Use AllocConsoleWithOptions(Default) for normal launches

SufficientDaikon · claude · SufficientDaikon · commit 1a86fe68aed3 · 2026-03-28T18:41:19.000+02:00
Per DHowett's feedback: plain AllocConsole() overrides DETACHED_PROCESS
from the parent's CreateProcess call. AllocConsoleWithOptions with
Default mode respects it. Extract shared TryAllocConsoleWithMode() and
add TryAllocConsoleDefault() alongside TryAllocConsoleNoWindow().

Co-Authored-By: Claude Opus 4.6 &lt;noreply@anthropic.com&gt;
diff --git a/src/Microsoft.PowerShell.ConsoleHost/host/msh/ManagedEntrance.cs b/src/Microsoft.PowerShell.ConsoleHost/host/msh/ManagedEntrance.cs
@@ -173,7 +173,13 @@ private static void EarlyConsoleInit(string[] args)
             else
             {
                 // Normal interactive launch: allocate a visible console.
-                Interop.Windows.AllocConsole();
+                // Use AllocConsoleWithOptions(Default) when available — it respects
+                // DETACHED_PROCESS from the parent's CreateProcess call, whereas
+                // plain AllocConsole() would override it and force-create a console.
+                if (!Interop.Windows.TryAllocConsoleDefault())
+                {
+                    Interop.Windows.AllocConsole();
+                }
             }
         }
 
diff --git a/src/System.Management.Automation/engine/Interop/Windows/AllocConsoleWithOptions.cs b/src/System.Management.Automation/engine/Interop/Windows/AllocConsoleWithOptions.cs
@@ -60,12 +60,28 @@ internal static partial int AllocConsoleWithOptions(
         /// Returns false if the API is not available (older Windows) or the call fails.
         /// </summary>
         internal static bool TryAllocConsoleNoWindow()
+        {
+            return TryAllocConsoleWithMode(AllocConsoleMode.NoWindow);
+        }
+
+        /// <summary>
+        /// Attempts to allocate a console using AllocConsoleWithOptions with Default mode.
+        /// Default mode respects DETACHED_PROCESS from the parent's CreateProcess call,
+        /// whereas plain AllocConsole() would override it and force-create a console.
+        /// Returns false if the API is not available (older Windows) or the call fails.
+        /// </summary>
+        internal static bool TryAllocConsoleDefault()
+        {
+            return TryAllocConsoleWithMode(AllocConsoleMode.Default);
+        }
+
+        private static bool TryAllocConsoleWithMode(AllocConsoleMode mode)
         {
             try
             {
                 var options = new AllocConsoleOptions
                 {
-                    Mode = AllocConsoleMode.NoWindow,
+                    Mode = mode,
                     UseShowWindow = 0,
                     ShowWindow = 0,
                 };

Original file line number	Diff line number	Diff line change
`@@ -173,7 +173,13 @@ private static void EarlyConsoleInit(string[] args)`
`173`	`173`	`else`
`174`	`174`	`{`
`175`	`175`	`// Normal interactive launch: allocate a visible console.`
`176`		`- Interop.Windows.AllocConsole();`
	`176`	`+ // Use AllocConsoleWithOptions(Default) when available — it respects`
	`177`	`+ // DETACHED_PROCESS from the parent's CreateProcess call, whereas`
	`178`	`+ // plain AllocConsole() would override it and force-create a console.`
	`179`	`+ if (!Interop.Windows.TryAllocConsoleDefault())`
	`180`	`+ {`
	`181`	`+ Interop.Windows.AllocConsole();`
	`182`	`+ }`
`177`	`183`	`}`
`178`	`184`	`}`
`179`	`185`