From 645cc71be4b02020a5f783fa0a007a8f579d12bf Mon Sep 17 00:00:00 2001
From: jmb462 <jmb462@gmail.com>
Date: Mon, 13 Sep 2021 22:54:20 +0200
Subject: [PATCH] Display an error message in settings when autoload name is
 invalid

---
 editor/editor_autoload_settings.cpp | 28 +++++++++++++++++++++-------
 editor/editor_autoload_settings.h   |  1 +
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/editor/editor_autoload_settings.cpp b/editor/editor_autoload_settings.cpp
index 362c4c34576..fcf79a80a78 100644
--- a/editor/editor_autoload_settings.cpp
+++ b/editor/editor_autoload_settings.cpp
@@ -64,7 +64,12 @@ void EditorAutoloadSettings::_notification(int p_what) {
 bool EditorAutoloadSettings::_autoload_name_is_valid(const String &p_name, String *r_error) {
 	if (!p_name.is_valid_identifier()) {
 		if (r_error) {
-			*r_error = TTR("Invalid name.") + "\n" + TTR("Valid characters:") + " a-z, A-Z, 0-9 or _";
+			*r_error = TTR("Invalid name.") + " ";
+			if (p_name.size() > 0 && p_name.left(1).is_numeric()) {
+				*r_error += TTR("Cannot begin with a digit.");
+			} else {
+				*r_error += TTR("Valid characters:") + " a-z, A-Z, 0-9 or _";
+			}
 		}
 
 		return false;
@@ -72,7 +77,7 @@ bool EditorAutoloadSettings::_autoload_name_is_valid(const String &p_name, Strin
 
 	if (ClassDB::class_exists(p_name)) {
 		if (r_error) {
-			*r_error = TTR("Invalid name.") + "\n" + TTR("Must not collide with an existing engine class name.");
+			*r_error = TTR("Invalid name.") + " " + TTR("Must not collide with an existing engine class name.");
 		}
 
 		return false;
@@ -89,7 +94,7 @@ bool EditorAutoloadSettings::_autoload_name_is_valid(const String &p_name, Strin
 	for (int i = 0; i < Variant::VARIANT_MAX; i++) {
 		if (Variant::get_type_name(Variant::Type(i)) == p_name) {
 			if (r_error) {
-				*r_error = TTR("Invalid name.") + "\n" + TTR("Must not collide with an existing built-in type name.");
+				*r_error = TTR("Invalid name.") + " " + TTR("Must not collide with an existing built-in type name.");
 			}
 
 			return false;
@@ -99,7 +104,7 @@ bool EditorAutoloadSettings::_autoload_name_is_valid(const String &p_name, Strin
 	for (int i = 0; i < CoreConstants::get_global_constant_count(); i++) {
 		if (CoreConstants::get_global_constant_name(i) == p_name) {
 			if (r_error) {
-				*r_error = TTR("Invalid name.") + "\n" + TTR("Must not collide with an existing global constant name.");
+				*r_error = TTR("Invalid name.") + " " + TTR("Must not collide with an existing global constant name.");
 			}
 
 			return false;
@@ -112,7 +117,7 @@ bool EditorAutoloadSettings::_autoload_name_is_valid(const String &p_name, Strin
 		for (const String &E : keywords) {
 			if (E == p_name) {
 				if (r_error) {
-					*r_error = TTR("Invalid name.") + "\n" + TTR("Keyword cannot be used as an autoload name.");
+					*r_error = TTR("Invalid name.") + " " + TTR("Keyword cannot be used as an autoload name.");
 				}
 
 				return false;
@@ -346,8 +351,11 @@ void EditorAutoloadSettings::_autoload_path_text_changed(const String p_path) {
 }
 
 void EditorAutoloadSettings::_autoload_text_changed(const String p_name) {
-	add_autoload->set_disabled(
-			autoload_add_path->get_text() == "" || !_autoload_name_is_valid(p_name, nullptr));
+	String error_string;
+	bool is_name_valid = _autoload_name_is_valid(p_name, &error_string);
+	add_autoload->set_disabled(autoload_add_path->get_text() == "" || !is_name_valid);
+	error_message->set_text(error_string);
+	error_message->set_visible(autoload_add_name->get_text() != "" && !is_name_valid);
 }
 
 Node *EditorAutoloadSettings::_create_autoload(const String &p_path) {
@@ -828,6 +836,12 @@ EditorAutoloadSettings::EditorAutoloadSettings() {
 	HBoxContainer *hbc = memnew(HBoxContainer);
 	add_child(hbc);
 
+	error_message = memnew(Label);
+	error_message->hide();
+	error_message->set_align(Label::Align::ALIGN_RIGHT);
+	error_message->add_theme_color_override("font_color", EditorNode::get_singleton()->get_gui_base()->get_theme_color(SNAME("error_color"), SNAME("Editor")));
+	add_child(error_message);
+
 	Label *l = memnew(Label);
 	l->set_text(TTR("Path:"));
 	hbc->add_child(l);
diff --git a/editor/editor_autoload_settings.h b/editor/editor_autoload_settings.h
index b709728856f..b8e054cd14d 100644
--- a/editor/editor_autoload_settings.h
+++ b/editor/editor_autoload_settings.h
@@ -70,6 +70,7 @@ class EditorAutoloadSettings : public VBoxContainer {
 	LineEdit *autoload_add_name;
 	Button *add_autoload;
 	LineEdit *autoload_add_path;
+	Label *error_message;
 	Button *browse_button;
 	EditorFileDialog *file_dialog;