Refactor ProjectSetting overrides

* Overrides no longer happen for set/get.
* They must be checked with a new function: `ProjectSettings::get_setting_with_override()`.
* GLOBAL_DEF/GLOBAL_GET updated to use this

This change solves many problems:
* General confusion about getting the actual or overriden setting.
* Feature tags available after settings are loaded were being ignored, they are now considered.
* Hacks required for the Project Settings editor to work.

Fixes #64100. Fixes #64014. Fixes #61908.

2 files changed, 36 insertions, 26 deletions

diff --git a/core/config/project_settings.cpp b/core/config/project_settings.cpp
index 0bf7430d84..73d7d7420f 100644
--- a/core/config/project_settings.cpp
+++ b/core/config/project_settings.cpp
@@ -291,31 +291,26 @@ bool ProjectSettings::_set(const StringName &p_name, const Variant &p_value) {
 			return true;
 		}
 
-		if (!disable_feature_overrides) {
+		{ // Feature overrides.
 			int dot = p_name.operator String().find(".");
 			if (dot != -1) {
 				Vector<String> s = p_name.operator String().split(".");
 
-				bool override_valid = false;
 				for (int i = 1; i < s.size(); i++) {
 					String feature = s[i].strip_edges();
-					if (OS::get_singleton()->has_feature(feature) || custom_features.has(feature)) {
-						override_valid = true;
-						break;
+					Pair<StringName, StringName> fo(feature, p_name);
+
+					if (!feature_overrides.has(s[0])) {
+						feature_overrides[s[0]] = LocalVector<Pair<StringName, StringName>>();
 					}
-				}
 
-				if (override_valid) {
-					feature_overrides[s[0]] = p_name;
+					feature_overrides[s[0]].push_back(fo);
 				}
 			}
 		}
 
 		if (props.has(p_name)) {
-			if (!props[p_name].overridden) {
-				props[p_name].variant = p_value;
-			}
-
+			props[p_name].variant = p_value;
 		} else {
 			props[p_name] = VariantContainer(p_value, last_order++);
 		}
@@ -340,16 +335,35 @@ bool ProjectSettings::_set(const StringName &p_name, const Variant &p_value) {
 bool ProjectSettings::_get(const StringName &p_name, Variant &r_ret) const {
 	_THREAD_SAFE_METHOD_
 
+	if (!props.has(p_name)) {
+		WARN_PRINT("Property not found: " + String(p_name));
+		return false;
+	}
+	r_ret = props[p_name].variant;
+	return true;
+}
+
+Variant ProjectSettings::get_setting_with_override(const StringName &p_name) const {
+	_THREAD_SAFE_METHOD_
+
 	StringName name = p_name;
-	if (!disable_feature_overrides && feature_overrides.has(name)) {
-		name = feature_overrides[name];
+	if (feature_overrides.has(name)) {
+		const LocalVector<Pair<StringName, StringName>> &overrides = feature_overrides[name];
+		for (uint32_t i = 0; i < overrides.size(); i++) {
+			if (OS::get_singleton()->has_feature(overrides[i].first)) { // Custom features are checked in OS.has_feature() already. No need to check twice.
+				if (props.has(overrides[i].second)) {
+					name = overrides[i].second;
+					break;
+				}
+			}
+		}
 	}
+
 	if (!props.has(name)) {
 		WARN_PRINT("Property not found: " + String(name));
-		return false;
+		return Variant();
 	}
-	r_ret = props[name].variant;
-	return true;
+	return props[name].variant;
 }
 
 struct _VCSort {
@@ -1101,10 +1115,6 @@ const HashMap<StringName, PropertyInfo> &ProjectSettings::get_custom_property_in
 	return custom_prop_info;
 }
 
-void ProjectSettings::set_disable_feature_overrides(bool p_disable) {
-	disable_feature_overrides = p_disable;
-}
-
 bool ProjectSettings::is_using_datapack() const {
 	return using_datapack;
 }
@@ -1169,6 +1179,7 @@ void ProjectSettings::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("has_setting", "name"), &ProjectSettings::has_setting);
 	ClassDB::bind_method(D_METHOD("set_setting", "name", "value"), &ProjectSettings::set_setting);
 	ClassDB::bind_method(D_METHOD("get_setting", "name", "default_value"), &ProjectSettings::get_setting, DEFVAL(Variant()));
+	ClassDB::bind_method(D_METHOD("get_setting_with_override", "name"), &ProjectSettings::get_setting_with_override);
 	ClassDB::bind_method(D_METHOD("set_order", "name", "position"), &ProjectSettings::set_order);
 	ClassDB::bind_method(D_METHOD("get_order", "name"), &ProjectSettings::get_order);
 	ClassDB::bind_method(D_METHOD("set_initial_value", "name", "value"), &ProjectSettings::set_initial_value);
diff --git a/core/config/project_settings.h b/core/config/project_settings.h
index 2aca1e7691..353e298919 100644
--- a/core/config/project_settings.h
+++ b/core/config/project_settings.h
@@ -34,6 +34,7 @@
 #include "core/object/class_db.h"
 #include "core/os/thread_safe.h"
 #include "core/templates/hash_map.h"
+#include "core/templates/local_vector.h"
 #include "core/templates/rb_set.h"
 
 class ProjectSettings : public Object {
@@ -69,7 +70,6 @@ protected:
 		Variant variant;
 		Variant initial;
 		bool hide_from_editor = false;
-		bool overridden = false;
 		bool restart_if_changed = false;
 #ifdef DEBUG_METHODS_ENABLED
 		bool ignore_value_in_docs = false;
@@ -91,12 +91,11 @@ protected:
 	RBMap<StringName, VariantContainer> props; // NOTE: Key order is used e.g. in the save_custom method.
 	String resource_path;
 	HashMap<StringName, PropertyInfo> custom_prop_info;
-	bool disable_feature_overrides = false;
 	bool using_datapack = false;
 	List<String> input_presets;
 
 	HashSet<String> custom_features;
-	HashMap<StringName, StringName> feature_overrides;
+	HashMap<StringName, LocalVector<Pair<StringName, StringName>>> feature_overrides;
 
 	HashMap<StringName, AutoloadInfo> autoloads;
 
@@ -181,7 +180,7 @@ public:
 
 	List<String> get_input_presets() const { return input_presets; }
 
-	void set_disable_feature_overrides(bool p_disable);
+	Variant get_setting_with_override(const StringName &p_name) const;
 
 	bool is_using_datapack() const;
 
@@ -205,7 +204,7 @@ Variant _GLOBAL_DEF(const PropertyInfo &p_info, const Variant &p_default, bool p
 #define GLOBAL_DEF_RST(m_var, m_value) _GLOBAL_DEF(m_var, m_value, true)
 #define GLOBAL_DEF_NOVAL(m_var, m_value) _GLOBAL_DEF(m_var, m_value, false, true)
 #define GLOBAL_DEF_RST_NOVAL(m_var, m_value) _GLOBAL_DEF(m_var, m_value, true, true)
-#define GLOBAL_GET(m_var) ProjectSettings::get_singleton()->get(m_var)
+#define GLOBAL_GET(m_var) ProjectSettings::get_singleton()->get_setting_with_override(m_var)
 
 #define GLOBAL_DEF_BASIC(m_var, m_value) _GLOBAL_DEF(m_var, m_value, false, false, true)
 #define GLOBAL_DEF_RST_BASIC(m_var, m_value) _GLOBAL_DEF(m_var, m_value, true, false, true)