From d318e7727e1e539446d2792d0e8a9dfea6b2d2e0 Mon Sep 17 00:00:00 2001
From: Steve Lee <slee@microsoft.com>
Date: Sat, 27 Apr 2019 11:20:33 -0700
Subject: [PATCH] Allow passing just a dash as an arg to a file via pwsh
 (#9479)

---
 .../host/msh/CommandLineParameterParser.cs    |  2 +-
 test/powershell/Host/ConsoleHost.Tests.ps1    | 19 ++++++++++++++++++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/Microsoft.PowerShell.ConsoleHost/host/msh/CommandLineParameterParser.cs b/src/Microsoft.PowerShell.ConsoleHost/host/msh/CommandLineParameterParser.cs
index 2f45e682f..6be2b04bf 100644
--- a/src/Microsoft.PowerShell.ConsoleHost/host/msh/CommandLineParameterParser.cs
+++ b/src/Microsoft.PowerShell.ConsoleHost/host/msh/CommandLineParameterParser.cs
@@ -1214,7 +1214,7 @@ namespace Microsoft.PowerShell
                         _collectedArgs.Add(new CommandParameter(pendingParameter, arg));
                         pendingParameter = null;
                     }
-                    else if (!string.IsNullOrEmpty(arg) && SpecialCharacters.IsDash(arg[0]))
+                    else if (!string.IsNullOrEmpty(arg) && SpecialCharacters.IsDash(arg[0]) && arg.Length > 1)
                     {
                         int offset = arg.IndexOf(':');
                         if (offset >= 0)
diff --git a/test/powershell/Host/ConsoleHost.Tests.ps1 b/test/powershell/Host/ConsoleHost.Tests.ps1
index 0c631bb66..f7d1c39dd 100644
--- a/test/powershell/Host/ConsoleHost.Tests.ps1
+++ b/test/powershell/Host/ConsoleHost.Tests.ps1
@@ -217,7 +217,7 @@ Describe "ConsoleHost unit tests" -tags "Feature" {
             $observed | Should -Be $BoolValue
         }
 
-        It "-File '<filename>' should return exit code from script"  -TestCases @(
+        It "-File '<filename>' should return exit code from script" -TestCases @(
             @{Filename = "test.ps1"},
             @{Filename = "test"}
         ) {
@@ -226,6 +226,23 @@ Describe "ConsoleHost unit tests" -tags "Feature" {
             & $powershell $testdrive/$Filename
             $LASTEXITCODE | Should -Be 123
         }
+
+        It "A single dash should be passed as an arg" {
+            $testScript = @'
+    [CmdletBinding()]param(
+        [string]$p1,
+        [string]$p2,
+        [Parameter(ValueFromPipeline)][string]$InputObject
+    )
+    process{
+        $input.replace($p1, $p2)
+    }
+'@
+            $testFilePath = Join-Path $TestDrive "test.ps1"
+            Set-Content -Path $testFilePath -Value $testScript
+            $observed = echo hello | pwsh $testFilePath e -
+            $observed | Should -BeExactly "h-llo"
+        }
     }
 
     Context "-SettingsFile Commandline switch" {