Add a new experimental feature to control native argument passing style on Windows (#18706)

src/System.Management.Automation/engine/ExperimentalFeature/ExperimentalFeature.cs

@@ -28,6 +28,7 @@ namespace System.Management.Automation
         internal const string PSFeedbackProvider = "PSFeedbackProvider";
         internal const string PSCommandWithArgs = "PSCommandWithArgs";
         internal const string PSConstrainedAuditLogging = "PSConstrainedAuditLogging";
+        internal const string PSWindowsNativeCommandArgPassing = "PSWindowsNativeCommandArgPassing";
 
         #endregion
 
@@ -139,7 +140,10 @@ namespace System.Management.Automation
                     description: "Enable `-CommandWithArgs` parameter for pwsh"),
                 new ExperimentalFeature(
                     name: PSConstrainedAuditLogging,
-                    description: "PowerShell restriction logging when WDAC (Windows Defender Application Control) Code Integrity policy is set to Audit mode.")
+                    description: "PowerShell restriction logging when WDAC (Windows Defender Application Control) Code Integrity policy is set to Audit mode."),
+                new ExperimentalFeature(
+                    name: "PSWindowsNativeCommandArgPassing",
+                    description: "Enable 'Windows' as the native command argument passing mode"),
             };
 
             EngineExperimentalFeatures = new ReadOnlyCollection<ExperimentalFeature>(engineFeatures);

src/System.Management.Automation/engine/InitialSessionState.cs

@@ -4534,7 +4534,7 @@ end {
             builtinVariables.Add(
                 new SessionStateVariableEntry(
                     SpecialVariables.NativeArgumentPassing,
-                    Platform.IsWindows ? NativeArgumentPassingStyle.Windows : NativeArgumentPassingStyle.Standard,
+                    GetPassingStyle(),
                     RunspaceInit.NativeCommandArgumentPassingDescription,
                     ScopedItemOptions.None,
                     new ArgumentTypeConverterAttribute(typeof(NativeArgumentPassingStyle))));
@@ -4542,6 +4542,26 @@ end {
             BuiltInVariables = builtinVariables.ToArray();
         }
 
+        /// <summary>
+        /// Assigns the default behavior for native argument passing.
+        /// If the system is non-Windows, we will return Standard.
+        /// If the experimental feature is enabled, we will return Windows.
+        /// Otherwise, we will return Legacy.
+        /// </summary>
+        private static NativeArgumentPassingStyle GetPassingStyle()
+        {
+#if UNIX
+            return NativeArgumentPassingStyle.Standard;
+#else
+            if (ExperimentalFeature.IsEnabled(ExperimentalFeature.PSWindowsNativeCommandArgPassing))
+            {
+                return NativeArgumentPassingStyle.Windows;
+            }
+
+            return NativeArgumentPassingStyle.Legacy;
+#endif
+        }
+
         internal static readonly SessionStateVariableEntry[] BuiltInVariables;
 
         /// <summary>

src/System.Management.Automation/engine/NativeCommandProcessor.cs

@@ -583,6 +583,11 @@ namespace System.Management.Automation
             // Get the start info for the process.
             ProcessStartInfo startInfo = GetProcessStartInfo(redirectOutput, redirectError, redirectInput, soloCommand);
 
+            // Send Telemetry indicating what argument passing mode we are in.
+            ApplicationInsightsTelemetry.SendExperimentalUseData(
+                ExperimentalFeature.PSWindowsNativeCommandArgPassing,
+                NativeParameterBinderController.ArgumentPassingStyle.ToString());
+
 #if !UNIX
             string commandPath = this.Path.ToLowerInvariant();
             if (commandPath.EndsWith("powershell.exe") || commandPath.EndsWith("powershell_ise.exe"))