From a9a235d469ee240ba2316b8f6da1cd15e87510d5 Mon Sep 17 00:00:00 2001
From: ayousuf23 <72010390+ayousuf23@users.noreply.github.com>
Date: Wed, 9 Feb 2022 15:59:29 -0500
Subject: [PATCH] Prevent tab completion if the word to complete is a single
 dash (#16781)

* added code to prevent tab completion if the word to complete is a single dash

* added a test for testing tab completion if the word to complete is a single dash

* Minor update and add comment

Co-authored-by: Dongbo Wang <dongbow@microsoft.com>
---
 .../engine/CommandCompletion/CompletionCompleters.cs       | 3 ++-
 test/powershell/Host/TabCompletion/TabCompletion.Tests.ps1 | 7 +++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/System.Management.Automation/engine/CommandCompletion/CompletionCompleters.cs b/src/System.Management.Automation/engine/CommandCompletion/CompletionCompleters.cs
index d8360e714d..f0157ae8b1 100644
--- a/src/System.Management.Automation/engine/CommandCompletion/CompletionCompleters.cs
+++ b/src/System.Management.Automation/engine/CommandCompletion/CompletionCompleters.cs
@@ -1329,7 +1329,8 @@ namespace System.Management.Automation
                         context.Options.Remove("LiteralPaths");
                 }
 
-                if (context.WordToComplete != string.Empty && context.WordToComplete.Contains('-'))
+                // The word to complete contains a dash and it's not the first character. We try command names in this case.
+                if (context.WordToComplete.IndexOf('-') > 0)
                 {
                     var commandResults = CompleteCommand(context);
                     if (commandResults != null)
diff --git a/test/powershell/Host/TabCompletion/TabCompletion.Tests.ps1 b/test/powershell/Host/TabCompletion/TabCompletion.Tests.ps1
index d2fa38dd2b..e05ba3352b 100644
--- a/test/powershell/Host/TabCompletion/TabCompletion.Tests.ps1
+++ b/test/powershell/Host/TabCompletion/TabCompletion.Tests.ps1
@@ -1435,6 +1435,13 @@ dir -Recurse `
             $res = TabExpansion2 -inputScript $inputStr -cursorColumn $inputStr.Length
             $res.CompletionMatches | Should -BeNullOrEmpty
         }
+
+        It "A single dash should not complete to anything" {
+            function test-{}
+            $inputStr = 'git -'
+            $res = TabExpansion2 -inputScript $inputStr -cursorColumn $inputStr.Length
+            $res.CompletionMatches | Should -BeNullOrEmpty
+        }
     }
 
     Context "Tab completion error tests" {