Introduce a minimum supported save game format

CHANGELOG.md

@@ -106,6 +106,7 @@
     Feature #6447: Add LOD support to Object Paging
     Feature #6491: Add support for Qt6
     Feature #6556: Lua API for sounds
+    Feature #6624: Drop support for old saves
     Feature #6726: Lua API for creating new objects
     Feature #6864: Lua file access API
     Feature #6922: Improve launcher appearance

apps/openmw/mwstate/statemanagerimp.cpp

@@ -411,10 +411,25 @@ void MWState::StateManager::loadGame(const Character* character, const std::file
         ESM::ESMReader reader;
         reader.open(filepath);
 
-        if (reader.getFormatVersion() > ESM::CurrentSaveGameFormatVersion)
-            throw VersionMismatchError(
-                "This save file was created using a newer version of OpenMW and is thus not supported. Please upgrade "
-                "to the newest OpenMW version to load this file.");
+        ESM::FormatVersion version = reader.getFormatVersion();
+        if (version > ESM::CurrentSaveGameFormatVersion)
+            throw VersionMismatchError("#{OMWEngine:LoadingRequiresNewVersionError}");
+        else if (version < ESM::MinSupportedSaveGameFormatVersion)
+        {
+            const char* release;
+            // Report the last version still capable of reading this save
+            if (version <= ESM::OpenMW0_48SaveGameFormatVersion)
+                release = "OpenMW 0.48.0";
+            else
+            {
+                // Insert additional else if statements above to cover future releases
+                static_assert(ESM::MinSupportedSaveGameFormatVersion <= ESM::OpenMW0_49SaveGameFormatVersion);
+                release = "OpenMW 0.49.0";
+            }
+            auto l10n = MWBase::Environment::get().getL10nManager()->getContext("OMWEngine");
+            std::string message = l10n->formatMessage("LoadingRequiresOldVersionError", { "version" }, { release });
+            throw VersionMismatchError(message);
+        }
 
         std::map<int, int> contentFileMap = buildContentFileIndexMap(reader);
         reader.setContentFileMapping(&contentFileMap);
@@ -607,11 +622,7 @@ void MWState::StateManager::loadGame(const Character* character, const std::file
         std::vector<std::string> buttons;
         buttons.emplace_back("#{Interface:OK}");
 
-        std::string error;
-        if (typeid(e) == typeid(VersionMismatchError))
-            error = "#{OMWEngine:LoadingFailed}: #{OMWEngine:LoadingRequiresNewVersionError}";
-        else
-            error = "#{OMWEngine:LoadingFailed}: " + std::string(e.what());
+        std::string error = "#{OMWEngine:LoadingFailed}: " + std::string(e.what());
 
         MWBase::Environment::get().getWindowManager()->interactiveMessageBox(error, buttons);
     }

components/esm3/formatversion.hpp

@@ -26,6 +26,10 @@ namespace ESM
     inline constexpr FormatVersion MaxUseEsmCellIdFormatVersion = 26;
     inline constexpr FormatVersion MaxActiveSpellSlotIndexFormatVersion = 27;
     inline constexpr FormatVersion CurrentSaveGameFormatVersion = 29;
+
+    inline constexpr FormatVersion MinSupportedSaveGameFormatVersion = 0;
+    inline constexpr FormatVersion OpenMW0_48SaveGameFormatVersion = 21;
+    inline constexpr FormatVersion OpenMW0_49SaveGameFormatVersion = CurrentSaveGameFormatVersion;
 }
 
 #endif

files/data/l10n/OMWEngine/de.yaml

@@ -25,6 +25,9 @@ BuildingNavigationMesh: "Baue Navigationsgitter"
 #LoadingRequiresNewVersionError: |-
 #    This save file was created using a newer version of OpenMW and is thus not supported.
 #    Please upgrade to the newest OpenMW version to load this file.
+# LoadingRequiresOldVersionError: |-
+#     This save file was created using an older version of OpenMW in a format that is no longer supported.
+#     Load and save this file using {version} to upgrade it.
 #NewGameConfirmation: "Do you want to start a new game and lose the current one?"
 #SaveGameDenied: "The game cannot be saved right now."
 #SavingInProgress: "Saving..."

files/data/l10n/OMWEngine/en.yaml

@@ -22,6 +22,9 @@ LoadingInProgress: "Loading Save Game"
 LoadingRequiresNewVersionError: |-
     This save file was created using a newer version of OpenMW and is thus not supported.
     Please upgrade to the newest OpenMW version to load this file.
+LoadingRequiresOldVersionError: |-
+    This save file was created using an older version of OpenMW in a format that is no longer supported.
+    Load and save this file using {version} to upgrade it.
 NewGameConfirmation: "Do you want to start a new game and lose the current one?"
 SaveGameDenied: "The game cannot be saved right now."
 SavingInProgress: "Saving..."

files/data/l10n/OMWEngine/fr.yaml

@@ -22,6 +22,9 @@ LoadingInProgress: "Chargement de la sauvegarde"
 LoadingRequiresNewVersionError: |-
     Ce fichier de sauvegarde provient d'une version plus récente d'OpenMW, il n'est par consequent pas supporté.
     Mettez à jour votre version d'OpenMW afin de pouvoir charger cette sauvegarde.
+# LoadingRequiresOldVersionError: |-
+#     This save file was created using an older version of OpenMW in a format that is no longer supported.
+#     Load and save this file using {version} to upgrade it.
 NewGameConfirmation: "Voulez-vous démarrer une nouvelle partie ? Toute progression non sauvegardée sera perdue."
 SaveGameDenied: "Sauvegarde impossible"
 SavingInProgress: "Sauvegarde en cours..."

files/data/l10n/OMWEngine/ru.yaml

@@ -22,6 +22,9 @@ LoadingInProgress: "Загрузка сохранения"
 LoadingRequiresNewVersionError: |-
     Это сохранение создано более новой версией OpenMW и поэтому не может быть загружено.
     Обновите OpenMW до последней версии, чтобы загрузить этот файл.
+# LoadingRequiresOldVersionError: |-
+#     This save file was created using an older version of OpenMW in a format that is no longer supported.
+#     Load and save this file using {version} to upgrade it.
 NewGameConfirmation: "Вы хотите начать новую игру? Текущая игра будет потеряна."
 SaveGameDenied: "В данный момент игру нельзя сохранить."
 SavingInProgress: "Сохранение..."

files/data/l10n/OMWEngine/sv.yaml

@@ -22,6 +22,9 @@ LoadingInProgress: "Laddar sparat spel"
 LoadingRequiresNewVersionError: |-
     Denna sparfil skapades i en nyare version av OpenMW och stöds därför inte.
     Uppgradera till den senaste versionen av OpenMW för att ladda filen.
+# LoadingRequiresOldVersionError: |-
+#     This save file was created using an older version of OpenMW in a format that is no longer supported.
+#     Load and save this file using {version} to upgrade it.
 NewGameConfirmation: "Vill du starta ett nytt spel och förlora det pågående spelet?"
 SaveGameDenied: "Spelet kan inte sparas just nu."
 SavingInProgress: "Sparar..."