From 76b7d23a1092bdc13aaf8467079f82c8e6f4a409 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pedro=20J=2E=20Est=C3=A9banez?= <pedrojrulez@gmail.com>
Date: Tue, 14 Sep 2021 13:05:45 +0200
Subject: [PATCH 1/2] Unify determination of default property values

---
 editor/editor_inspector.cpp      | 177 ++---------------------------
 editor/editor_inspector.h        |   3 -
 editor/scene_tree_dock.cpp       |  21 ++--
 scene/property_utils.cpp         | 186 +++++++++++++++++++++++++++++++
 scene/property_utils.h           |  51 +++++++++
 scene/resources/packed_scene.cpp | 178 ++++++-----------------------
 scene/resources/packed_scene.h   |  15 ++-
 7 files changed, 300 insertions(+), 331 deletions(-)
 create mode 100644 scene/property_utils.cpp
 create mode 100644 scene/property_utils.h

diff --git a/editor/editor_inspector.cpp b/editor/editor_inspector.cpp
index 88e8f9120d32..5986bce1c3c1 100644
--- a/editor/editor_inspector.cpp
+++ b/editor/editor_inspector.cpp
@@ -29,12 +29,14 @@
 /*************************************************************************/
 
 #include "editor_inspector.h"
+
 #include "array_property_edit.h"
 #include "dictionary_property_edit.h"
 #include "editor_feature_profile.h"
 #include "editor_node.h"
 #include "editor_scale.h"
 #include "multi_node_edit.h"
+#include "scene/property_utils.h"
 #include "scene/resources/packed_scene.h"
 
 Size2 EditorProperty::get_minimum_size() const {
@@ -318,177 +320,12 @@ bool EditorProperty::is_read_only() const {
 	return read_only;
 }
 
-bool EditorPropertyRevert::may_node_be_in_instance(Node *p_node) {
-	Node *edited_scene = EditorNode::get_singleton()->get_edited_scene();
-
-	bool might_be = false;
-	Node *node = p_node;
-
-	while (node) {
-		if (node == edited_scene) {
-			if (node->get_scene_inherited_state().is_valid()) {
-				might_be = true;
-				break;
-			}
-			might_be = false;
-			break;
-		}
-		if (node->get_scene_instance_state().is_valid()) {
-			might_be = true;
-			break;
-		}
-		node = node->get_owner();
-	}
-
-	return might_be; // or might not be
-}
-
-bool EditorPropertyRevert::get_instanced_node_original_property(Node *p_node, const StringName &p_prop, Variant &value, bool p_check_class_default) {
-	Node *node = p_node;
-	Node *orig = node;
-
-	Node *edited_scene = EditorNode::get_singleton()->get_edited_scene();
-
-	bool found = false;
-
-	while (node) {
-		Ref<SceneState> ss;
-
-		if (node == edited_scene) {
-			ss = node->get_scene_inherited_state();
-
-		} else {
-			ss = node->get_scene_instance_state();
-		}
-
-		if (ss.is_valid()) {
-			NodePath np = node->get_path_to(orig);
-			int node_idx = ss->find_node_by_path(np);
-			if (node_idx >= 0) {
-				bool lfound = false;
-				Variant lvar;
-				lvar = ss->get_property_value(node_idx, p_prop, lfound);
-				if (lfound) {
-					found = true;
-					value = lvar;
-				}
-			}
-		}
-		if (node == edited_scene) {
-			//just in case
-			break;
-		}
-		node = node->get_owner();
-	}
-
-	if (p_check_class_default && !found && p_node) {
-		//if not found, try default class value
-		Variant attempt = ClassDB::class_get_default_property_value(p_node->get_class_name(), p_prop);
-		if (attempt.get_type() != Variant::NIL) {
-			found = true;
-			value = attempt;
-		}
-	}
-
-	return found;
-}
-
-bool EditorPropertyRevert::is_node_property_different(Node *p_node, const Variant &p_current, const Variant &p_orig) {
-	// this is a pretty difficult function, because a property may not be saved but may have
-	// the flag to not save if one or if zero
-
-	//make sure there is an actual state
-	{
-		Node *node = p_node;
-		if (!node) {
-			return false;
-		}
-
-		Node *edited_scene = EditorNode::get_singleton()->get_edited_scene();
-		bool found_state = false;
-
-		while (node) {
-			Ref<SceneState> ss;
-
-			if (node == edited_scene) {
-				ss = node->get_scene_inherited_state();
-
-			} else {
-				ss = node->get_scene_instance_state();
-			}
-
-			if (ss.is_valid()) {
-				found_state = true;
-				break;
-			}
-			if (node == edited_scene) {
-				//just in case
-				break;
-			}
-			node = node->get_owner();
-		}
-
-		if (!found_state) {
-			return false; //pointless to check if we are not comparing against anything.
-		}
-	}
-
-	return is_property_value_different(p_current, p_orig);
-}
-
-bool EditorPropertyRevert::is_property_value_different(const Variant &p_a, const Variant &p_b) {
-	if (p_a.get_type() == Variant::REAL && p_b.get_type() == Variant::REAL) {
-		//this must be done because, as some scenes save as text, there might be a tiny difference in floats due to numerical error
-		return !Math::is_equal_approx((float)p_a, (float)p_b);
-	} else {
-		return p_a != p_b;
-	}
-}
-
 Variant EditorPropertyRevert::get_property_revert_value(Object *p_object, const StringName &p_property) {
-	// If the object implements property_can_revert, rely on that completely
-	// (i.e. don't then try to revert to default value - the property_get_revert implementation
-	// can do that if so desired)
 	if (p_object->has_method("property_can_revert") && p_object->call("property_can_revert", p_property)) {
 		return p_object->call("property_get_revert", p_property);
 	}
 
-	Ref<Script> scr = p_object->get_script();
-	Node *node = Object::cast_to<Node>(p_object);
-	if (node && EditorPropertyRevert::may_node_be_in_instance(node)) {
-		//if this node is an instance or inherits, but it has a script attached which is unrelated
-		//to the one set for the parent and also has a default value for the property, consider that
-		//has precedence over the value from the parent, because that is an explicit source of defaults
-		//closer in the tree to the current node
-		bool ignore_parent = false;
-		if (scr.is_valid()) {
-			Variant sorig;
-			if (EditorPropertyRevert::get_instanced_node_original_property(node, "script", sorig) && !scr->inherits_script(sorig)) {
-				Variant dummy;
-				if (scr->get_property_default_value(p_property, dummy)) {
-					ignore_parent = true;
-				}
-			}
-		}
-
-		if (!ignore_parent) {
-			//check for difference including instantiation
-			Variant vorig;
-			if (EditorPropertyRevert::get_instanced_node_original_property(node, p_property, vorig, false)) {
-				return vorig;
-			}
-		}
-	}
-
-	if (scr.is_valid()) {
-		Variant orig_value;
-		if (scr->get_property_default_value(p_property, orig_value)) {
-			return orig_value;
-		}
-	}
-
-	//report default class value instead
-	return ClassDB::class_get_default_property_value(p_object->get_class_name(), p_property);
+	return PropertyUtils::get_property_default_value(p_object, p_property);
 }
 
 bool EditorPropertyRevert::can_property_revert(Object *p_object, const StringName &p_property) {
@@ -497,7 +334,7 @@ bool EditorPropertyRevert::can_property_revert(Object *p_object, const StringNam
 		return false;
 	}
 	Variant current_value = p_object->get(p_property);
-	return EditorPropertyRevert::is_property_value_different(current_value, revert_value);
+	return PropertyUtils::is_property_value_different(current_value, revert_value);
 }
 
 void EditorProperty::update_reload_status() {
@@ -505,10 +342,10 @@ void EditorProperty::update_reload_status() {
 		return; //no property, so nothing to do
 	}
 
-	bool has_reload = EditorPropertyRevert::can_property_revert(object, property);
+	bool new_can_revert = EditorPropertyRevert::can_property_revert(object, property);
 
-	if (has_reload != can_revert) {
-		can_revert = has_reload;
+	if (new_can_revert != can_revert) {
+		can_revert = new_can_revert;
 		update();
 	}
 }
diff --git a/editor/editor_inspector.h b/editor/editor_inspector.h
index 3a0038f2c94a..bf27ccfd97c8 100644
--- a/editor/editor_inspector.h
+++ b/editor/editor_inspector.h
@@ -39,7 +39,6 @@ class UndoRedo;
 
 class EditorPropertyRevert {
 public:
-	static bool may_node_be_in_instance(Node *p_node);
 	static bool get_instanced_node_original_property(Node *p_node, const StringName &p_prop, Variant &value, bool p_check_class_default = true);
 	static bool is_node_property_different(Node *p_node, const Variant &p_current, const Variant &p_orig);
 	static bool is_property_value_different(const Variant &p_a, const Variant &p_b);
@@ -81,8 +80,6 @@ class EditorProperty : public Container {
 	bool use_folding;
 	bool draw_top_bg;
 
-	bool _is_property_different(const Variant &p_current, const Variant &p_orig);
-	bool _get_instanced_node_original_property(const StringName &p_prop, Variant &value);
 	void _focusable_focused(int p_index);
 
 	bool selectable;
diff --git a/editor/scene_tree_dock.cpp b/editor/scene_tree_dock.cpp
index 4d70f63b37d0..d1bd68b331f2 100644
--- a/editor/scene_tree_dock.cpp
+++ b/editor/scene_tree_dock.cpp
@@ -34,7 +34,6 @@
 #include "core/os/input.h"
 #include "core/os/keyboard.h"
 #include "core/project_settings.h"
-
 #include "editor/editor_feature_profile.h"
 #include "editor/editor_node.h"
 #include "editor/editor_scale.h"
@@ -46,6 +45,7 @@
 #include "editor/plugins/spatial_editor_plugin.h"
 #include "editor/script_editor_debugger.h"
 #include "scene/main/viewport.h"
+#include "scene/property_utils.h"
 #include "scene/resources/packed_scene.h"
 
 void SceneTreeDock::_nodes_drag_begin() {
@@ -3086,7 +3086,9 @@ void SceneTreeDock::_clear_clipboard() {
 void SceneTreeDock::_create_remap_for_node(Node *p_node, Map<RES, RES> &r_remap) {
 	List<PropertyInfo> props;
 	p_node->get_property_list(&props);
-	bool is_instanced = EditorPropertyRevert::may_node_be_in_instance(p_node);
+
+	Vector<SceneState::PackState> states_stack;
+	bool states_stack_ready = false;
 
 	for (List<PropertyInfo>::Element *E = props.front(); E; E = E->next()) {
 		if (!(E->get().usage & PROPERTY_USAGE_STORAGE)) {
@@ -3097,13 +3099,14 @@ void SceneTreeDock::_create_remap_for_node(Node *p_node, Map<RES, RES> &r_remap)
 		if (v.is_ref()) {
 			RES res = v;
 			if (res.is_valid()) {
-				if (is_instanced) {
-					Variant orig;
-					if (EditorPropertyRevert::get_instanced_node_original_property(p_node, E->get().name, orig)) {
-						if (!EditorPropertyRevert::is_node_property_different(p_node, v, orig)) {
-							continue;
-						}
-					}
+				if (!states_stack_ready) {
+					states_stack = PropertyUtils::get_node_states_stack(p_node);
+					states_stack_ready = true;
+				}
+
+				Variant orig = PropertyUtils::get_property_default_value(p_node, E->get().name, &states_stack);
+				if (!PropertyUtils::is_property_value_different(v, orig)) {
+					continue;
 				}
 
 				if ((res->get_path() == "" || res->get_path().find("::") > -1) && !r_remap.has(res)) {
diff --git a/scene/property_utils.cpp b/scene/property_utils.cpp
new file mode 100644
index 000000000000..4e1cb50a168c
--- /dev/null
+++ b/scene/property_utils.cpp
@@ -0,0 +1,186 @@
+/*************************************************************************/
+/*  property_utils.cpp                                                   */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "property_utils.h"
+
+#include "core/core_string_names.h"
+#include "core/engine.h"
+#include "core/local_vector.h"
+#include "editor/editor_node.h"
+#include "scene/resources/packed_scene.h"
+
+bool PropertyUtils::is_property_value_different(const Variant &p_a, const Variant &p_b) {
+	if (p_a.get_type() == Variant::REAL && p_b.get_type() == Variant::REAL) {
+		//this must be done because, as some scenes save as text, there might be a tiny difference in floats due to numerical error
+		return !Math::is_equal_approx((float)p_a, (float)p_b);
+	} else {
+		// For our purposes, treating null object as NIL is the right thing to do
+		const Variant &a = p_a.get_type() == Variant::OBJECT && (Object *)p_a == nullptr ? Variant() : p_a;
+		const Variant &b = p_b.get_type() == Variant::OBJECT && (Object *)p_b == nullptr ? Variant() : p_b;
+		return a != b;
+	}
+}
+
+Variant PropertyUtils::get_property_default_value(const Object *p_object, const StringName &p_property, const Vector<SceneState::PackState> *p_states_stack_cache, bool p_update_exports, const Node *p_owner, bool *r_is_class_default) {
+	// This function obeys the way property values are set when an object is instantiated,
+	// which is the following (the latter wins):
+	// 1. Default value from builtin class
+	// 2. Default value from script exported variable (from the topmost script)
+	// 3. Value overrides from the instantiation/inheritance stack
+
+	if (r_is_class_default) {
+		*r_is_class_default = false;
+	}
+
+	Ref<Script> topmost_script;
+
+	if (const Node *node = Object::cast_to<Node>(p_object)) {
+		// Check inheritance/instantiation ancestors
+		const Vector<SceneState::PackState> &states_stack = p_states_stack_cache ? *p_states_stack_cache : PropertyUtils::get_node_states_stack(node, p_owner);
+		for (int i = 0; i < states_stack.size(); ++i) {
+			const SceneState::PackState &ia = states_stack[i];
+			bool found = false;
+			Variant value_in_ancestor = ia.state->get_property_value(ia.node, p_property, found);
+			if (found) {
+				return value_in_ancestor;
+			}
+			// Save script for later
+			bool has_script = false;
+			Variant script = ia.state->get_property_value(ia.node, CoreStringNames::get_singleton()->_script, has_script);
+			if (has_script) {
+				Ref<Script> scr = script;
+				if (scr.is_valid()) {
+					topmost_script = scr;
+				}
+			}
+		}
+	}
+
+	// Let's see what default is set by the topmost script having a default, if any
+	if (topmost_script.is_null()) {
+		topmost_script = p_object->get_script();
+	}
+	if (topmost_script.is_valid()) {
+		Variant default_value;
+		// Should be called in the editor only and not at runtime,
+		// otherwise it can cause problems because of missing instance state support.
+		if (p_update_exports && Engine::get_singleton()->is_editor_hint()) {
+			topmost_script->update_exports();
+		}
+		if (topmost_script->get_property_default_value(p_property, default_value)) {
+			return default_value;
+		}
+	}
+
+	// Fall back to the default from the native class
+	if (r_is_class_default) {
+		*r_is_class_default = true;
+	}
+	return ClassDB::class_get_default_property_value(p_object->get_class_name(), p_property);
+}
+
+// Like SceneState::PackState, but using a raw pointer to avoid the cost of
+// updating the reference count during the internal work of the functions below
+namespace {
+struct _FastPackState {
+	SceneState *state = nullptr;
+	int node = -1;
+};
+} // namespace
+
+static bool _collect_inheritance_chain(const Ref<SceneState> &p_state, const NodePath &p_path, LocalVector<_FastPackState> &r_states_stack) {
+	bool found = false;
+
+	LocalVector<_FastPackState> inheritance_states;
+
+	Ref<SceneState> state = p_state;
+	while (state.is_valid()) {
+		int node = state->find_node_by_path(p_path);
+		if (node >= 0) {
+			// This one has state for this node
+			inheritance_states.push_back({ state.ptr(), node });
+			found = true;
+		}
+		state = state->get_base_scene_state();
+	}
+
+	for (int i = inheritance_states.size() - 1; i >= 0; --i) {
+		r_states_stack.push_back(inheritance_states[i]);
+	}
+
+	return found;
+}
+
+Vector<SceneState::PackState> PropertyUtils::get_node_states_stack(const Node *p_node, const Node *p_owner, bool *r_instanced_by_owner) {
+	if (r_instanced_by_owner) {
+		*r_instanced_by_owner = true;
+	}
+
+	LocalVector<_FastPackState> states_stack;
+	{
+		const Node *owner = p_owner;
+#ifdef TOOLS_ENABLED
+		if (!p_owner && Engine::get_singleton()->is_editor_hint()) {
+			owner = EditorNode::get_singleton()->get_edited_scene();
+		}
+#endif
+
+		const Node *n = p_node;
+		while (n) {
+			if (n == owner) {
+				const Ref<SceneState> &state = n->get_scene_inherited_state();
+				if (_collect_inheritance_chain(state, n->get_path_to(p_node), states_stack)) {
+					if (r_instanced_by_owner) {
+						*r_instanced_by_owner = false;
+					}
+				}
+				break;
+			} else if (n->get_filename() != String()) {
+				const Ref<SceneState> &state = n->get_scene_instance_state();
+				_collect_inheritance_chain(state, n->get_path_to(p_node), states_stack);
+			}
+			n = n->get_owner();
+		}
+	}
+
+	// Convert to the proper type for returning, inverting the vector on the go
+	// (it was more convenient to fill the vector in reverse order)
+	Vector<SceneState::PackState> states_stack_ret;
+	{
+		states_stack_ret.resize(states_stack.size());
+		_FastPackState *ps = states_stack.ptr();
+		for (int i = states_stack.size() - 1; i >= 0; --i) {
+			states_stack_ret.write[i].state.reference_ptr(ps->state);
+			states_stack_ret.write[i].node = ps->node;
+			++ps;
+		}
+	}
+	return states_stack_ret;
+}
diff --git a/scene/property_utils.h b/scene/property_utils.h
new file mode 100644
index 000000000000..2a1151fc8861
--- /dev/null
+++ b/scene/property_utils.h
@@ -0,0 +1,51 @@
+/*************************************************************************/
+/*  property_utils.h                                                     */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef PROPERTY_UTILS_H
+#define PROPERTY_UTILS_H
+
+#include "scene/main/node.h"
+#include "scene/resources/packed_scene.h"
+
+class PropertyUtils {
+public:
+	static bool is_property_value_different(const Variant &p_a, const Variant &p_b);
+	// Gets the most pure default value, the one that would be set when the node has just been instantiated
+	static Variant get_property_default_value(const Object *p_object, const StringName &p_property, const Vector<SceneState::PackState> *p_states_stack_cache = nullptr, bool p_update_exports = false, const Node *p_owner = nullptr, bool *r_is_class_default = nullptr);
+
+	// Gets the instance/inheritance states of this node, in order of precedence,
+	// that is, from the topmost (the most able to override values) to the lowermost
+	// (Note that in nested instancing the one with the greatest precedence is the furthest
+	// in the tree, since every owner found while traversing towards the root gets a chance
+	// to override property values.)
+	static Vector<SceneState::PackState> get_node_states_stack(const Node *p_node, const Node *p_owner = nullptr, bool *r_instanced_by_owner = nullptr);
+};
+
+#endif // PROPERTY_UTILS_H
diff --git a/scene/resources/packed_scene.cpp b/scene/resources/packed_scene.cpp
index cf4b799bfd9a..6692619c17fa 100644
--- a/scene/resources/packed_scene.cpp
+++ b/scene/resources/packed_scene.cpp
@@ -34,10 +34,12 @@
 #include "core/engine.h"
 #include "core/io/resource_loader.h"
 #include "core/project_settings.h"
+#include "editor/editor_inspector.h"
 #include "scene/2d/node_2d.h"
 #include "scene/3d/spatial.h"
 #include "scene/gui/control.h"
 #include "scene/main/instance_placeholder.h"
+#include "scene/property_utils.h"
 
 #define PACKED_SCENE_VERSION 2
 
@@ -413,61 +415,22 @@ Error SceneState::_parse_node(Node *p_owner, Node *p_node, int p_parent_idx, Map
 	// with the instance states, we can query for identical properties/groups
 	// and only save what has changed
 
-	List<PackState> pack_state_stack;
-
-	bool instanced_by_owner = true;
-
-	{
-		Node *n = p_node;
-
-		while (n) {
-			if (n == p_owner) {
-				Ref<SceneState> state = n->get_scene_inherited_state();
-				if (state.is_valid()) {
-					int node = state->find_node_by_path(n->get_path_to(p_node));
-					if (node >= 0) {
-						//this one has state for this node, save
-						PackState ps;
-						ps.node = node;
-						ps.state = state;
-						pack_state_stack.push_back(ps);
-						instanced_by_owner = false;
-					}
-				}
-
-				if (p_node->get_filename() != String() && p_node->get_owner() == p_owner && instanced_by_owner) {
-					if (p_node->get_scene_instance_load_placeholder()) {
-						//it's a placeholder, use the placeholder path
-						nd.instance = _vm_get_variant(p_node->get_filename(), variant_map);
-						nd.instance |= FLAG_INSTANCE_IS_PLACEHOLDER;
-					} else {
-						//must instance ourselves
-						Ref<PackedScene> instance = ResourceLoader::load(p_node->get_filename());
-						if (!instance.is_valid()) {
-							return ERR_CANT_OPEN;
-						}
+	bool instanced_by_owner = false;
+	Vector<SceneState::PackState> states_stack = PropertyUtils::get_node_states_stack(p_node, p_owner, &instanced_by_owner);
 
-						nd.instance = _vm_get_variant(instance, variant_map);
-					}
-				}
-				n = nullptr;
-			} else {
-				if (n->get_filename() != String()) {
-					//is an instance
-					Ref<SceneState> state = n->get_scene_instance_state();
-					if (state.is_valid()) {
-						int node = state->find_node_by_path(n->get_path_to(p_node));
-						if (node >= 0) {
-							//this one has state for this node, save
-							PackState ps;
-							ps.node = node;
-							ps.state = state;
-							pack_state_stack.push_back(ps);
-						}
-					}
-				}
-				n = n->get_owner();
+	if (p_node->get_filename() != String() && p_node->get_owner() == p_owner && instanced_by_owner) {
+		if (p_node->get_scene_instance_load_placeholder()) {
+			//it's a placeholder, use the placeholder path
+			nd.instance = _vm_get_variant(p_node->get_filename(), variant_map);
+			nd.instance |= FLAG_INSTANCE_IS_PLACEHOLDER;
+		} else {
+			//must instance ourselves
+			Ref<PackedScene> instance = ResourceLoader::load(p_node->get_filename());
+			if (!instance.is_valid()) {
+				return ERR_CANT_OPEN;
 			}
+
+			nd.instance = _vm_get_variant(instance, variant_map);
 		}
 	}
 
@@ -476,90 +439,23 @@ Error SceneState::_parse_node(Node *p_owner, Node *p_node, int p_parent_idx, Map
 
 	List<PropertyInfo> plist;
 	p_node->get_property_list(&plist);
-	StringName type = p_node->get_class();
-
-	Ref<Script> script = p_node->get_script();
-	if (Engine::get_singleton()->is_editor_hint() && script.is_valid()) {
-		// Should be called in the editor only and not at runtime,
-		// otherwise it can cause problems because of missing instance state support.
-		script->update_exports();
-	}
 
 	for (List<PropertyInfo>::Element *E = plist.front(); E; E = E->next()) {
 		if (!(E->get().usage & PROPERTY_USAGE_STORAGE)) {
 			continue;
 		}
 
-		String name = E->get().name;
-		Variant value = p_node->get(E->get().name);
-
-		bool isdefault = false;
-		Variant default_value = ClassDB::class_get_default_property_value(type, name);
-
-		if (default_value.get_type() != Variant::NIL) {
-			isdefault = bool(Variant::evaluate(Variant::OP_EQUAL, value, default_value));
+		// If instance or inheriting, not saving if property requested so, or it's meta
+		if (states_stack.size() && ((E->get().usage & PROPERTY_USAGE_NO_INSTANCE_STATE) || E->get().name == "__meta__")) {
+			continue;
 		}
 
-		if (!isdefault && script.is_valid() && script->get_property_default_value(name, default_value)) {
-			isdefault = bool(Variant::evaluate(Variant::OP_EQUAL, value, default_value));
-		}
-		// the version above makes more sense, because it does not rely on placeholder or usage flag
-		// in the script, just the default value function.
-		// if (E->get().usage & PROPERTY_USAGE_SCRIPT_DEFAULT_VALUE) {
-		// 	isdefault = true; //is script default value
-		// }
-
-		if (pack_state_stack.size()) {
-			// we are on part of an instanced subscene
-			// or part of instanced scene.
-			// only save what has been changed
-			// only save changed properties in instance
-
-			if ((E->get().usage & PROPERTY_USAGE_NO_INSTANCE_STATE) || E->get().name == "__meta__") {
-				//property has requested that no instance state is saved, sorry
-				//also, meta won't be overridden or saved
-				continue;
-			}
-
-			bool exists = false;
-			Variant original;
-
-			for (List<PackState>::Element *F = pack_state_stack.back(); F; F = F->prev()) {
-				//check all levels of pack to see if the property exists somewhere
-				const PackState &ps = F->get();
-
-				original = ps.state->get_property_value(ps.node, E->get().name, exists);
-				if (exists) {
-					break;
-				}
-			}
-
-			if (exists) {
-				//check if already exists and did not change
-				if (value.get_type() == Variant::REAL && original.get_type() == Variant::REAL) {
-					//this must be done because, as some scenes save as text, there might be a tiny difference in floats due to numerical error
-					float a = value;
-					float b = original;
-
-					if (Math::is_equal_approx(a, b)) {
-						continue;
-					}
-				} else if (bool(Variant::evaluate(Variant::OP_EQUAL, value, original))) {
-					continue;
-				}
-			}
-
-			if (!exists && isdefault) {
-				//does not exist in original node, but it's the default value
-				//so safe to skip too.
-				continue;
-			}
+		String name = E->get().name;
+		Variant value = p_node->get(name);
 
-		} else {
-			if (isdefault) {
-				//it's the default value, no point in saving it
-				continue;
-			}
+		Variant default_value = PropertyUtils::get_property_default_value(p_node, name, &states_stack, true);
+		if (!PropertyUtils::is_property_value_different(value, default_value)) {
+			continue;
 		}
 
 		NodeData::Property prop;
@@ -585,10 +481,10 @@ Error SceneState::_parse_node(Node *p_owner, Node *p_node, int p_parent_idx, Map
 		*/
 
 		bool skip = false;
-		for (List<PackState>::Element *F = pack_state_stack.front(); F; F = F->next()) {
+		for (int i = 0; i < states_stack.size(); ++i) {
+			const auto &ia = states_stack[i];
 			//check all levels of pack to see if the group was added somewhere
-			const PackState &ps = F->get();
-			if (ps.state->is_node_in_group(ps.node, gi.name)) {
+			if (ia.state->is_node_in_group(ia.node, gi.name)) {
 				skip = true;
 				break;
 			}
@@ -618,7 +514,7 @@ Error SceneState::_parse_node(Node *p_owner, Node *p_node, int p_parent_idx, Map
 
 	// Save the right type. If this node was created by an instance
 	// then flag that the node should not be created but reused
-	if (pack_state_stack.empty() && !is_editable_instance) {
+	if (states_stack.empty() && !is_editable_instance) {
 		//this node is not part of an instancing process, so save the type
 		nd.type = _nm_get_string(p_node->get_class(), name_map);
 	} else {
@@ -932,7 +828,7 @@ void SceneState::clear() {
 	base_scene_idx = -1;
 }
 
-Ref<SceneState> SceneState::_get_base_scene_state() const {
+Ref<SceneState> SceneState::get_base_scene_state() const {
 	if (base_scene_idx >= 0) {
 		Ref<PackedScene> ps = variants[base_scene_idx];
 		if (ps.is_valid()) {
@@ -947,8 +843,8 @@ int SceneState::find_node_by_path(const NodePath &p_node) const {
 	ERR_FAIL_COND_V_MSG(node_path_cache.size() == 0, -1, "This operation requires the node cache to have been built.");
 
 	if (!node_path_cache.has(p_node)) {
-		if (_get_base_scene_state().is_valid()) {
-			int idx = _get_base_scene_state()->find_node_by_path(p_node);
+		if (get_base_scene_state().is_valid()) {
+			int idx = get_base_scene_state()->find_node_by_path(p_node);
 			if (idx != -1) {
 				int rkey = _find_base_scene_node_remap_key(idx);
 				if (rkey == -1) {
@@ -963,11 +859,11 @@ int SceneState::find_node_by_path(const NodePath &p_node) const {
 
 	int nid = node_path_cache[p_node];
 
-	if (_get_base_scene_state().is_valid() && !base_scene_node_remap.has(nid)) {
+	if (get_base_scene_state().is_valid() && !base_scene_node_remap.has(nid)) {
 		//for nodes that _do_ exist in current scene, still try to look for
 		//the node in the instanced scene, as a property may be missing
 		//from the local one
-		int idx = _get_base_scene_state()->find_node_by_path(p_node);
+		int idx = get_base_scene_state()->find_node_by_path(p_node);
 		if (idx != -1) {
 			base_scene_node_remap[nid] = idx;
 		}
@@ -1007,7 +903,7 @@ Variant SceneState::get_property_value(int p_node, const StringName &p_property,
 	//property not found, try on instance
 
 	if (base_scene_node_remap.has(p_node)) {
-		return _get_base_scene_state()->get_property_value(base_scene_node_remap[p_node], p_property, found);
+		return get_base_scene_state()->get_property_value(base_scene_node_remap[p_node], p_property, found);
 	}
 
 	return Variant();
@@ -1026,7 +922,7 @@ bool SceneState::is_node_in_group(int p_node, const StringName &p_group) const {
 	}
 
 	if (base_scene_node_remap.has(p_node)) {
-		return _get_base_scene_state()->is_node_in_group(base_scene_node_remap[p_node], p_group);
+		return get_base_scene_state()->is_node_in_group(base_scene_node_remap[p_node], p_group);
 	}
 
 	return false;
@@ -1065,7 +961,7 @@ bool SceneState::is_connection(int p_node, const StringName &p_signal, int p_to_
 	}
 
 	if (base_scene_node_remap.has(p_node) && base_scene_node_remap.has(p_to_node)) {
-		return _get_base_scene_state()->is_connection(base_scene_node_remap[p_node], p_signal, base_scene_node_remap[p_to_node], p_to_method);
+		return get_base_scene_state()->is_connection(base_scene_node_remap[p_node], p_signal, base_scene_node_remap[p_to_node], p_to_method);
 	}
 
 	return false;
@@ -1483,7 +1379,7 @@ bool SceneState::has_connection(const NodePath &p_node_from, const StringName &p
 			}
 		}
 
-		ss = ss->_get_base_scene_state();
+		ss = ss->get_base_scene_state();
 	} while (ss.is_valid());
 
 	return false;
diff --git a/scene/resources/packed_scene.h b/scene/resources/packed_scene.h
index 68d7d232d310..11365728ffd6 100644
--- a/scene/resources/packed_scene.h
+++ b/scene/resources/packed_scene.h
@@ -69,12 +69,6 @@ class SceneState : public Reference {
 		Vector<int> groups;
 	};
 
-	struct PackState {
-		Ref<SceneState> state;
-		int node;
-		PackState() { node = -1; }
-	};
-
 	Vector<NodeData> nodes;
 
 	struct ConnectionData {
@@ -95,8 +89,6 @@ class SceneState : public Reference {
 
 	uint64_t last_modified_time;
 
-	_FORCE_INLINE_ Ref<SceneState> _get_base_scene_state() const;
-
 	static bool disable_placeholders;
 
 	PoolVector<String> _get_node_groups(int p_idx) const;
@@ -120,6 +112,11 @@ class SceneState : public Reference {
 		GEN_EDIT_STATE_MAIN,
 	};
 
+	struct PackState {
+		Ref<SceneState> state;
+		int node = -1;
+	};
+
 	static void set_disable_placeholders(bool p_disable);
 
 	int find_node_by_path(const NodePath &p_node) const;
@@ -140,6 +137,8 @@ class SceneState : public Reference {
 	bool can_instance() const;
 	Node *instance(GenEditState p_edit_state) const;
 
+	Ref<SceneState> get_base_scene_state() const;
+
 	//unbuild API
 
 	int get_node_count() const;

From 4dba25b3ff7683425692fb0d89c79895de8337fc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pedro=20J=2E=20Est=C3=A9banez?= <pedrojrulez@gmail.com>
Date: Tue, 26 Oct 2021 21:12:35 +0200
Subject: [PATCH 2/2] Add property value pinning

---
 doc/classes/EditorProperty.xml   |  10 +-
 doc/classes/PackedScene.xml      |   4 +
 doc/classes/SceneState.xml       |   4 +
 editor/editor_inspector.cpp      | 165 +++++++++++++++++++++++++++++--
 editor/editor_inspector.h        |  17 +++-
 editor/editor_node.cpp           |   2 +-
 scene/2d/node_2d.cpp             |  10 ++
 scene/2d/node_2d.h               |   4 +
 scene/main/canvas_layer.cpp      |  10 ++
 scene/main/canvas_layer.h        |   4 +
 scene/main/node.cpp              |  54 ++++++++++
 scene/main/node.h                |   7 ++
 scene/resources/packed_scene.cpp |  63 ++++++++++--
 scene/resources/packed_scene.h   |   2 +
 14 files changed, 335 insertions(+), 21 deletions(-)

diff --git a/doc/classes/EditorProperty.xml b/doc/classes/EditorProperty.xml
index 10b170f99d70..568c5341d928 100644
--- a/doc/classes/EditorProperty.xml
+++ b/doc/classes/EditorProperty.xml
@@ -102,7 +102,7 @@
 		</signal>
 		<signal name="property_checked">
 			<argument index="0" name="property" type="String" />
-			<argument index="1" name="bool" type="String" />
+			<argument index="1" name="checked" type="bool" />
 			<description>
 				Emitted when a property was checked. Used internally.
 			</description>
@@ -120,6 +120,14 @@
 				Emit it if you want to key a property with a single value.
 			</description>
 		</signal>
+		<signal name="property_pinned">
+			<argument index="0" name="property" type="String" />
+			<argument index="1" name="pinned" type="bool" />
+			<description>
+				Emit it if you want to mark (or unmark) the value of a property for being saved regardless of being equal to the default value.
+				The default value is the one the property will get when the node is just instantiated and can come from an ancestor scene in the inheritance/instancing chain, a script or a builtin class.
+			</description>
+		</signal>
 		<signal name="resource_selected">
 			<argument index="0" name="path" type="String" />
 			<argument index="1" name="resource" type="Resource" />
diff --git a/doc/classes/PackedScene.xml b/doc/classes/PackedScene.xml
index 6c2728dd422a..84b7505261c0 100644
--- a/doc/classes/PackedScene.xml
+++ b/doc/classes/PackedScene.xml
@@ -86,5 +86,9 @@
 			If passed to [method instance], provides local scene resources to the local scene. Only the main scene should receive the main edit state.
 			[b]Note:[/b] Only available in editor builds.
 		</constant>
+		<constant name="GEN_EDIT_STATE_MAIN_INHERITED" value="3" enum="GenEditState">
+			It's similar to [constant GEN_EDIT_STATE_MAIN], but for the case where the scene is being instantiated to be the base of another one.
+			[b]Note:[/b] Only available in editor builds.
+		</constant>
 	</constants>
 </class>
diff --git a/doc/classes/SceneState.xml b/doc/classes/SceneState.xml
index 040cf8d86a49..01d3337b438c 100644
--- a/doc/classes/SceneState.xml
+++ b/doc/classes/SceneState.xml
@@ -168,5 +168,9 @@
 			If passed to [method PackedScene.instance], provides local scene resources to the local scene. Only the main scene should receive the main edit state.
 			[b]Note:[/b] Only available in editor builds.
 		</constant>
+		<constant name="GEN_EDIT_STATE_MAIN_INHERITED" value="3" enum="GenEditState">
+			If passed to [method PackedScene.instance], it's similar to [constant GEN_EDIT_STATE_MAIN], but for the case where the scene is being instantiated to be the base of another one.
+			[b]Note:[/b] Only available in editor builds.
+		</constant>
 	</constants>
 </class>
diff --git a/editor/editor_inspector.cpp b/editor/editor_inspector.cpp
index 5986bce1c3c1..487dbbc3a86c 100644
--- a/editor/editor_inspector.cpp
+++ b/editor/editor_inspector.cpp
@@ -261,6 +261,14 @@ void EditorProperty::_notification(int p_what) {
 			revert_rect = Rect2();
 		}
 
+		if (!pin_hidden && is_pinned) {
+			Ref<Texture> pinned_icon = get_icon("Pin", "EditorIcons");
+			int margin_w = get_constant("hseparator", "Tree") * 2;
+			text_limit -= margin_w + pinned_icon->get_width();
+			int text_w = MIN(font->get_string_size(label).x, text_limit);
+			draw_texture(pinned_icon, Vector2(ofs + text_w + margin_w, (size.height - pinned_icon->get_height()) / 2), color);
+		}
+
 		int v_ofs = (size.height - font->get_height()) / 2;
 		draw_string(font, Point2(ofs, v_ofs + font->get_ascent()), label, color, text_limit);
 
@@ -337,15 +345,22 @@ bool EditorPropertyRevert::can_property_revert(Object *p_object, const StringNam
 	return PropertyUtils::is_property_value_different(current_value, revert_value);
 }
 
-void EditorProperty::update_reload_status() {
+void EditorProperty::update_revert_and_pin_status() {
 	if (property == StringName()) {
 		return; //no property, so nothing to do
 	}
 
+	bool new_is_pinned = false;
+	if (can_pin) {
+		Node *node = Object::cast_to<Node>(object);
+		CRASH_COND(!node);
+		new_is_pinned = node->is_property_pinned(property);
+	}
 	bool new_can_revert = EditorPropertyRevert::can_property_revert(object, property);
 
-	if (new_can_revert != can_revert) {
+	if (new_can_revert != can_revert || new_is_pinned != is_pinned) {
 		can_revert = new_can_revert;
+		is_pinned = new_is_pinned;
 		update();
 	}
 }
@@ -516,6 +531,14 @@ void EditorProperty::_gui_input(const Ref<InputEvent> &p_event) {
 			update();
 			emit_signal("property_checked", property, checked);
 		}
+	} else if (mb.is_valid() && mb->is_pressed() && mb->get_button_index() == BUTTON_RIGHT) {
+		_update_popup();
+		if (menu->get_item_count()) {
+			menu->set_position(get_global_mouse_position());
+			menu->set_as_minsize();
+			menu->popup();
+			select();
+		}
 	}
 }
 
@@ -575,6 +598,56 @@ float EditorProperty::get_name_split_ratio() const {
 void EditorProperty::set_object_and_property(Object *p_object, const StringName &p_property) {
 	object = p_object;
 	property = p_property;
+	_update_pin_flags();
+}
+
+static bool _is_value_potential_override(Node *p_node, const String &p_property) {
+	// Consider a value is potentially overriding another if either of the following is true:
+	// a) The node is foreign (inheriting or an instance), so the original value may come from another scene.
+	// b) The node belongs to the scene, but the original value comes from somewhere but the builtin class (i.e., a script).
+	Node *edited_scene = EditorNode::get_singleton()->get_edited_scene();
+	Vector<SceneState::PackState> states_stack = PropertyUtils::get_node_states_stack(p_node, edited_scene);
+	if (states_stack.size()) {
+		return true;
+	} else {
+		bool is_class_default = false;
+		PropertyUtils::get_property_default_value(p_node, p_property, &states_stack, false, nullptr, &is_class_default);
+		return !is_class_default;
+	}
+}
+
+void EditorProperty::_update_pin_flags() {
+	can_pin = false;
+	pin_hidden = true;
+	if (read_only) {
+		return;
+	}
+	if (Node *node = Object::cast_to<Node>(object)) {
+		// Avoid errors down the road by ignoring nodes which are not part of a scene
+		if (!node->get_owner()) {
+			bool is_scene_root = false;
+			for (int i = 0; i < EditorNode::get_singleton()->get_editor_data().get_edited_scene_count(); ++i) {
+				if (EditorNode::get_singleton()->get_editor_data().get_edited_scene_root(i) == node) {
+					is_scene_root = true;
+					break;
+				}
+			}
+			if (!is_scene_root) {
+				return;
+			}
+		}
+		if (!_is_value_potential_override(node, property)) {
+			return;
+		}
+		pin_hidden = false;
+		{
+			Set<StringName> storable_properties;
+			node->get_storable_properties(storable_properties);
+			if (storable_properties.has(node->get_property_store_alias(property))) {
+				can_pin = true;
+			}
+		}
+	}
 }
 
 Control *EditorProperty::make_custom_tooltip(const String &p_text) const {
@@ -627,6 +700,7 @@ void EditorProperty::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_edited_object"), &EditorProperty::get_edited_object);
 
 	ClassDB::bind_method(D_METHOD("_gui_input"), &EditorProperty::_gui_input);
+	ClassDB::bind_method(D_METHOD("_menu_option"), &EditorProperty::_menu_option);
 	ClassDB::bind_method(D_METHOD("_focusable_focused"), &EditorProperty::_focusable_focused);
 
 	ClassDB::bind_method(D_METHOD("get_tooltip_text"), &EditorProperty::get_tooltip_text);
@@ -646,7 +720,8 @@ void EditorProperty::_bind_methods() {
 	ADD_SIGNAL(MethodInfo("multiple_properties_changed", PropertyInfo(Variant::POOL_STRING_ARRAY, "properties"), PropertyInfo(Variant::ARRAY, "value")));
 	ADD_SIGNAL(MethodInfo("property_keyed", PropertyInfo(Variant::STRING, "property")));
 	ADD_SIGNAL(MethodInfo("property_keyed_with_value", PropertyInfo(Variant::STRING, "property"), PropertyInfo(Variant::NIL, "value", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NIL_IS_VARIANT)));
-	ADD_SIGNAL(MethodInfo("property_checked", PropertyInfo(Variant::STRING, "property"), PropertyInfo(Variant::STRING, "bool")));
+	ADD_SIGNAL(MethodInfo("property_checked", PropertyInfo(Variant::STRING, "property"), PropertyInfo(Variant::BOOL, "checked")));
+	ADD_SIGNAL(MethodInfo("property_pinned", PropertyInfo(Variant::STRING, "property"), PropertyInfo(Variant::BOOL, "pinned")));
 	ADD_SIGNAL(MethodInfo("resource_selected", PropertyInfo(Variant::STRING, "path"), PropertyInfo(Variant::OBJECT, "resource", PROPERTY_HINT_RESOURCE_TYPE, "Resource")));
 	ADD_SIGNAL(MethodInfo("object_id_selected", PropertyInfo(Variant::STRING, "property"), PropertyInfo(Variant::INT, "id")));
 	ADD_SIGNAL(MethodInfo("selected", PropertyInfo(Variant::STRING, "path"), PropertyInfo(Variant::INT, "focusable_idx")));
@@ -654,6 +729,8 @@ void EditorProperty::_bind_methods() {
 	MethodInfo vm;
 	vm.name = "update_property";
 	BIND_VMETHOD(vm);
+
+	ClassDB::bind_method(D_METHOD("_update_revert_and_pin_status"), &EditorProperty::update_revert_and_pin_status);
 }
 
 EditorProperty::EditorProperty() {
@@ -671,13 +748,47 @@ EditorProperty::EditorProperty() {
 	revert_hover = false;
 	check_hover = false;
 	can_revert = false;
+	can_pin = false;
+	pin_hidden = false;
+	is_pinned = false;
 	use_folding = false;
 	property_usage = 0;
 	selected = false;
 	selected_focusable = -1;
 	label_reference = nullptr;
 	bottom_editor = nullptr;
+	menu = nullptr;
 }
+
+void EditorProperty::_update_popup() {
+	if (menu) {
+		menu->clear();
+	} else {
+		menu = memnew(PopupMenu);
+		add_child(menu);
+		menu->connect("id_pressed", this, "_menu_option");
+	}
+	if (!pin_hidden) {
+		if (can_pin) {
+			menu->add_check_item(TTR("Pin value"), MENU_PIN_VALUE);
+			menu->set_item_checked(menu->get_item_index(MENU_PIN_VALUE), is_pinned);
+			menu->set_item_tooltip(menu->get_item_index(MENU_PIN_VALUE), TTR("Pinning a value forces it to be saved even if it's equal to the default."));
+		} else {
+			menu->add_check_item(vformat(TTR("Pin value [Disabled because '%s' is editor-only]"), property), MENU_PIN_VALUE);
+			menu->set_item_disabled(menu->get_item_index(MENU_PIN_VALUE), true);
+		}
+	}
+}
+
+void EditorProperty::_menu_option(int p_option) {
+	switch (p_option) {
+		case MENU_PIN_VALUE: {
+			emit_signal("property_pinned", property, !is_pinned);
+			update();
+		} break;
+	}
+}
+
 ////////////////////////////////////////////////
 ////////////////////////////////////////////////
 
@@ -1142,6 +1253,7 @@ void EditorInspector::_parse_added_editors(VBoxContainer *current_vbox, Ref<Edit
 			ep->connect("property_keyed", this, "_property_keyed");
 			ep->connect("property_keyed_with_value", this, "_property_keyed_with_value");
 			ep->connect("property_checked", this, "_property_checked");
+			ep->connect("property_pinned", this, "_property_pinned");
 			ep->connect("selected", this, "_property_selected");
 			ep->connect("multiple_properties_changed", this, "_multiple_properties_changed");
 			ep->connect("resource_selected", this, "_resource_selected", varray(), CONNECT_DEFERRED);
@@ -1170,7 +1282,8 @@ void EditorInspector::_parse_added_editors(VBoxContainer *current_vbox, Ref<Edit
 
 			ep->set_read_only(read_only);
 			ep->update_property();
-			ep->update_reload_status();
+			ep->_update_pin_flags();
+			ep->update_revert_and_pin_status();
 		}
 	}
 	ped->added_editors.clear();
@@ -1566,6 +1679,7 @@ void EditorInspector::update_tree() {
 					ep->connect("property_keyed", this, "_property_keyed");
 					ep->connect("property_keyed_with_value", this, "_property_keyed_with_value");
 					ep->connect("property_checked", this, "_property_checked");
+					ep->connect("property_pinned", this, "_property_pinned");
 					ep->connect("selected", this, "_property_selected");
 					ep->connect("multiple_properties_changed", this, "_multiple_properties_changed");
 					ep->connect("resource_selected", this, "_resource_selected", varray(), CONNECT_DEFERRED);
@@ -1576,7 +1690,8 @@ void EditorInspector::update_tree() {
 						ep->set_tooltip(property_prefix + p.name);
 					}
 					ep->update_property();
-					ep->update_reload_status();
+					ep->_update_pin_flags();
+					ep->update_revert_and_pin_status();
 
 					if (current_selected && ep->property == current_selected) {
 						ep->select(current_focusable);
@@ -1605,7 +1720,7 @@ void EditorInspector::update_property(const String &p_prop) {
 
 	for (List<EditorProperty *>::Element *E = editor_property_map[p_prop].front(); E; E = E->next()) {
 		E->get()->update_property();
-		E->get()->update_reload_status();
+		E->get()->update_revert_and_pin_status();
 	}
 }
 
@@ -1844,7 +1959,7 @@ void EditorInspector::_edit_set(const String &p_name, const Variant &p_value, bo
 
 	if (editor_property_map.has(p_name)) {
 		for (List<EditorProperty *>::Element *E = editor_property_map[p_name].front(); E; E = E->next()) {
-			E->get()->update_reload_status();
+			E->get()->update_revert_and_pin_status();
 		}
 	}
 }
@@ -1935,7 +2050,7 @@ void EditorInspector::_property_checked(const String &p_path, bool p_checked) {
 		if (editor_property_map.has(p_path)) {
 			for (List<EditorProperty *>::Element *E = editor_property_map[p_path].front(); E; E = E->next()) {
 				E->get()->update_property();
-				E->get()->update_reload_status();
+				E->get()->update_revert_and_pin_status();
 			}
 		}
 
@@ -1944,6 +2059,35 @@ void EditorInspector::_property_checked(const String &p_path, bool p_checked) {
 	}
 }
 
+void EditorInspector::_property_pinned(const String &p_path, bool p_pinned) {
+	if (!object) {
+		return;
+	}
+
+	Node *node = Object::cast_to<Node>(object);
+	ERR_FAIL_COND(!node);
+
+	if (undo_redo) {
+		undo_redo->create_action(vformat(p_pinned ? TTR("Pinned %s") : TTR("Unpinned %s"), p_path));
+		undo_redo->add_do_method(node, "_set_property_pinned", p_path, p_pinned);
+		undo_redo->add_undo_method(node, "_set_property_pinned", p_path, !p_pinned);
+		if (editor_property_map.has(p_path)) {
+			for (List<EditorProperty *>::Element *E = editor_property_map[p_path].front(); E; E = E->next()) {
+				undo_redo->add_do_method(E->get(), "_update_revert_and_pin_status");
+				undo_redo->add_undo_method(E->get(), "_update_revert_and_pin_status");
+			}
+		}
+		undo_redo->commit_action();
+	} else {
+		node->set_property_pinned(p_path, p_pinned);
+		if (editor_property_map.has(p_path)) {
+			for (List<EditorProperty *>::Element *E = editor_property_map[p_path].front(); E; E = E->next()) {
+				E->get()->update_revert_and_pin_status();
+			}
+		}
+	}
+}
+
 void EditorInspector::_property_selected(const String &p_path, int p_focusable) {
 	property_selected = p_path;
 	property_focusable = p_focusable;
@@ -2008,7 +2152,7 @@ void EditorInspector::_notification(int p_what) {
 				for (Map<StringName, List<EditorProperty *>>::Element *F = editor_property_map.front(); F; F = F->next()) {
 					for (List<EditorProperty *>::Element *E = F->get().front(); E; E = E->next()) {
 						E->get()->update_property();
-						E->get()->update_reload_status();
+						E->get()->update_revert_and_pin_status();
 					}
 				}
 			}
@@ -2027,7 +2171,7 @@ void EditorInspector::_notification(int p_what) {
 				if (editor_property_map.has(prop)) {
 					for (List<EditorProperty *>::Element *E = editor_property_map[prop].front(); E; E = E->next()) {
 						E->get()->update_property();
-						E->get()->update_reload_status();
+						E->get()->update_revert_and_pin_status();
 					}
 				}
 				pending.erase(pending.front());
@@ -2090,6 +2234,7 @@ void EditorInspector::_bind_methods() {
 	ClassDB::bind_method("_property_keyed", &EditorInspector::_property_keyed);
 	ClassDB::bind_method("_property_keyed_with_value", &EditorInspector::_property_keyed_with_value);
 	ClassDB::bind_method("_property_checked", &EditorInspector::_property_checked);
+	ClassDB::bind_method("_property_pinned", &EditorInspector::_property_pinned);
 	ClassDB::bind_method("_property_selected", &EditorInspector::_property_selected);
 	ClassDB::bind_method("_resource_selected", &EditorInspector::_resource_selected);
 	ClassDB::bind_method("_object_id_selected", &EditorInspector::_object_id_selected);
diff --git a/editor/editor_inspector.h b/editor/editor_inspector.h
index bf27ccfd97c8..e65acb4d7583 100644
--- a/editor/editor_inspector.h
+++ b/editor/editor_inspector.h
@@ -50,6 +50,11 @@ class EditorPropertyRevert {
 class EditorProperty : public Container {
 	GDCLASS(EditorProperty, Container);
 
+public:
+	enum MenuItems {
+		MENU_PIN_VALUE,
+	};
+
 private:
 	String label;
 	int text_size;
@@ -76,10 +81,15 @@ class EditorProperty : public Container {
 	bool check_hover;
 
 	bool can_revert;
+	bool can_pin;
+	bool pin_hidden;
+	bool is_pinned;
 
 	bool use_folding;
 	bool draw_top_bg;
 
+	void _update_popup();
+	void _menu_option(int p_option);
 	void _focusable_focused(int p_index);
 
 	bool selectable;
@@ -91,9 +101,12 @@ class EditorProperty : public Container {
 	Vector<Control *> focusables;
 	Control *label_reference;
 	Control *bottom_editor;
+	PopupMenu *menu;
 
 	mutable String tooltip_text;
 
+	void _update_pin_flags();
+
 protected:
 	void _notification(int p_what);
 	static void _bind_methods();
@@ -115,7 +128,7 @@ class EditorProperty : public Container {
 	StringName get_edited_property();
 
 	virtual void update_property();
-	void update_reload_status();
+	void update_revert_and_pin_status();
 
 	virtual bool use_keying_next() const;
 
@@ -305,8 +318,8 @@ class EditorInspector : public ScrollContainer {
 	void _multiple_properties_changed(Vector<String> p_paths, Array p_values);
 	void _property_keyed(const String &p_path, bool p_advance);
 	void _property_keyed_with_value(const String &p_path, const Variant &p_value, bool p_advance);
-
 	void _property_checked(const String &p_path, bool p_checked);
+	void _property_pinned(const String &p_path, bool p_pinned);
 
 	void _resource_selected(const String &p_path, RES p_resource);
 	void _property_selected(const String &p_path, int p_focusable);
diff --git a/editor/editor_node.cpp b/editor/editor_node.cpp
index 2ac679257bbf..7ad39767950f 100644
--- a/editor/editor_node.cpp
+++ b/editor/editor_node.cpp
@@ -3588,7 +3588,7 @@ Error EditorNode::load_scene(const String &p_scene, bool p_ignore_broken_deps, b
 		sdata->set_path(lpath, true); //take over path
 	}
 
-	Node *new_scene = sdata->instance(PackedScene::GEN_EDIT_STATE_MAIN);
+	Node *new_scene = sdata->instance(p_set_inherited ? PackedScene::GEN_EDIT_STATE_MAIN_INHERITED : PackedScene::GEN_EDIT_STATE_MAIN);
 
 	if (!new_scene) {
 		sdata.unref();
diff --git a/scene/2d/node_2d.cpp b/scene/2d/node_2d.cpp
index edd8cb8cdf42..9425f33c25ca 100644
--- a/scene/2d/node_2d.cpp
+++ b/scene/2d/node_2d.cpp
@@ -439,6 +439,16 @@ void Node2D::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "z_as_relative"), "set_z_as_relative", "is_z_relative");
 }
 
+#ifdef TOOLS_ENABLED
+StringName Node2D::get_property_store_alias(const StringName &p_property) const {
+	if (p_property == "rotation_degrees") {
+		return "rotation";
+	} else {
+		return Node::get_property_store_alias(p_property);
+	}
+}
+#endif
+
 Node2D::Node2D() {
 	angle = 0;
 	_scale = Vector2(1, 1);
diff --git a/scene/2d/node_2d.h b/scene/2d/node_2d.h
index 631fc445ed39..3c29be14eb73 100644
--- a/scene/2d/node_2d.h
+++ b/scene/2d/node_2d.h
@@ -116,6 +116,10 @@ class Node2D : public CanvasItem {
 
 	Transform2D get_transform() const;
 
+#ifdef TOOLS_ENABLED
+	virtual StringName get_property_store_alias(const StringName &p_property) const;
+#endif
+
 	Node2D();
 };
 
diff --git a/scene/main/canvas_layer.cpp b/scene/main/canvas_layer.cpp
index b0c4a6d73cd6..153f3350309d 100644
--- a/scene/main/canvas_layer.cpp
+++ b/scene/main/canvas_layer.cpp
@@ -306,6 +306,16 @@ void CanvasLayer::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::REAL, "follow_viewport_scale", PROPERTY_HINT_RANGE, "0.001,1000,0.001,or_greater,or_lesser"), "set_follow_viewport_scale", "get_follow_viewport_scale");
 }
 
+#ifdef TOOLS_ENABLED
+StringName CanvasLayer::get_property_store_alias(const StringName &p_property) const {
+	if (p_property == "rotation_degrees") {
+		return "rotation";
+	} else {
+		return Node::get_property_store_alias(p_property);
+	}
+}
+#endif
+
 CanvasLayer::CanvasLayer() {
 	vp = nullptr;
 	scale = Vector2(1, 1);
diff --git a/scene/main/canvas_layer.h b/scene/main/canvas_layer.h
index cb10c6299b0a..7c8a4803bf06 100644
--- a/scene/main/canvas_layer.h
+++ b/scene/main/canvas_layer.h
@@ -102,6 +102,10 @@ class CanvasLayer : public Node {
 
 	RID get_canvas() const;
 
+#ifdef TOOLS_ENABLED
+	StringName get_property_store_alias(const StringName &p_property) const;
+#endif
+
 	CanvasLayer();
 	~CanvasLayer();
 };
diff --git a/scene/main/node.cpp b/scene/main/node.cpp
index dd06b9671e4b..0e2af71ce68b 100644
--- a/scene/main/node.cpp
+++ b/scene/main/node.cpp
@@ -1866,6 +1866,56 @@ Node *Node::get_deepest_editable_node(Node *p_start_node) const {
 	return node;
 }
 
+#ifdef TOOLS_ENABLED
+void Node::set_property_pinned(const StringName &p_property, bool p_pinned) {
+	bool current_pinned = false;
+	bool has_pinned = has_meta("_edit_pinned_properties_");
+	Array pinned;
+	String psa = get_property_store_alias(p_property);
+	if (has_pinned) {
+		pinned = get_meta("_edit_pinned_properties_");
+		current_pinned = pinned.has(psa);
+	}
+
+	if (current_pinned != p_pinned) {
+		if (p_pinned) {
+			pinned.append(psa);
+			if (!has_pinned) {
+				set_meta("_edit_pinned_properties_", pinned);
+			}
+		} else {
+			pinned.erase(psa);
+			if (pinned.empty()) {
+				remove_meta("_edit_pinned_properties_");
+			}
+		}
+	}
+}
+
+bool Node::is_property_pinned(const StringName &p_property) const {
+	if (!has_meta("_edit_pinned_properties_")) {
+		return false;
+	}
+	Array pinned = get_meta("_edit_pinned_properties_");
+	String psa = get_property_store_alias(p_property);
+	return pinned.has(psa);
+}
+
+StringName Node::get_property_store_alias(const StringName &p_property) const {
+	return p_property;
+}
+#endif
+
+void Node::get_storable_properties(Set<StringName> &r_storable_properties) const {
+	List<PropertyInfo> pi;
+	get_property_list(&pi);
+	for (List<PropertyInfo>::Element *E = pi.front(); E; E = E->next()) {
+		if ((E->get().usage & PROPERTY_USAGE_STORAGE)) {
+			r_storable_properties.insert(E->get().name);
+		}
+	}
+}
+
 String Node::to_string() {
 	if (get_script_instance()) {
 		bool valid;
@@ -2811,6 +2861,10 @@ void Node::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("_get_import_path"), &Node::get_import_path);
 	ADD_PROPERTY(PropertyInfo(Variant::NODE_PATH, "_import_path", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NOEDITOR | PROPERTY_USAGE_INTERNAL), "_set_import_path", "_get_import_path");
 
+#ifdef TOOLS_ENABLED
+	ClassDB::bind_method(D_METHOD("_set_property_pinned", "property", "pinned"), &Node::set_property_pinned);
+#endif
+
 	{
 		MethodInfo mi;
 
diff --git a/scene/main/node.h b/scene/main/node.h
index 28f68ba56955..1f37f2e6fca5 100644
--- a/scene/main/node.h
+++ b/scene/main/node.h
@@ -314,6 +314,13 @@ class Node : public Object {
 	bool is_editable_instance(const Node *p_node) const;
 	Node *get_deepest_editable_node(Node *start_node) const;
 
+#ifdef TOOLS_ENABLED
+	void set_property_pinned(const StringName &p_property, bool p_pinned);
+	bool is_property_pinned(const StringName &p_property) const;
+	virtual StringName get_property_store_alias(const StringName &p_property) const;
+#endif
+	void get_storable_properties(Set<StringName> &r_storable_properties) const;
+
 	virtual String to_string();
 
 	/* NOTIFICATIONS */
diff --git a/scene/resources/packed_scene.cpp b/scene/resources/packed_scene.cpp
index 6692619c17fa..d5a8c978e893 100644
--- a/scene/resources/packed_scene.cpp
+++ b/scene/resources/packed_scene.cpp
@@ -47,6 +47,30 @@ bool SceneState::can_instance() const {
 	return nodes.size() > 0;
 }
 
+static Array _sanitize_node_pinned_properties(Node *p_node) {
+	if (!p_node->has_meta("_edit_pinned_properties_")) {
+		return Array();
+	}
+	Array pinned = p_node->get_meta("_edit_pinned_properties_");
+	if (pinned.empty()) {
+		return Array();
+	}
+	Set<StringName> storable_properties;
+	p_node->get_storable_properties(storable_properties);
+	int i = 0;
+	do {
+		if (storable_properties.has(pinned[i])) {
+			i++;
+		} else {
+			pinned.remove(i);
+		}
+	} while (i < pinned.size());
+	if (pinned.empty()) {
+		p_node->remove_meta("_edit_pinned_properties_");
+	}
+	return pinned;
+}
+
 Node *SceneState::instance(GenEditState p_edit_state) const {
 	// nodes where instancing failed (because something is missing)
 	List<Node *> stray_instances;
@@ -227,7 +251,7 @@ Node *SceneState::instance(GenEditState p_edit_state) const {
 									} else {
 										Node *base = i == 0 ? node : ret_nodes[0];
 
-										if (p_edit_state == GEN_EDIT_STATE_MAIN) {
+										if (p_edit_state == GEN_EDIT_STATE_MAIN || p_edit_state == GEN_EDIT_STATE_MAIN_INHERITED) {
 											//for the main scene, use the resource as is
 											res->configure_for_local_scene(base, resources_local_to_scene);
 											resources_local_to_scene[res] = res;
@@ -291,6 +315,13 @@ Node *SceneState::instance(GenEditState p_edit_state) const {
 			}
 		}
 
+		// we only want to deal with pinned flag if instancing as pure main (no instance, no inheriting)
+		if (p_edit_state == GEN_EDIT_STATE_MAIN) {
+			_sanitize_node_pinned_properties(node);
+		} else {
+			node->remove_meta("_edit_pinned_properties_");
+		}
+
 		ret_nodes[i] = node;
 
 		if (node && gen_node_path_cache && ret_nodes[0]) {
@@ -440,22 +471,38 @@ Error SceneState::_parse_node(Node *p_owner, Node *p_node, int p_parent_idx, Map
 	List<PropertyInfo> plist;
 	p_node->get_property_list(&plist);
 
+	Array pinned_props = _sanitize_node_pinned_properties(p_node);
+
 	for (List<PropertyInfo>::Element *E = plist.front(); E; E = E->next()) {
 		if (!(E->get().usage & PROPERTY_USAGE_STORAGE)) {
 			continue;
 		}
 
+		Variant forced_value;
+
 		// If instance or inheriting, not saving if property requested so, or it's meta
-		if (states_stack.size() && ((E->get().usage & PROPERTY_USAGE_NO_INSTANCE_STATE) || E->get().name == "__meta__")) {
-			continue;
+		if (states_stack.size()) {
+			if ((E->get().usage & PROPERTY_USAGE_NO_INSTANCE_STATE)) {
+				continue;
+			}
+			// Meta is normally not saved in instances/inherited (see GH-12838), but we need to save the pinned list
+			if (E->get().name == "__meta__") {
+				if (pinned_props.size()) {
+					Dictionary meta_override;
+					meta_override["_edit_pinned_properties_"] = pinned_props;
+					forced_value = meta_override;
+				}
+			}
 		}
 
 		String name = E->get().name;
-		Variant value = p_node->get(name);
+		Variant value = forced_value.get_type() == Variant::NIL ? p_node->get(name) : forced_value;
 
-		Variant default_value = PropertyUtils::get_property_default_value(p_node, name, &states_stack, true);
-		if (!PropertyUtils::is_property_value_different(value, default_value)) {
-			continue;
+		if (!pinned_props.has(name) && forced_value.get_type() == Variant::NIL) {
+			Variant default_value = PropertyUtils::get_property_default_value(p_node, name, &states_stack, true);
+			if (!PropertyUtils::is_property_value_different(value, default_value)) {
+				continue;
+			}
 		}
 
 		NodeData::Property prop;
@@ -1504,6 +1551,7 @@ void SceneState::_bind_methods() {
 	BIND_ENUM_CONSTANT(GEN_EDIT_STATE_DISABLED);
 	BIND_ENUM_CONSTANT(GEN_EDIT_STATE_INSTANCE);
 	BIND_ENUM_CONSTANT(GEN_EDIT_STATE_MAIN);
+	BIND_ENUM_CONSTANT(GEN_EDIT_STATE_MAIN_INHERITED);
 }
 
 SceneState::SceneState() {
@@ -1594,6 +1642,7 @@ void PackedScene::_bind_methods() {
 	BIND_ENUM_CONSTANT(GEN_EDIT_STATE_DISABLED);
 	BIND_ENUM_CONSTANT(GEN_EDIT_STATE_INSTANCE);
 	BIND_ENUM_CONSTANT(GEN_EDIT_STATE_MAIN);
+	BIND_ENUM_CONSTANT(GEN_EDIT_STATE_MAIN_INHERITED);
 }
 
 PackedScene::PackedScene() {
diff --git a/scene/resources/packed_scene.h b/scene/resources/packed_scene.h
index 11365728ffd6..d09b94c1284f 100644
--- a/scene/resources/packed_scene.h
+++ b/scene/resources/packed_scene.h
@@ -110,6 +110,7 @@ class SceneState : public Reference {
 		GEN_EDIT_STATE_DISABLED,
 		GEN_EDIT_STATE_INSTANCE,
 		GEN_EDIT_STATE_MAIN,
+		GEN_EDIT_STATE_MAIN_INHERITED,
 	};
 
 	struct PackState {
@@ -207,6 +208,7 @@ class PackedScene : public Resource {
 		GEN_EDIT_STATE_DISABLED,
 		GEN_EDIT_STATE_INSTANCE,
 		GEN_EDIT_STATE_MAIN,
+		GEN_EDIT_STATE_MAIN_INHERITED,
 	};
 
 	Error pack(Node *p_scene);