Fix scratch runner redirected exit code capture

scripts/run-clean-scratch-iterations.ps1

@@ -67,6 +67,16 @@ function Format-ProcessArgument {
     return '"' + ($Value -replace '(\\*)"', '$1$1\"' -replace '(\\+)$', '$1$1') + '"'
 }
 
+function ConvertTo-PowerShellLiteral {
+    param(
+        [Parameter(Mandatory = $true)]
+        [AllowEmptyString()]
+        [string]$Value
+    )
+
+    return "'" + ($Value -replace "'", "''") + "'"
+}
+
 function Invoke-External {
     param(
         [Parameter(Mandatory = $true)]
@@ -80,6 +90,7 @@ function Invoke-External {
     Push-Location $WorkingDirectory
     $stdoutPath = New-LogCapturePath -Suffix '.stdout.log'
     $stderrPath = New-LogCapturePath -Suffix '.stderr.log'
+    $wrapperPath = New-LogCapturePath -Suffix '.invoke.ps1'
     try {
         $resolvedFilePath = $FilePath
         if (Test-Path $FilePath) {
@@ -88,21 +99,32 @@ function Invoke-External {
 
         $startFilePath = $resolvedFilePath
         $startArgumentList = @($ArgumentList)
+        $powershellPath = (Get-Command powershell.exe -ErrorAction Stop).Source
 
         if ([System.IO.Path]::GetExtension($resolvedFilePath).Equals('.ps1', [System.StringComparison]::OrdinalIgnoreCase)) {
-            $powershellPath = (Get-Command powershell.exe -ErrorAction Stop).Source
             $startFilePath = $powershellPath
             $startArgumentList = @('-NoLogo', '-NoProfile', '-ExecutionPolicy', 'Bypass', '-File', $resolvedFilePath) + @($ArgumentList)
         }
 
-        $formattedArgumentList = @($startArgumentList | ForEach-Object { Format-ProcessArgument -Value $_ })
+        $invocationExpression = '& ' + (ConvertTo-PowerShellLiteral -Value $startFilePath)
+        if ($startArgumentList.Count -gt 0) {
+            $invocationExpression += ' ' + (($startArgumentList | ForEach-Object { ConvertTo-PowerShellLiteral -Value $_ }) -join ' ')
+        }
+
+        $wrapperContent = @(
+            '$ErrorActionPreference = ''Stop'''
+            "$invocationExpression 1> $(ConvertTo-PowerShellLiteral -Value $stdoutPath) 2> $(ConvertTo-PowerShellLiteral -Value $stderrPath)"
+            'exit $LASTEXITCODE'
+            ''
+        )
+        Set-Content -Path $wrapperPath -Value $wrapperContent -Encoding UTF8
+
+        $formattedArgumentList = @(@('-NoLogo', '-NoProfile', '-ExecutionPolicy', 'Bypass', '-File', $wrapperPath) | ForEach-Object { Format-ProcessArgument -Value $_ })
 
         $process = Start-Process `
-            -FilePath $startFilePath `
+            -FilePath $powershellPath `
             -ArgumentList $formattedArgumentList `
             -WorkingDirectory $WorkingDirectory `
-            -RedirectStandardOutput $stdoutPath `
-            -RedirectStandardError $stderrPath `
             -PassThru
 
         $stdoutIndex = 0
@@ -115,6 +137,8 @@ function Invoke-External {
             $process.Refresh()
         }
 
+        $process.WaitForExit()
+        $process.Refresh()
         Write-LogCaptureDelta -Path $stdoutPath -LineIndex ([ref]$stdoutIndex)
         Write-LogCaptureDelta -Path $stderrPath -LineIndex ([ref]$stderrIndex)
 
@@ -123,7 +147,7 @@ function Invoke-External {
         }
     }
     finally {
-        foreach ($capturePath in @($stdoutPath, $stderrPath)) {
+        foreach ($capturePath in @($stdoutPath, $stderrPath, $wrapperPath)) {
             if (Test-Path $capturePath) {
                 Remove-Item $capturePath -Force -ErrorAction SilentlyContinue
             }