Print suggestions when requesting a nonexistent InputMap action

Co-authored-by: Marc Gilleron <marc.gilleron@gmail.com>

2 files changed, 39 insertions, 9 deletions

diff --git a/core/input/input_map.cpp b/core/input/input_map.cpp
index 7d85fd6492..aab4e6593c 100644
--- a/core/input/input_map.cpp
+++ b/core/input/input_map.cpp
@@ -54,8 +54,36 @@ void InputMap::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("load_from_project_settings"), &InputMap::load_from_project_settings);
 }
 
+/**
+ * Returns an nonexistent action error message with a suggestion of the closest
+ * matching action name (if possible).
+ */
+String InputMap::_suggest_actions(const StringName &p_action) const {
+	List<StringName> actions = get_actions();
+	StringName closest_action;
+	float closest_similarity = 0.0;
+
+	// Find the most action with the most similar name.
+	for (List<StringName>::Element *E = actions.front(); E; E = E->next()) {
+		const float similarity = String(E->get()).similarity(p_action);
+
+		if (similarity > closest_similarity) {
+			closest_action = E->get();
+			closest_similarity = similarity;
+		}
+	}
+
+	String error_message = vformat("The InputMap action \"%s\" doesn't exist.", p_action);
+
+	if (closest_similarity >= 0.4) {
+		// Only include a suggestion in the error message if it's similar enough.
+		error_message += vformat(" Did you mean \"%s\"?", closest_action);
+	}
+	return error_message;
+}
+
 void InputMap::add_action(const StringName &p_action, float p_deadzone) {
-	ERR_FAIL_COND_MSG(input_map.has(p_action), "InputMap already has action '" + String(p_action) + "'.");
+	ERR_FAIL_COND_MSG(input_map.has(p_action), "InputMap already has action \"" + String(p_action) + "\".");
 	input_map[p_action] = Action();
 	static int last_id = 1;
 	input_map[p_action].id = last_id;
@@ -64,7 +92,8 @@ void InputMap::add_action(const StringName &p_action, float p_deadzone) {
 }
 
 void InputMap::erase_action(const StringName &p_action) {
-	ERR_FAIL_COND_MSG(!input_map.has(p_action), "Request for nonexistent InputMap action '" + String(p_action) + "'.");
+	ERR_FAIL_COND_MSG(!input_map.has(p_action), _suggest_actions(p_action));
+
 	input_map.erase(p_action);
 }
 
@@ -122,20 +151,20 @@ bool InputMap::has_action(const StringName &p_action) const {
 }
 
 float InputMap::action_get_deadzone(const StringName &p_action) {
-	ERR_FAIL_COND_V_MSG(!input_map.has(p_action), 0.0f, "Request for nonexistent InputMap action '" + String(p_action) + "'.");
+	ERR_FAIL_COND_V_MSG(!input_map.has(p_action), 0.0f, _suggest_actions(p_action));
 
 	return input_map[p_action].deadzone;
 }
 
 void InputMap::action_set_deadzone(const StringName &p_action, float p_deadzone) {
-	ERR_FAIL_COND_MSG(!input_map.has(p_action), "Request for nonexistent InputMap action '" + String(p_action) + "'.");
+	ERR_FAIL_COND_MSG(!input_map.has(p_action), _suggest_actions(p_action));
 
 	input_map[p_action].deadzone = p_deadzone;
 }
 
 void InputMap::action_add_event(const StringName &p_action, const Ref<InputEvent> &p_event) {
 	ERR_FAIL_COND_MSG(p_event.is_null(), "It's not a reference to a valid InputEvent object.");
-	ERR_FAIL_COND_MSG(!input_map.has(p_action), "Request for nonexistent InputMap action '" + String(p_action) + "'.");
+	ERR_FAIL_COND_MSG(!input_map.has(p_action), _suggest_actions(p_action));
 	if (_find_event(input_map[p_action], p_event, true)) {
 		return; // Already addded.
 	}
@@ -144,12 +173,12 @@ void InputMap::action_add_event(const StringName &p_action, const Ref<InputEvent
 }
 
 bool InputMap::action_has_event(const StringName &p_action, const Ref<InputEvent> &p_event) {
-	ERR_FAIL_COND_V_MSG(!input_map.has(p_action), false, "Request for nonexistent InputMap action '" + String(p_action) + "'.");
+	ERR_FAIL_COND_V_MSG(!input_map.has(p_action), false, _suggest_actions(p_action));
 	return (_find_event(input_map[p_action], p_event, true) != nullptr);
 }
 
 void InputMap::action_erase_event(const StringName &p_action, const Ref<InputEvent> &p_event) {
-	ERR_FAIL_COND_MSG(!input_map.has(p_action), "Request for nonexistent InputMap action '" + String(p_action) + "'.");
+	ERR_FAIL_COND_MSG(!input_map.has(p_action), _suggest_actions(p_action));
 
 	List<Ref<InputEvent>>::Element *E = _find_event(input_map[p_action], p_event, true);
 	if (E) {
@@ -161,7 +190,7 @@ void InputMap::action_erase_event(const StringName &p_action, const Ref<InputEve
 }
 
 void InputMap::action_erase_events(const StringName &p_action) {
-	ERR_FAIL_COND_MSG(!input_map.has(p_action), "Request for nonexistent InputMap action '" + String(p_action) + "'.");
+	ERR_FAIL_COND_MSG(!input_map.has(p_action), _suggest_actions(p_action));
 
 	input_map[p_action].inputs.clear();
 }
@@ -193,7 +222,7 @@ bool InputMap::event_is_action(const Ref<InputEvent> &p_event, const StringName
 
 bool InputMap::event_get_action_status(const Ref<InputEvent> &p_event, const StringName &p_action, bool p_exact_match, bool *p_pressed, float *p_strength, float *p_raw_strength) const {
 	OrderedHashMap<StringName, Action>::Element E = input_map.find(p_action);
-	ERR_FAIL_COND_V_MSG(!E, false, "Request for nonexistent InputMap action '" + String(p_action) + "'.");
+	ERR_FAIL_COND_V_MSG(!E, false, _suggest_actions(p_action));
 
 	Ref<InputEventAction> input_event_action = p_event;
 	if (input_event_action.is_valid()) {
diff --git a/core/input/input_map.h b/core/input/input_map.h
index 99c71e1e53..0e0567464a 100644
--- a/core/input/input_map.h
+++ b/core/input/input_map.h
@@ -61,6 +61,7 @@ private:
 
 	Array _action_get_events(const StringName &p_action);
 	Array _get_actions();
+	String _suggest_actions(const StringName &p_action) const;
 
 protected:
 	static void _bind_methods();