Merge pull request #60597 from reduz/missing-node-resource-placeholders

7 files changed, 247 insertions, 24 deletions

diff --git a/core/io/missing_resource.cpp b/core/io/missing_resource.cpp
new file mode 100644
index 0000000000..7aae6c6f0a
--- /dev/null
+++ b/core/io/missing_resource.cpp
@@ -0,0 +1,90 @@
+/*************************************************************************/
+/*  missing_resource.cpp                                                 */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 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 "missing_resource.h"
+
+bool MissingResource::_set(const StringName &p_name, const Variant &p_value) {
+	if (is_recording_properties()) {
+		properties.insert(p_name, p_value);
+		return true; //always valid to set (add)
+	} else {
+		if (!properties.has(p_name)) {
+			return false;
+		}
+
+		properties[p_name] = p_value;
+		return true;
+	}
+}
+
+bool MissingResource::_get(const StringName &p_name, Variant &r_ret) const {
+	if (!properties.has(p_name)) {
+		return false;
+	}
+	r_ret = properties[p_name];
+	return true;
+}
+
+void MissingResource::_get_property_list(List<PropertyInfo> *p_list) const {
+	for (OrderedHashMap<StringName, Variant>::ConstElement E = properties.front(); E; E = E.next()) {
+		p_list->push_back(PropertyInfo(E.value().get_type(), E.key()));
+	}
+}
+
+void MissingResource::set_original_class(const String &p_class) {
+	original_class = p_class;
+}
+
+String MissingResource::get_original_class() const {
+	return original_class;
+}
+
+void MissingResource::set_recording_properties(bool p_enable) {
+	recording_properties = p_enable;
+}
+
+bool MissingResource::is_recording_properties() const {
+	return recording_properties;
+}
+
+void MissingResource::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_original_class", "name"), &MissingResource::set_original_class);
+	ClassDB::bind_method(D_METHOD("get_original_class"), &MissingResource::get_original_class);
+
+	ClassDB::bind_method(D_METHOD("set_recording_properties", "enable"), &MissingResource::set_recording_properties);
+	ClassDB::bind_method(D_METHOD("is_recording_properties"), &MissingResource::is_recording_properties);
+
+	// Expose, but not save.
+	ADD_PROPERTY(PropertyInfo(Variant::STRING, "original_class", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NONE), "set_original_class", "get_original_class");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "recording_properties", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NONE), "set_recording_properties", "is_recording_properties");
+}
+
+MissingResource::MissingResource() {
+}
diff --git a/core/io/missing_resource.h b/core/io/missing_resource.h
new file mode 100644
index 0000000000..e87efe1a98
--- /dev/null
+++ b/core/io/missing_resource.h
@@ -0,0 +1,63 @@
+/*************************************************************************/
+/*  missing_resource.h                                                   */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2022 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 MISSING_RESOURCE_H
+#define MISSING_RESOURCE_H
+
+#include "core/io/resource.h"
+
+#define META_PROPERTY_MISSING_RESOURCES "metadata/_missing_resources"
+#define META_MISSING_RESOURCES "_missing_resources"
+
+class MissingResource : public Resource {
+	GDCLASS(MissingResource, Resource)
+	OrderedHashMap<StringName, Variant> properties;
+
+	String original_class;
+	bool recording_properties = false;
+
+protected:
+	bool _set(const StringName &p_name, const Variant &p_value);
+	bool _get(const StringName &p_name, Variant &r_ret) const;
+	void _get_property_list(List<PropertyInfo> *p_list) const;
+
+	static void _bind_methods();
+
+public:
+	void set_original_class(const String &p_class);
+	String get_original_class() const;
+
+	void set_recording_properties(bool p_enable);
+	bool is_recording_properties() const;
+
+	MissingResource();
+};
+
+#endif // MISSING_RESOURCE_H
diff --git a/core/io/resource_format_binary.cpp b/core/io/resource_format_binary.cpp
index c9eb0e5234..fbb4293961 100644
--- a/core/io/resource_format_binary.cpp
+++ b/core/io/resource_format_binary.cpp
@@ -35,6 +35,7 @@
 #include "core/io/file_access_compressed.h"
 #include "core/io/image.h"
 #include "core/io/marshalls.h"
+#include "core/io/missing_resource.h"
 #include "core/version.h"
 
 //#define print_bl(m_what) print_line(m_what)
@@ -728,13 +729,23 @@ Error ResourceLoaderBinary::load() {
 			}
 		}
 
+		MissingResource *missing_resource = nullptr;
+
 		if (res.is_null()) {
 			//did not replace
 
 			Object *obj = ClassDB::instantiate(t);
 			if (!obj) {
-				error = ERR_FILE_CORRUPT;
-				ERR_FAIL_V_MSG(ERR_FILE_CORRUPT, local_path + ":Resource of unrecognized type in file: " + t + ".");
+				if (ResourceLoader::is_creating_missing_resources_if_class_unavailable_enabled()) {
+					//create a missing resource
+					missing_resource = memnew(MissingResource);
+					missing_resource->set_original_class(t);
+					missing_resource->set_recording_properties(true);
+					obj = missing_resource;
+				} else {
+					error = ERR_FILE_CORRUPT;
+					ERR_FAIL_V_MSG(ERR_FILE_CORRUPT, local_path + ":Resource of unrecognized type in file: " + t + ".");
+				}
 			}
 
 			Resource *r = Object::cast_to<Resource>(obj);
@@ -760,6 +771,8 @@ Error ResourceLoaderBinary::load() {
 
 		//set properties
 
+		Dictionary missing_resource_properties;
+
 		for (int j = 0; j < pc; j++) {
 			StringName name = _get_string();
 
@@ -775,8 +788,32 @@ Error ResourceLoaderBinary::load() {
 				return error;
 			}
 
-			res->set(name, value);
+			bool set_valid = true;
+			if (value.get_type() == Variant::OBJECT && missing_resource != nullptr) {
+				// If the property being set is a missing resource (and the parent is not),
+				// then setting it will most likely not work.
+				// Instead, save it as metadata.
+
+				Ref<MissingResource> mr = value;
+				if (mr.is_valid()) {
+					missing_resource_properties[name] = mr;
+					set_valid = false;
+				}
+			}
+
+			if (set_valid) {
+				res->set(name, value);
+			}
+		}
+
+		if (missing_resource) {
+			missing_resource->set_recording_properties(false);
+		}
+
+		if (!missing_resource_properties.is_empty()) {
+			res->set_meta(META_MISSING_RESOURCES, missing_resource_properties);
 		}
+
 #ifdef TOOLS_ENABLED
 		res->set_edited(false);
 #endif
@@ -1833,6 +1870,15 @@ int ResourceFormatSaverBinaryInstance::get_string_index(const String &p_string)
 	return strings.size() - 1;
 }
 
+static String _resource_get_class(Ref<Resource> p_resource) {
+	Ref<MissingResource> missing_resource = p_resource;
+	if (missing_resource.is_valid()) {
+		return missing_resource->get_original_class();
+	} else {
+		return p_resource->get_class();
+	}
+}
+
 Error ResourceFormatSaverBinaryInstance::save(const String &p_path, const Ref<Resource> &p_resource, uint32_t p_flags) {
 	Error err;
 	Ref<FileAccess> f;
@@ -1885,7 +1931,7 @@ Error ResourceFormatSaverBinaryInstance::save(const String &p_path, const Ref<Re
 		return ERR_CANT_CREATE;
 	}
 
-	save_unicode_string(f, p_resource->get_class());
+	save_unicode_string(f, _resource_get_class(p_resource));
 	f->store_64(0); //offset to import metadata
 	{
 		uint32_t format_flags = FORMAT_FLAG_NAMED_SCENE_IDS | FORMAT_FLAG_UIDS;
@@ -1902,10 +1948,12 @@ Error ResourceFormatSaverBinaryInstance::save(const String &p_path, const Ref<Re
 
 	List<ResourceData> resources;
 
+	Dictionary missing_resource_properties = p_resource->get_meta(META_MISSING_RESOURCES, Dictionary());
+
 	{
 		for (const Ref<Resource> &E : saved_resources) {
 			ResourceData &rd = resources.push_back(ResourceData())->get();
-			rd.type = E->get_class();
+			rd.type = _resource_get_class(E);
 
 			List<PropertyInfo> property_list;
 			E->get_property_list(&property_list);
@@ -1914,6 +1962,10 @@ Error ResourceFormatSaverBinaryInstance::save(const String &p_path, const Ref<Re
 				if (skip_editor && F.name.begins_with("__editor")) {
 					continue;
 				}
+				if (F.name == META_PROPERTY_MISSING_RESOURCES) {
+					continue;
+				}
+
 				if ((F.usage & PROPERTY_USAGE_STORAGE)) {
 					Property p;
 					p.name_idx = get_string_index(F.name);
@@ -1929,6 +1981,14 @@ Error ResourceFormatSaverBinaryInstance::save(const String &p_path, const Ref<Re
 						p.value = E->get(F.name);
 					}
 
+					if (p.pi.type == Variant::OBJECT && missing_resource_properties.has(F.name)) {
+						// Was this missing resource overriden? If so do not save the old value.
+						Ref<Resource> res = p.value;
+						if (res.is_null()) {
+							p.value = missing_resource_properties[F.name];
+						}
+					}
+
 					Variant default_value = ClassDB::class_get_default_property_value(E->get_class(), F.name);
 
 					if (default_value.get_type() != Variant::NIL && bool(Variant::evaluate(Variant::OP_EQUAL, p.value, default_value))) {
@@ -1990,7 +2050,7 @@ Error ResourceFormatSaverBinaryInstance::save(const String &p_path, const Ref<Re
 				String new_id;
 
 				while (true) {
-					new_id = r->get_class() + "_" + Resource::generate_scene_unique_id();
+					new_id = _resource_get_class(r) + "_" + Resource::generate_scene_unique_id();
 					if (!used_unique_ids.has(new_id)) {
 						break;
 					}
diff --git a/core/io/resource_loader.cpp b/core/io/resource_loader.cpp
index c8cebd672a..d125dd4e91 100644
--- a/core/io/resource_loader.cpp
+++ b/core/io/resource_loader.cpp
@@ -979,6 +979,10 @@ void ResourceLoader::remove_custom_resource_format_loader(String script_path) {
 	}
 }
 
+void ResourceLoader::set_create_missing_resources_if_class_unavailable(bool p_enable) {
+	create_missing_resources_if_class_unavailable = p_enable;
+}
+
 void ResourceLoader::add_custom_loaders() {
 	// Custom loaders registration exploits global class names
 
@@ -1030,6 +1034,7 @@ void *ResourceLoader::err_notify_ud = nullptr;
 DependencyErrorNotify ResourceLoader::dep_err_notify = nullptr;
 void *ResourceLoader::dep_err_notify_ud = nullptr;
 
+bool ResourceLoader::create_missing_resources_if_class_unavailable = false;
 bool ResourceLoader::abort_on_missing_resource = true;
 bool ResourceLoader::timestamp_on_load = false;
 
diff --git a/core/io/resource_loader.h b/core/io/resource_loader.h
index 15ecfacf4a..ea18ac23fd 100644
--- a/core/io/resource_loader.h
+++ b/core/io/resource_loader.h
@@ -110,6 +110,7 @@ private:
 	static void *dep_err_notify_ud;
 	static DependencyErrorNotify dep_err_notify;
 	static bool abort_on_missing_resource;
+	static bool create_missing_resources_if_class_unavailable;
 	static HashMap<String, Vector<String>> translation_remaps;
 	static HashMap<String, String> path_remaps;
 
@@ -222,6 +223,9 @@ public:
 	static void add_custom_loaders();
 	static void remove_custom_loaders();
 
+	static void set_create_missing_resources_if_class_unavailable(bool p_enable);
+	_FORCE_INLINE_ static bool is_creating_missing_resources_if_class_unavailable_enabled() { return create_missing_resources_if_class_unavailable; }
+
 	static void initialize();
 	static void finalize();
 };
diff --git a/core/object/object.cpp b/core/object/object.cpp
index 1defd85a14..2b62041533 100644
--- a/core/object/object.cpp
+++ b/core/object/object.cpp
@@ -434,15 +434,6 @@ void Object::set(const StringName &p_name, const Variant &p_value, bool *r_valid
 		}
 	}
 
-	// Something inside the object... :|
-	bool success = _setv(p_name, p_value);
-	if (success) {
-		if (r_valid) {
-			*r_valid = true;
-		}
-		return;
-	}
-
 #ifdef TOOLS_ENABLED
 	if (script_instance) {
 		bool valid;
@@ -456,6 +447,15 @@ void Object::set(const StringName &p_name, const Variant &p_value, bool *r_valid
 	}
 #endif
 
+	// Something inside the object... :|
+	bool success = _setv(p_name, p_value);
+	if (success) {
+		if (r_valid) {
+			*r_valid = true;
+		}
+		return;
+	}
+
 	if (r_valid) {
 		*r_valid = false;
 	}
@@ -518,15 +518,6 @@ Variant Object::get(const StringName &p_name, bool *r_valid) const {
 		return ret;
 
 	} else {
-		// Something inside the object... :|
-		bool success = _getv(p_name, ret);
-		if (success) {
-			if (r_valid) {
-				*r_valid = true;
-			}
-			return ret;
-		}
-
 #ifdef TOOLS_ENABLED
 		if (script_instance) {
 			bool valid;
@@ -539,6 +530,14 @@ Variant Object::get(const StringName &p_name, bool *r_valid) const {
 			}
 		}
 #endif
+		// Something inside the object... :|
+		bool success = _getv(p_name, ret);
+		if (success) {
+			if (r_valid) {
+				*r_valid = true;
+			}
+			return ret;
+		}
 
 		if (r_valid) {
 			*r_valid = false;
diff --git a/core/register_core_types.cpp b/core/register_core_types.cpp
index 415b56cd83..e60d325f74 100644
--- a/core/register_core_types.cpp
+++ b/core/register_core_types.cpp
@@ -49,6 +49,7 @@
 #include "core/io/image_loader.h"
 #include "core/io/json.h"
 #include "core/io/marshalls.h"
+#include "core/io/missing_resource.h"
 #include "core/io/packed_data_container.h"
 #include "core/io/packet_peer.h"
 #include "core/io/packet_peer_dtls.h"
@@ -151,6 +152,7 @@ void register_core_types() {
 	GDREGISTER_CLASS(RefCounted);
 	GDREGISTER_CLASS(WeakRef);
 	GDREGISTER_CLASS(Resource);
+	GDREGISTER_VIRTUAL_CLASS(MissingResource);
 	GDREGISTER_CLASS(Image);
 
 	GDREGISTER_CLASS(Shortcut);