[dizicheng]

Problem

On 64-bit Windows, WeaselSetup.exe runs as a 32-bit (WOW64) process. In previous versions, 32-bit applications (such as 32-bit WPS Office, TianRuo OCR, and 32-bit games) frequently fail to load Weasel, resulting in a disabled IME status (circle with a slash icon) and inability to input Chinese (fixes #1831, relates to #1716).

Root Causes

1. Implicit redirection reliance: install_ime_file and uninstall_ime_file relied on a single destination path (C:\Windows\system32\weasel.dll) and implicit filesystem redirection to copy files to SysWOW64 and System32. During upgrades or reinstallation, 32-bit weasel.dll in SysWOW64 could be removed without being properly restored.
2. Spawning child processes during disabled redirection: In install_ime_file, func (register_text_service) was invoked while Wow64DisableWow64FsRedirection was active. Microsoft MSDN explicitly warns:

   "Do not call CreateProcess or ShellExecute while file system redirection is disabled, because it can result in unpredictable behavior."

3. Bare name regsvr32.exe & unused is_wow64 parameter: register_text_service accepted bool is_wow64 but completely ignored it in its implementation, launching regsvr32.exe without an absolute path. Consequently, 32-bit and 64-bit registrations could not be reliably dispatched to their respective bitness utilities.

Solution (Minimal Diff)

1. Explicit 32-bit path resolution: In install_ime_file and uninstall_ime_file, explicitly resolve GetSystemWow64DirectoryW on 64-bit systems to ensure 32-bit weasel.dll is consistently copied to and deleted from SysWOW64.
2. Revert redirection before spawning child processes: In install_ime_file, call Wow64RevertWow64FsRedirection immediately after file copying completes, ensuring ShellExecuteExW is never executed while redirection is disabled.
3. Architecture-aware absolute regsvr32.exe paths: Utilize the existing is_wow64 parameter in register_text_service:
   • For 64-bit registration: use %windir%\Sysnative\regsvr32.exe (accessible from 32-bit WOW64 process) or System32 fallback.
   • For 32-bit registration on 64-bit systems: use %windir%\SysWOW64\regsvr32.exe.
   • For 32-bit systems: use %windir%\System32\regsvr32.exe.

Verification

• Verified on Windows 10 22H2 (x64) with 32-bit WPS Office (et.exe / wps.exe): 32-bit weasel.dll is correctly registered in WOW6432Node, loaded by 32-bit host processes, and Chinese input functions as expected.
• Preserved existing ARM64 / ARM32 redirection DLL logic without disruption.

[fxliang]

我记得之前都是OK的，是哪个提交引入的回归？

[dizicheng]

我记得之前都是OK的，是哪个提交引入的回归？

在提交 d636e0a（PR #1775 refactor: drop WeaselIME）之前，小狼毫一直同时分发并注册 TSF（weasel.dll）和 IMM32（weasel.ime）。 像 32 位 WPS Office 这类历史悠久的桌面软件（以及大量 32 位老游戏），历来原生优先支持经典的 Win32 IMM32 架构。当时哪怕 32 位的 TSF（SysWOW64\weasel.dll）注册有缺失，WPS 也会直接无缝退回到 weasel.ime 处理键盘输入，因此此前在 WPS 中输入中文一直表现正常。

是哪个提交导致了现象的显现？

1. 彻底移除 IMM 兜底：d636e0a（refactor: drop WeaselIME）正式移除了 weasel.ime，小狼毫转为纯 TSF（TSF-only build）。此时 32 位 WPS 等软件无法再回退到 IMM，只能完全依赖 32 位的 TSF 模块（SysWOW64\weasel.dll）。
2. 安装升级时的清理时机：c6a3fa2（installer: ensure old ime/dll files deleted by running WeaselSetup.exe /u before installing）在每次安装前都会执行 /u。由于 32 位的 SysWOW64\weasel.dll 通常不会被 64 位的常驻进程（如 Explorer）占用，在卸载时会被立刻干净删除并注销 COM；而在紧接着重新安装时，受限于重定向机制，32 位 TSF 容易未能正确重新入驻。