When config migration occurs, log a message and show a notice dialog

src/control/XournalMain.cpp

@@ -72,19 +72,22 @@ void XournalMain::initLocalisation() {
     std::cout.imbue(std::locale());
 }
 
-void XournalMain::migrateSettings() {
-    Path newConfigPath(g_get_user_config_dir());
-    newConfigPath /= g_get_prgname();
+bool XournalMain::migrateSettings() {
+    Path newConfigPath = Util::getConfigFolder();
 
     if (!newConfigPath.exists()) {
         Path oldConfigPath(g_get_home_dir());
         oldConfigPath /= ".xournalpp";
 
         if (oldConfigPath.exists()) {
+            g_message("Migrating configuration from %s to %s", oldConfigPath.str().c_str(),
+                      newConfigPath.str().c_str());
             fs::create_directories(newConfigPath.str());
             fs::copy(oldConfigPath.str(), newConfigPath.str(), fs::copy_options::recursive);
+            return true;
         }
     }
+    return false;
 }
 
 void XournalMain::checkForErrorlog() {
@@ -276,7 +279,7 @@ auto XournalMain::exportPdf(const char* input, const char* output) -> int {
 auto XournalMain::run(int argc, char* argv[]) -> int {
     g_set_prgname("com.github.xournalpp.xournalpp");
     this->initLocalisation();
-    this->migrateSettings();
+    bool hasMigrated = this->migrateSettings();
 
     GError* error = nullptr;
     GOptionContext* context = g_option_context_new("FILE");
@@ -393,6 +396,17 @@ auto XournalMain::run(int argc, char* argv[]) -> int {
     // This fixes it, see #405
     Util::execInUiThread([=]() { control->getWindow()->getXournal()->layoutPages(); });
 
+    if (hasMigrated) {
+        Util::execInUiThread([=]() {
+            Path oldConfigPath(g_get_home_dir());
+            oldConfigPath /= ".xournalpp";
+            const char* msg = "Due to a recent update, Xournal++ has changed where its configuration files are "
+                              "stored.\nThey have been automatically copied from\n{1}\nto\n{2}";
+            XojMsgBox::showErrorToUser(control->getGtkWindow(),
+                                       FS(_F(msg) % oldConfigPath.c_str() % Util::getConfigFolder().c_str()));
+        });
+    }
+
     gtk_main();
 
     control->saveSettings();

src/control/XournalMain.h

@@ -31,7 +31,11 @@ public:
 
 private:
     static void initLocalisation();
-    static void migrateSettings();
+
+    /**
+     * Returns true if configuration settings were migrated.
+     */
+    static bool migrateSettings();
 
     static void checkForErrorlog();
     static void checkForEmergencySave(Control* control);

src/util/Util.cpp

@@ -80,9 +80,14 @@ auto Util::getAutosaveFilename() -> Path {
     return p;
 }
 
-auto Util::getConfigSubfolder(const Path& subfolder) -> Path {
+auto Util::getConfigFolder() -> Path {
     Path p(g_get_user_config_dir());
     p /= g_get_prgname();
+    return p;
+}
+
+auto Util::getConfigSubfolder(const Path& subfolder) -> Path {
+    Path p = getConfigFolder();
     p /= subfolder;
 
     return Util::ensureFolderExists(p);

src/util/Util.h

@@ -38,6 +38,10 @@ pid_t getPid();
 void openFileWithDefaultApplicaion(const Path& filename);
 void openFileWithFilebrowser(const Path& filename);
 
+/**
+ * Return the configuration folder path (may not be guaranteed to exist).
+ */
+Path getConfigFolder();
 Path getConfigSubfolder(const Path& subfolder = "");
 Path getCacheSubfolder(const Path& subfolder = "");
 Path getDataSubfolder(const Path& subfolder = "");