[Aqiang6]

Problem

On Windows, settings changes (language, hotkeys, theme, …) are silently lost on every restart when "launch at login" is disabled and no autostart entry exists in HKCU\...\Run.

auto-launch's disable() returns an error when the registry value it is asked to delete does not exist. Since set_settings applies the login-startup toggle before persisting, that error aborts set_settings before settings.json is ever written — and the frontend swallows the error, so the failure is invisible:

pub fn set_settings(app: AppHandle, settings: Settings) -> Result<(), String> {
    let autolaunch = app.autolaunch();
    apply_launch_at_login(&*autolaunch, settings.launch_at_login)?;  // <- Err aborts here
    settings_store::save(&settings).map_err(|e| e.to_string())?;    // <- never reached
    ...
}

Reproduction: fresh install (no Run entry) with launchAtLogin: false (the default) → change language to zh-CN → restart → language reverts to en, and AppData\Roaming\flashot\settings.json was never created.

Fix

Query the current autostart state first and only touch the registry when it differs from the requested state:

• add is_enabled to the LaunchAtLogin trait (delegating to AutoLaunchManager::is_enabled)
• skip the toggle in apply_launch_at_login when is_enabled()? == launch_at_login
• extend FakeLaunchAtLogin with an enabled state and add a regression test covering the exact failing path (apply_launch_at_login_skips_disable_when_autostart_already_off), plus state-transition assertions on the existing enable/disable tests

Testing

• cargo test apply_launch_at_login — 3 passed (including the new regression test)
• full suite on Windows (MSVC, x86_64-pc-windows-msvc): 226 passed, 0 failed
• manually verified on Windows 11: fresh state → change language to zh-CN and remap hotkeys → settings.json written immediately → persists across restarts

中文说明

问题： 未开启开机自启且注册表 Run 项不存在时，auto-launch 的 disable() 会因"值不存在"报错，导致 set_settings 在写入 settings.json 之前就中断，前端又静默吞掉错误——表现为"改语言/快捷键当次生效、重启后还原"。

修复： 先查询自启状态，状态与请求一致时直接跳过注册表操作，并补充回归测试。

[poneding]

thanks for your contributions.