Update pybind11 from 2.13.6 to 3.0.1

MODULE.bazel

@@ -52,32 +52,30 @@ bazel_dep(name = "zlib", version = "1.3.1.bcr.8")
 
 # OR-Tools wrappers dependencies
 bazel_dep(name = "gazelle", version = "0.43.0")
-bazel_dep(name = "pybind11_abseil", version = "202402.0")
 bazel_dep(name = "pybind11_bazel", version = "2.13.6")
-bazel_dep(name = "pybind11_protobuf", version = "0.0.0-20240524-1d7a729")
-bazel_dep(name = "swig", version = "4.3.0")
-
 git_override(
     module_name = "pybind11_bazel",
-    commit = "2b6082a4d9d163a52299718113fa41e4b7978db5",
-    patch_strip = 1,
-    patches = ["//:patches/pybind11_bazel.patch"],
+    commit = "d5f6a112138c672daec4ca279f33baae95ca10ec", # Incomming 3.0.1 2026/03
+    #commit = "2b6082a4d9d163a52299718113fa41e4b7978db5", # 2024/09
+    #patch_strip = 1,
+    #patches = ["//:patches/pybind11_bazel.patch"], # patch for 2024/09
     remote = "https://github.com/pybind/pybind11_bazel.git",
 )
-
+bazel_dep(name = "pybind11_abseil", version = "202402.0")
 git_override(
     module_name = "pybind11_abseil",
     commit = "70f8b693b3b70573ca785ef62d9f48054f45d786",
     patch_strip = 1,
     patches = ["//:patches/pybind11_abseil.patch"],
     remote = "https://github.com/pybind/pybind11_abseil.git",
 )
-
+bazel_dep(name = "pybind11_protobuf", version = "0.0.0-20240524-1d7a729")
 git_override(
     module_name = "pybind11_protobuf",
     commit = "f02a2b7653bc50eb5119d125842a3870db95d251",
     remote = "https://github.com/pybind/pybind11_protobuf.git",
 )
+bazel_dep(name = "swig", version = "4.3.0")
 
 # Python
 # https://rules-python.readthedocs.io/en/latest/toolchains.html#library-modules-with-dev-only-python-usage

cmake/dependencies/CMakeLists.txt

@@ -229,17 +229,10 @@ if(BUILD_PYTHON)
     FetchContent_Declare(
       pybind11
       GIT_REPOSITORY "https://github.com/pybind/pybind11.git"
-      #GIT_TAG "master" # COMPILE FAIL
-      #GIT_TAG "f365314" # 2025/03/24 COMPILE FAIL
-      #GIT_TAG "48eb5ad" # 2025/03/23 TEST PASS
-      # ...
-      #GIT_TAG "a1d00916" # 2024/08/15 TEST PASS
-      #GIT_TAG "bd5951b6" # 2024/08/14 TEST FAIL
-      GIT_TAG "v2.13.6" # TEST PASS with a1d00916 patch apply
-      #GIT_SHALLOW TRUE
+      #GIT_TAG "v3.0.2" # 2026/02/17
+      GIT_TAG "v3.0.1" # 2025/08/22
+      GIT_SHALLOW TRUE
       UPDATE_COMMAND git reset --hard
-      PATCH_COMMAND git apply --ignore-whitespace
-      "${CMAKE_CURRENT_LIST_DIR}/../../patches/pybind11-v2.13.6.patch"
       SYSTEM
     )
     set(PYBIND11_FINDPYTHON ON)

cmake/python.cmake

@@ -780,7 +780,7 @@ add_custom_command(
   COMMAND ${stubgen_EXECUTABLE} -p ortools.math_opt.core.python.solver --output .
   COMMAND ${stubgen_EXECUTABLE} -p ortools.pdlp.python.pdlp --output .
   COMMAND ${stubgen_EXECUTABLE} -p ortools.routing.pywraprouting --output .
-  COMMAND ${stubgen_EXECUTABLE} -p ortools.routing.python.model --output .
+  COMMAND ${stubgen_EXECUTABLE} -p ortools.routing.python.routing --output .
   COMMAND ${stubgen_EXECUTABLE} -p ortools.sat.python.cp_model_helper --output .
   COMMAND ${stubgen_EXECUTABLE} -p ortools.scheduling.python.rcpsp --output .
   COMMAND ${stubgen_EXECUTABLE} -p ortools.set_cover.python.set_cover --output .

ortools/math_opt/elemental/python/elemental.cc

@@ -117,20 +117,9 @@ bool PyToCppEnum(PyObject* const py_enum, EnumT& cpp_enum,
 // the latter).
 template <const absl::string_view& name>
 struct AsArray {
-  constexpr AsArray() {
-#if __cplusplus >= 202002L
-    std::copy(name.begin(), name.end(), array);
-#else
-    // `std::copy` is not constexpr before C++20.
-    char* p = array;
-    for (const char c : name) {
-      *p++ = c;
-    }
-    *p = '\0';
-#endif
-  }
+  char array[name.size() + 1];
 
-  char array[name.size() + 1] = {};
+  constexpr AsArray() { std::copy(name.begin(), name.end(), array); }
 };
 
 // An RAII object that allows creating a UTF8 string from a numpy unicode
@@ -300,6 +289,16 @@ struct type_caster<ElementId<element_type>> {
   }
 };
 
+#if defined(PYBIND11_HAS_NATIVE_ENUM)
+// We must first disable the default pybind11 handler for enums to make our
+// specialization non-ambiguous:
+// https://pybind11.readthedocs.io/en/stable/classes.html#enumerations-and-internal-types
+template <typename AttrType>
+struct type_caster_enum_type_enabled<
+    AttrType, enable_if_t<(GetIndexIfAttr<AttrType>() >= 0)>>
+    : std::false_type {};
+#endif
+
 // Type caster for casting enum values from python enums to C++ `Elemental`
 // enums.
 template <typename AttrType>

ortools/sat/python/cp_model_helper.cc

@@ -1871,8 +1871,7 @@ PYBIND11_MODULE(cp_model_helper, m) {
       .def(py::init<std::shared_ptr<CpModelProto>, int>())
       .def(py::init<std::shared_ptr<CpModelProto>>())  // new variable.
       .def_property_readonly(
-          "proto", &IntVar::proto, py::return_value_policy::reference,
-          py::keep_alive<1, 0>(),
+          "proto", &IntVar::proto, py::return_value_policy::reference_internal,
           "Returns the IntegerVariableProto of this variable.")
       .def_property_readonly("model_proto", &IntVar::model_proto,
                              "Returns the CP model protobuf")
@@ -2120,8 +2119,7 @@ PYBIND11_MODULE(cp_model_helper, m) {
       .def_property_readonly("model_proto", &Constraint::model_proto,
                              "Returns the model protobuf.")
       .def_property_readonly("proto", &Constraint::proto,
-                             py::return_value_policy::reference,
-                             py::keep_alive<1, 0>(),
+                             py::return_value_policy::reference_internal,
                              "Returns the ConstraintProto of this constraint.")
       .def_property("name", &Constraint::name, &Constraint::SetName,
                     "The name of the constraint.")
@@ -2236,9 +2234,9 @@ intervals into the schedule.
                              "Returns the index of the interval variable.")
       .def_property_readonly("model_proto", &IntervalVar::model_proto,
                              "Returns the model protobuf.")
-      .def_property_readonly(
-          "proto", &IntervalVar::proto, py::return_value_policy::reference,
-          py::keep_alive<1, 0>(), "Returns the interval constraint protobuf.")
+      .def_property_readonly("proto", &IntervalVar::proto,
+                             py::return_value_policy::reference_internal,
+                             "Returns the interval constraint protobuf.")
       .def_property("name", &IntervalVar::name, &IntervalVar::SetName,
                     "The name of the interval variable.")
       .def(

ortools/util/python/wrappers.cc

@@ -370,7 +370,7 @@ class Generator {
     .def_property_readonly(
         "$0",
         []($1 self) { return self->mutable_$2(); },
-        py::return_value_policy::reference, py::keep_alive<0, 1>()))",
+        py::return_value_policy::reference_internal))",
           field.name(), current_context_.self_mutable_name, field.name());
       // We'll need to generate the wrapping for
       // `google::protobuf::RepeatedPtrField<$3>`.
@@ -383,7 +383,7 @@ class Generator {
     .def_property_readonly(
         "$0",
         []($1 self) { return self->mutable_$0(); },
-        py::return_value_policy::reference, py::keep_alive<0, 1>()))",
+        py::return_value_policy::reference_internal))",
                                 field.name(),
                                 current_context_.self_mutable_name);
       // We'll need to generate the wrapping for