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fix: redirect stdin from NUL when launching the server on Windows (#1279) #1290

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Merged
Scriptwonder merged 1 commit into from
Jul 28, 2026
+18 −2
Merged

fix: redirect stdin from NUL when launching the server on Windows (#1279) #1290

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7 changes: 5 additions & 2 deletions MCPForUnity/Editor/Services/Server/TerminalLauncher.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -42,10 +42,13 @@ public System.Diagnostics.ProcessStartInfo CreateHeadlessProcessStartInfo(string
}

#if UNITY_EDITOR_WIN
// cmd.exe /c "<command> >> "<log>" 2>&1"
// cmd.exe /c "<command> < NUL >> "<log>" 2>&1"
// The whole payload after /c is wrapped in one outer pair of quotes; cmd strips the
// outermost quotes, so inner quotes around the log path survive for paths with spaces.
string winRedirect = $"{command} >> \"{logFilePath}\" 2>&1";
// stdin is redirected from NUL because the Editor is a console-less GUI process: with
// CreateNoWindow and no console handle, uvx.exe would inherit an invalid stdin and die
// with "The handle is invalid. (os error 6)" before launching the server.
string winRedirect = $"{command} < NUL >> \"{logFilePath}\" 2>&1";
return new System.Diagnostics.ProcessStartInfo
{
FileName = "cmd.exe",
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13 changes: 13 additions & 0 deletions TestProjects/UnityMCPTests/Assets/Tests/EditMode/Services/Server/TerminalLauncherTests.cs
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Expand Up @@ -212,6 +212,19 @@ public void CreateHeadlessProcessStartInfo_RedirectsOutputToLogFile()
StringAssert.Contains(">>", startInfo.Arguments, "output should be appended to the log via >>");
}

#if UNITY_EDITOR_WIN
[Test]
public void CreateHeadlessProcessStartInfo_RedirectsStdinFromNul()
{
// Regression guard for #1279: the Editor is a console-less GUI process, so a child
// launched with CreateNoWindow inherits an invalid stdin and uvx.exe fails with
// "The handle is invalid. (os error 6)". stdin must come from NUL instead.
var startInfo = _launcher.CreateHeadlessProcessStartInfo("uvx run-server", LogPath());

StringAssert.Contains("< NUL", startInfo.Arguments, "stdin should be redirected from NUL");
}
#endif

[Test]
public void CreateHeadlessProcessStartInfo_LogPathWithSpaces_IsQuoted()
{
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