Setup SSH: adding -4 option only of ForceIP4 is selected (#95)

* Adding -4 option only of ForceIPvç is selected
* Document intentional spacing in SSH format strings (#96)


Co-authored-by: MichaelKoster70 <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: MichaelKoster70 <[email protected]>

Author: MichaelKoster70

src/Extension/RemoteDebuggerLauncher/PackageConstants.cs

@@ -181,13 +181,18 @@ public static class SecureShell
          public const string DefaultKnownHostsFileName = "known_hosts";
 
          /// <summary>SSH key scanner arguments.</summary>
-         public const string KeyScanArguments = "-4 -p {1} {0}";
+         /// <remarks>No space after {2} because SshForceIPv4 includes a trailing space.</remarks>
+         public const string KeyScanArguments = "{2}-p {1} {0}";
+
+         /// <summary>Argument for SSH to force IPv4 usage.</summary>
+         public const string SshForceIPv4 = "-4 ";
 
          /// <summary>SSH executable.</summary>
          public const string SshExecutable = "ssh.exe";
 
          /// <summary>The SSH arguments to add server fingerprint to known_hosts file.</summary>
-         public const string SshArguments = "{0}@{1} -p {2} -i \"{3}\" \"echo DONE\"";
+         /// <remarks>No space after {4} because SshForceIPv4 includes a trailing space.</remarks>
+         public const string SshArguments = "{0}@{1} {4}-p {2} -i \"{3}\" \"echo DONE\"";
 
          /// <summary>HTTPS Developer Certificate name.</summary>
          public const string HttpsCertificateName = "DevCert.pfx";

src/Extension/RemoteDebuggerLauncher/RemoteOperations/SecureShellKeySetupService.cs

@@ -11,6 +11,7 @@
 using System.IO;
 using System.Text;
 using System.Threading.Tasks;
+using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.Threading;
 using RemoteDebuggerLauncher.Infrastructure;
 using Renci.SshNet;
@@ -106,7 +107,7 @@ public async Task AuthorizeKeyAsync(SecureShellKeySetupSettings settings)
          var defaultKeysFolder = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), PackageConstants.SecureShell.DefaultKeyPairFolder);
          var knownHostsFilePath = Path.Combine(defaultKeysFolder, PackageConstants.SecureShell.DefaultKnownHostsFileName);
 
-         var arguments = string.Format(PackageConstants.SecureShell.KeyScanArguments, settings.HostName, settings.HostPort);
+         var arguments = string.Format(PackageConstants.SecureShell.KeyScanArguments, settings.HostName, settings.HostPort, settings.ForceIPv4 ? PackageConstants.SecureShell.SshForceIPv4 : string.Empty);
          var startInfo = new ProcessStartInfo(PackageConstants.SecureShell.KeyScanExecutable, arguments)
          {
             CreateNoWindow = true,
@@ -124,6 +125,8 @@ public async Task AuthorizeKeyAsync(SecureShellKeySetupSettings settings)
             var stdError = await process.StandardError.ReadToEndAsync();
             var exitCode = await process.WaitForExitAsync();
 
+            await ThreadHelper.JoinableTaskFactory.SwitchToMainThreadAsync();
+
             if (exitCode == 0)
             {
                if (FileHelper.ContainsText(knownHostsFilePath, settings.HostName))
@@ -155,7 +158,7 @@ private async Task<bool> RegisterServerFingerprintWithConnectionAsync(SecureShel
          const string SshDoneMarker = "DONE";
 
          // open a pseudo console windows to run the ssh command
-         var arguments = string.Format(PackageConstants.SecureShell.SshArguments, settings.UserName, settings.HostName, settings.HostPort, settings.PrivateKeyFile);
+         var arguments = string.Format(PackageConstants.SecureShell.SshArguments, settings.UserName, settings.HostName, settings.HostPort, settings.PrivateKeyFile, settings.ForceIPv4 ? PackageConstants.SecureShell.SshForceIPv4 : string.Empty);
          var startInfo = new ProcessStartInfo(PackageConstants.SecureShell.SshExecutable, arguments)
          {
             CreateNoWindow = false,

src/Extension/RemoteDebuggerLauncher/RemoteOperations/SecureShellKeySetupSettings.cs

@@ -1,4 +1,4 @@
-// ----------------------------------------------------------------------------
+// ----------------------------------------------------------------------------
 // <copyright company="Michael Koster">
 //   Copyright (c) Michael Koster. All rights reserved.
 //   Licensed under the MIT License.
@@ -17,6 +17,7 @@ namespace RemoteDebuggerLauncher.RemoteOperations
    internal class SecureShellKeySetupSettings
    {
       private readonly bool forceIPv4;
+
       public SecureShellKeySetupSettings(SetupSshViewModel viewModel)
       {
          HostName = viewModel.HostName;
@@ -67,5 +68,10 @@ public SecureShellKeySetupSettings(SetupSshViewModel viewModel)
       /// Gets the private key file.
       /// </summary>
       public string PrivateKeyFile { get; }
+
+      /// <summary>
+      /// Gets a value indicating whether to force IPv4 usage.
+      /// </summary>
+      public bool ForceIPv4 => forceIPv4;
    }
 }