From cf6876e71639145eff189658e939a43338cc92f6 Mon Sep 17 00:00:00 2001
From: Steve Lee <slee@microsoft.com>
Date: Thu, 1 Apr 2021 13:03:19 -0700
Subject: [PATCH] Allow `Set-Clipboard` to accept empty string (#14579)

---
 .../commands/management/Clipboard.cs          | 31 ++++++++++---------
 .../Clipboard.Tests.ps1                       | 10 ++++++
 2 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/src/Microsoft.PowerShell.Commands.Management/commands/management/Clipboard.cs b/src/Microsoft.PowerShell.Commands.Management/commands/management/Clipboard.cs
index 5ce64350fb..45e2a183b3 100644
--- a/src/Microsoft.PowerShell.Commands.Management/commands/management/Clipboard.cs
+++ b/src/Microsoft.PowerShell.Commands.Management/commands/management/Clipboard.cs
@@ -19,7 +19,8 @@ namespace Microsoft.PowerShell.Commands.Internal
         private static string StartProcess(
             string tool,
             string args,
-            string stdin = "")
+            string stdin = "",
+            bool readStdout = true)
         {
             ProcessStartInfo startInfo = new();
             startInfo.UseShellExecute = false;
@@ -28,7 +29,7 @@ namespace Microsoft.PowerShell.Commands.Internal
             startInfo.RedirectStandardError = true;
             startInfo.FileName = tool;
             startInfo.Arguments = args;
-            string stdout;
+            string stdout = string.Empty;
 
             using (Process process = new())
             {
@@ -43,15 +44,15 @@ namespace Microsoft.PowerShell.Commands.Internal
                     return string.Empty;
                 }
 
-                if (!string.IsNullOrEmpty(stdin))
+                process.StandardInput.Write(stdin);
+                process.StandardInput.Close();
+
+                if (readStdout)
                 {
-                    process.StandardInput.Write(stdin);
-                    process.StandardInput.Close();
+                    stdout = process.StandardOutput.ReadToEnd();
                 }
 
-                stdout = process.StandardOutput.ReadToEnd();
                 process.WaitForExit(250);
-
                 _clipboardSupported = process.ExitCode == 0;
             }
 
@@ -93,11 +94,6 @@ namespace Microsoft.PowerShell.Commands.Internal
 
         public static void SetText(string text)
         {
-            if (string.IsNullOrEmpty(text))
-            {
-                return;
-            }
-
             if (_clipboardSupported == false)
             {
                 _internalClipboard = text;
@@ -114,7 +110,14 @@ namespace Microsoft.PowerShell.Commands.Internal
             else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
             {
                 tool = "xclip";
-                args = "-selection clipboard -in";
+                if (string.IsNullOrEmpty(text))
+                {
+                    args = "-selection clipboard /dev/null";
+                }
+                else
+                {
+                    args = "-selection clipboard -in";
+                }
             }
             else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
             {
@@ -126,7 +129,7 @@ namespace Microsoft.PowerShell.Commands.Internal
                 return;
             }
 
-            StartProcess(tool, args, text);
+            StartProcess(tool, args, text, readStdout: false);
             if (_clipboardSupported == false)
             {
                 _internalClipboard = text;
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Management/Clipboard.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Management/Clipboard.Tests.ps1
index d28394c9f2..8cfc07b875 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Management/Clipboard.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Management/Clipboard.Tests.ps1
@@ -41,5 +41,15 @@ Describe 'Clipboard cmdlet tests' -Tag CI {
             'world' | Set-Clipboard -Append
             Get-Clipboard -Raw | Should -BeExactly "hello$([Environment]::NewLine)world"
         }
+
+        It 'Set-Clipboard accepts <value> string' -TestCases @(
+            @{ value = 'empty'; text = "" }
+            @{ value = 'null' ; text = $null }
+        ){
+            param ($text)
+
+            $text | Set-Clipboard
+            Get-Clipboard -Raw | Should -BeNullOrEmpty
+        }
     }
 }