Achievements: Don't double-free login callback on request failure

Callback always runs.

src/core/achievements.cpp

@@ -2008,29 +2008,21 @@ bool Achievements::IsLoggedInOrLoggingIn()
   return (IsLoggedIn() || s_state.login_request);
 }
 
-bool Achievements::LoginAsync(const char* username, const char* password, Error* error,
-                              LoginCompletionCallback callback)
+void Achievements::LoginAsync(const char* username, const char* password, LoginCompletionCallback callback)
 {
   auto lock = GetLock();
 
   // We need to use a temporary client if achievements aren't currently active.
   if (!s_state.client && !CreateClient(lock, true))
   {
-    Error::SetString(error, "Failed to create client.");
-    return false;
+    callback(false, "Failed to create client.");
+    return;
   }
 
+  // Callback always runs regardless of whether an async request was created.
   LoginCompletionCallback* const callback_copy = new LoginCompletionCallback(std::move(callback));
-  if (!rc_client_begin_login_with_password(s_state.client, username, password,
-                                           RESOLVE_CLIENT_CALLBACK(ClientLoginWithPasswordCallback), callback_copy))
-  {
-    Error::SetString(error, "Failed to create login request.");
-    delete callback_copy;
-    return false;
-  }
-
-  // Login attempt started.
-  return true;
+  rc_client_begin_login_with_password(s_state.client, username, password,
+                                      RESOLVE_CLIENT_CALLBACK(ClientLoginWithPasswordCallback), callback_copy);
 }
 
 void Achievements::ClientLoginWithPasswordCallback(int result, const char* error_message, rc_client_t* client,

src/core/achievements.h

@@ -107,7 +107,7 @@ bool DoState(StateWrapper& sw);
 /// Attempts to log in to RetroAchievements using the specified credentials.
 /// If the login is successful, the token returned by the server will be saved.
 using LoginCompletionCallback = std::function<void(bool result, std::string&& error_message)>;
-bool LoginAsync(const char* username, const char* password, Error* error, LoginCompletionCallback callback);
+void LoginAsync(const char* username, const char* password, LoginCompletionCallback callback);
 
 /// Logs out of RetroAchievements, clearing any credentials.
 void Logout();

src/core/fullscreenui_settings.cpp

@@ -5844,31 +5844,25 @@ void FullscreenUI::DrawAchievementsLoginWindow()
   {
     OpenBackgroundProgressDialog(LOGIN_PROGRESS_NAME, FSUI_STR("Logging in to RetroAchievements..."), 0, 0, 0);
 
-    static constexpr auto set_error = [](const std::string& description) {
-      s_settings_locals.achievements_login_error = std::make_unique<std::string>(fmt::format(
-        FSUI_FSTR("Login Failed.\nError: {}\nPlease check your username and password, and try again."), description));
-    };
-
-    if (Error error; !Achievements::LoginAsync(
-          s_settings_locals.achievements_login_username, s_settings_locals.achievements_login_password, &error,
-          [](bool result, std::string&& error_message) {
-            // callback runs on core thread
-            DebugAssert(Host::IsOnCoreThread());
-            VideoThread::RunOnThread([result, error_message = std::move(error_message)]() {
-              CloseBackgroundProgressDialog(LOGIN_PROGRESS_NAME);
-
-              if (result)
-              {
-                CloseFixedPopupDialog();
-                return;
-              }
+    Achievements::LoginAsync(
+      s_settings_locals.achievements_login_username, s_settings_locals.achievements_login_password,
+      [](bool result, std::string&& error_message) {
+        // callback runs on core thread
+        DebugAssert(Host::IsOnCoreThread());
+        VideoThread::RunOnThread([result, error_message = std::move(error_message)]() {
+          CloseBackgroundProgressDialog(LOGIN_PROGRESS_NAME);
+
+          if (result)
+          {
+            CloseFixedPopupDialog();
+            return;
+          }
 
-              set_error(error_message);
-            });
-          }))
-    {
-      set_error(error.GetDescription());
-    }
+          s_settings_locals.achievements_login_error = std::make_unique<std::string>(
+            fmt::format(FSUI_FSTR("Login Failed.\nError: {}\nPlease check your username and password, and try again."),
+                        error_message));
+        });
+      });
   }
 
   if (HorizontalMenuButton(FSUI_ICONVSTR(ICON_FA_XMARK, "Cancel"), !is_logging_in))

src/duckstation-qt/achievementlogindialog.cpp

@@ -53,18 +53,15 @@ void AchievementLoginDialog::loginClicked()
 
   // Use QPointer<> to safely check if the dialog still exists when the login finishes, since the callback
   // runs on the core thread and we need to queue it back to the UI thread.
-  if (Error error; !Achievements::LoginAsync(
-        username.toUtf8().constData(), password.toUtf8().constData(), &error,
-        [dialog = QPointer(this)](bool result, std::string&& error_message) mutable {
-          DebugAssert(Host::IsOnCoreThread());
-          Host::RunOnUIThread([dialog = std::move(dialog), error_message = std::move(error_message), result]() {
-            if (dialog)
-              dialog->processLoginResult(result, QString::fromStdString(error_message));
-          });
-        }))
-  {
-    processLoginResult(false, QString::fromStdString(error.GetDescription()));
-  }
+  Achievements::LoginAsync(username.toUtf8().constData(), password.toUtf8().constData(),
+                           [dialog = QPointer(this)](bool result, std::string&& error_message) mutable {
+                             DebugAssert(Host::IsOnCoreThread());
+                             Host::RunOnUIThread(
+                               [dialog = std::move(dialog), error_message = std::move(error_message), result]() {
+                                 if (dialog)
+                                   dialog->processLoginResult(result, QString::fromStdString(error_message));
+                               });
+                           });
 }
 
 void AchievementLoginDialog::cancelClicked()