Add application/config/project_settings_override option to override project settings

core/project_settings.cpp

@@ -307,7 +307,7 @@ void ProjectSettings::_convert_to_last_version() {
  *    If a project file is found, load it or fail.
  *    If nothing was found, error out.
  */
-Error ProjectSettings::setup(const String &p_path, const String &p_main_pack, bool p_upwards) {
+Error ProjectSettings::_setup(const String &p_path, const String &p_main_pack, bool p_upwards) {
 
 	// If looking for files in a network client, use it directly
 
@@ -450,6 +450,18 @@ Error ProjectSettings::setup(const String &p_path, const String &p_main_pack, bo
 	return OK;
 }
 
+Error ProjectSettings::setup(const String &p_path, const String &p_main_pack, bool p_upwards) {
+	Error err = _setup(p_path, p_main_pack, p_upwards);
+	if (err == OK) {
+		String custom_settings = GLOBAL_DEF("application/config/project_settings_override", "");
+		if (custom_settings != "") {
+			_load_settings_text(custom_settings);
+		}
+	}
+
+	return err;
+}
+
 bool ProjectSettings::has_setting(String p_var) const {
 
 	_THREAD_SAFE_METHOD_
@@ -995,6 +1007,7 @@ ProjectSettings::ProjectSettings() {
 	GLOBAL_DEF("application/run/disable_stderr", false);
 	GLOBAL_DEF("application/config/use_custom_user_dir", false);
 	GLOBAL_DEF("application/config/custom_user_dir_name", "");
+	GLOBAL_DEF("application/config/project_settings_override", "");
 
 	action = Dictionary();
 	action["deadzone"] = Variant(0.5f);

core/project_settings.h

@@ -112,6 +112,8 @@ protected:
 
 	void _add_property_info_bind(const Dictionary &p_info);
 
+	Error _setup(const String &p_path, const String &p_main_pack, bool p_upwards = false);
+
 protected:
 	static void _bind_methods();
 

doc/classes/ProjectSettings.xml

@@ -184,6 +184,9 @@
 		<member name="application/config/use_custom_user_dir" type="bool" setter="" getter="">
 			Allow the project to save to its own custom user dir (in AppData on windows or ~/.config on unixes). This setting only works for desktop exporters. A name must be set in the "custom_user_dir_name" setting for this to take effect.
 		</member>
+		<member name="application/config/project_settings_override" type="String" setter="" getter="">
+			Specifies a file to override project settings. For example: user://custom_settings.cfg.
+		</member>
 		<member name="application/run/disable_stderr" type="bool" setter="" getter="">
 			Disable printing to stderr on exported build.
 		</member>