[WIP] Emit POSTINITIALIZE notification after init()

In godot 4.4 and later

Author: beicause

godot-core/src/builtin/string/gstring.rs

@@ -328,7 +328,11 @@ impl From<&str> for GString {
 
         unsafe {
             Self::new_with_string_uninit(|string_ptr| {
+                #[cfg(before_api = "4.3")]
                 let ctor = interface_fn!(string_new_with_utf8_chars_and_len);
+                #[cfg(since_api = "4.3")]
+                let ctor = interface_fn!(string_new_with_utf8_chars_and_len2);
+
                 ctor(
                     string_ptr,
                     bytes.as_ptr() as *const std::ffi::c_char,

godot-core/src/classes/class_runtime.rs

@@ -170,10 +170,15 @@ pub(crate) fn construct_engine_object<T>() -> Gd<T>
 where
     T: GodotClass + Bounds<Declarer = bounds::DeclEngine>,
 {
-    // SAFETY: adhere to Godot API; valid class name and returned pointer is an object.
     unsafe {
-        let object_ptr = sys::interface_fn!(classdb_construct_object)(T::class_name().string_sys());
-        Gd::from_obj_sys(object_ptr)
+        let object_ptr = sys::classdb_construct_object(T::class_name().string_sys());
+        let obj = Gd::<T>::from_obj_sys(object_ptr);
+        if cfg!(since_api = "4.4") {
+            obj.clone()
+                .upcast_object()
+                .notify(crate::classes::notify::ObjectNotification::POSTINITIALIZE);
+        }
+        obj
     }
 }
 

godot-core/src/obj/bounds.rs

@@ -398,11 +398,7 @@ impl Declarer for DeclEngine {
     where
         T: GodotDefault + Bounds<Declarer = Self>,
     {
-        unsafe {
-            let object_ptr =
-                sys::interface_fn!(classdb_construct_object)(T::class_name().string_sys());
-            Gd::from_obj_sys(object_ptr)
-        }
+        crate::classes::construct_engine_object()
     }
 }
 

godot-core/src/registry/callbacks.rs

@@ -35,7 +35,19 @@ pub unsafe extern "C" fn create<T: cap::GodotDefault>(
     _class_userdata: *mut std::ffi::c_void,
     _notify_postinitialize: sys::GDExtensionBool,
 ) -> sys::GDExtensionObjectPtr {
-    create_custom(T::__godot_user_init).unwrap_or(std::ptr::null_mut())
+    if let Ok(object_ptr) = create_custom(T::__godot_user_init) {
+        let mut obj = Gd::<Object>::from_obj_sys_weak(object_ptr);
+        obj.notify(crate::classes::notify::ObjectNotification::POSTINITIALIZE);
+
+        // Mark initialization as complete, now that user constructor has finished.
+        // base.mark_initialized();
+
+        std::mem::forget(obj);
+
+        object_ptr
+    } else {
+        std::ptr::null_mut()
+    }
 }
 
 #[cfg(before_api = "4.4")]

godot-ffi/src/lib.rs

@@ -471,6 +471,18 @@ pub unsafe fn discover_main_thread() {
     }
 }
 
+/// # Safety
+/// `class_name` is assumed to be valid.
+pub unsafe fn classdb_construct_object(
+    class_name: GDExtensionConstStringNamePtr,
+) -> GDExtensionObjectPtr {
+    if cfg!(before_api = "4.4") {
+        interface_fn!(classdb_construct_object)(class_name)
+    } else {
+        interface_fn!(classdb_construct_object2)(class_name)
+    }
+}
+
 // ----------------------------------------------------------------------------------------------------------------------------------------------
 // Macros to access low-level function bindings
 

itest/rust/src/object_tests/base_init_test.rs

@@ -7,8 +7,10 @@
 
 use godot::builtin::real_consts::FRAC_PI_3;
 use godot::builtin::Vector2;
+use godot::classes::notify::ObjectNotification;
 use godot::classes::{ClassDb, RefCounted};
 use godot::obj::{Gd, InstanceId, NewAlloc, NewGd, WithBaseField};
+use godot::prelude::*;
 use godot::task::TaskHandle;
 
 use crate::framework::{expect_panic, itest, next_frame};
@@ -168,3 +170,30 @@ fn base_init_to_gd() {
         });
     });
 }
+
+#[derive(GodotClass)]
+#[class(init)]
+struct RefcPostinit {
+    pub base: Base<RefCounted>,
+}
+
+#[godot_api]
+impl IRefCounted for RefcPostinit {
+    fn on_notification(&mut self, what: ObjectNotification) {
+        #[cfg(since_api = "4.4")]
+        {
+            if what == ObjectNotification::POSTINITIALIZE {
+                self.base
+                    .to_init_gd()
+                    .set_meta("meta", &"inited".to_variant());
+            } else if what == ObjectNotification::PREDELETE {
+                assert_eq!(self.base().get_meta("meta"), "inited".to_variant())
+            }
+        }
+    }
+}
+
+#[itest]
+fn base_postinit_refcounted() {
+    RefcPostinit::new_gd();
+}

itest/rust/src/object_tests/virtual_methods_test.rs

@@ -520,6 +520,8 @@ fn test_notifications() {
     assert_eq!(
         obj.bind().sequence,
         vec![
+            #[cfg(since_api = "4.4")]
+            ReceivedEvent::Notification(NodeNotification::POSTINITIALIZE),
             ReceivedEvent::Notification(NodeNotification::UNPAUSED),
             ReceivedEvent::Notification(NodeNotification::EDITOR_POST_SAVE),
             ReceivedEvent::Ready,