Change Get-ChildItem to treat trailing slash in path as indicating a directory when used with -Recurse (#17704)

src/System.Management.Automation/engine/SessionStateContainer.cs

@@ -1324,8 +1324,8 @@ namespace System.Management.Automation
                 try
                 {
                     // If we're recursing, do some path fixups to match user
-                    // expectations:
-                    if (recurse)
+                    // expectations, but only if the last part is a file and not a directory:
+                    if (recurse && !path.EndsWith(Path.DirectorySeparatorChar) && !path.EndsWith(Path.AltDirectorySeparatorChar))
                     {
                         string childName = GetChildName(path, context);
 

src/System.Management.Automation/namespaces/FileSystemProvider.cs

@@ -1373,13 +1373,18 @@ namespace Microsoft.PowerShell.Commands
             path = NormalizePath(path);
             FileInfo result = new FileInfo(path);
 
-            // FileInfo.Exists is always false for a directory path, so we check the attribute for existence.
             var attributes = result.Attributes;
-            if ((int)attributes == -1) { /* Path doesn't exist. */ return null; }
-
             bool hidden = attributes.HasFlag(FileAttributes.Hidden);
             isContainer = attributes.HasFlag(FileAttributes.Directory);
 
+            // FileInfo allows for a file path to end in a trailing slash, but the resulting object
+            // is incomplete.  A trailing slash should indicate a directory.  So if the path ends in a
+            // trailing slash and is not a directory, return null
+            if (!isContainer && path.EndsWith(Path.DirectorySeparatorChar))
+            {
+                return null;
+            }
+
             FlagsExpression<FileAttributes> evaluator = null;
             FlagsExpression<FileAttributes> switchEvaluator = null;
             GetChildDynamicParameters fspDynamicParam = DynamicParameters as GetChildDynamicParameters;

test/powershell/Modules/Microsoft.PowerShell.Management/Get-ChildItem.Tests.ps1

@@ -217,6 +217,17 @@ Describe "Get-ChildItem" -Tags "CI" {
         It "Should list the folder present when path length equal to MAX_PATH" {
             (Get-ChildItem -Path TestDrive:\$item_I -Recurse -Force).Name.Length | Should -BeGreaterThan 0
         }
+
+        It 'Trailing slash for -Path should treat it as a folder only when used with -recurse' {
+            $foo = New-Item -ItemType Directory -Path TestDrive:\foo
+            $foo2 = New-Item -ItemType Directory -Path TestDrive:\foo\foo
+            $bar = New-Item -ItemType File -Path TestDrive:\foo\bar
+            $bar2 = New-Item -ItemType File -Path TestDrive:\foo\foo\bar
+
+            { Get-ChildItem -Path testdrive:/foo/bar/ -Recurse -ErrorAction Stop } | Should -Throw -ErrorId 'ItemNotFound,Microsoft.PowerShell.Commands.GetChildItemCommand'
+            $barFiles = Get-ChildItem -Path testdrive:/foo/bar -Recurse
+            $barFiles.Count | Should -Be 2
+        }
     }
 
     Context 'Env: Provider' {