(svn r26629) -Fix [FS#6012]: If the video driver fails to supply a list of resolutions, display an error message.

src/lang/english.txt

@@ -969,6 +969,7 @@ STR_GAME_OPTIONS_BASE_MUSIC_TOOLTIP                             :{BLACK}Select t
 STR_GAME_OPTIONS_BASE_MUSIC_STATUS                              :{RED}{NUM} corrupted file{P "" s}
 STR_GAME_OPTIONS_BASE_MUSIC_DESCRIPTION_TOOLTIP                 :{BLACK}Additional information about the base music set
 
+STR_ERROR_RESOLUTION_LIST_FAILED                                :{WHITE}Failed to retrieve a list of supported resolutions
 STR_ERROR_FULLSCREEN_FAILED                                     :{WHITE}Fullscreen mode failed
 
 # Custom currency window

src/settings_gui.cpp

@@ -268,6 +268,8 @@ struct GameOptionsWindow : Window {
 			}
 
 			case WID_GO_RESOLUTION_DROPDOWN: // Setup resolution dropdown
+				if (_num_resolutions == 0) break;
+
 				list = new DropDownList();
 				*selected_index = GetCurRes();
 				for (int i = 0; i < _num_resolutions; i++) {
@@ -433,6 +435,8 @@ struct GameOptionsWindow : Window {
 				DropDownList *list = this->BuildDropDownList(widget, &selected);
 				if (list != NULL) {
 					ShowDropDownList(this, list, selected, widget);
+				} else {
+					if (widget == WID_GO_RESOLUTION_DROPDOWN) ShowErrorMessage(STR_ERROR_RESOLUTION_LIST_FAILED, INVALID_STRING_ID, WL_ERROR);
 				}
 				break;
 			}

src/widgets/dropdown.cpp

@@ -116,6 +116,8 @@ struct DropdownWindow : Window {
 	DropdownWindow(Window *parent, const DropDownList *list, int selected, int button, bool instant_close, const Point &position, const Dimension &size, Colours wi_colour, bool scroll)
 			: Window(&_dropdown_desc)
 	{
+		assert(list->Length() > 0);
+
 		this->position = position;
 
 		this->CreateNestedTree();