Fix up copilot code for dnx shim

Use top level statements and argument escaper

Author: dsplaisted

src/Layout/dnx/dnx.cs

@@ -4,56 +4,49 @@
 using System;
 using System.Diagnostics;
 using System.IO;
+using Microsoft.DotNet.Cli.Utils;
 
-class Program
+
+// Get the path to the current executable
+string? exePath = Environment.ProcessPath;
+if (exePath == null)
 {
-    static int Main(string[] args)
-    {
-        // Get the path to the current executable
-        string? exePath = Process.GetCurrentProcess().MainModule?.FileName;
-        if (exePath == null)
-        {
-            Console.Error.WriteLine("Could not determine the path to the current executable.");
-            return 1;
-        }
-        string? exeDir = Path.GetDirectoryName(exePath);
-        if (exeDir == null)
-        {
-            Console.Error.WriteLine("Could not determine the directory of the current executable.");
-            return 1;
-        }
-        // Path to dotnet in the same directory
-        string dotnetPath = Path.Combine(exeDir, "dotnet");
+    Console.Error.WriteLine("Could not determine the path to the current executable.");
+    return 1;
+}
+string? exeDir = Path.GetDirectoryName(exePath);
+if (exeDir == null)
+{
+    Console.Error.WriteLine("Could not determine the directory of the current executable.");
+    return 1;
+}
+// Path to dotnet in the same directory
+string dotnetPath = Path.Combine(exeDir, "dotnet");
 #if WINDOWS
-        dotnetPath += ".exe";
+dotnetPath += ".exe";
 #endif
-        // Build argument list: "dnx" + all args
-        string arguments = "dnx";
-        if (args.Length > 0)
-        {
-            arguments += " " + string.Join(" ", args.Select(a => $"\"{a.Replace("\"", "\\\"")}"));
-        }
-        var psi = new ProcessStartInfo
-        {
-            FileName = dotnetPath,
-            Arguments = arguments,
-            UseShellExecute = false
-        };
-        try
-        {
-            using var process = Process.Start(psi);
-            if (process == null)
-            {
-                Console.Error.WriteLine($"Failed to start process: {dotnetPath}");
-                return 1;
-            }
-            process.WaitForExit();
-            return process.ExitCode;
-        }
-        catch (Exception ex)
-        {
-            Console.Error.WriteLine($"Error launching process: {ex.Message}");
-            return 1;
-        }
+
+string argumentsToForward = ArgumentEscaper.EscapeAndConcatenateArgArrayForProcessStart(["dnx", ..args]);
+
+var psi = new ProcessStartInfo
+{
+    FileName = dotnetPath,
+    Arguments = argumentsToForward,
+    UseShellExecute = false
+};
+try
+{
+    using var process = Process.Start(psi);
+    if (process == null)
+    {
+        Console.Error.WriteLine($"Failed to start process: {dotnetPath}");
+        return 1;
     }
+    process.WaitForExit();
+    return process.ExitCode;
+}
+catch (Exception ex)
+{
+    Console.Error.WriteLine($"Error launching process: {ex.ToString()}");
+    return 1;
 }

src/Layout/dnx/dnx.csproj

@@ -12,6 +12,10 @@
     <_IsPublishing>true</_IsPublishing>
   </PropertyGroup>
 
+  <ItemGroup>
+    <Compile Include="$(RepoRoot)src\Cli\Microsoft.DotNet.Cli.Utils\ArgumentEscaper.cs" />
+  </ItemGroup>
+
   <Target Name="PublishOnBuild" AfterTargets="Build" DependsOnTargets="Publish" Condition="'$(PublishAot)' == 'true'" />
 
 </Project>