.CPL should be added to PATHEXT (#9828)

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

@@ -35,6 +35,34 @@ namespace System.Management.Automation
         /// </summary>
         internal AutomationEngine(PSHost hostInterface, InitialSessionState iss)
         {
+#if !UNIX
+            // Update the env variable PathEXT to contain .CPL
+            var pathext = Environment.GetEnvironmentVariable("PathEXT");
+            pathext = pathext ?? string.Empty;
+            bool cplExist = false;
+            if (pathext != string.Empty)
+            {
+                string[] entries = pathext.Split(Utils.Separators.Semicolon);
+                foreach (string entry in entries)
+                {
+                    string ext = entry.Trim();
+                    if (ext.Equals(".CPL", StringComparison.OrdinalIgnoreCase))
+                    {
+                        cplExist = true;
+                        break;
+                    }
+                }
+            }
+
+            if (!cplExist)
+            {
+                pathext = (pathext == string.Empty) ? ".CPL" :
+                    pathext.EndsWith(";", StringComparison.OrdinalIgnoreCase)
+                    ? (pathext + ".CPL") : (pathext + ";.CPL");
+                Environment.SetEnvironmentVariable("PathEXT", pathext);
+            }
+#endif
+
             Context = new ExecutionContext(this, hostInterface, iss);
 
             EngineParser = new Language.Parser();

test/powershell/engine/Basic/DefaultCommands.Tests.ps1

@@ -605,3 +605,9 @@ Describe "Verify approved aliases list" -Tags "CI" {
         $result | Should -BeNullOrEmpty
     }
 }
+
+Describe "PATHEXT defaults" -Tags 'CI' {
+    It "PATHEXT contains .CPL" -Skip:(!$IsWindows) {
+        $env:PATHEXT.Split(";") | Should -Contain ".CPL"
+    }
+}