support sending property change events

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.25)
 
-project(pyunrealsdk VERSION 1.6.0)
+project(pyunrealsdk VERSION 1.7.0)
 
 function(_pyunrealsdk_add_base_target_args target_name)
     target_compile_features(${target_name} PUBLIC cxx_std_20)

changelog.md

@@ -1,5 +1,32 @@
 # Changelog
 
+## v1.7.0
+
+- Added support for sending property changed events. This is typically best done via the
+  `unrealsdk.unreal.notify_changes` context manager.
+
+  [97e3e0c2](https://github.com/bl-sdk/unrealsdk/commit/97e3e0c2)
+
+- Fixed that it was possible for the `unrealsdk` module in the global namespace to get replaced, if
+  something during the init script messed with `sys.modules`. It is now imported during
+  initialization.
+
+  [91cfee4b](https://github.com/bl-sdk/unrealsdk/commit/91cfee4b)
+
+### unrealsdk v1.8.0
+For reference, the unrealsdk v1.8.0 changes this includes are:
+
+> - Added support for sending property changed events, via `UObject::post_edit_change_property` and
+>   `UObject::post_edit_change_chain_property`.
+>   
+>   [a6040da4](https://github.com/bl-sdk/unrealsdk/commit/a6040da4)
+> 
+> - Made the error message when assigning incompatible array types more clear.
+> 
+>   See also https://github.com/bl-sdk/unrealsdk/issues/60 .
+> 
+>   [6222756c](https://github.com/bl-sdk/unrealsdk/commit/6222756c)
+
 ## v1.6.0
 
 - `WrappedStruct` now supports being copied via the `copy` module.

src/pyunrealsdk/commands.cpp

@@ -90,17 +90,10 @@ void py_cmd_handler(const wchar_t* line, size_t size, size_t cmd_len) {
     try {
         const py::gil_scoped_acquire gil{};
 
-        // Make sure unrealsdk is already in globals, for convenience
-        // The init script and `pyexec` commands both use a local dict, so this won't affect them
-        auto globals = py::globals();
-        if (!globals.contains("unrealsdk")) {
-            globals["unrealsdk"] = py::module_::import("unrealsdk");
-        }
-
         const py::str code_block{
             PyUnicode_FromWideChar(str.c_str(), static_cast<py::ssize_t>(str.size()))};
 
-        py::exec(code_block, globals);
+        py::exec(code_block);
     } catch (const std::exception& ex) {
         logging::log_python_exception(ex);
     }
@@ -178,6 +171,13 @@ void register_module(py::module_& mod) {
 }
 
 void register_commands(void) {
+    // Make sure unrealsdk is already in globals, for convenience
+    // The init script and `pyexec` commands both use a local dict, so this won't affect them
+    auto globals = py::globals();
+    if (!globals.contains("unrealsdk")) {
+        globals["unrealsdk"] = py::module_::import("unrealsdk");
+    }
+
     unrealsdk::commands::add_command(L"pyexec", &pyexec_cmd_handler);
     unrealsdk::commands::add_command(L"py", &py_cmd_handler);
 }

src/pyunrealsdk/unreal_bindings/uobject.cpp

@@ -6,6 +6,8 @@
 #include "unrealsdk/format.h"
 #include "unrealsdk/unreal/classes/uclass.h"
 #include "unrealsdk/unreal/classes/uobject.h"
+#include "unrealsdk/unreal/classes/uproperty.h"
+#include "unrealsdk/unreal/find_class.h"
 #include "unrealsdk/unreal/structs/fname.h"
 #include "unrealsdk/unrealsdk.h"
 #include "unrealsdk/utils.h"
@@ -29,6 +31,11 @@ UObject* uobject_init(const py::args& /* args */, const py::kwargs& /* kwargs */
     throw py::type_error("Cannot create new instances of unreal objects.");
 }
 
+// Dummy class to make the context manager on
+struct ContextManager {};
+
+size_t should_notify_counter = 0;
+
 }  // namespace
 
 void register_uobject(py::module_& mod) {
@@ -126,8 +133,12 @@ void register_uobject(py::module_& mod) {
                     }
                 }
 
-                py_setattr_direct(py_find_field(py::cast<FName>(name), self->Class),
-                                  reinterpret_cast<uintptr_t>(self), value);
+                auto field = py_find_field(py::cast<FName>(name), self->Class);
+                py_setattr_direct(field, reinterpret_cast<uintptr_t>(self), value);
+
+                if (should_notify_counter > 0 && field->is_instance(find_class<UProperty>())) {
+                    self->post_edit_change_property(reinterpret_cast<UProperty*>(field));
+                }
             },
             "Writes a value to an unreal field on the object.\n"
             "\n"
@@ -144,6 +155,10 @@ void register_uobject(py::module_& mod) {
                     throw py::attribute_error("cannot access null attribute");
                 }
                 py_setattr_direct(field, reinterpret_cast<uintptr_t>(self), value);
+
+                if (should_notify_counter > 0 && field->is_instance(find_class<UProperty>())) {
+                    self->post_edit_change_property(reinterpret_cast<UProperty*>(field));
+                }
             },
             "Writes a value to an unreal field on the object.\n"
             "\n"
@@ -162,11 +177,68 @@ void register_uobject(py::module_& mod) {
             "\n"
             "Returns:\n"
             "    This object's address.")
+        .def(
+            "_post_edit_change_property",
+            [](UObject* self, std::variant<FName, UProperty*> prop) {
+                std::visit([self](auto&& val) { self->post_edit_change_property(val); }, prop);
+            },
+            "Notifies the engine that we've made an external change to a property.\n"
+            "\n"
+            "This only works on top level properties, those directly on the object.\n"
+            "\n"
+            "Also see the notify_changes() context manager, which calls this automatically.\n"
+            "\n"
+            "Args:\n"
+            "    prop: The property, or the name of the property, which was changed.",
+            "args"_a)
+        .def(
+            "_post_edit_change_chain_property",
+            [](UObject* self, UProperty* prop, const py::args& args) {
+                std::vector<UProperty*> chain;
+                chain.reserve(args.size());
+
+                for (const auto& val : args) {
+                    chain.push_back(py::cast<UProperty*>(val));
+                }
+                self->post_edit_change_chain_property(prop, chain);
+            },
+            "Notifies the engine that we've made an external change to a chain of properties.\n"
+            "\n"
+            "This version allows notifying about changes inside (nested) structs.\n"
+            "\n"
+            "Args:\n"
+            "    prop: The property which was changed.\n"
+            "    *chain: The chain of properties to follow.",
+            "prop"_a)
         .def_readwrite("ObjectFlags", &UObject::ObjectFlags)
         .def_readwrite("InternalIndex", &UObject::InternalIndex)
         .def_readwrite("Class", &UObject::Class)
         .def_readwrite("Name", &UObject::Name)
         .def_readwrite("Outer", &UObject::Outer);
+
+    // Create under an empty handle to prevent this type being normally accessible
+    py::class_<ContextManager>(py::handle(), "context_manager", pybind11::module_local())
+        .def("__enter__", [](const py::object& /*self*/) { should_notify_counter++; })
+        .def("__exit__", [](const py::object& /*self */, const py::object& /*exc_type*/,
+                            const py::object& /*exc_value*/, const py::object& /*traceback*/) {
+            if (should_notify_counter > 0) {
+                should_notify_counter--;
+            }
+        });
+
+    mod.def(
+        "notify_changes", []() { return ContextManager{}; },
+        "Context manager to automatically notify the engine when you edit an object.\n"
+        "\n"
+        "This essentially just automatically calls obj._post_edit_change_property() after\n"
+        "every setattr.\n"
+        "\n"
+        "Note that this only tracks top-level changes, it cannot track changes to inner\n"
+        "struct fields, You will have to manually call obj._post_edit_chain_property()\n"
+        "for them.\n"
+        "\n"
+        "Returns:\n"
+        "    A new context manager.");
 }
 
 }  // namespace pyunrealsdk::unreal

stubs/unrealsdk/unreal/__init__.pyi

@@ -4,7 +4,7 @@ from __future__ import annotations
 
 from ._bound_function import BoundFunction
 from ._uenum import UEnum
-from ._uobject import UObject
+from ._uobject import UObject, notify_changes
 from ._uobject_children import (
     UArrayProperty,
     UBlueprintGeneratedClass,
@@ -97,6 +97,7 @@ __all__: tuple[str, ...] = (
     "WrappedMulticastDelegate",
     "WrappedStruct",
     "dir_includes_unreal",
+    "notify_changes",
 )
 
 def dir_includes_unreal(should_include: bool) -> None:

stubs/unrealsdk/unreal/_uobject.pyi

@@ -1,8 +1,9 @@
 from __future__ import annotations
 
+from contextlib import AbstractContextManager
 from typing import Any, Never
 
-from ._uobject_children import UClass, UField
+from ._uobject_children import UClass, UField, UProperty
 
 class UObject:
     """
@@ -86,6 +87,27 @@ class UObject:
         Returns:
             This object's name.
         """
+    def _post_edit_change_property(self, prop: str | UProperty) -> None:
+        """
+        Notifies the engine that we've made an external change to a property.
+
+        This only works on top level properties, those directly on the object.
+
+        Also see the notify_changes() context manager, which calls this automatically.
+
+        Args:
+            prop: The property, or the name of the property, which was changed.
+        """
+    def _post_edit_change_chain_property(self, prop: UProperty, *chain: UProperty) -> None:
+        """
+        Notifies the engine that we've made an external change to a chain of properties.
+
+        This version allows notifying about changes inside (nested) structs.
+
+        Args:
+            prop: The property which was changed.
+            *chain: The chain of properties to follow.
+        """
     def _set_field(self, field: UField, value: Any) -> None:
         """
         Writes a value to an unreal field on the object.
@@ -99,3 +121,18 @@ class UObject:
             field: The field to set.
             value: The value to write.
         """
+
+def notify_changes() -> AbstractContextManager[None]:
+    """
+    Context manager to automatically notify the engine when you edit an object.
+
+    This essentially just automatically calls obj._post_edit_change_property() after
+    every setattr.
+
+    Note that this only tracks top-level changes, it cannot track changes to inner
+    struct fields, You will have to manually call obj._post_edit_chain_property()
+    for them.
+
+    Returns:
+        A new context manager.
+    """