Make sure null ride type gets handled properly

data/language/english_uk.txt

@@ -4068,6 +4068,8 @@ STR_5760    :Hong Kong Dollars (HK$)
 STR_5761    :New Taiwan Dollar (NT$)
 STR_5762    :Chinese Yuan (CN{YEN})
 STR_5763    :All files
+STR_5764    :Invalid ride type
+STR_5765    :Cannot edit rides of invalid type
 
 #############
 # Scenarios #

src/localisation/string_ids.h

@@ -2372,6 +2372,9 @@ enum {
 
 	STR_ALL_FILES = 5763,
 
+	STR_INVALID_RIDE_TYPE = 5764,
+	STR_CANT_EDIT_INVALID_RIDE_TYPE = 5765,
+
 	// Have to include resource strings (from scenarios and objects) for the time being now that language is partially working
 	STR_COUNT = 32768
 };

src/ride/ride.c

@@ -841,6 +841,11 @@ void reset_all_ride_build_dates()
 
 static int ride_check_if_construction_allowed(rct_ride *ride)
 {
+	rct_ride_type *rideType = get_ride_entry_by_ride(ride);
+	if (rideType == NULL) {
+		window_error_open(STR_INVALID_RIDE_TYPE, STR_CANT_EDIT_INVALID_RIDE_TYPE);
+		return 0;
+	}
 	if (ride->lifecycle_flags & RIDE_LIFECYCLE_BROKEN_DOWN) {
 		RCT2_GLOBAL(RCT2_ADDRESS_COMMON_FORMAT_ARGS + 6, uint16) = ride->name;
 		RCT2_GLOBAL(RCT2_ADDRESS_COMMON_FORMAT_ARGS + 8, uint32) = ride->name_arguments;
@@ -1684,13 +1689,15 @@ int ride_modify(rct_xy_element *input)
 	int rideIndex, x, y, z, direction, type;
 	rct_xy_element mapElement, endOfTrackElement;
 	rct_ride *ride;
+	rct_ride_type *rideType;
 	rct_window *constructionWindow;
 
 	mapElement = *input;
 	rideIndex = mapElement.element->properties.track.ride_index;
 	ride = get_ride(rideIndex);
+	rideType = get_ride_entry(rideIndex);
 
-	if (!ride_check_if_construction_allowed(ride))
+	if ((ride == NULL) || (rideType == NULL) || !ride_check_if_construction_allowed(ride))
 		return 0;
 
 	if (ride->lifecycle_flags & RIDE_LIFECYCLE_INDESTRUCTIBLE) {
@@ -4940,7 +4947,10 @@ void loc_6B51C0(int rideIndex)
 
 		ride_try_get_origin_element(rideIndex, &trackElement);
 		ride_find_track_gap(&trackElement, &trackElement);
-		ride_modify(&trackElement);
+		int ok = ride_modify(&trackElement);
+		if (ok == 0) {
+			return;
+		}
 
 		w = window_find_by_class(WC_RIDE_CONSTRUCTION);
 		if (w != NULL)

src/ride/track.c

@@ -4384,7 +4384,7 @@ static money32 track_place(int rideIndex, int type, int originX, int originY, in
 		return MONEY32_UNDEFINED;
 	}
 	rct_ride_type *rideEntry = get_ride_entry(ride->subtype);
-	if (rideEntry == (rct_ride_type *)0xFFFFFFFF)
+	if (rideEntry == (rct_ride_type *)0xFFFFFFFF || rideEntry == NULL)
 	{
 		log_warning("Invalid ride type for track placement, rideIndex = %d", rideIndex);
 		return MONEY32_UNDEFINED;

src/windows/ride.c

@@ -1159,7 +1159,10 @@ void window_ride_disable_tabs(rct_window *w)
 
 	rct_ride_type *type = get_ride_entry(ride->subtype);
 
-	if ((type->flags & RIDE_ENTRY_FLAG_19) != 0)
+	if (type == NULL) {
+		disabled_tabs |= 1 << WIDX_TAB_2 | 1 << WIDX_TAB_3 | 1 << WIDX_TAB_4 | 1 << WIDX_TAB_5 | 1 << WIDX_TAB_6
+					   | 1 << WIDX_TAB_7 | 1 << WIDX_TAB_8 | 1 << WIDX_TAB_9 | 1 << WIDX_TAB_10;
+	} else if ((type->flags & RIDE_ENTRY_FLAG_19) != 0)
 		disabled_tabs |= (1 << WIDX_TAB_5); // 0x100
 
 	w->disabled_widgets = disabled_tabs;
@@ -3360,6 +3363,9 @@ static void window_ride_maintenance_mousedown(int widgetIndex, rct_window *w, rc
 
 	ride = get_ride(w->number);
 	ride_type = get_ride_entry(ride->subtype);
+	if (ride_type == NULL) {
+		return;
+	}
 
 	switch (widgetIndex) {
 	case WIDX_INSPECTION_INTERVAL_DROPDOWN:

src/windows/ride_construction.c

@@ -2693,6 +2693,9 @@ static void window_ride_construction_update_enabled_track_pieces()
 	rct_ride *ride = get_ride(_currentRideIndex);
 	rct_ride_type *rideEntry = get_ride_entry_by_ride(ride);
 
+	if (rideEntry == NULL)
+		return;
+
 	int rideType = _currentTrackCovered & 2 ? RCT2_ADDRESS(0x0097D4F5, uint8)[ride->type * 8] : ride->type;
 	_enabledRidePiecesA = rideEntry->enabledTrackPiecesA & RCT2_ADDRESS(0x01357444, uint32)[rideType];
 	_enabledRidePiecesB = rideEntry->enabledTrackPiecesB & RCT2_ADDRESS(0x01357644, uint32)[rideType];