From 1caae7e87d2bb6562db0d6456cf792e81ad416f0 Mon Sep 17 00:00:00 2001
From: Camila Ayres <hello@camilasan.com>
Date: Mon, 14 Apr 2025 17:56:01 +0200
Subject: [PATCH 01/10] refactor(migration): move logic from Application to
 related classes.

- First look for legacy locations and then try to restore general, proxy
and accounts settings.
- Functions handling account migration go into AccountManager and
functions handling legacy config check go in ConfigFile.

Signed-off-by: Camila Ayres <hello@camilasan.com>
---
 src/gui/accountmanager.cpp | 264 +++++++++++++++++++------------------
 src/gui/accountmanager.h   |   8 +-
 src/gui/application.cpp    | 184 ++------------------------
 src/gui/application.h      |   4 -
 src/libsync/configfile.cpp | 120 +++++++++++++++++
 src/libsync/configfile.h   |   9 ++
 6 files changed, 280 insertions(+), 309 deletions(-)

diff --git a/src/gui/accountmanager.cpp b/src/gui/accountmanager.cpp
index 12c353da23be4..d6b4177f266a6 100644
--- a/src/gui/accountmanager.cpp
+++ b/src/gui/accountmanager.cpp
@@ -63,12 +63,6 @@ constexpr auto webflowAuthPrefix = "webflow_";
 
 constexpr auto networkProxyPasswordKeychainKeySuffixC = "_proxy_password";
 
-constexpr auto legacyRelativeConfigLocationC = "/ownCloud/owncloud.cfg";
-constexpr auto legacyCfgFileNameC = "owncloud.cfg";
-
-constexpr auto unbrandedRelativeConfigLocationC = "/Nextcloud/nextcloud.cfg";
-constexpr auto unbrandedCfgFileNameC = "nextcloud.cfg";
-
 // The maximum versions that this client can read
 constexpr auto maxAccountsVersion = 13;
 constexpr auto maxAccountVersion = 13;
@@ -89,12 +83,15 @@ AccountManager *AccountManager::instance()
     return &instance;
 }
 
-AccountManager::AccountsRestoreResult AccountManager::restore(const bool alsoRestoreLegacySettings)
+AccountManager::AccountsRestoreResult AccountManager::restore(const QString &legacyConfigFile, const bool alsoRestoreLegacySettings)
 {
     QStringList skipSettingsKeys;
     backwardMigrationSettingsKeys(&skipSettingsKeys, &skipSettingsKeys);
 
-    const auto settings = ConfigFile::settingsWithGroup(QLatin1String(accountsC));
+    const auto isLegacyMigration = !legacyConfigFile.isEmpty();
+    auto settings = isLegacyMigration ? std::make_unique<QSettings>(legacyConfigFile, QSettings::IniFormat)
+                                      : ConfigFile::settingsWithGroup(QLatin1String(accountsC));
+
     if (settings->status() != QSettings::NoError || !settings->isWritable()) {
         qCWarning(lcAccountManager) << "Could not read settings from" << settings->fileName()
                                     << settings->status();
@@ -107,13 +104,23 @@ AccountManager::AccountsRestoreResult AccountManager::restore(const bool alsoRes
         return AccountsRestoreSuccessWithSkipped;
     }
 
-    // If there are no accounts, check the old format.
-    if (settings->childGroups().isEmpty() && !settings->contains(QLatin1String(versionC)) && alsoRestoreLegacySettings) {
-        restoreFromLegacySettings();
-        return AccountsRestoreSuccessFromLegacyVersion;
+    qCWarning(lcAccountManager) << "Restoring settings" << settings->allKeys().join(", ") << "from" << (isLegacyMigration ? legacyConfigFile
+                                                                                                                          : ConfigFile().configFile());
+    // migrate general and proxy settings
+    if (isLegacyMigration && alsoRestoreLegacySettings) {
+        ConfigFile configFile;
+        configFile.setVfsEnabled(settings->value(configFile.isVfsEnabledC).toBool());
+        configFile.setLaunchOnSystemStartup(settings->value(configFile.launchOnSystemStartupC).toBool());
+        configFile.setOptionalServerNotifications(settings->value(configFile.optionalServerNotificationsC).toBool());
+        configFile.setPromptDeleteFiles(settings->value(configFile.promptDeleteC).toBool());
+        configFile.setShowCallNotifications(settings->value(configFile.showCallNotificationsC).toBool());
+        configFile.setShowChatNotifications(settings->value(configFile.showChatNotificationsC).toBool());
+        configFile.setShowInExplorerNavigationPane(settings->value(configFile.showInExplorerNavigationPaneC).toBool());
+        ClientProxy().saveProxyConfigurationFromSettings(*settings);
     }
 
-    auto result = AccountsRestoreSuccess;
+    auto result = isLegacyMigration ? AccountsRestoreSuccess : AccountsRestoreSuccessFromLegacyVersion;
+    settings->beginGroup(accountsC);
     const auto settingsChildGroups = settings->childGroups();
     for (const auto &accountId : settingsChildGroups) {
         settings->beginGroup(accountId);
@@ -135,6 +142,7 @@ AccountManager::AccountsRestoreResult AccountManager::restore(const bool alsoRes
         }
         settings->endGroup();
     }
+    settings->endGroup();
 
     return result;
 }
@@ -164,124 +172,6 @@ void AccountManager::backwardMigrationSettingsKeys(QStringList *deleteKeys, QStr
     }
 }
 
-bool AccountManager::restoreFromLegacySettings()
-{
-    qCInfo(lcAccountManager) << "Migrate: restoreFromLegacySettings, checking settings group"
-                             << Theme::instance()->appName();
-
-    // try to open the correctly themed settings
-    auto settings = ConfigFile::settingsWithGroup(Theme::instance()->appName());
-
-    auto wasLegacyImportDialogDisplayed = false;
-    const auto displayLegacyImportDialog = Theme::instance()->displayLegacyImportDialog();
-
-    // if the settings file could not be opened, the childKeys list is empty
-    // then try to load settings from a very old place
-    if (settings->childKeys().isEmpty()) {
-        // Legacy settings used QDesktopServices to get the location for the config folder in 2.4 and before
-        const auto legacy2_4CfgSettingsLocation = QString(QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) + QStringLiteral("/data"));
-        const auto legacy2_4CfgFileParentFolder = legacy2_4CfgSettingsLocation.left(legacy2_4CfgSettingsLocation.lastIndexOf('/'));
-
-        // 2.5+ (rest of 2.x series)
-        const auto legacy2_5CfgSettingsLocation = QStandardPaths::writableLocation(Utility::isWindows() ? QStandardPaths::AppDataLocation : QStandardPaths::AppConfigLocation);
-        const auto legacy2_5CfgFileParentFolder = legacy2_5CfgSettingsLocation.left(legacy2_5CfgSettingsLocation.lastIndexOf('/'));
-
-        // Now try the locations we use today
-        const auto fullLegacyCfgFile = QDir::fromNativeSeparators(settings->fileName());
-        const auto legacyCfgFileParentFolder = fullLegacyCfgFile.left(fullLegacyCfgFile.lastIndexOf('/'));
-        const auto legacyCfgFileGrandParentFolder = legacyCfgFileParentFolder.left(legacyCfgFileParentFolder.lastIndexOf('/'));
-
-        const auto legacyCfgFileNamePath = QString(QStringLiteral("/") + legacyCfgFileNameC);
-        const auto legacyCfgFileRelativePath = QString(legacyRelativeConfigLocationC);
-
-        auto legacyLocations = QVector<QString>{legacy2_4CfgFileParentFolder + legacyCfgFileRelativePath,
-                                                legacy2_5CfgFileParentFolder + legacyCfgFileRelativePath,
-                                                legacyCfgFileParentFolder + legacyCfgFileNamePath,
-                                                legacyCfgFileGrandParentFolder + legacyCfgFileRelativePath};
-
-        if (Theme::instance()->isBranded()) {
-            const auto unbrandedCfgFileNamePath = QString(QStringLiteral("/") + unbrandedCfgFileNameC);
-            const auto unbrandedCfgFileRelativePath = QString(unbrandedRelativeConfigLocationC);
-            legacyLocations.append({legacyCfgFileParentFolder + unbrandedCfgFileNamePath, legacyCfgFileGrandParentFolder + unbrandedCfgFileRelativePath});
-        }
-
-        for (const auto &configFile : legacyLocations) {
-            auto oCSettings = std::make_unique<QSettings>(configFile, QSettings::IniFormat);
-            if (oCSettings->status() != QSettings::Status::NoError) {
-                qCInfo(lcAccountManager) << "Error reading legacy configuration file" << oCSettings->status();
-                break;
-            }
-
-            oCSettings->beginGroup(QLatin1String(accountsC));
-            const auto accountsListSize = oCSettings->childGroups().size();
-            oCSettings->endGroup();
-            if (const QFileInfo configFileInfo(configFile);
-                configFileInfo.exists() && configFileInfo.isReadable()) {
-                qCInfo(lcAccountManager) << "Migrate: checking old config " << configFile;
-                if (!forceLegacyImport() && accountsListSize > 0 && displayLegacyImportDialog) {
-                    wasLegacyImportDialogDisplayed = true;
-                    const auto importQuestion = accountsListSize > 1
-                        ? tr("%1 accounts were detected from a legacy desktop client.\n"
-                             "Should the accounts be imported?").arg(QString::number(accountsListSize))
-                        : tr("1 account was detected from a legacy desktop client.\n"
-                             "Should the account be imported?");
-                    const auto importMessageBox = new QMessageBox(QMessageBox::Question, tr("Legacy import"), importQuestion);
-                    importMessageBox->addButton(tr("Import"), QMessageBox::AcceptRole);
-                    const auto skipButton = importMessageBox->addButton(tr("Skip"), QMessageBox::DestructiveRole);
-                    importMessageBox->exec();
-                    if (importMessageBox->clickedButton() == skipButton) {
-                        return false;
-                    }
-                }
-
-                qCInfo(lcAccountManager) << "Copy settings" << oCSettings->allKeys().join(", ");
-                settings = std::move(oCSettings);
-
-                ConfigFile::setDiscoveredLegacyConfigPath(configFileInfo.canonicalPath());
-                break;
-            } else {
-                qCInfo(lcAccountManager) << "Migrate: could not read old config " << configFile;
-            }
-        }
-    }
-
-    ConfigFile configFile;
-    configFile.setVfsEnabled(settings->value(configFile.isVfsEnabledC).toBool());
-    configFile.setLaunchOnSystemStartup(settings->value(configFile.launchOnSystemStartupC).toBool());
-    configFile.setOptionalServerNotifications(settings->value(configFile.optionalServerNotificationsC).toBool());
-    configFile.setPromptDeleteFiles(settings->value(configFile.promptDeleteC).toBool());
-    configFile.setShowCallNotifications(settings->value(configFile.showCallNotificationsC).toBool());
-    configFile.setShowChatNotifications(settings->value(configFile.showChatNotificationsC).toBool());
-    configFile.setShowInExplorerNavigationPane(settings->value(configFile.showInExplorerNavigationPaneC).toBool());
-    ClientProxy().saveProxyConfigurationFromSettings(*settings);
-    configFile.setUseUploadLimit(settings->value(configFile.useUploadLimitC).toInt());
-    configFile.setUploadLimit(settings->value(configFile.uploadLimitC).toInt());
-    configFile.setUseDownloadLimit(settings->value(configFile.useDownloadLimitC).toInt());
-    configFile.setDownloadLimit(settings->value(configFile.downloadLimitC).toInt());
-
-    // Try to load the single account.
-    if (!settings->childKeys().isEmpty()) {
-        settings->beginGroup(accountsC);
-        const auto childGroups = settings->childGroups();
-        for (const auto &accountId : childGroups) {
-            settings->beginGroup(accountId);
-            if (const auto acc = loadAccountHelper(*settings)) {
-                addAccount(acc);
-            }
-            settings->endGroup();
-        }
-        return true;
-    }
-
-    if (wasLegacyImportDialogDisplayed) {
-        QMessageBox::information(nullptr,
-                                 tr("Legacy import"),
-                                 tr("Could not import accounts from legacy client configuration."));
-    }
-
-    return false;
-}
-
 void AccountManager::save(bool saveCredentials)
 {
     const auto settings = ConfigFile::settingsWithGroup(QLatin1String(accountsC));
@@ -713,4 +603,116 @@ void AccountManager::setForceLegacyImport(const bool forceLegacyImport)
     _forceLegacyImport = forceLegacyImport;
     Q_EMIT forceLegacyImportChanged();
 }
+
+void AccountManager::setupAccountsAndFolders()
+{
+    const auto accountsRestoreResult = restoreLegacyAccount();
+
+    const auto foldersListSize = FolderMan::instance()->setupFolders();
+
+    const auto prettyNamesList = [](const QList<AccountStatePtr> &accounts) {
+        QStringList list;
+        for (const auto &account : accounts) {
+            list << account->account()->prettyName().prepend("- ");
+        }
+        return list.join("\n");
+    };
+
+    if (const auto accounts = AccountManager::instance()->accounts();
+        accountsRestoreResult == AccountManager::AccountsRestoreSuccessFromLegacyVersion
+        && !accounts.isEmpty()) {
+
+        const auto accountsListSize = accounts.size();
+        if (Theme::instance()->displayLegacyImportDialog()) {
+            const auto accountsRestoreMessage = accountsListSize > 1
+                ? tr("%1 accounts", "number of accounts imported").arg(QString::number(accountsListSize))
+                : tr("1 account");
+            const auto foldersRestoreMessage = foldersListSize > 1
+                ? tr("%1 folders", "number of folders imported").arg(QString::number(foldersListSize))
+                : tr("1 folder");
+            const auto messageBox = new QMessageBox(QMessageBox::Information,
+                                                    tr("Legacy import"),
+                                                    tr("Imported %1 and %2 from a legacy desktop client.\n%3",
+                                                       "number of accounts and folders imported. list of users.")
+                                                        .arg(accountsRestoreMessage,
+                                                             foldersRestoreMessage,
+                                                             prettyNamesList(accounts))
+                                                    );
+            messageBox->setWindowModality(Qt::NonModal);
+            messageBox->open();
+        }
+
+        qCWarning(lcAccountManager) << "Migration result AccountManager::AccountsRestoreResult:" << accountsRestoreResult;
+        qCWarning(lcAccountManager) << "Folders migrated: " << foldersListSize;
+        qCWarning(lcAccountManager) << accountsListSize << "account(s) were migrated:" << prettyNamesList(accounts);
+
+    } else {
+        qCWarning(lcAccountManager) << "Migration result AccountManager::AccountsRestoreResult: " << accountsRestoreResult;
+        qCWarning(lcAccountManager) << "Folders migrated: " << foldersListSize;
+        qCWarning(lcAccountManager) << "No accounts were migrated, prompting user to set up accounts and folders from scratch.";
+    }
+}
+
+AccountManager::AccountsRestoreResult AccountManager::restoreLegacyAccount()
+{
+    ConfigFile configFile;
+    const auto tryMigrate = configFile.overrideServerUrl().isEmpty();
+
+    auto accountsRestoreResult = AccountManager::AccountsRestoreFailure;
+    const auto legacyConfigFile = ConfigFile().findLegacyConfigFile();
+    if (legacyConfigFile.isEmpty()) {
+        return accountsRestoreResult;
+    }
+
+    const auto displayLegacyImportDialog = Theme::instance()->displayLegacyImportDialog();
+    auto oCSettings = std::make_unique<QSettings>(legacyConfigFile, QSettings::IniFormat);
+    oCSettings->beginGroup(QLatin1String(accountsC));
+    const auto accountsListSize = oCSettings->childGroups().size();
+    oCSettings->endGroup();
+
+    auto showDialogs = false;
+    if (!forceLegacyImport() && accountsListSize > 0 && displayLegacyImportDialog) {
+        showDialogs = true;
+        const auto importQuestion = accountsListSize > 1
+            ? tr("%1 accounts were detected from a legacy desktop client.\n"
+                 "Should the accounts be imported?").arg(QString::number(accountsListSize))
+            : tr("1 account was detected from a legacy desktop client.\n"
+                 "Should the account be imported?");
+        const auto importMessageBox = new QMessageBox(QMessageBox::Question, tr("Legacy import"), importQuestion);
+        importMessageBox->addButton(tr("Import"), QMessageBox::AcceptRole);
+        const auto skipButton = importMessageBox->addButton(tr("Skip"), QMessageBox::DestructiveRole);
+        importMessageBox->exec();
+        if (importMessageBox->clickedButton() == skipButton) {
+            QMessageBox::information(nullptr,
+                                     tr("Legacy import"),
+                                     tr("Could not import accounts from legacy client configuration."));
+            return accountsRestoreResult;
+        }
+
+        if (accountsRestoreResult = restore(legacyConfigFile, tryMigrate);
+            accountsRestoreResult == AccountManager::AccountsRestoreFailure) {
+            // If there is an error reading the account settings, try again
+            // after a couple of seconds, if that fails, give up.
+            // (non-existence is not an error)
+            Utility::sleep(5);
+            if (accountsRestoreResult = AccountManager::instance()->restore(legacyConfigFile, tryMigrate);
+                accountsRestoreResult == AccountManager::AccountsRestoreFailure
+                && showDialogs) {
+                qCCritical(lcAccountManager) << "Could not read the account settings, quitting";
+                QMessageBox::critical(
+                    nullptr,
+                    tr("Error accessing the configuration file"),
+                    tr("There was an error while accessing the configuration "
+                       "file at %1. Please make sure the file can be accessed by your system account.")
+                        .arg(ConfigFile().configFile()),
+                    QMessageBox::Ok
+                    );
+                QTimer::singleShot(0, qApp, &QCoreApplication::quit);
+            }
+        }
+    }
+
+    return accountsRestoreResult;
+}
+
 }
diff --git a/src/gui/accountmanager.h b/src/gui/accountmanager.h
index 9c965e497ad55..bb78f82610ef4 100644
--- a/src/gui/accountmanager.h
+++ b/src/gui/accountmanager.h
@@ -9,6 +9,8 @@
 #include "account.h"
 #include "accountstate.h"
 
+class QSettings;
+
 namespace OCC {
 
 /**
@@ -39,7 +41,7 @@ class AccountManager : public QObject
      * Returns false if there was an error reading the settings,
      * but note that settings not existing is not an error.
      */
-    AccountsRestoreResult restore(const bool alsoRestoreLegacySettings = true);
+    AccountsRestoreResult restore(const QString &legacyConfigFile, const bool alsoRestoreLegacySettings = true);
 
     /**
      * Add this account in the list of saved accounts.
@@ -82,6 +84,8 @@ class AccountManager : public QObject
      */
     static void backwardMigrationSettingsKeys(QStringList *deleteKeys, QStringList *ignoreKeys);
 
+    AccountManager::AccountsRestoreResult restoreLegacyAccount();
+    void setupAccountsAndFolders();
 public slots:
     /// Saves account data when adding user, when updating e.g. dav user, not including the credentials
     void saveAccount(const OCC::AccountPtr &newAccountData);
@@ -113,8 +117,6 @@ public slots:
     void saveAccountHelper(const AccountPtr &account, QSettings &settings, bool saveCredentials = true);
     AccountPtr loadAccountHelper(QSettings &settings);
 
-    bool restoreFromLegacySettings();
-
     [[nodiscard]] bool isAccountIdAvailable(const QString &id) const;
     [[nodiscard]] QString generateFreeAccountId() const;
 
diff --git a/src/gui/application.cpp b/src/gui/application.cpp
index 38dac21532aec..63056c05c75f1 100644
--- a/src/gui/application.cpp
+++ b/src/gui/application.cpp
@@ -247,46 +247,19 @@ Application::Application(int &argc, char **argv)
     setApplicationName(_theme->appName());
     setWindowIcon(_theme->applicationIcon());
 
-    if (!ConfigFile().exists()) {
-        setApplicationName(_theme->appNameGUI());
-        QString legacyDir = QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + "/" + APPLICATION_CONFIG_NAME;
-
-        if (legacyDir.endsWith('/')) {
-            legacyDir.chop(1); // macOS 10.11.x does not like trailing slash for rename/move.
-        }
-        setApplicationName(_theme->appName());
-        if (QFileInfo(legacyDir).isDir()) {
-            auto confDir = ConfigFile().configPath();
-
-            // macOS 10.11.x does not like trailing slash for rename/move.
-            if (confDir.endsWith('/')) {
-                confDir.chop(1);
-            }
-
-            qCInfo(lcApplication) << "Migrating old config from" << legacyDir << "to" << confDir;
-
-            if (!QFile::rename(legacyDir, confDir)) {
-                qCWarning(lcApplication) << "Failed to move the old config directory to its new location (" << legacyDir << "to" << confDir << ")";
+    parseOptions(arguments());
 
-                // Try to move the files one by one
-                if (QFileInfo(confDir).isDir() || QDir().mkdir(confDir)) {
-                    const QStringList filesList = QDir(legacyDir).entryList(QDir::Files);
-                    qCInfo(lcApplication) << "Will move the individual files" << filesList;
-                    for (const auto &name : filesList) {
-                        if (!QFile::rename(legacyDir + "/" + name,  confDir + "/" + name)) {
-                            qCWarning(lcApplication) << "Fallback move of " << name << "also failed";
-                        }
-                    }
-                }
-            } else {
-#ifndef Q_OS_WIN
-                // Create a symbolic link so a downgrade of the client would still find the config.
-                QFile::link(confDir, legacyDir);
-#endif
-            }
+    ConfigFile configFile;
+    if (configFile.exists()) {
+        if (const auto genericConfigLocation = QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + "/" + APPLICATION_CONFIG_NAME;
+            configFile.setupConfigFolderFromLegacyLocation(genericConfigLocation)) {
+            qCWarning(lcApplication) << "Setup of config folder and files from legacy location" << genericConfigLocation << "failed.";
         }
     } else {
-        setupConfigFile();
+        if (const auto appDataLocation = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
+            configFile.setupConfigFolderFromLegacyLocation(appDataLocation)) {
+            qCWarning(lcApplication) << "Setup of config folder and files from legacy location" << appDataLocation << "failed.";
+        }
     }
 
     if (_theme->doNotUseProxy()) {
@@ -298,7 +271,6 @@ Application::Application(int &argc, char **argv)
         }
     }
 
-    parseOptions(arguments());
     //no need to waste time;
     if (_helpOnly || _versionOnly) {
         return;
@@ -382,7 +354,9 @@ Application::Application(int &argc, char **argv)
     connect(this, &SharedTools::QtSingleApplication::messageReceived, this, &Application::slotParseMessage);
 
     // create accounts and folders from a legacy desktop client or from the current config file
-    setupAccountsAndFolders();
+    _folderManager.reset(new FolderMan);
+    FolderMan::instance()->setSyncEnabled(true);
+    AccountManager::instance()->setupAccountsAndFolders();
 
     setQuitOnLastWindowClosed(false);
 
@@ -468,138 +442,6 @@ Application::~Application()
     AccountManager::instance()->shutdown();
 }
 
-void Application::setupAccountsAndFolders()
-{
-    _folderManager.reset(new FolderMan);
-    FolderMan::instance()->setSyncEnabled(true);
-
-    const auto accountsRestoreResult = restoreLegacyAccount();
-
-    const auto foldersListSize = FolderMan::instance()->setupFolders();
-
-    const auto prettyNamesList = [](const QList<AccountStatePtr> &accounts) {
-        QStringList list;
-        for (const auto &account : accounts) {
-            list << account->account()->prettyName().prepend("- ");
-        }
-        return list.join("\n");
-    };
-
-    if (const auto accounts = AccountManager::instance()->accounts();
-        accountsRestoreResult == AccountManager::AccountsRestoreSuccessFromLegacyVersion
-        && !accounts.isEmpty()) {
-
-        const auto accountsListSize = accounts.size();
-        if (Theme::instance()->displayLegacyImportDialog()) {
-            const auto accountsRestoreMessage = accountsListSize > 1
-                ? tr("%1 accounts", "number of accounts imported").arg(QString::number(accountsListSize))
-                : tr("1 account");
-            const auto foldersRestoreMessage = foldersListSize > 1
-                ? tr("%1 folders", "number of folders imported").arg(QString::number(foldersListSize))
-                : tr("1 folder");
-            const auto messageBox = new QMessageBox(QMessageBox::Information,
-                                                    tr("Legacy import"),
-                                                    tr("Imported %1 and %2 from a legacy desktop client.\n%3",
-                                                       "number of accounts and folders imported. list of users.")
-                                                        .arg(accountsRestoreMessage,
-                                                             foldersRestoreMessage,
-                                                             prettyNamesList(accounts))
-                                                    );
-            messageBox->setWindowModality(Qt::NonModal);
-            messageBox->open();
-        }
-
-        qCWarning(lcApplication) << "Migration result AccountManager::AccountsRestoreResult:" << accountsRestoreResult;
-        qCWarning(lcApplication) << "Folders migrated: " << foldersListSize;
-        qCWarning(lcApplication) << accountsListSize << "account(s) were migrated:" << prettyNamesList(accounts);
-
-    } else {
-        qCWarning(lcApplication) << "Migration result AccountManager::AccountsRestoreResult: " << accountsRestoreResult;
-        qCWarning(lcApplication) << "Folders migrated: " << foldersListSize;
-        qCWarning(lcApplication) << "No accounts were migrated, prompting user to set up accounts and folders from scratch.";
-    }
-}
-
-void Application::setupConfigFile()
-{
-    // Migrate from version <= 2.4
-    setApplicationName(_theme->appNameGUI());
-#ifndef QT_WARNING_DISABLE_DEPRECATED // Was added in Qt 5.9
-    #define QT_WARNING_DISABLE_DEPRECATED QT_WARNING_DISABLE_GCC("-Wdeprecated-declarations")
-#endif
-    QT_WARNING_PUSH
-    QT_WARNING_DISABLE_DEPRECATED
-    QT_WARNING_POP
-    setApplicationName(_theme->appName());
-
-    auto oldDir = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
-
-    // macOS 10.11.x does not like trailing slash for rename/move.
-    if (oldDir.endsWith('/')) {
-        oldDir.chop(1);
-    }
-
-    if (!QFileInfo(oldDir).isDir()) {
-        return;
-    }
-
-    auto confDir = ConfigFile().configPath();
-
-    // macOS 10.11.x does not like trailing slash for rename/move.
-    if (confDir.endsWith('/')) {
-        confDir.chop(1);
-    }
-
-    qCInfo(lcApplication) << "Migrating old config from" << oldDir << "to" << confDir;
-    if (!QFile::rename(oldDir, confDir)) {
-        qCWarning(lcApplication) << "Failed to move the old config directory to its new location (" << oldDir << "to" << confDir << ")";
-
-        // Try to move the files one by one
-        if (QFileInfo(confDir).isDir() || QDir().mkdir(confDir)) {
-            const QStringList filesList = QDir(oldDir).entryList(QDir::Files);
-            qCInfo(lcApplication) << "Will move the individual files" << filesList;
-            for (const auto &name : filesList) {
-                if (!QFile::rename(oldDir + "/" + name,  confDir + "/" + name)) {
-                    qCWarning(lcApplication) << "Fallback move of " << name << "also failed";
-                }
-            }
-        }
-    } else {
-#ifndef Q_OS_WIN
-        // Create a symbolic link so a downgrade of the client would still find the config.
-        QFile::link(confDir, oldDir);
-#endif
-    }
-}
-
-AccountManager::AccountsRestoreResult Application::restoreLegacyAccount()
-{
-    ConfigFile cfg;
-    const auto tryMigrate = cfg.overrideServerUrl().isEmpty();
-    auto accountsRestoreResult = AccountManager::AccountsRestoreFailure;
-    if (accountsRestoreResult = AccountManager::instance()->restore(tryMigrate);
-        accountsRestoreResult == AccountManager::AccountsRestoreFailure) {
-        // If there is an error reading the account settings, try again
-        // after a couple of seconds, if that fails, give up.
-        // (non-existence is not an error)
-        Utility::sleep(5);
-        if (accountsRestoreResult = AccountManager::instance()->restore(tryMigrate);
-            accountsRestoreResult == AccountManager::AccountsRestoreFailure) {
-            qCCritical(lcApplication) << "Could not read the account settings, quitting";
-            QMessageBox::critical(
-                nullptr,
-                tr("Error accessing the configuration file"),
-                tr("There was an error while accessing the configuration "
-                   "file at %1. Please make sure the file can be accessed by your system account.")
-                    .arg(ConfigFile().configFile()),
-                QMessageBox::Ok
-            );
-            QTimer::singleShot(0, qApp, &QCoreApplication::quit);
-        }
-    }
-    return accountsRestoreResult;
-}
-
 void Application::slotAccountStateRemoved(AccountState *accountState)
 {
     if (_gui) {
diff --git a/src/gui/application.h b/src/gui/application.h
index caba9df0e893f..92a4c9e6462cb 100644
--- a/src/gui/application.h
+++ b/src/gui/application.h
@@ -100,10 +100,6 @@ protected slots:
 
     void handleEditLocallyFromOptions();
 
-    AccountManager::AccountsRestoreResult restoreLegacyAccount();
-    void setupConfigFile();
-    void setupAccountsAndFolders();
-
     /**
      * Maybe a newer version of the client was used with this config file:
      * if so, backup, confirm with user and remove the config that can't be read.
diff --git a/src/libsync/configfile.cpp b/src/libsync/configfile.cpp
index a1eed97c33853..866dad4b5f261 100644
--- a/src/libsync/configfile.cpp
+++ b/src/libsync/configfile.cpp
@@ -97,6 +97,12 @@ static const QString defaultEnterpriseChannel = "enterprise";
 static constexpr char languageC[] = "language";
 
 static constexpr int deleteFilesThresholdDefaultValue = 100;
+
+constexpr auto accountsC = "Accounts";
+constexpr auto legacyRelativeConfigLocationC = "/ownCloud/owncloud.cfg";
+constexpr auto legacyCfgFileNameC = "owncloud.cfg";
+constexpr auto unbrandedRelativeConfigLocationC = "/copyNextcloud/copyNextcloud.cfg";
+constexpr auto unbrandedCfgFileNameC = "copyNextcloud.cfg";
 }
 
 namespace OCC {
@@ -1294,4 +1300,118 @@ void ConfigFile::setDiscoveredLegacyConfigPath(const QString &discoveredLegacyCo
     _discoveredLegacyConfigPath = discoveredLegacyConfigPath;
 }
 
+bool ConfigFile::setupConfigFolderFromLegacyLocation(const QString &legacyLocation) const
+{
+    // Migrate from version <= 2.4
+    qApp->setApplicationName(Theme::instance()->appNameGUI());
+#ifndef QT_WARNING_DISABLE_DEPRECATED // Was added in Qt 5.9
+    #define QT_WARNING_DISABLE_DEPRECATED QT_WARNING_DISABLE_GCC("-Wdeprecated-declarations")
+#endif
+QT_WARNING_PUSH
+QT_WARNING_DISABLE_DEPRECATED
+QT_WARNING_POP
+    qApp->setApplicationName(Theme::instance()->appName());
+
+    auto legacyDir = legacyLocation;
+    if (legacyDir.endsWith('/')) {
+        legacyDir.chop(1); // macOS 10.11.x does not like trailing slash for rename/move.
+    }
+
+    if (!QFileInfo(legacyDir).isDir()) {
+        return false;
+    }
+
+    auto confDir = ConfigFile().configPath();
+    if (confDir.endsWith('/')) {
+        confDir.chop(1);
+    }
+
+    qCInfo(lcConfigFile) << "Migrating old config from" << legacyDir << "to" << confDir;
+    if (!QFile::rename(legacyDir, confDir)) {
+        qCWarning(lcConfigFile) << "Failed to move the old config directory" << legacyDir << "to new location" << confDir;
+        if (QFileInfo(confDir).isDir() || QDir().mkdir(confDir)) {
+            const QStringList filesList = QDir(legacyDir).entryList(QDir::Files);
+            qCInfo(lcConfigFile) << "Will move the individual files:" << filesList;
+            auto setupCompleted = false;
+            for (const auto &name : filesList) {
+                if (!QFile::rename(legacyDir + "/" + name,  confDir + "/" + name)) {
+                    qCDebug(lcConfigFile) << "Fallback move of " << name << "also failed";
+                    continue;
+                }
+                setupCompleted = true;
+                qCInfo(lcConfigFile)  << "Move of " << name << "succeeded.";
+            }
+            return setupCompleted;
+        }
+    } else {
+#ifndef Q_OS_WIN
+        // Create a symbolic link so a downgrade of the client would still find the config.
+        return QFile::link(confDir, legacyDir);
+#endif
+    }
+
+    return false;
+}
+
+QString ConfigFile::findLegacyConfigFile() const
+{
+    qCInfo(lcConfigFile) << "Migrate: restoreFromLegacySettings, checking settings group"
+                          << Theme::instance()->appName();
+
+           // try to open the correctly themed settings
+    auto settings = ConfigFile::settingsWithGroup(Theme::instance()->appName());
+
+
+    QString validLegacyConfigFile;
+    // if the settings file could not be opened, the childKeys list is empty
+    // then try to load settings from a very old place
+    if (settings->childKeys().isEmpty()) {
+        // Legacy settings used QDesktopServices to get the location for the config folder in 2.4 and before
+        const auto legacy2_4CfgSettingsLocation = QString(QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) + QStringLiteral("/data"));
+        const auto legacy2_4CfgFileParentFolder = legacy2_4CfgSettingsLocation.left(legacy2_4CfgSettingsLocation.lastIndexOf('/'));
+
+               // 2.5+ (rest of 2.x series)
+        const auto legacy2_5CfgSettingsLocation = QStandardPaths::writableLocation(Utility::isWindows() ? QStandardPaths::AppDataLocation : QStandardPaths::AppConfigLocation);
+        const auto legacy2_5CfgFileParentFolder = legacy2_5CfgSettingsLocation.left(legacy2_5CfgSettingsLocation.lastIndexOf('/'));
+
+               // Now try the locations we use today
+        const auto fullLegacyCfgFile = QDir::fromNativeSeparators(settings->fileName());
+        const auto legacyCfgFileParentFolder = fullLegacyCfgFile.left(fullLegacyCfgFile.lastIndexOf('/'));
+        const auto legacyCfgFileGrandParentFolder = legacyCfgFileParentFolder.left(legacyCfgFileParentFolder.lastIndexOf('/'));
+
+        const auto legacyCfgFileNamePath = QString(QStringLiteral("/") + legacyCfgFileNameC);
+        const auto legacyCfgFileRelativePath = QString(legacyRelativeConfigLocationC);
+
+        auto legacyLocations = QVector<QString>{legacy2_4CfgFileParentFolder + legacyCfgFileRelativePath,
+                                                legacy2_5CfgFileParentFolder + legacyCfgFileRelativePath,
+                                                legacyCfgFileParentFolder + legacyCfgFileNamePath,
+                                                legacyCfgFileGrandParentFolder + legacyCfgFileRelativePath};
+
+        if (Theme::instance()->isBranded()) {
+            const auto unbrandedCfgFileNamePath = QString(QStringLiteral("/") + unbrandedCfgFileNameC);
+            const auto unbrandedCfgFileRelativePath = QString(unbrandedRelativeConfigLocationC);
+            legacyLocations.append({legacyCfgFileParentFolder + unbrandedCfgFileNamePath, legacyCfgFileGrandParentFolder + unbrandedCfgFileRelativePath});
+        }
+
+        for (const auto &configFile : legacyLocations) {
+            auto oCSettings = std::make_unique<QSettings>(configFile, QSettings::IniFormat);
+            if (oCSettings->status() != QSettings::Status::NoError) {
+                qCInfo(lcConfigFile) << "Error reading legacy configuration file" << oCSettings->status();
+                break;
+            }
+
+            if (const QFileInfo configFileInfo(configFile);
+                configFileInfo.exists() && configFileInfo.isReadable()) {
+                qCInfo(lcConfigFile) << "Migrate: checking old config " << configFile;
+                validLegacyConfigFile = configFile;
+                ConfigFile::setDiscoveredLegacyConfigPath(configFileInfo.canonicalPath());
+                break;
+            } else {
+                qCInfo(lcConfigFile()) << "Migrate: could not read old config " << configFile;
+            }
+        }
+    }
+
+    return validLegacyConfigFile;
+}
 }
diff --git a/src/libsync/configfile.h b/src/libsync/configfile.h
index 28fe084032cc9..6b63cc778a59a 100644
--- a/src/libsync/configfile.h
+++ b/src/libsync/configfile.h
@@ -258,6 +258,15 @@ class OWNCLOUDSYNC_EXPORT ConfigFile
     static constexpr char uploadLimitC[] = "BWLimit/uploadLimit";
     static constexpr char downloadLimitC[] = "BWLimit/downloadLimit";
 
+    bool setupConfigFolderFromLegacyLocation(const QString &legacyLocation) const;
+    /**
+     * Looks for config files with different names from older client versions
+     * in different locations
+     *
+     * Returns the found config file path found.
+     */
+    [[nodiscard]] QString findLegacyConfigFile() const;
+
 protected:
     [[nodiscard]] QVariant getPolicySetting(const QString &policy, const QVariant &defaultValue = QVariant()) const;
     void storeData(const QString &group, const QString &key, const QVariant &value);

From 03008a3650202f7445387c37e6e296ffb687def2 Mon Sep 17 00:00:00 2001
From: Camila Ayres <hello@camilasan.com>
Date: Fri, 2 May 2025 21:20:37 +0200
Subject: [PATCH 02/10] fix(migration): run client with --conf-dir after
 upgrade.

The client was failing to pick up the config file.

Signed-off-by: Camila Ayres <hello@camilasan.com>
---
 src/gui/accountmanager.cpp | 69 +++++++++++++++++++++-----------------
 src/gui/accountmanager.h   |  2 +-
 src/gui/application.cpp    | 22 ++++++++----
 src/libsync/configfile.cpp | 23 ++++++++++---
 src/libsync/configfile.h   |  5 ++-
 5 files changed, 77 insertions(+), 44 deletions(-)

diff --git a/src/gui/accountmanager.cpp b/src/gui/accountmanager.cpp
index d6b4177f266a6..ec3b074b33f86 100644
--- a/src/gui/accountmanager.cpp
+++ b/src/gui/accountmanager.cpp
@@ -606,7 +606,7 @@ void AccountManager::setForceLegacyImport(const bool forceLegacyImport)
 
 void AccountManager::setupAccountsAndFolders()
 {
-    const auto accountsRestoreResult = restoreLegacyAccount();
+    const auto accountsRestoreResult = restoreExistingAccounts();
 
     const auto foldersListSize = FolderMan::instance()->setupFolders();
 
@@ -653,25 +653,32 @@ void AccountManager::setupAccountsAndFolders()
     }
 }
 
-AccountManager::AccountsRestoreResult AccountManager::restoreLegacyAccount()
+AccountManager::AccountsRestoreResult AccountManager::restoreExistingAccounts()
 {
     ConfigFile configFile;
     const auto tryMigrate = configFile.overrideServerUrl().isEmpty();
 
-    auto accountsRestoreResult = AccountManager::AccountsRestoreFailure;
-    const auto legacyConfigFile = ConfigFile().findLegacyConfigFile();
-    if (legacyConfigFile.isEmpty()) {
-        return accountsRestoreResult;
-    }
+    auto isALegacyClientRestore = false;
+    const auto whichConfigFileToRestore = [&](){
+        const auto legacyConfigFile = configFile.discoveredLegacyConfigFile();
+        if (legacyConfigFile.isEmpty()) {
+            return configFile.configFile();
+        }
+
+        isALegacyClientRestore = true;
+        return legacyConfigFile;
+    };
 
-    const auto displayLegacyImportDialog = Theme::instance()->displayLegacyImportDialog();
-    auto oCSettings = std::make_unique<QSettings>(legacyConfigFile, QSettings::IniFormat);
+    auto accountsRestoreResult = AccountManager::AccountsRestoreFailure;
+    const auto configFileToRestore = whichConfigFileToRestore();
+    auto oCSettings = std::make_unique<QSettings>(configFileToRestore, QSettings::IniFormat);
     oCSettings->beginGroup(QLatin1String(accountsC));
     const auto accountsListSize = oCSettings->childGroups().size();
     oCSettings->endGroup();
-
     auto showDialogs = false;
-    if (!forceLegacyImport() && accountsListSize > 0 && displayLegacyImportDialog) {
+    if (!forceLegacyImport() && accountsListSize > 0
+        && Theme::instance()->displayLegacyImportDialog()
+        && isALegacyClientRestore) {
         showDialogs = true;
         const auto importQuestion = accountsListSize > 1
             ? tr("%1 accounts were detected from a legacy desktop client.\n"
@@ -688,27 +695,27 @@ AccountManager::AccountsRestoreResult AccountManager::restoreLegacyAccount()
                                      tr("Could not import accounts from legacy client configuration."));
             return accountsRestoreResult;
         }
+    }
 
-        if (accountsRestoreResult = restore(legacyConfigFile, tryMigrate);
-            accountsRestoreResult == AccountManager::AccountsRestoreFailure) {
-            // If there is an error reading the account settings, try again
-            // after a couple of seconds, if that fails, give up.
-            // (non-existence is not an error)
-            Utility::sleep(5);
-            if (accountsRestoreResult = AccountManager::instance()->restore(legacyConfigFile, tryMigrate);
-                accountsRestoreResult == AccountManager::AccountsRestoreFailure
-                && showDialogs) {
-                qCCritical(lcAccountManager) << "Could not read the account settings, quitting";
-                QMessageBox::critical(
-                    nullptr,
-                    tr("Error accessing the configuration file"),
-                    tr("There was an error while accessing the configuration "
-                       "file at %1. Please make sure the file can be accessed by your system account.")
-                        .arg(ConfigFile().configFile()),
-                    QMessageBox::Ok
-                    );
-                QTimer::singleShot(0, qApp, &QCoreApplication::quit);
-            }
+    if (accountsRestoreResult = restore(configFileToRestore, tryMigrate);
+        accountsRestoreResult == AccountManager::AccountsRestoreFailure) {
+        // If there is an error reading the account settings, try again
+        // after a couple of seconds, if that fails, give up.
+        // (non-existence is not an error)
+        Utility::sleep(5);
+        if (accountsRestoreResult = AccountManager::instance()->restore(configFileToRestore, tryMigrate);
+            accountsRestoreResult == AccountManager::AccountsRestoreFailure
+            && showDialogs) {
+            qCCritical(lcAccountManager) << "Could not read the account settings, quitting";
+            QMessageBox::critical(
+                nullptr,
+                tr("Error accessing the configuration file"),
+                tr("There was an error while accessing the configuration "
+                   "file at %1. Please make sure the file can be accessed by your system account.")
+                    .arg(ConfigFile().configFile()),
+                QMessageBox::Ok
+                );
+            QTimer::singleShot(0, qApp, &QCoreApplication::quit);
         }
     }
 
diff --git a/src/gui/accountmanager.h b/src/gui/accountmanager.h
index bb78f82610ef4..f781590058bee 100644
--- a/src/gui/accountmanager.h
+++ b/src/gui/accountmanager.h
@@ -84,7 +84,7 @@ class AccountManager : public QObject
      */
     static void backwardMigrationSettingsKeys(QStringList *deleteKeys, QStringList *ignoreKeys);
 
-    AccountManager::AccountsRestoreResult restoreLegacyAccount();
+    AccountManager::AccountsRestoreResult restoreExistingAccounts();
     void setupAccountsAndFolders();
 public slots:
     /// Saves account data when adding user, when updating e.g. dav user, not including the credentials
diff --git a/src/gui/application.cpp b/src/gui/application.cpp
index 63056c05c75f1..23629bb329cb4 100644
--- a/src/gui/application.cpp
+++ b/src/gui/application.cpp
@@ -250,18 +250,24 @@ Application::Application(int &argc, char **argv)
     parseOptions(arguments());
 
     ConfigFile configFile;
-    if (configFile.exists()) {
-        if (const auto genericConfigLocation = QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + "/" + APPLICATION_CONFIG_NAME;
-            configFile.setupConfigFolderFromLegacyLocation(genericConfigLocation)) {
-            qCWarning(lcApplication) << "Setup of config folder and files from legacy location" << genericConfigLocation << "failed.";
-        }
+
+    // First check if there is an existing config from a previous version
+    if (configFile.exists() && configVersionMigration()) {
+        qCWarning(lcApplication) << "Config version migration was not possible.";
     } else {
+        // check legacy location for existing config files
+        // if (const auto genericConfigLocation = QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + "/" + APPLICATION_CONFIG_NAME;
+        //     !configFile.setupConfigFolderFromLegacyLocation(genericConfigLocation)) {
+        //     qCWarning(lcApplication) << "Setup of config folder and files from legacy location" << genericConfigLocation << "failed.";
+        // } else
+
         if (const auto appDataLocation = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
-            configFile.setupConfigFolderFromLegacyLocation(appDataLocation)) {
+            !configFile.setupConfigFolderFromLegacyLocation(appDataLocation)) {
             qCWarning(lcApplication) << "Setup of config folder and files from legacy location" << appDataLocation << "failed.";
         }
     }
 
+<<<<<<< HEAD
     if (_theme->doNotUseProxy()) {
         ConfigFile().setProxyType(QNetworkProxy::NoProxy);
         for (const auto &accountState : AccountManager::instance()->accounts()) {
@@ -271,6 +277,8 @@ Application::Application(int &argc, char **argv)
         }
     }
 
+=======
+>>>>>>> 94a1ec663e (fix(migration): run client with --conf-dir after upgrade.)
     //no need to waste time;
     if (_helpOnly || _versionOnly) {
         return;
@@ -353,7 +361,7 @@ Application::Application(int &argc, char **argv)
 
     connect(this, &SharedTools::QtSingleApplication::messageReceived, this, &Application::slotParseMessage);
 
-    // create accounts and folders from a legacy desktop client or from the current config file
+    // create accounts and folders from a legacy desktop client or for a new config file
     _folderManager.reset(new FolderMan);
     FolderMan::instance()->setSyncEnabled(true);
     AccountManager::instance()->setupAccountsAndFolders();
diff --git a/src/libsync/configfile.cpp b/src/libsync/configfile.cpp
index 866dad4b5f261..c0012e2884dcc 100644
--- a/src/libsync/configfile.cpp
+++ b/src/libsync/configfile.cpp
@@ -113,6 +113,7 @@ Q_LOGGING_CATEGORY(lcConfigFile, "nextcloud.sync.configfile", QtInfoMsg)
 
 QString ConfigFile::_confDir = {};
 QString ConfigFile::_discoveredLegacyConfigPath = {};
+QString ConfigFile::_discoveredLegacyConfigFile = {};
 
 static chrono::milliseconds millisecondsValue(const QSettings &setting, const char *key,
     chrono::milliseconds defaultValue)
@@ -1300,6 +1301,20 @@ void ConfigFile::setDiscoveredLegacyConfigPath(const QString &discoveredLegacyCo
     _discoveredLegacyConfigPath = discoveredLegacyConfigPath;
 }
 
+QString ConfigFile::discoveredLegacyConfigFile()
+{
+    return _discoveredLegacyConfigFile;
+}
+
+void ConfigFile::setDiscoveredLegacyConfigFile(const QString &discoveredLegacyConfigFile)
+{
+    if (_discoveredLegacyConfigFile == discoveredLegacyConfigFile) {
+        return;
+    }
+
+    _discoveredLegacyConfigFile = discoveredLegacyConfigFile;
+}
+
 bool ConfigFile::setupConfigFolderFromLegacyLocation(const QString &legacyLocation) const
 {
     // Migrate from version <= 2.4
@@ -1353,15 +1368,14 @@ QT_WARNING_POP
     return false;
 }
 
-QString ConfigFile::findLegacyConfigFile() const
+QString ConfigFile::findLegacyClientConfigFile() const
 {
     qCInfo(lcConfigFile) << "Migrate: restoreFromLegacySettings, checking settings group"
                           << Theme::instance()->appName();
 
-           // try to open the correctly themed settings
+    // try to open the correctly themed settings
     auto settings = ConfigFile::settingsWithGroup(Theme::instance()->appName());
 
-
     QString validLegacyConfigFile;
     // if the settings file could not be opened, the childKeys list is empty
     // then try to load settings from a very old place
@@ -1404,7 +1418,8 @@ QString ConfigFile::findLegacyConfigFile() const
                 configFileInfo.exists() && configFileInfo.isReadable()) {
                 qCInfo(lcConfigFile) << "Migrate: checking old config " << configFile;
                 validLegacyConfigFile = configFile;
-                ConfigFile::setDiscoveredLegacyConfigPath(configFileInfo.canonicalPath());
+                setDiscoveredLegacyConfigFile(configFileInfo.filePath());
+                setDiscoveredLegacyConfigPath(configFileInfo.canonicalPath());
                 break;
             } else {
                 qCInfo(lcConfigFile()) << "Migrate: could not read old config " << configFile;
diff --git a/src/libsync/configfile.h b/src/libsync/configfile.h
index 6b63cc778a59a..af6a2550ab35a 100644
--- a/src/libsync/configfile.h
+++ b/src/libsync/configfile.h
@@ -244,6 +244,8 @@ class OWNCLOUDSYNC_EXPORT ConfigFile
     /// Set during first time migration of legacy accounts in AccountManager
     [[nodiscard]] static QString discoveredLegacyConfigPath();
     static void setDiscoveredLegacyConfigPath(const QString &discoveredLegacyConfigPath);
+    [[nodiscard]] static QString discoveredLegacyConfigFile();
+    static void setDiscoveredLegacyConfigFile(const QString &discoveredLegacyConfigFile);
 
     static constexpr char isVfsEnabledC[] = "isVfsEnabled";
     static constexpr char launchOnSystemStartupC[] = "launchOnSystemStartup";
@@ -265,7 +267,7 @@ class OWNCLOUDSYNC_EXPORT ConfigFile
      *
      * Returns the found config file path found.
      */
-    [[nodiscard]] QString findLegacyConfigFile() const;
+    [[nodiscard]] QString findLegacyClientConfigFile() const;
 
 protected:
     [[nodiscard]] QVariant getPolicySetting(const QString &policy, const QVariant &defaultValue = QVariant()) const;
@@ -285,6 +287,7 @@ class OWNCLOUDSYNC_EXPORT ConfigFile
 
     static QString _confDir;
     static QString _discoveredLegacyConfigPath;
+    static QString _discoveredLegacyConfigFile;
 };
 }
 #endif // CONFIGFILE_H

From ebf731d9108d04f7411a34355d631903868a95a0 Mon Sep 17 00:00:00 2001
From: Camila Ayres <hello@camilasan.com>
Date: Fri, 2 May 2025 22:13:18 +0200
Subject: [PATCH 03/10] refactor(migration): move logic from Application to
 related classes.

- Separate logic from widgets.
- Functions handling account migration go into AccountManager and
functions handling legacy config check go in ConfigFile.

Signed-off-by: Camila Ayres <hello@camilasan.com>
---
 src/gui/accountmanager.cpp | 127 ++++++------------
 src/gui/accountmanager.h   |   5 +-
 src/gui/application.cpp    | 259 +++++++++++++++++++------------------
 src/gui/application.h      |   8 +-
 src/gui/folderman.cpp      |  10 +-
 src/libsync/configfile.cpp |  64 +++++++--
 src/libsync/configfile.h   |  16 ++-
 7 files changed, 256 insertions(+), 233 deletions(-)

diff --git a/src/gui/accountmanager.cpp b/src/gui/accountmanager.cpp
index ec3b074b33f86..36b989872cf86 100644
--- a/src/gui/accountmanager.cpp
+++ b/src/gui/accountmanager.cpp
@@ -525,9 +525,9 @@ AccountPtr AccountManager::createAccount()
     const auto acc = Account::create();
     acc->setSslErrorHandler(new SslDialogErrorHandler);
     connect(acc.data(), &Account::proxyAuthenticationRequired,
-        ProxyAuthHandler::instance(), &ProxyAuthHandler::handleProxyAuthenticationRequired);
+            ProxyAuthHandler::instance(), &ProxyAuthHandler::handleProxyAuthenticationRequired);
     connect(acc.data(), &Account::lockFileError,
-        Systray::instance(), &Systray::showErrorMessageDialog);
+            Systray::instance(), &Systray::showErrorMessageDialog);
 
     return acc;
 }
@@ -604,82 +604,57 @@ void AccountManager::setForceLegacyImport(const bool forceLegacyImport)
     Q_EMIT forceLegacyImportChanged();
 }
 
-void AccountManager::setupAccountsAndFolders()
-{
-    const auto accountsRestoreResult = restoreExistingAccounts();
 
-    const auto foldersListSize = FolderMan::instance()->setupFolders();
+int AccountManager::setupAccounts()
+{
+    if (!confirmRestoreExistingAccounts()) {
+        return 0;
+    }
 
-    const auto prettyNamesList = [](const QList<AccountStatePtr> &accounts) {
-        QStringList list;
-        for (const auto &account : accounts) {
-            list << account->account()->prettyName().prepend("- ");
-        }
-        return list.join("\n");
-    };
-
-    if (const auto accounts = AccountManager::instance()->accounts();
-        accountsRestoreResult == AccountManager::AccountsRestoreSuccessFromLegacyVersion
-        && !accounts.isEmpty()) {
-
-        const auto accountsListSize = accounts.size();
-        if (Theme::instance()->displayLegacyImportDialog()) {
-            const auto accountsRestoreMessage = accountsListSize > 1
-                ? tr("%1 accounts", "number of accounts imported").arg(QString::number(accountsListSize))
-                : tr("1 account");
-            const auto foldersRestoreMessage = foldersListSize > 1
-                ? tr("%1 folders", "number of folders imported").arg(QString::number(foldersListSize))
-                : tr("1 folder");
-            const auto messageBox = new QMessageBox(QMessageBox::Information,
-                                                    tr("Legacy import"),
-                                                    tr("Imported %1 and %2 from a legacy desktop client.\n%3",
-                                                       "number of accounts and folders imported. list of users.")
-                                                        .arg(accountsRestoreMessage,
-                                                             foldersRestoreMessage,
-                                                             prettyNamesList(accounts))
-                                                    );
-            messageBox->setWindowModality(Qt::NonModal);
-            messageBox->open();
+    ConfigFile configFile;
+    const auto tryMigrate = configFile.overrideServerUrl().isEmpty();
+    const auto configFileToRestore = configFile.configFileToRestore();
+    auto accountsRestoreResult = AccountManager::AccountsRestoreResult::AccountsRestoreSuccess;
+    if (accountsRestoreResult = restore(configFileToRestore, tryMigrate);
+        accountsRestoreResult == AccountManager::AccountsRestoreFailure) {
+        // If there is an error reading the account settings, try again
+        // after a couple of seconds, if that fails, give up.
+        // (non-existence is not an error)
+        Utility::sleep(5);
+        if (accountsRestoreResult = restore(configFileToRestore, tryMigrate);
+            accountsRestoreResult == AccountManager::AccountsRestoreFailure) {
+            qCCritical(lcAccountManager) << "Could not read the account settings, quitting";
+            QMessageBox::critical(
+                nullptr,
+                tr("Error accessing the configuration file"),
+                tr("There was an error while accessing the configuration "
+                   "file at %1. Please make sure the file can be accessed by your system account.")
+                    .arg(ConfigFile().configFile()),
+                QMessageBox::Ok
+                );
+            QTimer::singleShot(0, qApp, &QCoreApplication::quit);
+            return 0;
         }
+    }
 
-        qCWarning(lcAccountManager) << "Migration result AccountManager::AccountsRestoreResult:" << accountsRestoreResult;
-        qCWarning(lcAccountManager) << "Folders migrated: " << foldersListSize;
-        qCWarning(lcAccountManager) << accountsListSize << "account(s) were migrated:" << prettyNamesList(accounts);
+    const auto accountsMigrated = AccountManager::instance()->accounts().size();
+    qCWarning(lcAccountManager) << "Migration result AccountManager::AccountsRestoreResult:" << accountsRestoreResult;
+    qCWarning(lcAccountManager) << "Accounts migrated:" << accountsMigrated;
 
-    } else {
-        qCWarning(lcAccountManager) << "Migration result AccountManager::AccountsRestoreResult: " << accountsRestoreResult;
-        qCWarning(lcAccountManager) << "Folders migrated: " << foldersListSize;
-        qCWarning(lcAccountManager) << "No accounts were migrated, prompting user to set up accounts and folders from scratch.";
-    }
+    return accountsMigrated;
 }
 
-AccountManager::AccountsRestoreResult AccountManager::restoreExistingAccounts()
+bool AccountManager::confirmRestoreExistingAccounts() const
 {
     ConfigFile configFile;
-    const auto tryMigrate = configFile.overrideServerUrl().isEmpty();
-
-    auto isALegacyClientRestore = false;
-    const auto whichConfigFileToRestore = [&](){
-        const auto legacyConfigFile = configFile.discoveredLegacyConfigFile();
-        if (legacyConfigFile.isEmpty()) {
-            return configFile.configFile();
-        }
-
-        isALegacyClientRestore = true;
-        return legacyConfigFile;
-    };
-
-    auto accountsRestoreResult = AccountManager::AccountsRestoreFailure;
-    const auto configFileToRestore = whichConfigFileToRestore();
+    const auto configFileToRestore = configFile.configFileToRestore();
     auto oCSettings = std::make_unique<QSettings>(configFileToRestore, QSettings::IniFormat);
     oCSettings->beginGroup(QLatin1String(accountsC));
     const auto accountsListSize = oCSettings->childGroups().size();
     oCSettings->endGroup();
-    auto showDialogs = false;
     if (!forceLegacyImport() && accountsListSize > 0
         && Theme::instance()->displayLegacyImportDialog()
-        && isALegacyClientRestore) {
-        showDialogs = true;
+        && !configFile.discoveredLegacyConfigFile().isEmpty()) {
         const auto importQuestion = accountsListSize > 1
             ? tr("%1 accounts were detected from a legacy desktop client.\n"
                  "Should the accounts be imported?").arg(QString::number(accountsListSize))
@@ -693,33 +668,11 @@ AccountManager::AccountsRestoreResult AccountManager::restoreExistingAccounts()
             QMessageBox::information(nullptr,
                                      tr("Legacy import"),
                                      tr("Could not import accounts from legacy client configuration."));
-            return accountsRestoreResult;
-        }
-    }
-
-    if (accountsRestoreResult = restore(configFileToRestore, tryMigrate);
-        accountsRestoreResult == AccountManager::AccountsRestoreFailure) {
-        // If there is an error reading the account settings, try again
-        // after a couple of seconds, if that fails, give up.
-        // (non-existence is not an error)
-        Utility::sleep(5);
-        if (accountsRestoreResult = AccountManager::instance()->restore(configFileToRestore, tryMigrate);
-            accountsRestoreResult == AccountManager::AccountsRestoreFailure
-            && showDialogs) {
-            qCCritical(lcAccountManager) << "Could not read the account settings, quitting";
-            QMessageBox::critical(
-                nullptr,
-                tr("Error accessing the configuration file"),
-                tr("There was an error while accessing the configuration "
-                   "file at %1. Please make sure the file can be accessed by your system account.")
-                    .arg(ConfigFile().configFile()),
-                QMessageBox::Ok
-                );
-            QTimer::singleShot(0, qApp, &QCoreApplication::quit);
+            return false;
         }
     }
 
-    return accountsRestoreResult;
+    return true;
 }
 
 }
diff --git a/src/gui/accountmanager.h b/src/gui/accountmanager.h
index f781590058bee..fee75e39b3718 100644
--- a/src/gui/accountmanager.h
+++ b/src/gui/accountmanager.h
@@ -84,8 +84,9 @@ class AccountManager : public QObject
      */
     static void backwardMigrationSettingsKeys(QStringList *deleteKeys, QStringList *ignoreKeys);
 
-    AccountManager::AccountsRestoreResult restoreExistingAccounts();
-    void setupAccountsAndFolders();
+    bool confirmRestoreExistingAccounts() const;
+    int setupAccounts();
+
 public slots:
     /// Saves account data when adding user, when updating e.g. dav user, not including the credentials
     void saveAccount(const OCC::AccountPtr &newAccountData);
diff --git a/src/gui/application.cpp b/src/gui/application.cpp
index 23629bb329cb4..364cd4f1486b5 100644
--- a/src/gui/application.cpp
+++ b/src/gui/application.cpp
@@ -115,93 +115,7 @@ namespace {
 
 // ----------------------------------------------------------------------------------
 
-bool Application::configVersionMigration()
-{
-    QStringList deleteKeys, ignoreKeys;
-    AccountManager::backwardMigrationSettingsKeys(&deleteKeys, &ignoreKeys);
-    FolderMan::backwardMigrationSettingsKeys(&deleteKeys, &ignoreKeys);
-
-    ConfigFile configFile;
-
-    // Did the client version change?
-    // (The client version is adjusted further down)
-    const auto currentVersion = QVersionNumber::fromString(MIRALL_VERSION_STRING);
-    const auto previousVersion = QVersionNumber::fromString(configFile.clientVersionString());
-    const auto versionChanged = previousVersion != currentVersion;
-    const auto downgrading = previousVersion > currentVersion;
-
-    if (versionChanged) {
-        qCInfo(lcApplication) << "Version changed. Removing updater settings from config.";
-        configFile.cleanUpdaterConfiguration();
-    }
-
-    if (!versionChanged && !(!deleteKeys.isEmpty() || (!ignoreKeys.isEmpty() && versionChanged))) {
-        return true;
-    }
-
-    // 'Launch on system startup' defaults to true > 3.11.x
-    const auto theme = Theme::instance();
-    configFile.setLaunchOnSystemStartup(configFile.launchOnSystemStartup());
-    Utility::setLaunchOnStartup(theme->appName(), theme->appNameGUI(), configFile.launchOnSystemStartup());
-
-    // default is now off to displaying dialog warning user of too many files deletion
-    configFile.setPromptDeleteFiles(false);
-
-    // back up all old config files
-    QStringList backupFilesList;
-    QDir configDir(configFile.configPath());
-    const auto anyConfigFileNameList = configDir.entryInfoList({"*.cfg"}, QDir::Files);
-    for (const auto &oldConfig : anyConfigFileNameList) {
-        const auto oldConfigFileName = oldConfig.fileName();
-        const auto oldConfigFilePath = oldConfig.filePath();
-        const auto newConfigFileName = configFile.configFile();
-        backupFilesList.append(configFile.backup(oldConfigFileName));
-        if (oldConfigFilePath != newConfigFileName) {
-            if (!QFile::rename(oldConfigFilePath, newConfigFileName)) {
-                qCWarning(lcApplication) << "Failed to rename configuration file from" << oldConfigFilePath << "to" << newConfigFileName;
-            }
-        }
-    }
-
-    // We want to message the user either for destructive changes,
-    // or if we're ignoring something and the client version changed.
-    if (configFile.showConfigBackupWarning() && backupFilesList.count() > 0) {
-        QMessageBox box(
-            QMessageBox::Warning,
-            APPLICATION_SHORTNAME,
-            tr("Some settings were configured in %1 versions of this client and "
-               "use features that are not available in this version.<br>"
-               "<br>"
-               "Continuing will mean <b>%2 these settings</b>.<br>"
-               "<br>"
-               "The current configuration file was already backed up to <i>%3</i>.")
-                .arg((downgrading ? tr("newer", "newer software version") : tr("older", "older software version")),
-                     deleteKeys.isEmpty()? tr("ignoring") : tr("deleting"),
-                     backupFilesList.join("<br>")));
-        box.addButton(tr("Quit"), QMessageBox::AcceptRole);
-        auto continueBtn = box.addButton(tr("Continue"), QMessageBox::DestructiveRole);
-
-        box.exec();
-        if (box.clickedButton() != continueBtn) {
-            QTimer::singleShot(0, qApp, &QCoreApplication::quit);
-            return false;
-        }
-    }
-
-    if (!deleteKeys.isEmpty()) {
-        auto settings = ConfigFile::settingsWithGroup("foo");
-        settings->endGroup();
-
-        // Wipe confusing keys from the future, ignore the others
-        for (const auto &badKey : std::as_const(deleteKeys)) {
-            settings->remove(badKey);
-            qCInfo(lcApplication) << "Migration: removed" << badKey << "key from settings.";
-        }
-    }
 
-    configFile.setClientVersionString(MIRALL_VERSION_STRING);
-    return true;
-}
 
 ownCloudGui *Application::gui() const
 {
@@ -249,25 +163,37 @@ Application::Application(int &argc, char **argv)
 
     parseOptions(arguments());
 
-    ConfigFile configFile;
+    //no need to waste time;
+    if (_helpOnly || _versionOnly) {
+        return;
+    }
 
-    // First check if there is an existing config from a previous version
-    if (configFile.exists() && configVersionMigration()) {
-        qCWarning(lcApplication) << "Config version migration was not possible.";
-    } else {
-        // check legacy location for existing config files
-        // if (const auto genericConfigLocation = QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + "/" + APPLICATION_CONFIG_NAME;
-        //     !configFile.setupConfigFolderFromLegacyLocation(genericConfigLocation)) {
-        //     qCWarning(lcApplication) << "Setup of config folder and files from legacy location" << genericConfigLocation << "failed.";
-        // } else
-
-        if (const auto appDataLocation = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
-            !configFile.setupConfigFolderFromLegacyLocation(appDataLocation)) {
-            qCWarning(lcApplication) << "Setup of config folder and files from legacy location" << appDataLocation << "failed.";
+    ConfigFile configFile;
+    // First check if there is a valid config file
+    if (const auto configExists = configFile.exists(); configExists && makeConfigSettingsBackwardCompatible()) {
+        qCWarning(lcApplication) << "Existing config is compatible with current version.";
+    } else if (!configExists) {
+        // look for previous used application name for config folder.
+        if (const auto genericConfigLocation = QString(QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + "/" + APPLICATION_CONFIG_NAME);
+            configFile.setupConfigFolderFromLegacyLocation(genericConfigLocation)) {
+            qCWarning(lcApplication) << "Copy of config folder and files from legacy location" << genericConfigLocation << "suceeded.";
+
+        // app data folder
+        } else if (const auto appDataLocation = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
+            configFile.setupConfigFolderFromLegacyLocation(genericConfigLocation)) {
+            qCWarning(lcApplication) << "Copy of config folder and files from legacy location" << appDataLocation << "suceeded.";
+        } else {
+            configFile.findLegacyClientConfigFile();
         }
     }
 
-<<<<<<< HEAD
+    if (_quitInstance) {
+        QTimer::singleShot(0, qApp, &QApplication::quit);
+        return;
+    }
+
+    setupAccountsAndFolders();
+
     if (_theme->doNotUseProxy()) {
         ConfigFile().setProxyType(QNetworkProxy::NoProxy);
         for (const auto &accountState : AccountManager::instance()->accounts()) {
@@ -277,18 +203,6 @@ Application::Application(int &argc, char **argv)
         }
     }
 
-=======
->>>>>>> 94a1ec663e (fix(migration): run client with --conf-dir after upgrade.)
-    //no need to waste time;
-    if (_helpOnly || _versionOnly) {
-        return;
-    }
-
-    if (_quitInstance) {
-        QTimer::singleShot(0, qApp, &QApplication::quit);
-        return;
-    }
-
     if (isRunning()) {
         return;
     }
@@ -296,12 +210,6 @@ Application::Application(int &argc, char **argv)
     setupLogging();
     setupTranslations();
 
-    // try to migrate legacy accounts and folders from a previous client version
-    // only copy the settings and check what should be skipped
-    if (!configVersionMigration()) {
-        qCWarning(lcApplication) << "Config version migration was not possible.";
-    }
-
     ConfigFile cfg;
     {
         auto shouldExit = false;
@@ -361,11 +269,6 @@ Application::Application(int &argc, char **argv)
 
     connect(this, &SharedTools::QtSingleApplication::messageReceived, this, &Application::slotParseMessage);
 
-    // create accounts and folders from a legacy desktop client or for a new config file
-    _folderManager.reset(new FolderMan);
-    FolderMan::instance()->setSyncEnabled(true);
-    AccountManager::instance()->setupAccountsAndFolders();
-
     setQuitOnLastWindowClosed(false);
 
     // Setting up the gui class will allow tray notifications for the
@@ -436,6 +339,114 @@ Application::Application(int &argc, char **argv)
 #endif
 }
 
+bool Application::confirmConfigChangesOrQuitApp(bool isDeleteKeysEmpty, const QStringList backupFilesList)
+{
+    // Message the user about changes
+    QMessageBox box(
+        QMessageBox::Warning,
+        APPLICATION_SHORTNAME,
+        tr("Some settings were configured in %1 versions of this client and "
+           "use features that are not available in this version.<br>"
+           "<br>"
+           "Continuing will mean <b>%2 these settings</b>.<br>"
+           "<br>"
+           "The current configuration file was already backed up to <i>%3</i>.")
+            .arg((ConfigFile().isDowngrade() ? tr("newer", "newer software version") : tr("older", "older software version")),
+                 isDeleteKeysEmpty? tr("ignoring") : tr("deleting"),
+                 backupFilesList.join("<br>")));
+    box.addButton(tr("Quit"), QMessageBox::AcceptRole);
+    auto continueBtn = box.addButton(tr("Continue"), QMessageBox::DestructiveRole);
+
+    box.exec();
+    if (box.clickedButton() != continueBtn) {
+        _quitInstance = true;
+        return false;
+    }
+
+    return true;
+}
+
+void Application::setupAccountsAndFolders()
+{
+    // create accounts and folders from a legacy desktop client or for a new config file
+    _folderManager.reset(new FolderMan);
+    FolderMan::instance()->setSyncEnabled(true);
+    const auto accounts = AccountManager::instance()->setupAccounts();
+    const auto folders = FolderMan::instance()->setupFolders();
+    if (accounts > 0 && Theme::instance()->displayLegacyImportDialog()) {
+        const auto prettyNamesList = [](const QList<AccountStatePtr> &accounts) {
+            QStringList list;
+            for (const auto &account : accounts) {
+                list << account->account()->prettyName().prepend("- ");
+            }
+            return list.join("\n");
+        };
+
+        const auto accountsRestoreMessage = accounts > 1
+            ? tr("%1 accounts", "number of accounts imported").arg(QString::number(accounts))
+            : tr("1 account");
+        const auto foldersRestoreMessage = folders > 1
+            ? tr("%1 folders", "number of folders imported").arg(QString::number(folders))
+            : tr("1 folder");
+        const auto messageBox = new QMessageBox(QMessageBox::Information,
+                                                tr("Legacy import"),
+                                                tr("Imported %1 and %2 from a legacy desktop client.\n%3",
+                                                   "number of accounts and folders imported. list of users.")
+                                                    .arg(accountsRestoreMessage,
+                                                         foldersRestoreMessage,
+                                                         prettyNamesList(AccountManager::instance()->accounts()))
+                                                );
+        messageBox->setWindowModality(Qt::NonModal);
+        messageBox->open();
+    }
+
+    ConfigFile().setClientVersionString(MIRALL_VERSION_STRING);
+}
+
+bool Application::makeConfigSettingsBackwardCompatible()
+{
+    ConfigFile configFile;
+    const auto didVersionChanged = configFile.isUpgrade() || configFile.isDowngrade();
+    if (!didVersionChanged) {
+        qCInfo(lcApplication) << "No upgrade or downgrade detected.";
+        return true;
+    }
+
+    configFile.cleanUpdaterConfiguration();
+
+    QStringList deleteKeys, ignoreKeys;
+    AccountManager::backwardMigrationSettingsKeys(&deleteKeys, &ignoreKeys);
+    FolderMan::backwardMigrationSettingsKeys(&deleteKeys, &ignoreKeys);
+    if (!didVersionChanged && !(!deleteKeys.isEmpty() || (!ignoreKeys.isEmpty() && didVersionChanged))) {
+        qCInfo(lcApplication) << "There are no settings to delete or to ignore. No need to change the current config file.";
+        return true;
+    }
+
+    const auto isDeleteKeysEmpty = deleteKeys.isEmpty();
+    if (const auto backupFilesList = configFile.backupConfigFiles();
+        configFile.showConfigBackupWarning()
+        && backupFilesList.size() > 0
+        && !confirmConfigChangesOrQuitApp(isDeleteKeysEmpty, backupFilesList)) {
+        return false;
+    }
+
+    if (!isDeleteKeysEmpty) {
+        auto settings = configFile.settingsWithGroup("foo");
+        settings->endGroup();
+
+        // Wipe confusing keys from the future, ignore the others
+        for (const auto &badKey : std::as_const(deleteKeys)) {
+            settings->remove(badKey);
+            qCDebug(lcApplication) << "Migration: removed" << badKey << "key from settings.";
+        }
+    }
+
+    configFile.setClientVersionString(MIRALL_VERSION_STRING);
+    qCDebug(lcApplication) << "Client version changed to" << configFile.clientVersionString();
+
+    return true;
+}
+
 Application::~Application()
 {
     // Make sure all folders are gone, otherwise removing the
diff --git a/src/gui/application.h b/src/gui/application.h
index 92a4c9e6462cb..30bf96967f08c 100644
--- a/src/gui/application.h
+++ b/src/gui/application.h
@@ -100,11 +100,9 @@ protected slots:
 
     void handleEditLocallyFromOptions();
 
-    /**
-     * Maybe a newer version of the client was used with this config file:
-     * if so, backup, confirm with user and remove the config that can't be read.
-     */
-    bool configVersionMigration();
+    bool makeConfigSettingsBackwardCompatible();
+    bool confirmConfigChangesOrQuitApp(bool isDeleteKeysEmpty, const QStringList backupFilesList);
+    void setupAccountsAndFolders();
 
     QPointer<ownCloudGui> _gui;
 
diff --git a/src/gui/folderman.cpp b/src/gui/folderman.cpp
index c11c4f1f1cc1f..d305343ea02c1 100644
--- a/src/gui/folderman.cpp
+++ b/src/gui/folderman.cpp
@@ -170,6 +170,10 @@ void FolderMan::registerFolderWithSocketApi(Folder *folder)
 
 int FolderMan::setupFolders()
 {
+    if (AccountManager::instance()->accounts().isEmpty()) {
+        return 0;
+    }
+
     Utility::registerUriHandlerForLocalEditing();
 
     unloadAndDeleteAllFolders();
@@ -186,7 +190,6 @@ int FolderMan::setupFolders()
 
     qCInfo(lcFolderMan) << "Setup folders from settings file";
 
-    // this is done in Application::configVersionMigration
     QStringList skipSettingsKeys;
     backwardMigrationSettingsKeys(&skipSettingsKeys, &skipSettingsKeys);
     const auto accounts = AccountManager::instance()->accounts();
@@ -225,7 +228,10 @@ int FolderMan::setupFolders()
         folder->processSwitchedToVirtualFiles();
     }
 
-    return _folderMap.size();
+    const auto foldersListSize = _folderMap.size();
+    qCWarning(lcFolderMan) << "Folders migrated: " << foldersListSize;
+
+    return foldersListSize;
 }
 
 void FolderMan::setupFoldersHelper(QSettings &settings, AccountStatePtr account, const QStringList &ignoreKeys, bool backwardsCompatible, bool foldersWithPlaceholders)
diff --git a/src/libsync/configfile.cpp b/src/libsync/configfile.cpp
index c0012e2884dcc..24c3de19281c0 100644
--- a/src/libsync/configfile.cpp
+++ b/src/libsync/configfile.cpp
@@ -98,11 +98,10 @@ static constexpr char languageC[] = "language";
 
 static constexpr int deleteFilesThresholdDefaultValue = 100;
 
-constexpr auto accountsC = "Accounts";
 constexpr auto legacyRelativeConfigLocationC = "/ownCloud/owncloud.cfg";
 constexpr auto legacyCfgFileNameC = "owncloud.cfg";
-constexpr auto unbrandedRelativeConfigLocationC = "/copyNextcloud/copyNextcloud.cfg";
-constexpr auto unbrandedCfgFileNameC = "copyNextcloud.cfg";
+constexpr auto unbrandedRelativeConfigLocationC = "/Nextcloud/nextcloud.cfg";
+constexpr auto unbrandedCfgFileNameC = "nextcloud.cfg";
 }
 
 namespace OCC {
@@ -1368,7 +1367,7 @@ QT_WARNING_POP
     return false;
 }
 
-QString ConfigFile::findLegacyClientConfigFile() const
+void ConfigFile::findLegacyClientConfigFile()
 {
     qCInfo(lcConfigFile) << "Migrate: restoreFromLegacySettings, checking settings group"
                           << Theme::instance()->appName();
@@ -1376,7 +1375,6 @@ QString ConfigFile::findLegacyClientConfigFile() const
     // try to open the correctly themed settings
     auto settings = ConfigFile::settingsWithGroup(Theme::instance()->appName());
 
-    QString validLegacyConfigFile;
     // if the settings file could not be opened, the childKeys list is empty
     // then try to load settings from a very old place
     if (settings->childKeys().isEmpty()) {
@@ -1384,11 +1382,11 @@ QString ConfigFile::findLegacyClientConfigFile() const
         const auto legacy2_4CfgSettingsLocation = QString(QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) + QStringLiteral("/data"));
         const auto legacy2_4CfgFileParentFolder = legacy2_4CfgSettingsLocation.left(legacy2_4CfgSettingsLocation.lastIndexOf('/'));
 
-               // 2.5+ (rest of 2.x series)
+        // 2.5+ (rest of 2.x series)
         const auto legacy2_5CfgSettingsLocation = QStandardPaths::writableLocation(Utility::isWindows() ? QStandardPaths::AppDataLocation : QStandardPaths::AppConfigLocation);
         const auto legacy2_5CfgFileParentFolder = legacy2_5CfgSettingsLocation.left(legacy2_5CfgSettingsLocation.lastIndexOf('/'));
 
-               // Now try the locations we use today
+        // Now try the locations we use today
         const auto fullLegacyCfgFile = QDir::fromNativeSeparators(settings->fileName());
         const auto legacyCfgFileParentFolder = fullLegacyCfgFile.left(fullLegacyCfgFile.lastIndexOf('/'));
         const auto legacyCfgFileGrandParentFolder = legacyCfgFileParentFolder.left(legacyCfgFileParentFolder.lastIndexOf('/'));
@@ -1416,8 +1414,7 @@ QString ConfigFile::findLegacyClientConfigFile() const
 
             if (const QFileInfo configFileInfo(configFile);
                 configFileInfo.exists() && configFileInfo.isReadable()) {
-                qCInfo(lcConfigFile) << "Migrate: checking old config " << configFile;
-                validLegacyConfigFile = configFile;
+                qCInfo(lcConfigFile) << "Migrate: saving old config file" << configFile;
                 setDiscoveredLegacyConfigFile(configFileInfo.filePath());
                 setDiscoveredLegacyConfigPath(configFileInfo.canonicalPath());
                 break;
@@ -1426,7 +1423,54 @@ QString ConfigFile::findLegacyClientConfigFile() const
             }
         }
     }
+}
+
+bool ConfigFile::isUpgrade() const
+{
+    return QVersionNumber::fromString(MIRALL_VERSION_STRING) > QVersionNumber::fromString(clientVersionString());
+}
+
+bool ConfigFile::isDowngrade() const
+{
+    return QVersionNumber::fromString(clientVersionString()) > QVersionNumber::fromString(MIRALL_VERSION_STRING);
+}
+
+QString ConfigFile::configFileToRestore() const
+{
+    const auto legacyConfigFile = discoveredLegacyConfigFile();
+    if (legacyConfigFile.isEmpty()) {
+        return configFile();
+    }
+
+    return legacyConfigFile;
+}
+
+QStringList ConfigFile::backupConfigFiles()
+{
+    // 'Launch on system startup' defaults to true > 3.11.x
+    const auto theme = Theme::instance();
+    setLaunchOnSystemStartup(launchOnSystemStartup());
+    Utility::setLaunchOnStartup(theme->appName(), theme->appNameGUI(), launchOnSystemStartup());
+
+    // default is now off to displaying dialog warning user of too many files deletion
+    setPromptDeleteFiles(false);
+
+    // back up all old config files
+    QStringList backupFilesList;
+    QDir configDir(configPath());
+    const auto anyConfigFileNameList = configDir.entryInfoList({"*.cfg"}, QDir::Files);
+    for (const auto &oldConfig : anyConfigFileNameList) {
+        const auto oldConfigFileName = oldConfig.fileName();
+        const auto oldConfigFilePath = oldConfig.filePath();
+        const auto newConfigFileName = configFile();
+        backupFilesList.append(backup(oldConfigFileName));
+        if (oldConfigFilePath != newConfigFileName) {
+            if (!QFile::rename(oldConfigFilePath, newConfigFileName)) {
+                qCWarning(lcConfigFile) << "Failed to rename configuration file from" << oldConfigFilePath << "to" << newConfigFileName;
+            }
+        }
+    }
 
-    return validLegacyConfigFile;
+    return backupFilesList;
 }
 }
diff --git a/src/libsync/configfile.h b/src/libsync/configfile.h
index af6a2550ab35a..8d74523aeed37 100644
--- a/src/libsync/configfile.h
+++ b/src/libsync/configfile.h
@@ -254,20 +254,30 @@ class OWNCLOUDSYNC_EXPORT ConfigFile
     static constexpr char showCallNotificationsC[] = "showCallNotifications";
     static constexpr char showChatNotificationsC[] = "showChatNotifications";
     static constexpr char showInExplorerNavigationPaneC[] = "showInExplorerNavigationPane";
-
     static constexpr char useUploadLimitC[] = "BWLimit/useUploadLimit";
     static constexpr char useDownloadLimitC[] = "BWLimit/useDownloadLimit";
     static constexpr char uploadLimitC[] = "BWLimit/uploadLimit";
     static constexpr char downloadLimitC[] = "BWLimit/downloadLimit";
 
-    bool setupConfigFolderFromLegacyLocation(const QString &legacyLocation) const;
+    [[nodiscard]]  bool setupConfigFolderFromLegacyLocation(const QString &legacyLocation) const;
+
     /**
      * Looks for config files with different names from older client versions
      * in different locations
      *
      * Returns the found config file path found.
      */
-    [[nodiscard]] QString findLegacyClientConfigFile() const;
+    void findLegacyClientConfigFile();
+
+    /**
+     * Maybe a newer version of the client was used with this config file: if so, backup.
+     * Return backup files list.
+     */
+    [[nodiscard]] QStringList backupConfigFiles();
+    [[nodiscard]] bool isUpgrade() const;
+    [[nodiscard]] bool isDowngrade() const;
+    [[nodiscard]] QString configFileToRestore() const;
+    [[nodiscard]] QString findLegacyConfigFile() const;
 
 protected:
     [[nodiscard]] QVariant getPolicySetting(const QString &policy, const QVariant &defaultValue = QVariant()) const;

From 45798db8f3f4d7c82bb9917fe1c821776c775c03 Mon Sep 17 00:00:00 2001
From: Camila Ayres <hello@camilasan.com>
Date: Wed, 30 Apr 2025 22:12:05 +0200
Subject: [PATCH 04/10] test(migration): wip! test each migration scenarion.

Signed-off-by: Camila Ayres <hello@camilasan.com>
---
 src/gui/folderman.h    |   2 +
 test/CMakeLists.txt    |   1 +
 test/testmigration.cpp | 290 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 293 insertions(+)
 create mode 100644 test/testmigration.cpp

diff --git a/src/gui/folderman.h b/src/gui/folderman.h
index 16e33b088089c..ad566a7e9261b 100644
--- a/src/gui/folderman.h
+++ b/src/gui/folderman.h
@@ -26,6 +26,7 @@ class TestFolderStatusModel;
 class ShareTestHelper;
 class EndToEndTestHelper;
 class TestSyncConflictsModel;
+class TestMigration;
 
 namespace OCC {
 
@@ -413,6 +414,7 @@ private slots:
     friend class ::ShareTestHelper;
     friend class ::EndToEndTestHelper;
     friend class ::TestFolderStatusModel;
+    friend class ::TestMigration;
 };
 
 } // namespace OCC
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index e4e9027a67277..eae537e8e547b 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -140,6 +140,7 @@ nextcloud_add_benchmark(LargeSync)
 nextcloud_add_test(Account)
 nextcloud_add_test(FolderMan)
 nextcloud_add_test(RemoteWipe)
+nextcloud_add_test(Migration)
 
 configure_file(test_journal.db "${PROJECT_BINARY_DIR}/bin/test_journal.db" COPYONLY)
 
diff --git a/test/testmigration.cpp b/test/testmigration.cpp
new file mode 100644
index 0000000000000..ade95db4ea7ec
--- /dev/null
+++ b/test/testmigration.cpp
@@ -0,0 +1,290 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <qglobal.h>
+#include <QTemporaryDir>
+#include <QtTest>
+#include <QtTest/qtestcase.h>
+
+#include "common/utility.h"
+#include "folderman.h"
+#include "account.h"
+#include "accountstate.h"
+#include "accountmanager.h"
+#include "configfile.h"
+#include "syncenginetestutils.h"
+#include "testhelper.h"
+#include "version.h"
+
+using namespace OCC;
+
+class TestMigration: public QObject
+{
+    Q_OBJECT
+
+    ConfigFile _configFile;
+    QTemporaryDir _temporaryDir;
+    std::unique_ptr<FolderMan> _folderMan;
+
+private:
+    static constexpr char legacyAppName[] = "ownCloud";
+    static constexpr char standardAppName[] = "Nextcloud";
+    static constexpr char brandedAppName[] = "Branded";
+    static constexpr char ocBrandedAppName[] = "branded";
+    static constexpr char legacyAppConfigContent[] = "[General]\n"
+        "clientVersion=5.3.2.15463\n"
+        "issuesWidgetFilter=FatalError, BlacklistedError, Excluded, Message, FilenameReserved\n"
+        "logHttp=false\n"
+        "optionalDesktopNotifications=true\n"
+        "\n"
+        "[Accounts]e\n"
+        "0\\Folders\\2ba4b09a-1223-aaaa-abcd-c2df238816d8\\davUrl=@Variant(http://oc.de/remote.php/dav/files/admin/)\n"
+        "0\\Folders\\2ba4b09a-1223-aaaa-abcd-c2df238816d8\\deployed=false\n"
+        "0\\Folders\\2ba4b09a-1223-aaaa-abcd-c2df238816d8\\displayString=ownCloud\n"
+        "0\\Folders\2ba4b09a-1223-aaaa-abcd-c2df238816d8\\ignoreHiddenFiles=true\n"
+        "0\\Folders\2ba4b09a-1223-aaaa-abcd-c2df238816d8\\journalPath=.sync_journal.db\n"
+        "0\\Folders\2ba4b09a-1223-aaaa-abcd-c2df238816d8\\localPath=/ownCloud/\n"
+        "0\\Folders\2ba4b09a-1223-aaaa-abcd-c2df238816d8\\paused=false\n"
+        "0\\Folders\\2ba4b09a-1223-aaaa-abcd-c2df238816d8\\priority=0\n"
+        "0\\Folders\\2ba4b09a-1223-aaaa-abcd-c2df238816d8\\targetPath=/\n"
+        "0\\Folders\\2ba4b09a-1223-aaaa-abcd-c2df238816d8\\version=13\n"
+        "0\\Folders\\2ba4b09a-1223-aaaa-abcd-c2df238816d8\\virtualFilesMode=off\n"
+        "0\\capabilities=@QVariant()\n"
+        "0\\dav_user=admin\n"
+        "0\\default_sync_root=/ownCloud\n"
+        "0\\display-name=admin\n"
+        "0\\http_CredentialVersion=1\n"
+        "0\\http_oauth=false\n"
+        "0\\http_user=admin\n"
+        "0\\supportsSpaces=true\n"
+        "0\\url=http://oc.de/\n"
+        "0\\user=admin\n"
+        "0\\userExplicitlySignedOut=false\n"
+        "0\\uuid=@Variant()\n"
+        "0\\version=13\n"
+        "version=13\n"
+        "\n"
+        "[Credentials]\n"
+        "ownCloud_credentials%oc.de%2ba4b09a-1223-aaaa-abcd-c2df238816d8\\http\\password=true";
+
+private slots:
+    void setupStandardConfigFolder()
+    {
+        QVERIFY(QDir(_temporaryDir.path()).mkpath(standardAppName));
+        const auto standardConfigFolder = QString(_temporaryDir.path() + "/" + standardAppName);
+        _configFile.setConfDir(standardConfigFolder);
+    }
+
+    void setupStandarConfig(const QString &version)
+    {
+        setupStandardConfigFolder();
+        QSettings settings(_configFile.configFile(), QSettings::IniFormat);
+        _configFile.setClientVersionString(version);
+        _configFile.setOptionalServerNotifications(true);
+        _configFile.setShowChatNotifications(true);
+        _configFile.setShowCallNotifications(true);
+        _configFile.setShowInExplorerNavigationPane(true);
+        _configFile.setShowInExplorerNavigationPane(true);
+        _configFile.setRemotePollInterval(std::chrono::milliseconds(1000));
+        _configFile.setAutoUpdateCheck(true, QString());
+        _configFile.setUpdateChannel("beta");
+        _configFile.setOverrideServerUrl("http://example.de");
+        _configFile.setOverrideLocalDir("A");
+        _configFile.setVfsEnabled(true);
+        _configFile.setProxyType(0);
+        _configFile.setVfsEnabled(true);
+        _configFile.setUseUploadLimit(0);
+        _configFile.setUploadLimit(1);
+        _configFile.setUseDownloadLimit(0);
+        _configFile.setUseDownloadLimit(1);
+        _configFile.setNewBigFolderSizeLimit(true, 500);
+        _configFile.setNotifyExistingFoldersOverLimit(true);
+        _configFile.setStopSyncingExistingFoldersOverLimit(true);
+        _configFile.setConfirmExternalStorage(true);
+        _configFile.setMoveToTrash(true);
+        _configFile.setForceLoginV2(true);
+        _configFile.setPromptDeleteFiles(true);
+        _configFile.setDeleteFilesThreshold(1);
+        _configFile.setMonoIcons(true);
+        _configFile.setAutomaticLogDir(true);
+        _configFile.setLogDir(_temporaryDir.path());
+        _configFile.setLogDebug(true);
+        _configFile.setLogExpire(72);
+        _configFile.setLogFlush(true);
+        _configFile.setCertificatePath(_temporaryDir.path());
+        _configFile.setCertificatePasswd("123456");
+        _configFile.setLaunchOnSystemStartup(true);
+        _configFile.setServerHasValidSubscription(true);
+        _configFile.setDesktopEnterpriseChannel("stable");
+        _configFile.setLanguage("pt");
+        settings.sync();
+        QVERIFY(_configFile.exists());
+        QScopedPointer<FakeQNAM> fakeQnam(new FakeQNAM({}));
+        OCC::AccountPtr account = OCC::Account::create();
+        account->setDavUser("user");
+        account->setDavDisplayName("Nextcloud user");
+        account->setProxyType(QNetworkProxy::ProxyType::HttpProxy);
+        account->setProxyUser("proxyuser");
+        account->setDownloadLimit(120);
+        account->setUploadLimit(120);
+        account->setDownloadLimitSetting(OCC::Account::AccountNetworkTransferLimitSetting::ManualLimit);
+        account->setServerVersion("30");
+        account->setCredentials(new FakeCredentials{fakeQnam.data()});
+        account->setUrl(QUrl(("http://example.de")));
+        const auto accountState = OCC::AccountManager::instance()->addAccount(account);
+        OCC::AccountManager::instance()->saveAccount(accountState->account());
+        OCC::FolderDefinition folderDefinition;
+        folderDefinition.localPath = "/standardAppName";
+        folderDefinition.targetPath = "/";
+        folderDefinition.alias = standardAppName;
+        _folderMan.reset({});
+        _folderMan.reset(new FolderMan{});
+        QVERIFY(_folderMan->addFolder(accountState, folderDefinition));
+    }
+
+
+    void initTestCase()
+    {
+        OCC::Logger::instance()->setLogFlush(true);
+        OCC::Logger::instance()->setLogDebug(true);
+
+        QStandardPaths::setTestModeEnabled(true);
+    }
+
+    // Upgrade - TODO: test running app with --confdir
+    void testUpgrade()
+    {
+        // create Nextcloud config with older version
+        setupStandarConfig("1.0.0");
+        const auto oldAppVersionNumber = QVersionNumber::fromString(_configFile.clientVersionString());
+        QVERIFY(_configFile.isUpgrade());
+
+        // backup old config
+        const auto backupFilesList = _configFile.backupConfigFiles();
+        QCOMPARE_GE(backupFilesList.size(), 1);
+
+        // successfully upgrade to new config
+        const auto afterUpgradeVersionNumber = MIRALL_VERSION_STRING;
+        _configFile.setClientVersionString(afterUpgradeVersionNumber);
+        QVERIFY(MIRALL_VERSION_STRING == _configFile.clientVersionString());
+
+        QCOMPARE_GE(AccountManager::instance()->accounts().size(), 1);
+        auto accounts = AccountManager::instance()->accounts().first()->settings();
+        QCOMPARE_GE(accounts->childGroups().size(), 1);
+        accounts->beginGroup(QLatin1String("Folders"));
+        QCOMPARE_GE(accounts->childGroups().size(), 1);
+        accounts->endGroup();
+    }
+
+    // From oC client to Nextcloud
+    void testMigrationFromOctoNextcloud()
+    {
+        QTemporaryDir tempDir;
+        QVERIFY(QDir(tempDir.path()).mkpath(legacyAppName));
+        const auto ocConfigFolder = QString(tempDir.path() + "/" + legacyAppName);
+        const auto ocConfig = QString(ocConfigFolder + "/" + QString(legacyAppName).toLower() + ".cfg");
+        QFile ocConfigFile(ocConfig);
+        QVERIFY(ocConfigFile.open(QFile::WriteOnly));
+        QCOMPARE_GE(ocConfigFile.write(legacyAppConfigContent, qstrlen(legacyAppConfigContent)), 0);
+        ocConfigFile.close();
+
+        ConfigFile configFile;
+
+        QVERIFY(QDir(tempDir.path()).mkpath(standardAppName));
+        const auto standardConfigFolder = QString(tempDir.path() + "/" + standardAppName);
+        configFile.setConfDir(standardConfigFolder);
+
+        // Nextcloud config file does not exist
+        QVERIFY(!configFile.exists());
+
+        // owncloud config files exists
+        configFile.findLegacyClientConfigFile();
+        const auto legacyConfigFile = configFile.discoveredLegacyConfigFile();
+        QVERIFY(!legacyConfigFile.isEmpty());
+        QCOMPARE(legacyConfigFile, ocConfig);
+
+        // TODO: add accounts and folders to AccountManager and FolderMan without UI interference
+        //_folderMan.reset({});
+        // _folderMan.reset(new FolderMan{});
+        // create accounts and folders from a legacy desktop client or for a new config file
+        // QVERIFY(AccountManager::instance()->restore(configFile.configFileToRestore()) != AccountManager::AccountsRestoreFailure);
+        // QCOMPARE_GE(FolderMan::instance()->setupFoldersMigration(), 1);
+        // QVERIFY(configFile.configFile().contains("nextcloud"));
+        // QCOMPARE_GE(AccountManager::instance()->accounts().size(), 1);
+        // auto accounts = AccountManager::instance()->accounts().first()->settings();
+        // QCOMPARE_GE(accounts->childGroups().size(), 1);
+        // accounts->beginGroup(QLatin1String("Folders"));
+        // QCOMPARE_GE(accounts->childGroups().size(), 1);
+        // accounts->endGroup();
+    }
+
+    // From branded oC client to branded Nextcloud
+    void testMigrationFromBrandedOctoBrandedNextcloud()
+    {
+        QCoreApplication::setApplicationName(brandedAppName);
+        setupStandardConfigFolder();
+
+        // branded legacy have directory name in lower case
+        QTemporaryDir tempDir;
+        QVERIFY(QDir(tempDir.path()).mkpath(ocBrandedAppName));
+        const auto ocBrandedConfigFolder = QString(tempDir.path() + "/" + ocBrandedAppName);
+        const auto ocBrandedConfig = QString(ocBrandedConfigFolder + "/" + QString(ocBrandedAppName) + ".cfg");
+        QFile::copy(_configFile.configFile(), QFileInfo(ocBrandedConfig).filePath());
+
+        QFile ocBrandedConfigFile(ocBrandedConfig);
+        QVERIFY(ocBrandedConfigFile.open(QFile::WriteOnly));
+        QCOMPARE_GE(ocBrandedConfigFile.write(legacyAppConfigContent, qstrlen(legacyAppConfigContent)), 0);
+        ocBrandedConfigFile.close();
+
+        ConfigFile configFile;
+        QVERIFY(QDir(tempDir.path()).mkpath(brandedAppName));
+        const auto brandedConfigFolder = QString(tempDir.path() + "/" + brandedAppName);
+        configFile.setConfDir(brandedConfigFolder);
+
+        const auto path3 = _configFile.configFile();
+        const auto path4 = configFile.configFile();
+
+        // our branded config file does not exist
+        QVERIFY(!configFile.exists());
+
+        // branded owncloud config files exists
+        configFile.findLegacyClientConfigFile();
+        const auto legacyConfigFile = configFile.discoveredLegacyConfigFile();
+        QVERIFY(!legacyConfigFile.isEmpty());
+        QCOMPARE(legacyConfigFile, ocBrandedConfig);
+    }
+
+
+    // From the standard Nextcloud client to a branded version
+    void testMigrationFromNextcloudToBranded()
+    {
+        setupStandardConfigFolder();
+
+        QTemporaryDir tempDir;
+        QVERIFY(QDir(tempDir.path()).mkpath(brandedAppName));
+        const auto brandedConfigFolder = QString(tempDir.path() + "/" + brandedAppName);
+        const auto brandedConfig = QString(brandedConfigFolder + "/" + QString(brandedAppName).toLower() + ".cfg");
+        QFile::copy(_configFile.configFile(), QFileInfo(brandedConfig).filePath());
+
+        ConfigFile configFile;
+        QVERIFY(QDir(tempDir.path()).mkpath(standardAppName));
+        const auto standardConfigFolder = QString(tempDir.path() + "/" + standardAppName);
+        configFile.setConfDir(standardConfigFolder);
+
+        // Nextcloud config file does not exist
+        QVERIFY(!configFile.exists());
+
+        // owncloud config files exists
+        configFile.findLegacyClientConfigFile();
+        const auto legacyConfigFile = configFile.discoveredLegacyConfigFile();
+        QVERIFY(!legacyConfigFile.isEmpty());
+        QCOMPARE(legacyConfigFile, brandedConfig);
+    }
+
+    // TODO: Downgrade
+};
+
+QTEST_GUILESS_MAIN(TestMigration)
+#include "testmigration.moc"

From 1c934f542fc66c37b0fe969c7b1d35b9739bf746 Mon Sep 17 00:00:00 2001
From: Camila Ayres <hello@camilasan.com>
Date: Tue, 13 May 2025 16:21:00 +0200
Subject: [PATCH 05/10] refactor: ConfigFile::findLegacyClientConfigFile().

Signed-off-by: Camila Ayres <hello@camilasan.com>
---
 src/libsync/configfile.cpp | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/libsync/configfile.cpp b/src/libsync/configfile.cpp
index 24c3de19281c0..28d2f783d33c4 100644
--- a/src/libsync/configfile.cpp
+++ b/src/libsync/configfile.cpp
@@ -1412,15 +1412,16 @@ void ConfigFile::findLegacyClientConfigFile()
                 break;
             }
 
-            if (const QFileInfo configFileInfo(configFile);
-                configFileInfo.exists() && configFileInfo.isReadable()) {
-                qCInfo(lcConfigFile) << "Migrate: saving old config file" << configFile;
-                setDiscoveredLegacyConfigFile(configFileInfo.filePath());
-                setDiscoveredLegacyConfigPath(configFileInfo.canonicalPath());
-                break;
-            } else {
+            const QFileInfo configFileInfo(configFile);
+            if (!configFileInfo.exists() || !configFileInfo.isReadable()) {
                 qCInfo(lcConfigFile()) << "Migrate: could not read old config " << configFile;
+                continue;
             }
+
+            qCInfo(lcConfigFile) << "Migrate: old config file" << configFile;
+            setDiscoveredLegacyConfigFile(configFileInfo.filePath());
+            setDiscoveredLegacyConfigPath(configFileInfo.canonicalPath());
+            break;
         }
     }
 }

From 19e9cee7c3031085ecd47e6cd4e8b2645b0dddeb Mon Sep 17 00:00:00 2001
From: Camila Ayres <hello@camilasan.com>
Date: Tue, 13 May 2025 16:43:17 +0200
Subject: [PATCH 06/10] refactor(migration): include more paths to search for
 legacy config files.

Signed-off-by: Camila Ayres <hello@camilasan.com>
---
 src/libsync/configfile.cpp | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/libsync/configfile.cpp b/src/libsync/configfile.cpp
index 28d2f783d33c4..dba96656f8075 100644
--- a/src/libsync/configfile.cpp
+++ b/src/libsync/configfile.cpp
@@ -1379,12 +1379,12 @@ void ConfigFile::findLegacyClientConfigFile()
     // then try to load settings from a very old place
     if (settings->childKeys().isEmpty()) {
         // Legacy settings used QDesktopServices to get the location for the config folder in 2.4 and before
-        const auto legacy2_4CfgSettingsLocation = QString(QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) + QStringLiteral("/data"));
-        const auto legacy2_4CfgFileParentFolder = legacy2_4CfgSettingsLocation.left(legacy2_4CfgSettingsLocation.lastIndexOf('/'));
+        const auto legacyStandardPaths = QString(QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) + QStringLiteral("/data"));
+        const auto legacyStandardPathsParentFolder = legacyStandardPaths.left(legacyStandardPaths.lastIndexOf('/'));
 
         // 2.5+ (rest of 2.x series)
-        const auto legacy2_5CfgSettingsLocation = QStandardPaths::writableLocation(Utility::isWindows() ? QStandardPaths::AppDataLocation : QStandardPaths::AppConfigLocation);
-        const auto legacy2_5CfgFileParentFolder = legacy2_5CfgSettingsLocation.left(legacy2_5CfgSettingsLocation.lastIndexOf('/'));
+        const auto standardPaths = QStandardPaths::writableLocation(Utility::isWindows() ? QStandardPaths::AppDataLocation : QStandardPaths::AppConfigLocation);
+        const auto standardPathsParentFolder = standardPaths.left(standardPaths.lastIndexOf('/'));
 
         // Now try the locations we use today
         const auto fullLegacyCfgFile = QDir::fromNativeSeparators(settings->fileName());
@@ -1394,17 +1394,21 @@ void ConfigFile::findLegacyClientConfigFile()
         const auto legacyCfgFileNamePath = QString(QStringLiteral("/") + legacyCfgFileNameC);
         const auto legacyCfgFileRelativePath = QString(legacyRelativeConfigLocationC);
 
-        auto legacyLocations = QVector<QString>{legacy2_4CfgFileParentFolder + legacyCfgFileRelativePath,
-                                                legacy2_5CfgFileParentFolder + legacyCfgFileRelativePath,
-                                                legacyCfgFileParentFolder + legacyCfgFileNamePath,
-                                                legacyCfgFileGrandParentFolder + legacyCfgFileRelativePath};
+        auto legacyLocations = QVector<QString>{legacyStandardPathsParentFolder + legacyCfgFileRelativePath,
+                                                standardPathsParentFolder + legacyCfgFileRelativePath,
+                                                legacyCfgFileGrandParentFolder + legacyCfgFileRelativePath,
+                                                legacyCfgFileParentFolder + legacyCfgFileNamePath};
 
         if (Theme::instance()->isBranded()) {
             const auto unbrandedCfgFileNamePath = QString(QStringLiteral("/") + unbrandedCfgFileNameC);
             const auto unbrandedCfgFileRelativePath = QString(unbrandedRelativeConfigLocationC);
-            legacyLocations.append({legacyCfgFileParentFolder + unbrandedCfgFileNamePath, legacyCfgFileGrandParentFolder + unbrandedCfgFileRelativePath});
+            legacyLocations.append({standardPathsParentFolder + unbrandedCfgFileRelativePath,
+                                    legacyCfgFileParentFolder + unbrandedCfgFileNamePath,
+                                    legacyCfgFileGrandParentFolder + unbrandedCfgFileRelativePath});
         }
 
+        qCInfo(lcConfigFile) << "Paths:" << legacyLocations;
+
         for (const auto &configFile : legacyLocations) {
             auto oCSettings = std::make_unique<QSettings>(configFile, QSettings::IniFormat);
             if (oCSettings->status() != QSettings::Status::NoError) {

From f76a16d89999fb9c601f2bf151da5ee25c7c30ed Mon Sep 17 00:00:00 2001
From: Camila Ayres <hello@camilasan.com>
Date: Tue, 13 May 2025 16:59:08 +0200
Subject: [PATCH 07/10] gui: display legacy file location when asking user to
 import it.

Signed-off-by: Camila Ayres <hello@camilasan.com>
---
 src/gui/accountmanager.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/gui/accountmanager.cpp b/src/gui/accountmanager.cpp
index 36b989872cf86..2d4d7ea0419fb 100644
--- a/src/gui/accountmanager.cpp
+++ b/src/gui/accountmanager.cpp
@@ -656,10 +656,10 @@ bool AccountManager::confirmRestoreExistingAccounts() const
         && Theme::instance()->displayLegacyImportDialog()
         && !configFile.discoveredLegacyConfigFile().isEmpty()) {
         const auto importQuestion = accountsListSize > 1
-            ? tr("%1 accounts were detected from a legacy desktop client.\n"
-                 "Should the accounts be imported?").arg(QString::number(accountsListSize))
-            : tr("1 account was detected from a legacy desktop client.\n"
-                 "Should the account be imported?");
+            ? tr("%1 accounts were detected from a legacy desktop client at %2.\n"
+                 "Should the accounts be imported?").arg(QString::number(accountsListSize), configFile.discoveredLegacyConfigFile())
+            : tr("1 account was detected from a legacy desktop client at %1.\n"
+                 "Should the account be imported?").arg(configFile.discoveredLegacyConfigFile());
         const auto importMessageBox = new QMessageBox(QMessageBox::Question, tr("Legacy import"), importQuestion);
         importMessageBox->addButton(tr("Import"), QMessageBox::AcceptRole);
         const auto skipButton = importMessageBox->addButton(tr("Skip"), QMessageBox::DestructiveRole);

From 8b5d26a9dc8dfbf9b04d90efc3f1031cb1c1c12b Mon Sep 17 00:00:00 2001
From: Camila Ayres <hello@camilasan.com>
Date: Wed, 14 May 2025 12:34:31 +0200
Subject: [PATCH 08/10] fix(migration): remove check for existing settings when
 looking for legacy file.

At that point we already know that the config file does not exist.

Signed-off-by: Camila Ayres <hello@camilasan.com>
---
 src/libsync/configfile.cpp | 100 +++++++++++++++++--------------------
 1 file changed, 46 insertions(+), 54 deletions(-)

diff --git a/src/libsync/configfile.cpp b/src/libsync/configfile.cpp
index dba96656f8075..04c2c1a035e3f 100644
--- a/src/libsync/configfile.cpp
+++ b/src/libsync/configfile.cpp
@@ -1369,64 +1369,56 @@ QT_WARNING_POP
 
 void ConfigFile::findLegacyClientConfigFile()
 {
-    qCInfo(lcConfigFile) << "Migrate: restoreFromLegacySettings, checking settings group"
-                          << Theme::instance()->appName();
-
-    // try to open the correctly themed settings
-    auto settings = ConfigFile::settingsWithGroup(Theme::instance()->appName());
-
-    // if the settings file could not be opened, the childKeys list is empty
-    // then try to load settings from a very old place
-    if (settings->childKeys().isEmpty()) {
-        // Legacy settings used QDesktopServices to get the location for the config folder in 2.4 and before
-        const auto legacyStandardPaths = QString(QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) + QStringLiteral("/data"));
-        const auto legacyStandardPathsParentFolder = legacyStandardPaths.left(legacyStandardPaths.lastIndexOf('/'));
-
-        // 2.5+ (rest of 2.x series)
-        const auto standardPaths = QStandardPaths::writableLocation(Utility::isWindows() ? QStandardPaths::AppDataLocation : QStandardPaths::AppConfigLocation);
-        const auto standardPathsParentFolder = standardPaths.left(standardPaths.lastIndexOf('/'));
-
-        // Now try the locations we use today
-        const auto fullLegacyCfgFile = QDir::fromNativeSeparators(settings->fileName());
-        const auto legacyCfgFileParentFolder = fullLegacyCfgFile.left(fullLegacyCfgFile.lastIndexOf('/'));
-        const auto legacyCfgFileGrandParentFolder = legacyCfgFileParentFolder.left(legacyCfgFileParentFolder.lastIndexOf('/'));
-
-        const auto legacyCfgFileNamePath = QString(QStringLiteral("/") + legacyCfgFileNameC);
-        const auto legacyCfgFileRelativePath = QString(legacyRelativeConfigLocationC);
-
-        auto legacyLocations = QVector<QString>{legacyStandardPathsParentFolder + legacyCfgFileRelativePath,
-                                                standardPathsParentFolder + legacyCfgFileRelativePath,
-                                                legacyCfgFileGrandParentFolder + legacyCfgFileRelativePath,
-                                                legacyCfgFileParentFolder + legacyCfgFileNamePath};
-
-        if (Theme::instance()->isBranded()) {
-            const auto unbrandedCfgFileNamePath = QString(QStringLiteral("/") + unbrandedCfgFileNameC);
-            const auto unbrandedCfgFileRelativePath = QString(unbrandedRelativeConfigLocationC);
-            legacyLocations.append({standardPathsParentFolder + unbrandedCfgFileRelativePath,
-                                    legacyCfgFileParentFolder + unbrandedCfgFileNamePath,
-                                    legacyCfgFileGrandParentFolder + unbrandedCfgFileRelativePath});
-        }
+    qCInfo(lcConfigFile) << "Migrate: findLegacyClientConfigFile" << Theme::instance()->appName();
+
+    // Legacy settings used QDesktopServices to get the location for the config folder in 2.4 and before
+    const auto legacyStandardPaths = QString(QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) + QStringLiteral("/data"));
+    const auto legacyStandardPathsParentFolder = legacyStandardPaths.left(legacyStandardPaths.lastIndexOf('/'));
+
+    // 2.5+ (rest of 2.x series)
+    const auto standardPaths = QStandardPaths::writableLocation(Utility::isWindows() ? QStandardPaths::AppDataLocation : QStandardPaths::AppConfigLocation);
+    const auto standardPathsParentFolder = standardPaths.left(standardPaths.lastIndexOf('/'));
+
+    // Now try the locations we use today
+    const auto fullLegacyCfgFile = QDir::fromNativeSeparators(configFile());
+    const auto legacyCfgFileParentFolder = fullLegacyCfgFile.left(fullLegacyCfgFile.lastIndexOf('/'));
+    const auto legacyCfgFileGrandParentFolder = legacyCfgFileParentFolder.left(legacyCfgFileParentFolder.lastIndexOf('/'));
+
+    const auto legacyCfgFileNamePath = QString(QStringLiteral("/") + legacyCfgFileNameC);
+    const auto legacyCfgFileRelativePath = QString(legacyRelativeConfigLocationC);
+
+    auto legacyLocations = QVector<QString>{legacyStandardPathsParentFolder + legacyCfgFileRelativePath,
+                                            standardPathsParentFolder + legacyCfgFileRelativePath,
+                                            legacyCfgFileGrandParentFolder + legacyCfgFileRelativePath,
+                                            legacyCfgFileParentFolder + legacyCfgFileNamePath};
+
+    if (Theme::instance()->isBranded()) {
+        const auto unbrandedCfgFileNamePath = QString(QStringLiteral("/") + unbrandedCfgFileNameC);
+        const auto unbrandedCfgFileRelativePath = QString(unbrandedRelativeConfigLocationC);
+        legacyLocations.append({standardPathsParentFolder + unbrandedCfgFileRelativePath,
+                                legacyCfgFileParentFolder + unbrandedCfgFileNamePath,
+                                legacyCfgFileGrandParentFolder + unbrandedCfgFileRelativePath});
+    }
 
-        qCInfo(lcConfigFile) << "Paths:" << legacyLocations;
+    qCDebug(lcConfigFile) << "Looking for existing config files at:" << legacyLocations;
 
-        for (const auto &configFile : legacyLocations) {
-            auto oCSettings = std::make_unique<QSettings>(configFile, QSettings::IniFormat);
-            if (oCSettings->status() != QSettings::Status::NoError) {
-                qCInfo(lcConfigFile) << "Error reading legacy configuration file" << oCSettings->status();
-                break;
-            }
-
-            const QFileInfo configFileInfo(configFile);
-            if (!configFileInfo.exists() || !configFileInfo.isReadable()) {
-                qCInfo(lcConfigFile()) << "Migrate: could not read old config " << configFile;
-                continue;
-            }
-
-            qCInfo(lcConfigFile) << "Migrate: old config file" << configFile;
-            setDiscoveredLegacyConfigFile(configFileInfo.filePath());
-            setDiscoveredLegacyConfigPath(configFileInfo.canonicalPath());
+    for (const auto &configFile : legacyLocations) {
+        auto oCSettings = std::make_unique<QSettings>(configFile, QSettings::IniFormat);
+        if (oCSettings->status() != QSettings::Status::NoError) {
+            qCInfo(lcConfigFile) << "Error reading legacy configuration file" << oCSettings->status();
             break;
         }
+
+        const QFileInfo configFileInfo(configFile);
+        if (!configFileInfo.exists() || !configFileInfo.isReadable()) {
+            qCInfo(lcConfigFile()) << "Migrate: could not read old config " << configFile;
+            continue;
+        }
+
+        qCInfo(lcConfigFile) << "Migrate: old config file" << configFile;
+        setDiscoveredLegacyConfigFile(configFileInfo.filePath());
+        setDiscoveredLegacyConfigPath(configFileInfo.canonicalPath());
+        break;
     }
 }
 

From a36d65d18f9b8e44ece1ce5685e5589d7ef90f0c Mon Sep 17 00:00:00 2001
From: Camila Ayres <hello@camilasan.com>
Date: Wed, 14 May 2025 18:21:29 +0200
Subject: [PATCH 09/10] refactor(migration): remove logic used for locating
 legacy config files.

The same logic is already implemented in ConfigFile::findLegacyClientConfigFile.

Signed-off-by: Camila Ayres <hello@camilasan.com>
---
 src/gui/application.cpp    | 14 +--------
 src/libsync/configfile.cpp | 58 +++-----------------------------------
 src/libsync/configfile.h   |  2 --
 3 files changed, 5 insertions(+), 69 deletions(-)

diff --git a/src/gui/application.cpp b/src/gui/application.cpp
index 364cd4f1486b5..f1b6b1b35be9d 100644
--- a/src/gui/application.cpp
+++ b/src/gui/application.cpp
@@ -169,22 +169,10 @@ Application::Application(int &argc, char **argv)
     }
 
     ConfigFile configFile;
-    // First check if there is a valid config file
     if (const auto configExists = configFile.exists(); configExists && makeConfigSettingsBackwardCompatible()) {
         qCWarning(lcApplication) << "Existing config is compatible with current version.";
     } else if (!configExists) {
-        // look for previous used application name for config folder.
-        if (const auto genericConfigLocation = QString(QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + "/" + APPLICATION_CONFIG_NAME);
-            configFile.setupConfigFolderFromLegacyLocation(genericConfigLocation)) {
-            qCWarning(lcApplication) << "Copy of config folder and files from legacy location" << genericConfigLocation << "suceeded.";
-
-        // app data folder
-        } else if (const auto appDataLocation = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
-            configFile.setupConfigFolderFromLegacyLocation(genericConfigLocation)) {
-            qCWarning(lcApplication) << "Copy of config folder and files from legacy location" << appDataLocation << "suceeded.";
-        } else {
-            configFile.findLegacyClientConfigFile();
-        }
+        configFile.findLegacyClientConfigFile();
     }
 
     if (_quitInstance) {
diff --git a/src/libsync/configfile.cpp b/src/libsync/configfile.cpp
index 04c2c1a035e3f..4bd018ad1a267 100644
--- a/src/libsync/configfile.cpp
+++ b/src/libsync/configfile.cpp
@@ -1314,59 +1314,6 @@ void ConfigFile::setDiscoveredLegacyConfigFile(const QString &discoveredLegacyCo
     _discoveredLegacyConfigFile = discoveredLegacyConfigFile;
 }
 
-bool ConfigFile::setupConfigFolderFromLegacyLocation(const QString &legacyLocation) const
-{
-    // Migrate from version <= 2.4
-    qApp->setApplicationName(Theme::instance()->appNameGUI());
-#ifndef QT_WARNING_DISABLE_DEPRECATED // Was added in Qt 5.9
-    #define QT_WARNING_DISABLE_DEPRECATED QT_WARNING_DISABLE_GCC("-Wdeprecated-declarations")
-#endif
-QT_WARNING_PUSH
-QT_WARNING_DISABLE_DEPRECATED
-QT_WARNING_POP
-    qApp->setApplicationName(Theme::instance()->appName());
-
-    auto legacyDir = legacyLocation;
-    if (legacyDir.endsWith('/')) {
-        legacyDir.chop(1); // macOS 10.11.x does not like trailing slash for rename/move.
-    }
-
-    if (!QFileInfo(legacyDir).isDir()) {
-        return false;
-    }
-
-    auto confDir = ConfigFile().configPath();
-    if (confDir.endsWith('/')) {
-        confDir.chop(1);
-    }
-
-    qCInfo(lcConfigFile) << "Migrating old config from" << legacyDir << "to" << confDir;
-    if (!QFile::rename(legacyDir, confDir)) {
-        qCWarning(lcConfigFile) << "Failed to move the old config directory" << legacyDir << "to new location" << confDir;
-        if (QFileInfo(confDir).isDir() || QDir().mkdir(confDir)) {
-            const QStringList filesList = QDir(legacyDir).entryList(QDir::Files);
-            qCInfo(lcConfigFile) << "Will move the individual files:" << filesList;
-            auto setupCompleted = false;
-            for (const auto &name : filesList) {
-                if (!QFile::rename(legacyDir + "/" + name,  confDir + "/" + name)) {
-                    qCDebug(lcConfigFile) << "Fallback move of " << name << "also failed";
-                    continue;
-                }
-                setupCompleted = true;
-                qCInfo(lcConfigFile)  << "Move of " << name << "succeeded.";
-            }
-            return setupCompleted;
-        }
-    } else {
-#ifndef Q_OS_WIN
-        // Create a symbolic link so a downgrade of the client would still find the config.
-        return QFile::link(confDir, legacyDir);
-#endif
-    }
-
-    return false;
-}
-
 void ConfigFile::findLegacyClientConfigFile()
 {
     qCInfo(lcConfigFile) << "Migrate: findLegacyClientConfigFile" << Theme::instance()->appName();
@@ -1395,7 +1342,10 @@ void ConfigFile::findLegacyClientConfigFile()
     if (Theme::instance()->isBranded()) {
         const auto unbrandedCfgFileNamePath = QString(QStringLiteral("/") + unbrandedCfgFileNameC);
         const auto unbrandedCfgFileRelativePath = QString(unbrandedRelativeConfigLocationC);
-        legacyLocations.append({standardPathsParentFolder + unbrandedCfgFileRelativePath,
+        const auto brandedLegacyCfgFilePath = QString(QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + QStringLiteral("/") + APPLICATION_SHORTNAME + QStringLiteral("/"));
+        const auto brandedLegacyCfgFile = QString(APPLICATION_CONFIG_NAME + QStringLiteral(".cfg"));
+        legacyLocations.append({brandedLegacyCfgFilePath + brandedLegacyCfgFile,
+                                standardPathsParentFolder + unbrandedCfgFileRelativePath,
                                 legacyCfgFileParentFolder + unbrandedCfgFileNamePath,
                                 legacyCfgFileGrandParentFolder + unbrandedCfgFileRelativePath});
     }
diff --git a/src/libsync/configfile.h b/src/libsync/configfile.h
index 8d74523aeed37..94ffa30e6b932 100644
--- a/src/libsync/configfile.h
+++ b/src/libsync/configfile.h
@@ -259,8 +259,6 @@ class OWNCLOUDSYNC_EXPORT ConfigFile
     static constexpr char uploadLimitC[] = "BWLimit/uploadLimit";
     static constexpr char downloadLimitC[] = "BWLimit/downloadLimit";
 
-    [[nodiscard]]  bool setupConfigFolderFromLegacyLocation(const QString &legacyLocation) const;
-
     /**
      * Looks for config files with different names from older client versions
      * in different locations

From bdde6f23f47346ee3c1710627ef3873cf9866325 Mon Sep 17 00:00:00 2001
From: Camila Ayres <hello@camilasan.com>
Date: Thu, 15 May 2025 11:18:00 +0200
Subject: [PATCH 10/10] wip: add Migration class.

Signed-off-by: Camila Ayres <hello@camilasan.com>
---
 src/libsync/CMakeLists.txt |   3 +-
 src/libsync/migration.cpp  | 313 +++++++++++++++++++++++++++++++++++++
 src/libsync/migration.h    |  59 +++++++
 3 files changed, 374 insertions(+), 1 deletion(-)
 create mode 100644 src/libsync/migration.cpp
 create mode 100644 src/libsync/migration.h

diff --git a/src/libsync/CMakeLists.txt b/src/libsync/CMakeLists.txt
index 8871024278d4c..3f47079235dce 100644
--- a/src/libsync/CMakeLists.txt
+++ b/src/libsync/CMakeLists.txt
@@ -208,7 +208,8 @@ ENDIF(NOT APPLE)
 
 find_package(Qt${QT_MAJOR_VERSION} REQUIRED COMPONENTS WebSockets Xml Sql Gui Svg Widgets)
 
-add_library(nextcloudsync SHARED ${libsync_SRCS})
+add_library(nextcloudsync SHARED ${libsync_SRCS}
+  migration.h migration.cpp)
 add_library(Nextcloud::sync ALIAS nextcloudsync)
 
 target_link_libraries(nextcloudsync
diff --git a/src/libsync/migration.cpp b/src/libsync/migration.cpp
new file mode 100644
index 0000000000000..7589beab1aa39
--- /dev/null
+++ b/src/libsync/migration.cpp
@@ -0,0 +1,313 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "migration.h"
+
+#include "theme.h"
+#include "config.h"
+#include "configfile.h"
+#include "common/utility.h"
+#include "version.h"
+#include "gui/folder.h"
+
+#include <QSettings>
+#include <QDir>
+#include <QFile>
+#include <QFileInfo>
+#include <QLoggingCategory>
+#include <QStandardPaths>
+#include <QVersionNumber>
+
+namespace {
+constexpr auto legacyRelativeConfigLocationC = "/ownCloud/owncloud.cfg";
+constexpr auto legacyCfgFileNameC = "owncloud.cfg";
+constexpr auto unbrandedRelativeConfigLocationC = "/Nextcloud/nextcloud.cfg";
+constexpr auto unbrandedCfgFileNameC = "nextcloud.cfg";
+
+constexpr auto accountsC = "Accounts";
+constexpr auto versionC = "version";
+
+constexpr auto maxAccountsVersion = 13;
+constexpr auto maxAccountVersion = 13;
+
+constexpr auto settingsAccountsC = "Accounts";
+constexpr auto settingsFoldersC = "Folders";
+constexpr auto settingsFoldersWithPlaceholdersC = "FoldersWithPlaceholders";
+constexpr auto settingsVersionC = "version";
+constexpr auto maxFoldersVersion = 1;
+}
+
+namespace OCC {
+
+Q_LOGGING_CATEGORY(lcMigration, "nextcloud.gui.migration", QtInfoMsg);
+
+Migration::Migration()
+{}
+
+QString Migration::discoveredLegacyConfigPath() const
+{
+    return _discoveredLegacyConfigPath;
+}
+
+void Migration::setDiscoveredLegacyConfigPath(const QString &discoveredLegacyConfigPath)
+{
+    if (_discoveredLegacyConfigPath == discoveredLegacyConfigPath) {
+        return;
+    }
+
+    _discoveredLegacyConfigPath = discoveredLegacyConfigPath;
+}
+
+QString Migration::discoveredLegacyConfigFile() const
+{
+    return _discoveredLegacyConfigFile;
+}
+
+void Migration::setDiscoveredLegacyConfigFile(const QString &discoveredLegacyConfigFile)
+{
+    if (_discoveredLegacyConfigFile == discoveredLegacyConfigFile) {
+        return;
+    }
+
+    _discoveredLegacyConfigFile = discoveredLegacyConfigFile;
+}
+
+void Migration::findLegacyClientConfigFile()
+{
+    qCInfo(lcMigration) << "Migrate: findLegacyClientConfigFile" << Theme::instance()->appName();
+
+           // Legacy settings used QDesktopServices to get the location for the config folder in 2.4 and before
+    const auto legacyStandardPaths = QString(QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) + QStringLiteral("/data"));
+    const auto legacyStandardPathsParentFolder = legacyStandardPaths.left(legacyStandardPaths.lastIndexOf('/'));
+
+           // 2.5+ (rest of 2.x series)
+    const auto standardPaths = QStandardPaths::writableLocation(Utility::isWindows() ? QStandardPaths::AppDataLocation : QStandardPaths::AppConfigLocation);
+    const auto standardPathsParentFolder = standardPaths.left(standardPaths.lastIndexOf('/'));
+
+           // Now try the locations we use today
+    const auto fullLegacyCfgFile = QDir::fromNativeSeparators(ConfigFile().configFile());
+    const auto legacyCfgFileParentFolder = fullLegacyCfgFile.left(fullLegacyCfgFile.lastIndexOf('/'));
+    const auto legacyCfgFileGrandParentFolder = legacyCfgFileParentFolder.left(legacyCfgFileParentFolder.lastIndexOf('/'));
+
+    const auto legacyCfgFileNamePath = QString(QStringLiteral("/") + legacyCfgFileNameC);
+    const auto legacyCfgFileRelativePath = QString(legacyRelativeConfigLocationC);
+
+    auto legacyLocations = QVector<QString>{legacyStandardPathsParentFolder + legacyCfgFileRelativePath,
+                                            standardPathsParentFolder + legacyCfgFileRelativePath,
+                                            legacyCfgFileGrandParentFolder + legacyCfgFileRelativePath,
+                                            legacyCfgFileParentFolder + legacyCfgFileNamePath};
+
+    if (Theme::instance()->isBranded()) {
+        const auto unbrandedCfgFileNamePath = QString(QStringLiteral("/") + unbrandedCfgFileNameC);
+        const auto unbrandedCfgFileRelativePath = QString(unbrandedRelativeConfigLocationC);
+        const auto brandedLegacyCfgFilePath = QString(QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + QStringLiteral("/") + APPLICATION_SHORTNAME + QStringLiteral("/"));
+        const auto brandedLegacyCfgFile = QString(APPLICATION_CONFIG_NAME + QStringLiteral(".cfg"));
+        legacyLocations.append({brandedLegacyCfgFilePath + brandedLegacyCfgFile,
+                                standardPathsParentFolder + unbrandedCfgFileRelativePath,
+                                legacyCfgFileParentFolder + unbrandedCfgFileNamePath,
+                                legacyCfgFileGrandParentFolder + unbrandedCfgFileRelativePath});
+    }
+
+    qCDebug(lcMigration) << "Looking for existing config files at:" << legacyLocations;
+
+    for (const auto &configFile : legacyLocations) {
+        auto oCSettings = std::make_unique<QSettings>(configFile, QSettings::IniFormat);
+        if (oCSettings->status() != QSettings::Status::NoError) {
+            qCInfo(lcMigration) << "Error reading legacy configuration file" << oCSettings->status();
+            break;
+        }
+
+        const QFileInfo configFileInfo(configFile);
+        if (!configFileInfo.exists() || !configFileInfo.isReadable()) {
+            qCInfo(lcMigration()) << "Migrate: could not read old config " << configFile;
+            continue;
+        }
+
+        qCInfo(lcMigration) << "Migrate: old config file" << configFile;
+        setDiscoveredLegacyConfigFile(configFileInfo.filePath());
+        setDiscoveredLegacyConfigPath(configFileInfo.canonicalPath());
+        break;
+    }
+}
+
+bool Migration::isUpgrade() const
+{
+    return QVersionNumber::fromString(MIRALL_VERSION_STRING) > QVersionNumber::fromString(ConfigFile().clientVersionString());
+}
+
+bool Migration::isDowngrade() const
+{
+    return QVersionNumber::fromString(ConfigFile().clientVersionString()) > QVersionNumber::fromString(MIRALL_VERSION_STRING);
+}
+
+QString Migration::configFileToRestore() const
+{
+    const auto legacyConfigFile = discoveredLegacyConfigFile();
+    if (legacyConfigFile.isEmpty()) {
+        return ConfigFile().configFile();
+    }
+
+    return legacyConfigFile;
+}
+
+QString Migration::backup(const QString &fileName) const
+{
+    const QString baseFilePath = ConfigFile().configPath() + fileName;
+    auto versionString = ConfigFile().clientVersionString();
+
+    if (!versionString.isEmpty()) {
+        versionString.prepend('_');
+    }
+
+    QString backupFile =
+        QStringLiteral("%1.backup_%2%3")
+            .arg(baseFilePath)
+            .arg(QDateTime::currentDateTime().toString("yyyyMMdd_HHmmss"))
+            .arg(versionString);
+
+    // If this exact file already exists it's most likely that a backup was
+    // already done. (two backup calls directly after each other, potentially
+    // even with source alterations in between!)
+    // QFile does not overwrite backupFile
+    if(!QFile::copy(baseFilePath, backupFile)) {
+        qCWarning(lcMigration) << "Failed to create a backup of the config file" << baseFilePath;
+    }
+
+    return backupFile;
+}
+
+QStringList Migration::backupConfigFiles() const
+{
+    // 'Launch on system startup' defaults to true > 3.11.x
+    const auto theme = Theme::instance();
+    ConfigFile().setLaunchOnSystemStartup(ConfigFile().launchOnSystemStartup());
+    Utility::setLaunchOnStartup(theme->appName(), theme->appNameGUI(), ConfigFile().launchOnSystemStartup());
+
+    // default is now off to displaying dialog warning user of too many files deletion
+    ConfigFile().setPromptDeleteFiles(false);
+
+    // back up all old config files
+    QStringList backupFilesList;
+    QDir configDir(ConfigFile().configPath());
+    const auto anyConfigFileNameList = configDir.entryInfoList({"*.cfg"}, QDir::Files);
+    for (const auto &oldConfig : anyConfigFileNameList) {
+        const auto oldConfigFileName = oldConfig.fileName();
+        const auto oldConfigFilePath = oldConfig.filePath();
+        const auto newConfigFileName = ConfigFile().configFile();
+        backupFilesList.append(backup(oldConfigFileName));
+        if (oldConfigFilePath != newConfigFileName) {
+            if (!QFile::rename(oldConfigFilePath, newConfigFileName)) {
+                qCWarning(lcMigration) << "Failed to rename configuration file from" << oldConfigFilePath << "to" << newConfigFileName;
+            }
+        }
+    }
+
+    return backupFilesList;
+}
+
+void Migration::accountbackwardMigrationSettingsKeys(QStringList *deleteKeys, QStringList *ignoreKeys)
+{
+    const auto settings = ConfigFile::settingsWithGroup(QLatin1String(accountsC));
+    const auto accountsVersion = settings->value(QLatin1String(versionC)).toInt();
+
+    qCInfo(lcMigration) << "Checking for accounts versions.";
+    qCInfo(lcMigration) << "Config accounts version:" << accountsVersion;
+    qCInfo(lcMigration) << "Max accounts Version is set to:" << maxAccountsVersion;
+    if (accountsVersion <= maxAccountsVersion) {
+        const auto settingsChildGroups = settings->childGroups();
+        for (const auto &accountId : settingsChildGroups) {
+            settings->beginGroup(accountId);
+            const auto accountVersion = settings->value(QLatin1String(versionC), 1).toInt();
+
+            if (accountVersion > maxAccountVersion) {
+                ignoreKeys->append(settings->group());
+                qCInfo(lcMigration) << "Ignoring account" << accountId << "because of version" << accountVersion;
+            }
+            settings->endGroup();
+        }
+    } else {
+        deleteKeys->append(settings->group());
+    }
+}
+
+void Migration::folderbackwardMigrationSettingsKeys(QStringList *deleteKeys, QStringList *ignoreKeys)
+{
+    auto settings = ConfigFile::settingsWithGroup(QLatin1String("Accounts"));
+
+    auto processSubgroup = [&](const QString &name) {
+        settings->beginGroup(name);
+        const auto foldersVersion = settings->value(QLatin1String(settingsVersionC), 1).toInt();
+        qCInfo(lcMigration) << "FolderDefinition::maxSettingsVersion:" << FolderDefinition::maxSettingsVersion();
+        if (foldersVersion <= maxFoldersVersion) {
+            for (const auto &folderAlias : settings->childGroups()) {
+                settings->beginGroup(folderAlias);
+                const auto folderVersion = settings->value(QLatin1String(settingsVersionC), 1).toInt();
+                if (folderVersion > FolderDefinition::maxSettingsVersion()) {
+                    qCInfo(lcMigration) << "Ignoring folder:" << folderAlias << "version:" << folderVersion;
+                    ignoreKeys->append(settings->group());
+                }
+                settings->endGroup();
+            }
+        } else {
+            qCInfo(lcMigration) << "Ignoring group:" << name << "version:" << foldersVersion;
+            deleteKeys->append(settings->group());
+        }
+        settings->endGroup();
+    };
+
+    const auto settingsChildGroups = settings->childGroups();
+    for (const auto &accountId : settingsChildGroups) {
+        settings->beginGroup(accountId);
+        processSubgroup("Folders");
+        processSubgroup("Multifolders");
+        processSubgroup("FoldersWithPlaceholders");
+        settings->endGroup();
+    }
+}
+
+bool Migration::makeConfigSettingsBackwardCompatible() const
+{
+    ConfigFile configFile;
+    const auto didVersionChanged = configFile.isUpgrade() || configFile.isDowngrade();
+    if (!didVersionChanged) {
+        qCInfo(lcMigration) << "No upgrade or downgrade detected.";
+        return true;
+    }
+
+    configFile.cleanUpdaterConfiguration();
+
+    QStringList deleteKeys, ignoreKeys;
+    // accountbackwardMigrationSettingsKeys(&deleteKeys, &ignoreKeys);
+    // folderbackwardMigrationSettingsKeys(&deleteKeys, &ignoreKeys);
+    if (!didVersionChanged && !(!deleteKeys.isEmpty() || (!ignoreKeys.isEmpty() && didVersionChanged))) {
+        qCInfo(lcMigration) << "There are no settings to delete or to ignore. No need to change the current config file.";
+        return true;
+    }
+
+    const auto isDeleteKeysEmpty = deleteKeys.isEmpty();
+    if (const auto backupFilesList = configFile.backupConfigFiles();
+        configFile.showConfigBackupWarning()
+        && backupFilesList.size() > 0
+        /*&& !confirmConfigChangesOrQuitApp(isDeleteKeysEmpty, backupFilesList)*/) {
+        return false;
+    }
+
+    if (!isDeleteKeysEmpty) {
+        auto settings = configFile.settingsWithGroup("foo");
+        settings->endGroup();
+
+               // Wipe confusing keys from the future, ignore the others
+        for (const auto &badKey : std::as_const(deleteKeys)) {
+            settings->remove(badKey);
+            qCDebug(lcMigration) << "Migration: removed" << badKey << "key from settings.";
+        }
+    }
+
+    configFile.setClientVersionString(MIRALL_VERSION_STRING);
+    qCDebug(lcMigration) << "Client version changed to" << configFile.clientVersionString();
+
+    return true;
+}
+}
diff --git a/src/libsync/migration.h b/src/libsync/migration.h
new file mode 100644
index 0000000000000..927e45bc590d9
--- /dev/null
+++ b/src/libsync/migration.h
@@ -0,0 +1,59 @@
+#ifndef MIGRATION_H
+#define MIGRATION_H
+
+#include <QString>
+
+namespace OCC {
+
+class Migration
+{
+public:
+    Migration();
+    /**
+     * Looks for config files with different names from older client versions
+     * in different locations
+     *
+     * Returns the found config file path found.
+     */
+    void findLegacyClientConfigFile();
+
+    /**
+     * Maybe a newer version of the client was used with this config file: if so, backup.
+     * Return backup files list.
+     */
+    [[nodiscard]] QStringList backupConfigFiles() const;
+    [[nodiscard]] bool isUpgrade() const;
+    [[nodiscard]] bool isDowngrade() const;
+    [[nodiscard]] QString configFileToRestore() const;
+    [[nodiscard]] QString findLegacyConfigFile() const;
+    [[nodiscard]] bool makeConfigSettingsBackwardCompatible() const;
+
+    [[nodiscard]] QString backup(const QString &fileName) const;
+
+    /**
+     * Returns the list of settings keys that can't be read because
+     * they are from the future.
+     */
+    void accountbackwardMigrationSettingsKeys(QStringList *deleteKeys, QStringList *ignoreKeys);
+
+    /**
+     * Returns a list of keys that can't be read because they are from
+     * future versions.
+     */
+    void folderbackwardMigrationSettingsKeys(QStringList *deleteKeys, QStringList *ignoreKeys);
+
+
+    /// Set during first time migration of legacy accounts in AccountManager
+    [[nodiscard]] QString discoveredLegacyConfigPath() const;
+    void setDiscoveredLegacyConfigPath(const QString &discoveredLegacyConfigPath);
+    [[nodiscard]] QString discoveredLegacyConfigFile() const;
+    void setDiscoveredLegacyConfigFile(const QString &discoveredLegacyConfigFile);
+
+private:
+    QString _confDir;
+    QString _discoveredLegacyConfigPath;
+    QString _discoveredLegacyConfigFile;
+
+};
+}
+#endif // MIGRATION_H