Add null check for args in CommandLineParser (#13451)

src/Microsoft.PowerShell.ConsoleHost/host/msh/CommandLineParameterParser.cs

@@ -712,6 +712,14 @@ namespace Microsoft.PowerShell
                 throw new InvalidOperationException("This instance has already been used. Create a new instance.");
             }
 
+            for (int i = 0; i < args.Length; i++)
+            {
+                if (args[i] is null)
+                {
+                    throw new ArgumentNullException(nameof(args), CommandLineParameterParserStrings.NullElementInArgs);
+                }
+            }
+
             // Indicates that we've called this method on this instance, and that when it's done, the state variables
             // will reflect the parse.
             _dirty = true;

src/Microsoft.PowerShell.ConsoleHost/resources/CommandLineParameterParserStrings.resx

@@ -219,4 +219,7 @@ Valid formats are:
   <data name="STANotImplemented" xml:space="preserve">
     <value>Parameter -STA is not supported on this platform.</value>
   </data>
+  <data name="NullElementInArgs" xml:space="preserve">
+    <value>The specified arguments must not contain null elements.</value>
+  </data>
 </root>

test/xUnit/csharp/test_CommandLineParser.cs

@@ -65,6 +65,15 @@ namespace PSTests.Parallel
             Assert.Throws<System.InvalidOperationException>(() => cpp.Parse(new string[0]));
         }
 
+        [Theory]
+        [InlineData("arg1", null, "arg3")]
+        public static void Test_ARGS_With_Null(params string[] commandLine)
+        {
+            var cpp = new CommandLineParameterParser();
+
+            Assert.Throws<System.ArgumentNullException>(() => cpp.Parse(commandLine));
+        }
+
         [Theory]
         [InlineData("noexistfilename")]
         public static void TestDefaultParameterIsFileName_Not_Exist(params string[] commandLine)