Fix Input::remove_joy_mapping

Erasing a joypad mapping can invalidate other attached joypads and the fallback mapping guid

core/input/input.cpp

@@ -149,6 +149,8 @@ void Input::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_vector", "negative_x", "positive_x", "negative_y", "positive_y", "deadzone"), &Input::get_vector, DEFVAL(-1.0f));
 	ClassDB::bind_method(D_METHOD("add_joy_mapping", "mapping", "update_existing"), &Input::add_joy_mapping, DEFVAL(false));
 	ClassDB::bind_method(D_METHOD("remove_joy_mapping", "guid"), &Input::remove_joy_mapping);
+	ClassDB::bind_method(D_METHOD("set_fallback_mapping", "guid"), &Input::set_fallback_mapping);
+	ClassDB::bind_method(D_METHOD("get_fallback_mapping"), &Input::get_fallback_mapping);
 	ClassDB::bind_method(D_METHOD("is_joy_known", "device"), &Input::is_joy_known);
 	ClassDB::bind_method(D_METHOD("get_joy_axis", "device", "axis"), &Input::get_joy_axis);
 	ClassDB::bind_method(D_METHOD("get_joy_name", "device"), &Input::get_joy_name);
@@ -1693,15 +1695,41 @@ void Input::add_joy_mapping(const String &p_mapping, bool p_update_existing) {
 }
 
 void Input::remove_joy_mapping(const String &p_guid) {
+	int fallback_mapping_offset = 0; // Fix the fallback, if we invalidate its index.
+
 	for (int i = map_db.size() - 1; i >= 0; i--) {
 		if (p_guid == map_db[i].uid) {
 			map_db.remove_at(i);
+
+			if (i == fallback_mapping) {
+				fallback_mapping = -1;
+			}
+			if (i < fallback_mapping) {
+				fallback_mapping_offset--;
+			}
 		}
 	}
+
+	if (fallback_mapping_offset < 0) {
+		fallback_mapping += fallback_mapping_offset;
+	}
+
 	for (KeyValue<int, Joypad> &E : joy_names) {
 		Joypad &joy = E.value;
 		if (joy.uid == p_guid) {
 			joy.mapping = -1;
+		} else if (joy.mapping == (fallback_mapping - fallback_mapping_offset)) {
+			// Fix the mapping for the joypad that uses an outdated fallback index.
+			joy.mapping = fallback_mapping;
+		} else {
+			// Re-validate the joypad's correct mapping. Fix it if necesary.
+			int mapping = -1;
+			for (int i = 0; i < map_db.size(); i++) {
+				if (joy.uid == map_db[i].uid) {
+					mapping = i;
+				}
+			}
+			joy.mapping = mapping;
 		}
 	}
 }
@@ -1715,6 +1743,11 @@ void Input::set_fallback_mapping(const String &p_guid) {
 	}
 }
 
+String Input::get_fallback_mapping() const {
+	ERR_FAIL_COND_V(fallback_mapping == -1, "");
+	return map_db[fallback_mapping].uid;
+}
+
 //platforms that use the remapping system can override and call to these ones
 bool Input::is_joy_known(int p_device) {
 	if (joy_names.has(p_device)) {

core/input/input.h

@@ -184,7 +184,7 @@ class Input : public Object {
 
 	HashSet<uint32_t> ignored_device_ids;
 
-	int fallback_mapping = -1;
+	int fallback_mapping = -1; // Index of the guid in map_db.
 
 	CursorShape default_shape = CURSOR_ARROW;
 
@@ -373,6 +373,7 @@ class Input : public Object {
 	bool should_ignore_device(int p_vendor_id, int p_product_id) const;
 	Dictionary get_joy_info(int p_device) const;
 	void set_fallback_mapping(const String &p_guid);
+	String get_fallback_mapping() const;
 
 #ifdef DEBUG_ENABLED
 	void flush_frame_parsed_events();

doc/classes/Input.xml

@@ -92,6 +92,12 @@
 				Returns the currently assigned cursor shape (see [enum CursorShape]).
 			</description>
 		</method>
+		<method name="get_fallback_mapping" qualifiers="const">
+			<return type="String" />
+			<description>
+				Returns the current GUID for the fallback mapping, or an empty String. Godot only fills this member automatically for Android.
+			</description>
+		</method>
 		<method name="get_gravity" qualifiers="const">
 			<return type="Vector3" />
 			<description>
@@ -118,7 +124,7 @@
 			<return type="String" />
 			<param index="0" name="device" type="int" />
 			<description>
-				Returns an SDL2-compatible device GUID on platforms that use gamepad remapping, e.g. [code]030000004c050000c405000000010000[/code]. Returns [code]"Default Gamepad"[/code] otherwise. Godot uses the [url=https://github.com/gabomdq/SDL_GameControllerDB]SDL2 game controller database[/url] to determine gamepad names and mappings based on this GUID.
+				Returns an SDL2-compatible device GUID on platforms that use gamepad remapping, e.g. [code]030000004c050000c405000000010000[/code]. Returns an empty String otherwise. Godot uses the [url=https://github.com/gabomdq/SDL_GameControllerDB]SDL2 game controller database[/url] to determine gamepad names and mappings based on this GUID. Although Godot overwrites [url=https://github.com/godotengine/godot/blob/master/core/input/godotcontrollerdb.txt]some of the GUIDs[/url].
 			</description>
 		</method>
 		<method name="get_joy_info" qualifiers="const">
@@ -140,7 +146,7 @@
 			<return type="String" />
 			<param index="0" name="device" type="int" />
 			<description>
-				Returns the name of the joypad at the specified device index, e.g. [code]PS4 Controller[/code]. Godot uses the [url=https://github.com/gabomdq/SDL_GameControllerDB]SDL2 game controller database[/url] to determine gamepad names.
+				Returns the name of the joypad at the specified device index, e.g. [code]PS4 Controller[/code]. Godot uses the [url=https://github.com/gabomdq/SDL_GameControllerDB]SDL2 game controller database[/url] to determine gamepad names. Although Godot overwrites [url=https://github.com/godotengine/godot/blob/master/core/input/godotcontrollerdb.txt]some of the names[/url], especially on Windows for XInput devices.
 			</description>
 		</method>
 		<method name="get_joy_vibration_duration">
@@ -309,6 +315,7 @@
 			<param index="0" name="guid" type="String" />
 			<description>
 				Removes all mappings from the internal database that match the given GUID.
+				If you didn't set a [member fallback_mapping], then this only affects Android: If the GUID is used as [member fallback_mapping], the fallback will be invalidated. Use [member get_fallback_mapping] before calling this function to check your current setting. Call [member set_fallback_mapping] to set a new fallback GUID, which must be known (see [member is_joy_known]).
 			</description>
 		</method>
 		<method name="set_accelerometer">
@@ -342,6 +349,13 @@
 				[b]Note:[/b] This method generates an [InputEventMouseMotion] to update cursor immediately.
 			</description>
 		</method>
+		<method name="set_fallback_mapping">
+			<return type="void" />
+			<param index="0" name="guid" type="String" />
+			<description>
+				Sets the GUID for the fallback mapping, which must be known (see [member is_joy_known]). Godot only fills this member automatically for Android.
+			</description>
+		</method>
 		<method name="set_gravity">
 			<return type="void" />
 			<param index="0" name="value" type="Vector3" />