From 6bc2b55fdf99bf70cf11bbc2a37ffa20aa9881d5 Mon Sep 17 00:00:00 2001
From: Steve Lee <slee@microsoft.com>
Date: Fri, 29 Mar 2019 13:22:52 -0700
Subject: [PATCH] return correct casing of filesystem path during normalization

---
 .../namespaces/FileSystemProvider.cs          | 41 ++++++++++++++++++-
 .../Set-Location.Tests.ps1                    |  6 +++
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/src/System.Management.Automation/namespaces/FileSystemProvider.cs b/src/System.Management.Automation/namespaces/FileSystemProvider.cs
index b62454ac5..733b12eb0 100644
--- a/src/System.Management.Automation/namespaces/FileSystemProvider.cs
+++ b/src/System.Management.Automation/namespaces/FileSystemProvider.cs
@@ -98,7 +98,46 @@ namespace Microsoft.PowerShell.Commands
         /// </returns>
         private static string NormalizePath(string path)
         {
-            return path.Replace(StringLiterals.AlternatePathSeparator, StringLiterals.DefaultPathSeparator);
+            return GetCorrectCasedPath(path.Replace(StringLiterals.AlternatePathSeparator, StringLiterals.DefaultPathSeparator));
+        }
+
+        /// <summary>
+        /// Get the correct casing for a path.  This method assumes it's being called by NormalizePath()
+        /// so that the path is already normalized.
+        /// </summary>
+        /// <param name="path">
+        /// The path to retrieve.
+        /// </param>
+        /// <returns>
+        /// The path with accurate casing if item exists, otherwise it returns path that was passed in.
+        /// </returns>
+        private static string GetCorrectCasedPath(string path)
+        {
+            string exactPath = string.Empty;
+            if (File.Exists(path) || Directory.Exists(path))
+            {
+                foreach (string item in path.Split(StringLiterals.DefaultPathSeparator))
+                {
+                    if (string.IsNullOrEmpty(exactPath))
+                    {
+                        exactPath = item + StringLiterals.DefaultPathSeparator;
+                    }
+                    else if (string.IsNullOrEmpty(item))
+                    {
+                        // This handles the trailing slash case
+                        continue;
+                    }
+                    else
+                    {
+                        exactPath = Directory.GetFileSystemEntries(exactPath, item).First();
+                    }
+                }
+                return exactPath;
+            }
+            else
+            {
+                return path;
+            }
         }
 
         /// <summary>
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Management/Set-Location.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Management/Set-Location.Tests.ps1
index 5824419f3..c401003c2 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Management/Set-Location.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Management/Set-Location.Tests.ps1
@@ -70,6 +70,12 @@ Describe "Set-Location" -Tags "CI" {
             Should -Throw -ErrorId "PathNotFound,Microsoft.PowerShell.Commands.SetLocationCommand"
     }
 
+    It "Should use actual casing of folder on case-insensitive filesystem" -Skip:($IsLinux) {
+        $testPath = New-Item -ItemType Directory -Path testdrive:/teST
+        Set-Location $testPath.FullName.ToUpper()
+        $(Get-Location).Path | Should -BeExactly $testPath.FullName
+    }
+
     Context 'Set-Location with no arguments' {
 
         It 'Should go to $env:HOME when Set-Location run with no arguments from FileSystem provider' {