Don't write an error if file already unblocked (Unblock-File) (#5362)

src/Microsoft.PowerShell.Commands.Utility/commands/utility/UnblockFile.cs

@@ -121,9 +121,17 @@ namespace Microsoft.PowerShell.Commands
                     }
                     catch (Win32Exception accessException)
                     {
-                        WriteError(new ErrorRecord(accessException, "RemoveItemUnauthorizedAccessError", ErrorCategory.PermissionDenied, path));
+                        // NativeErrorCode=2 - File not found.
+                        // If the block stream not found the 'path' was not blocked and we successfully return.
+                        if (accessException.NativeErrorCode != 2)
+                        {
+                            WriteError(new ErrorRecord(accessException, "RemoveItemUnauthorizedAccessError", ErrorCategory.PermissionDenied, path));
+                        }
+                        else
+                        {
+                            WriteVerbose(StringUtil.Format(UtilityCommonStrings.NoZoneIdentifierFileStream, path));
+                        }
                     }
-
                 }
             }
         }

src/Microsoft.PowerShell.Commands.Utility/resources/UtilityCommonStrings.resx

@@ -174,4 +174,7 @@
   <data name="TypeNotSupported" xml:space="preserve">
     <value>'{0}' is not supported in this system.</value>
   </data>
+  <data name="NoZoneIdentifierFileStream" xml:space="preserve">
+    <value>The file is not blocked: {0}</value>
+  </data>
 </root>

test/powershell/Modules/Microsoft.PowerShell.Utility/Unblock-File.Tests.ps1

@@ -47,6 +47,9 @@ Describe "Unblock-File" -Tags "CI" {
     It "With '-Path': file exist" {
         Unblock-File -Path $testfilepath
         Test-UnblockFile | Should Be $true
+
+        # If a file is not blocked we silently return without an error.
+        { Unblock-File -Path $testfilepath -ErrorAction Stop } | Should Not Throw
     }
 
     It "With '-LiteralPath': file exist" {
@@ -67,7 +70,6 @@ Describe "Unblock-File" -Tags "CI" {
         $TestFileCreated = Get-ChildItem $TestFile
         $TestFileCreated.IsReadOnly | Should Be $true
 
-        { Unblock-File -LiteralPath $TestFile -ErrorAction SilentlyContinue } | Should Not Throw
-        $error[0].FullyQualifiedErrorId | Should Be "RemoveItemUnauthorizedAccessError,Microsoft.PowerShell.Commands.UnblockFileCommand"
+        { Unblock-File -LiteralPath $TestFile -ErrorAction Stop } | ShouldBeErrorId "RemoveItemUnauthorizedAccessError,Microsoft.PowerShell.Commands.UnblockFileCommand"
     }
 }