Added ability to get a list of project settings changed.

Author: MauriceButler

core/config/project_settings.cpp

@@ -277,6 +277,13 @@ String ProjectSettings::globalize_path(const String &p_path) const {
 bool ProjectSettings::_set(const StringName &p_name, const Variant &p_value) {
 	_THREAD_SAFE_METHOD_
 
+	// Early return if value hasn't changed (unless it's being deleted)
+	if (p_value.get_type() != Variant::NIL) {
+		if (props.has(p_name) && props[p_name].variant == p_value) {
+			return true;
+		}
+	}
+
 	if (p_value.get_type() == Variant::NIL) {
 		props.erase(p_name);
 		if (p_name.operator String().begins_with("autoload/")) {
@@ -298,7 +305,7 @@ bool ProjectSettings::_set(const StringName &p_name, const Variant &p_value) {
 			}
 
 			_version++;
-			_queue_changed();
+			_queue_changed(p_name);
 			return true;
 		}
 
@@ -344,7 +351,7 @@ bool ProjectSettings::_set(const StringName &p_name, const Variant &p_value) {
 	}
 
 	_version++;
-	_queue_changed();
+	_queue_changed(p_name);
 	return true;
 }
 
@@ -520,20 +527,31 @@ void ProjectSettings::_get_property_list(List<PropertyInfo> *p_list) const {
 	}
 }
 
-void ProjectSettings::_queue_changed() {
-	if (is_changed || !MessageQueue::get_singleton() || MessageQueue::get_singleton()->get_max_buffer_usage() == 0) {
+void ProjectSettings::_queue_changed(const StringName &p_name) {
+	changed_settings.insert(p_name);
+
+	if (!MessageQueue::get_singleton() || MessageQueue::get_singleton()->get_max_buffer_usage() == 0) {
 		return;
 	}
-	is_changed = true;
-	callable_mp(this, &ProjectSettings::_emit_changed).call_deferred();
+
+	// Only queue the deferred call once per frame.
+	if (!is_changed) {
+		is_changed = true;
+		callable_mp(this, &ProjectSettings::_emit_changed).call_deferred();
+	}
 }
 
 void ProjectSettings::_emit_changed() {
 	if (!is_changed) {
 		return;
 	}
 	is_changed = false;
+
+	// Emit the general settings_changed signal to indicate changes are complete.
 	emit_signal("settings_changed");
+
+	// Clear the changed settings after emitting the signal
+	changed_settings.clear();
 }
 
 bool ProjectSettings::load_resource_pack(const String &p_pack, bool p_replace_files, int p_offset) {
@@ -1313,6 +1331,23 @@ Variant ProjectSettings::get_setting(const String &p_setting, const Variant &p_d
 	}
 }
 
+PackedStringArray ProjectSettings::get_changed_settings() const {
+	PackedStringArray arr;
+	for (const StringName &setting : changed_settings) {
+		arr.push_back(setting);
+	}
+	return arr;
+}
+
+bool ProjectSettings::check_changed_settings_in_group(const String &p_setting_prefix) const {
+	for (const StringName &setting : changed_settings) {
+		if (String(setting).begins_with(p_setting_prefix)) {
+			return true;
+		}
+	}
+	return false;
+}
+
 void ProjectSettings::refresh_global_class_list() {
 	// This is called after mounting a new PCK file to pick up class changes.
 	is_global_class_list_loaded = false; // Make sure we read from the freshly mounted PCK.
@@ -1509,6 +1544,9 @@ void ProjectSettings::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("save_custom", "file"), &ProjectSettings::_save_custom_bnd);
 
+	// Change tracking methods
+	ClassDB::bind_method(D_METHOD("get_changed_settings"), &ProjectSettings::get_changed_settings);
+	ClassDB::bind_method(D_METHOD("check_changed_settings_in_group", "setting_prefix"), &ProjectSettings::check_changed_settings_in_group);
 	ADD_SIGNAL(MethodInfo("settings_changed"));
 }
 

core/config/project_settings.h

@@ -46,6 +46,9 @@ class ProjectSettings : public Object {
 	// and will always detect the initial project settings as a "change".
 	uint32_t _version = 1;
 
+	// Track changed settings for get_changed_settings functionality
+	HashSet<StringName> changed_settings;
+
 public:
 	typedef HashMap<String, Variant> CustomMap;
 	static inline const String PROJECT_DATA_DIR_NAME_SUFFIX = "godot";
@@ -118,7 +121,7 @@ class ProjectSettings : public Object {
 	bool _property_can_revert(const StringName &p_name) const;
 	bool _property_get_revert(const StringName &p_name, Variant &r_property) const;
 
-	void _queue_changed();
+	void _queue_changed(const StringName &p_name);
 	void _emit_changed();
 
 	static inline ProjectSettings *singleton = nullptr;
@@ -209,6 +212,10 @@ class ProjectSettings : public Object {
 
 	bool has_custom_feature(const String &p_feature) const;
 
+	// Change tracking methods
+	PackedStringArray get_changed_settings() const;
+	bool check_changed_settings_in_group(const String &p_setting_prefix) const;
+
 	const HashMap<StringName, AutoloadInfo> &get_autoload_list() const;
 	void add_autoload(const AutoloadInfo &p_autoload);
 	void remove_autoload(const StringName &p_autoload);

doc/classes/ProjectSettings.xml

@@ -54,13 +54,26 @@
 				[b]Note:[/b] Setting [code]"usage"[/code] for the property is not supported. Use [method set_as_basic], [method set_restart_if_changed], and [method set_as_internal] to modify usage flags.
 			</description>
 		</method>
+		<method name="check_changed_settings_in_group" qualifiers="const">
+			<return type="bool" />
+			<param index="0" name="setting_prefix" type="String" />
+			<description>
+				Checks if any settings with the prefix [param setting_prefix] exist in the set of changed settings. See also [method get_changed_settings].
+			</description>
+		</method>
 		<method name="clear">
 			<return type="void" />
 			<param index="0" name="name" type="String" />
 			<description>
 				Clears the whole configuration (not recommended, may break things).
 			</description>
 		</method>
+		<method name="get_changed_settings" qualifiers="const">
+			<return type="PackedStringArray" />
+			<description>
+				Gets an array of the settings which have been changed since the last save. Note that internally [code]changed_settings[/code] is cleared after a successful save, so generally the most appropriate place to use this method is when processing [signal settings_changed].
+			</description>
+		</method>
 		<method name="get_global_class_list">
 			<return type="Dictionary[]" />
 			<description>

tests/core/config/test_project_settings.h

@@ -155,4 +155,80 @@ TEST_CASE("[ProjectSettings] localize_path") {
 	TestProjectSettingsInternalsAccessor::resource_path() = old_resource_path;
 }
 
+TEST_CASE("[SceneTree][ProjectSettings] settings_changed signal") {
+	SIGNAL_WATCH(ProjectSettings::get_singleton(), SNAME("settings_changed"));
+
+	ProjectSettings::get_singleton()->set_setting("test_signal_setting", "test_value");
+	MessageQueue::get_singleton()->flush();
+
+	SIGNAL_CHECK("settings_changed", { {} });
+
+	SIGNAL_UNWATCH(ProjectSettings::get_singleton(), SNAME("settings_changed"));
+}
+
+TEST_CASE("[ProjectSettings] get_changed_settings basic functionality") {
+	String setting_name = "test_changed_setting";
+	ProjectSettings::get_singleton()->set_setting(setting_name, "test_value");
+
+	PackedStringArray changes = ProjectSettings::get_singleton()->get_changed_settings();
+	CHECK(changes.has(setting_name));
+}
+
+TEST_CASE("[ProjectSettings] get_changed_settings multiple settings") {
+	ProjectSettings::get_singleton()->set_setting("test_setting_1", "value1");
+	ProjectSettings::get_singleton()->set_setting("test_setting_2", "value2");
+	ProjectSettings::get_singleton()->set_setting("another_group/setting", "value3");
+
+	PackedStringArray changes = ProjectSettings::get_singleton()->get_changed_settings();
+	CHECK(changes.has("test_setting_1"));
+	CHECK(changes.has("test_setting_2"));
+	CHECK(changes.has("another_group/setting"));
+}
+
+TEST_CASE("[ProjectSettings] check_changed_settings_in_group") {
+	ProjectSettings::get_singleton()->set_setting("group1/setting1", "value1");
+	ProjectSettings::get_singleton()->set_setting("group1/setting2", "value2");
+	ProjectSettings::get_singleton()->set_setting("group2/setting1", "value3");
+	ProjectSettings::get_singleton()->set_setting("other_setting", "value4");
+
+	CHECK(ProjectSettings::get_singleton()->check_changed_settings_in_group("group1/"));
+	CHECK(ProjectSettings::get_singleton()->check_changed_settings_in_group("group2/"));
+	CHECK_FALSE(ProjectSettings::get_singleton()->check_changed_settings_in_group("nonexistent/"));
+
+	CHECK(ProjectSettings::get_singleton()->check_changed_settings_in_group("group1"));
+	CHECK(ProjectSettings::get_singleton()->check_changed_settings_in_group("other_setting"));
+}
+
+TEST_CASE("[SceneTree][ProjectSettings] Changes cleared after settings_changed signal") {
+	SIGNAL_WATCH(ProjectSettings::get_singleton(), SNAME("settings_changed"));
+
+	ProjectSettings::get_singleton()->set_setting("signal_clear_test", "value");
+
+	PackedStringArray changes_before = ProjectSettings::get_singleton()->get_changed_settings();
+	CHECK(changes_before.has("signal_clear_test"));
+
+	MessageQueue::get_singleton()->flush();
+
+	SIGNAL_CHECK("settings_changed", { {} });
+
+	PackedStringArray changes_after = ProjectSettings::get_singleton()->get_changed_settings();
+	CHECK_FALSE(changes_after.has("signal_clear_test"));
+
+	SIGNAL_UNWATCH(ProjectSettings::get_singleton(), SNAME("settings_changed"));
+}
+
+TEST_CASE("[ProjectSettings] No tracking when setting same value") {
+	String setting_name = "same_value_test";
+	String test_value = "same_value";
+
+	ProjectSettings::get_singleton()->set_setting(setting_name, test_value);
+	int count_before = ProjectSettings::get_singleton()->get_changed_settings().size();
+
+	// Setting the same value should not be tracked due to early return.
+	ProjectSettings::get_singleton()->set_setting(setting_name, test_value);
+	int count_after = ProjectSettings::get_singleton()->get_changed_settings().size();
+
+	CHECK_EQ(count_before, count_after);
+}
+
 } // namespace TestProjectSettings