Highlight using error color the exception Message and underline in PositionMessage for Get-Error (#15786)

src/System.Management.Automation/FormatAndOutput/DefaultFormatters/PowerShellCore_format_ps1xml.cs

@@ -810,7 +810,12 @@ namespace System.Management.Automation.Runspaces
                             $maxDepth = 10
                             $ellipsis = ""`u{2026}""
                             $resetColor = ''
+                            $errorColor = ''
                             if ($Host.UI.SupportsVirtualTerminal -and ([string]::IsNullOrEmpty($env:__SuppressAnsiEscapeSequences))) {
+                                if ($null -ne $psstyle) {
+                                    $errorColor = $psstyle.Formatting.Error
+                                }
+
                                 $resetColor = [System.Management.Automation.VTUtility]::GetEscapeSequence(
                                     [System.Management.Automation.VTUtility+VT]::Reset
                                 )
@@ -947,6 +952,13 @@ namespace System.Management.Automation.Runspaces
                                             $value = $null
                                             if ([System.Management.Automation.LanguagePrimitives]::TryConvertTo($prop.Value, [string], [ref]$value) -and $value -ne $null)
                                             {
+                                                if ($prop.Name -eq 'PositionMessage') {
+                                                    $value = $value.Insert($value.IndexOf('~'), $errorColor)
+                                                }
+                                                elseif ($prop.Name -eq 'Message') {
+                                                    $value = $errorColor + $value
+                                                }
+
                                                 $isFirstLine = $true
                                                 if ($value.Contains($newline)) {
                                                     # the 3 is to account for ' : '

test/powershell/Modules/Microsoft.PowerShell.Utility/Get-Error.Tests.ps1

@@ -125,4 +125,29 @@ Describe 'Get-Error tests' -Tag CI {
 
         $out | Should -BeLikeExactly "*$expectedExceptionType*"
     }
+
+    It 'Get-Error uses Error color for Message and PositionMessage members' -Skip:(!$EnabledExperimentalFeatures.Contains("PSAnsiRendering")) {
+        $suppressVT = $false
+        if (Test-Path env:/__SuppressAnsiEscapeSequences) {
+            $suppressVT = $true
+            $env:__SuppressAnsiEscapeSequences = $null
+        }
+
+        try {
+            $out = pwsh -noprofile -command '$PSStyle.OutputRendering = "ANSI"; [System.Management.Automation.Internal.InternalTestHooks]::SetTestHook("BypassOutputRedirectionCheck", $true); try { 1/0 } catch { }; Get-Error' | Out-String
+
+            # need to escape the open square bracket so the regex works
+            $resetColor = $PSStyle.Reset.Replace('[','\[')
+            $errorColor = $PSStyle.Formatting.Error.Replace('[','\[')
+            $out | Should -Match "Message +: ${resetColor}${errorColor}[A-z]+"
+            # match the position message underline
+            $out | Should -Match ".*?${errorColor}~~~"
+        }
+        finally
+        {
+            if ($suppressVT) {
+                $env:__SuppressAnsiEscapeSequences = 1
+            }
+        }
+    }
 }