Windows 安装服务时自覆盖 Bug：srcBin 与 destBin 相同导致 install 失败

[forwads]

Title

Windows: npc install fails with replace executable failed when executable is already in target directory

Environment

• OS: Windows 11 x64
• Version: v0.26.36
• Download: Official Release (windows_amd64_client.tar.gz)

Reproduce

Verify that the client works correctly:

npc.exe -server=example.com:8024 -vkey=REDACTED_VKEY -type=tcp

Output:

Successful connection with server example.com:8024

Then install the service:

npc.exe install -server=example.com:8024 -vkey=REDACTED_VKEY -type=tcp

or use the interactive menu:

1 -> Register system service

Both produce:

替换可执行文件失败:
open C:\windows_amd64_client_npc\npc.exe:
The system cannot find the file specified.

The Windows service is never created.

Root cause

I checked the source code in lib/install/install.go.

InstallNpc() calls:

copyStaticFile(common.GetAppPath(), "npc")

copyStaticFile() builds:

srcBin := filepath.Join(common.GetAppPath(), "npc.exe")
destBin := filepath.Join(common.GetAppPath(), "npc.exe")

In this case:

srcBin == destBin

replaceExecutable() then executes:

os.Rename(destBin, destBin+".old")

After that it tries:

os.Rename(srcBin, destBin)

or falls back to:

copyFile(srcBin, destBin)

Since srcBin has already been renamed to .old, copyFile() calls:

os.Open(srcBin)

which returns:

The system cannot find the file specified

So this appears to be a self-replacement bug when srcBin and destBin are the same executable.

Suggested fix

Skip replacement when srcBin and destBin refer to the same file, for example:

absSrc, _ := filepath.Abs(srcBin)
absDst, _ := filepath.Abs(destBin)

if strings.EqualFold(absSrc, absDst) {
    return nil
}

or avoid calling replaceExecutable() if the executable is already located in the destination directory.