Stop main menu and CSM formspec input errors from crashing the game entirely on Android

src/client/game.cpp

@@ -195,8 +195,18 @@ struct LocalFormspecHandler : public TextDest
 			return;
 		}
 
-		if (m_client->modsLoaded())
-			m_client->getScript()->on_formspec_input(m_formname, fields);
+		if (m_client->modsLoaded()) {
+			try {
+				m_client->getScript()->on_formspec_input(m_formname, fields);
+			} catch (LuaError &e) {
+				const std::string error_message = std::string("LuaError: ") + e.what() +
+						strgettext("\nCheck debug.txt for details.");
+				m_client->setFatalError(error_message);
+#ifdef __ANDROID__
+				porting::handleError("LuaError (on_formspec_input)", error_message);
+#endif
+			}
+		}
 	}
 
 	Client *m_client = nullptr;

src/gui/guiEngine.cpp

@@ -48,7 +48,11 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 /******************************************************************************/
 void TextDestGuiEngine::gotText(const StringMap &fields)
 {
-	m_engine->getScriptIface()->handleMainMenuButtons(fields);
+	try {
+		m_engine->getScriptIface()->handleMainMenuButtons(fields);
+	} catch (LuaError &e) {
+		m_engine->handleMainMenuLuaError(e.what());
+	}
 }
 
 /******************************************************************************/
@@ -199,11 +203,7 @@ GUIEngine::GUIEngine(JoystickController *joystick,
 
 		run();
 	} catch (LuaError &e) {
-		errorstream << "Main menu error: " << e.what() << std::endl;
-		m_data->script_data.errormessage = e.what();
-#ifdef __ANDROID__
-		porting::handleError("Main menu error", e.what());
-#endif
+		handleMainMenuLuaError(e.what());
 	}
 
 	m_menu->quitMenu();
@@ -211,6 +211,18 @@ GUIEngine::GUIEngine(JoystickController *joystick,
 	m_menu = NULL;
 }
 
+void GUIEngine::handleMainMenuLuaError(const char* errmsg) {
+	errorstream << "Main menu error: " << errmsg << std::endl;
+	m_data->script_data.errormessage = errmsg;
+#ifdef __ANDROID__
+	porting::handleError("Main menu error", errmsg);
+#endif
+
+	// Make the menu quit. Since an error message has been set this won't
+	// actually start the game.
+	m_startgame = true;
+}
+
 /******************************************************************************/
 bool GUIEngine::loadMainMenuScript()
 {

src/gui/guiEngine.h

@@ -157,6 +157,8 @@ public:
 	/** default destructor */
 	virtual ~GUIEngine();
 
+	void handleMainMenuLuaError(const char* errmsg);
+
 	/**
 	 * return MainMenuScripting interface
 	 */