Convert -ChildPath parameter to string[] for Join-Path cmdlet (#24677)

src/Microsoft.PowerShell.Commands.Management/commands/management/CombinePathCommand.cs

@@ -32,7 +32,8 @@ namespace Microsoft.PowerShell.Commands
         [Parameter(Position = 1, Mandatory = true, ValueFromPipelineByPropertyName = true)]
         [AllowNull]
         [AllowEmptyString]
-        public string ChildPath { get; set; }
+        [AllowEmptyCollection]
+        public string[] ChildPath { get; set; }
 
         /// <summary>
         /// Gets or sets additional childPaths to the command.
@@ -64,7 +65,15 @@ namespace Microsoft.PowerShell.Commands
                 Path != null,
                 "Since Path is a mandatory parameter, paths should never be null");
 
-            string combinedChildPath = ChildPath;
+            string combinedChildPath = string.Empty;
+
+            if (this.ChildPath != null)
+            {
+                foreach (string childPath in this.ChildPath)
+                {
+                    combinedChildPath = SessionState.Path.Combine(combinedChildPath, childPath, CmdletProviderContext);
+                }
+            }
 
             // join the ChildPath elements
             if (AdditionalChildPath != null)

test/powershell/Modules/Microsoft.PowerShell.Management/Join-Path.Tests.ps1

@@ -50,4 +50,38 @@ Describe "Join-Path cmdlet tests" -Tags "CI" {
     $result.Count | Should -Be 1
     $result       | Should -BeExactly "one${sepChar}two${sepChar}three${sepChar}four${sepChar}five"
   }
+  It "Join-Path -Path <Path> -ChildPath <ChildPath> should return '<ExpectedResult>'" -TestCases @(
+    @{
+        Path = 'one'
+        ChildPath = 'two', 'three'
+        ExpectedResult = "one${sepChar}two${sepChar}three"
+    }
+    @{
+        Path = 'one', 'two'
+        ChildPath = 'three', 'four'
+        ExpectedResult = @(
+            "one${sepChar}three${sepChar}four"
+            "two${sepChar}three${sepChar}four"
+        )
+    }
+    @{
+        Path = 'one'
+        ChildPath = @()
+        ExpectedResult = "one${sepChar}"
+    }
+    @{
+        Path = 'one'
+        ChildPath = $null
+        ExpectedResult = "one${sepChar}"
+    }
+    @{
+        Path = 'one'
+        ChildPath = [string]::Empty
+        ExpectedResult = "one${sepChar}"
+    }
+  ) {
+    param($Path, $ChildPath, $ExpectedResult)
+    $result = Join-Path -Path $Path -ChildPath $ChildPath
+    $result | Should -BeExactly $ExpectedResult
+  }
 }