_index_sequence<N>{});
+}
+
 template <typename ArrayType, typename Value, bool Resizable, size_t Size = 0>
 struct array_caster {
     using value_conv = make_caster<Value>;
 
 private:
-    template <bool R = Resizable>
-    bool require_size(enable_if_t<R, size_t> size) {
-        if (value.size() != size) {
-            value.resize(size);
+    std::unique_ptr<ArrayType> value;
+
+    template <bool R = Resizable, enable_if_t<R, int> = 0>
+    bool convert_elements(handle seq, bool convert) {
+        auto l = reinterpret_borrow<sequence>(seq);
+        value.reset(new ArrayType{});
+        // Using `resize` to preserve the behavior exactly as it was before PR #5305
+        // For the `resize` to work, `Value` must be default constructible.
+        // For `std::valarray`, this is a requirement:
+        // https://en.cppreference.com/w/cpp/named_req/NumericType
+        value->resize(l.size());
+        size_t ctr = 0;
+        for (const auto &it : l) {
+            value_conv conv;
+            if (!conv.load(it, convert)) {
+                return false;
+            }
+            (*value)[ctr++] = cast_op<Value &&>(std::move(conv));
         }
         return true;
     }
-    template <bool R = Resizable>
-    bool require_size(enable_if_t<!R, size_t> size) {
-        return size == Size;
-    }
 
-public:
-    bool load(handle src, bool convert) {
-        if (!isinstance<sequence>(src)) {
+    template <bool R = Resizable, enable_if_t<!R, int> = 0>
+    bool convert_elements(handle seq, bool convert) {
+        auto l = reinterpret_borrow<sequence>(seq);
+        if (l.size() != Size) {
             return false;
         }
-        auto l = reinterpret_borrow<sequence>(src);
-        if (!require_size(l.size())) {
-            return false;
-        }
-        size_t ctr = 0;
-        for (const auto &it : l) {
+        // The `temp` storage is needed to support `Value` types that are not
+        // default-constructible.
+        // Deliberate choice: no template specializations, for simplicity, and
+        // because the compile time overhead for the specializations is deemed
+        // more significant than the runtime overhead for the `temp` storage.
+        std::vector<Value> temp;
+        temp.reserve(l.size());
+        for (auto it : l) {
             value_conv conv;
             if (!conv.load(it, convert)) {
                 return false;
             }
-            value[ctr++] = cast_op<Value &&>(std::move(conv));
+            temp.emplace_back(cast_op<Value &&>(std::move(conv)));
         }
+        value.reset(new ArrayType(vector_to_array<ArrayType, Size>(std::move(temp))));
         return true;
     }
 
+public:
+    bool load(handle src, bool convert) {
+        if (!PyObjectTypeIsConvertibleToStdVector(src.ptr())) {
+            return false;
+        }
+        if (isinstance<sequence>(src)) {
+            return convert_elements(src, convert);
+        }
+        if (!convert) {
+            return false;
+        }
+        // Designed to be behavior-equivalent to passing tuple(src) from Python:
+        // The conversion to a tuple will first exhaust the generator object, to ensure that
+        // the generator is not left in an unpredictable (to the caller) partially-consumed
+        // state.
+        assert(isinstance<iterable>(src));
+        return convert_elements(tuple(reinterpret_borrow<iterable>(src)), convert);
+    }
+
     template <typename T>
     static handle cast(T &&src, return_value_policy policy, handle parent) {
         list l(src.size());
@@ -272,12 +448,36 @@ public:
         return l.release();
     }
 
-    PYBIND11_TYPE_CASTER(ArrayType,
-                         const_name<Resizable>(const_name(""), const_name("Annotated["))
-                             + const_name("list[") + value_conv::name + const_name("]")
-                             + const_name<Resizable>(const_name(""),
-                                                     const_name(", FixedSize(")
-                                                         + const_name<Size>() + const_name(")]")));
+    // Code copied from PYBIND11_TYPE_CASTER macro.
+    // Intentionally preserving the behavior exactly as it was before PR #5305
+    template <typename T_, enable_if_t<std::is_same<ArrayType, remove_cv_t<T_>>::value, int> = 0>
+    static handle cast(T_ *src, return_value_policy policy, handle parent) {
+        if (!src) {
+            return none().release();
+        }
+        if (policy == return_value_policy::take_ownership) {
+            auto h = cast(std::move(*src), policy, parent);
+            delete src; // WARNING: Assumes `src` was allocated with `new`.
+            return h;
+        }
+        return cast(*src, policy, parent);
+    }
+
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    operator ArrayType *() { return &(*value); }
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    operator ArrayType &() { return *value; }
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    operator ArrayType &&() && { return std::move(*value); }
+
+    template <typename T_>
+    using cast_op_type = movable_cast_op_type<T_>;
+
+    static constexpr auto name
+        = const_name<Resizable>(const_name(""), const_name("Annotated[")) + const_name("list[")
+          + value_conv::name + const_name("]")
+          + const_name<Resizable>(
+              const_name(""), const_name(", FixedSize(") + const_name<Size>() + const_name(")]"));
 };
 
 template <typename Type, size_t Size>
diff --git a/tests/test_stl.cpp b/tests/test_stl.cpp
index e7db8aaa..84bd4755 100644
--- a/tests/test_stl.cpp
+++ b/tests/test_stl.cpp
@@ -193,6 +193,23 @@ TEST_SUBMODULE(stl, m) {
     m.def("cast_array", []() { return std::array<int, 2>{{1, 2}}; });
     m.def("load_array", [](const std::array<int, 2> &a) { return a[0] == 1 && a[1] == 2; });
 
+    struct NoDefaultCtor {
+        explicit constexpr NoDefaultCtor(int val) : val{val} {}
+        int val;
+    };
+
+    struct NoDefaultCtorArray {
+        explicit constexpr NoDefaultCtorArray(int i)
+            : arr{{NoDefaultCtor(10 + i), NoDefaultCtor(20 + i)}} {}
+        std::array<NoDefaultCtor, 2> arr;
+    };
+
+    // test_array_no_default_ctor
+    py::class_<NoDefaultCtor>(m, "NoDefaultCtor").def_readonly("val", &NoDefaultCtor::val);
+    py::class_<NoDefaultCtorArray>(m, "NoDefaultCtorArray")
+        .def(py::init<int>())
+        .def_readwrite("arr", &NoDefaultCtorArray::arr);
+
     // test_valarray
     m.def("cast_valarray", []() { return std::valarray<int>{1, 4, 9}; });
     m.def("load_valarray", [](const std::valarray<int> &v) {
diff --git a/tests/test_stl.py b/tests/test_stl.py
index 65fda54c..340cdc35 100644
--- a/tests/test_stl.py
+++ b/tests/test_stl.py
@@ -48,6 +48,13 @@ def test_array(doc):
     )
 
 
+def test_array_no_default_ctor():
+    lst = m.NoDefaultCtorArray(3)
+    assert [e.val for e in lst.arr] == [13, 23]
+    lst.arr = m.NoDefaultCtorArray(4).arr
+    assert [e.val for e in lst.arr] == [14, 24]
+
+
 def test_valarray(doc):
     """std::valarray <-> list"""
     lst = m.cast_valarray()
diff --git a/tools/pybind11NewTools.cmake b/tools/pybind11NewTools.cmake
index a8b0800b..1bd6e9e1 100644
--- a/tools/pybind11NewTools.cmake
+++ b/tools/pybind11NewTools.cmake
@@ -23,6 +23,7 @@ else()
 endif()
 
 if(NOT Python_FOUND AND NOT Python3_FOUND)
+  message(FATAL_ERROR "Should not pass here")
   if(NOT DEFINED Python_FIND_IMPLEMENTATIONS)
     set(Python_FIND_IMPLEMENTATIONS CPython PyPy)
   endif()