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dsarno wants to merge 11 commits into from
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Fix/auto port fallback #101

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cd8256f
Fix macOS port conflict: Disable SO_REUSEADDR and improve UI port dis…
dsarno Dec 4, 2025
5c83dec
Fix macOS port conflict: Disable SO_REUSEADDR and improve UI port dis…
dsarno Dec 4, 2025
b693edc
Address CodeRabbit feedback: UX improvements and code quality fixes
dsarno Dec 4, 2025
fed3042
Fix: Harden Python detection on Windows to handle App Execution Aliases
dsarno Dec 4, 2025
11932f2
Refactor: Pre-resolve conflicts for McpConnectionSection and middleware
dsarno Dec 4, 2025
b7cb948
Merge remote-tracking branch 'origin/fix/auto-port-fallback' into fix…
dsarno Dec 4, 2025
dde79a9
Fix: Remove leftover merge conflict markers in StdioBridgeHost.cs
dsarno Dec 4, 2025
9df1260
fix: clarify create_script tool description regarding base64 encoding
dsarno Dec 4, 2025
222ea10
fix: improve python detection on macOS by checking specific Homebrew …
dsarno Dec 4, 2025
7bcc217
Fix duplicate SetEnabled call and improve macOS Python detection
dsarno Dec 4, 2025
0de71a3
Fix port display not reverting to saved preference when session ends
dsarno Dec 4, 2025
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26 changes: 25 additions & 1 deletion MCPForUnity/Editor/Helpers/PortManager.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -119,17 +119,41 @@ private static int FindAvailablePort()
/// <returns>True if port is available</returns>
public static bool IsPortAvailable(int port)
{
// Start with quick loopback check
try
{
var testListener = new TcpListener(IPAddress.Loopback, port);
testListener.Start();
testListener.Stop();
return true;
}
catch (SocketException)
{
return false;
}

#if UNITY_EDITOR_OSX
// On macOS, the OS might report the port as available (SO_REUSEADDR) even if another process
// is using it, unless we also check active connections or try a stricter bind.
// Double check by trying to Connect to it. If we CAN connect, it's NOT available.
try
{
using var client = new TcpClient();
var connectTask = client.ConnectAsync(IPAddress.Loopback, port);
// If we connect successfully, someone is listening -> Not available
if (connectTask.Wait(50) && client.Connected)
{
if (IsDebugEnabled()) McpLog.Info($"[PortManager] Port {port} bind succeeded but connection also succeeded -> Not available (Conflict).");
return false;
}
}
Comment on lines +140 to +148
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@greptile-apps greptile-apps bot Dec 4, 2025

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style: Resource leak: TcpClient is created without using statement, but client.ConnectAsync() returns a Task that's awaited synchronously with .Wait(50). If connection times out or succeeds, the TcpClient may not be properly disposed before entering the catch block or returning.

Suggested change
using var client = new TcpClient();
var connectTask = client.ConnectAsync(IPAddress.Loopback, port);
// If we connect successfully, someone is listening -> Not available
if (connectTask.Wait(50) && client.Connected)
{
if (IsDebugEnabled()) McpLog.Info($"[PortManager] Port {port} bind succeeded but connection also succeeded -> Not available (Conflict).");
return false;
}
}
try
{
using var client = new TcpClient();
var connectTask = client.ConnectAsync(IPAddress.Loopback, port);
// If we connect successfully, someone is listening -> Not available
if (connectTask.Wait(50) && client.Connected)
{
if (IsDebugEnabled()) McpLog.Info($"[PortManager] Port {port} bind succeeded but connection also succeeded -> Not available (Conflict).");
return false;
}
}
Prompt To Fix With AI 
This is a comment left during a code review.
Path: MCPForUnity/Editor/Helpers/PortManager.cs
Line: 140:148

Comment:
**style:** Resource leak: `TcpClient` is created without using statement, but `client.ConnectAsync()` returns a `Task` that's awaited synchronously with `.Wait(50)`. If connection times out or succeeds, the `TcpClient` may not be properly disposed before entering the `catch` block or returning.

```suggestion
            try
            {
                using var client = new TcpClient();
                var connectTask = client.ConnectAsync(IPAddress.Loopback, port);
                // If we connect successfully, someone is listening -> Not available
                if (connectTask.Wait(50) && client.Connected)
                {
                    if (IsDebugEnabled()) McpLog.Info($"[PortManager] Port {port} bind succeeded but connection also succeeded -> Not available (Conflict).");
                    return false;
                }
            }
```

How can I resolve this? If you propose a fix, please make it concise.

catch
{
// Connection failed -> likely available (or firewall blocked, but we assume available)
if (IsDebugEnabled()) McpLog.Info($"[PortManager] Port {port} connection failed -> likely available.");
}
#endif

return true;
}

/// <summary>
Expand Down
6 changes: 5 additions & 1 deletion MCPForUnity/Editor/Services/Transport/Transports/StdioBridgeHost.cs
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -307,11 +307,13 @@ public static void Start()
try
{
listener = new TcpListener(IPAddress.Loopback, currentUnityPort);
#if !UNITY_EDITOR_OSX
listener.Server.SetSocketOption(
SocketOptionLevel.Socket,
SocketOptionName.ReuseAddress,
true
);
#endif
#if UNITY_EDITOR_WIN
try
{
Expand Down Expand Up @@ -355,7 +357,7 @@ public static void Start()
}
catch { }

currentUnityPort = PortManager.GetPortWithFallback();
currentUnityPort = PortManager.DiscoverNewPort();

if (IsDebugEnabled())
{
Expand All @@ -370,11 +372,13 @@ public static void Start()
}

listener = new TcpListener(IPAddress.Loopback, currentUnityPort);
#if !UNITY_EDITOR_OSX
listener.Server.SetSocketOption(
SocketOptionLevel.Socket,
SocketOptionName.ReuseAddress,
true
);
#endif
#if UNITY_EDITOR_WIN
try
{
Expand Down
15 changes: 9 additions & 6 deletions MCPForUnity/Editor/Windows/Components/Connection/McpConnectionSection.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -173,6 +173,9 @@ public void UpdateConnectionStatus()
statusIndicator.RemoveFromClassList("disconnected");
statusIndicator.AddToClassList("connected");
connectionToggleButton.text = "End Session";

// Force the UI to reflect the actual port being used
unityPortField.value = bridgeService.CurrentPort.ToString();
}
else
{
Expand All @@ -185,12 +188,12 @@ public void UpdateConnectionStatus()
healthIndicator.RemoveFromClassList("healthy");
healthIndicator.RemoveFromClassList("warning");
healthIndicator.AddToClassList("unknown");
}

int savedPort = EditorPrefs.GetInt(EditorPrefKeys.UnitySocketPort, 0);
if (savedPort == 0)
{
unityPortField.value = bridgeService.CurrentPort.ToString();
int savedPort = EditorPrefs.GetInt(EditorPrefKeys.UnitySocketPort, 0);
if (savedPort == 0)
{
unityPortField.value = bridgeService.CurrentPort.ToString();
}
}
}

Expand Down
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