Ensure command-line error prevents execution of command

Fixes 6683

1 files changed, 6 insertions, 0 deletions

diff --git a/src/wix/WixToolset.Core/CommandLine/CommandLine.cs b/src/wix/WixToolset.Core/CommandLine/CommandLine.cs
index 0921f9ff..07dcc2d2 100644
--- a/src/wix/WixToolset.Core/CommandLine/CommandLine.cs
+++ b/src/wix/WixToolset.Core/CommandLine/CommandLine.cs
@@ -118,6 +118,12 @@ namespace WixToolset.Core.CommandLine
                 extension.PostParse();
             }
 
+            // If we hit an error, do not return a command.
+            if (!String.IsNullOrEmpty(parser.ErrorArgument))
+            {
+                return null;
+            }
+
             return command ?? new HelpCommand(extensions, branding);
         }