Powershell Invoke-Build script to save Invoke-ScriptAnalyzer results to checkstyle.xml format

project.build.ps1

using namespace Microsoft.Windows.PowerShell.ScriptAnalyzer.Generic

# Synopsis: Statically analyses the codebase for badness.
Add-BuildTask lint -Inputs ${Sources} -Outputs "${PSScriptRoot}/checkstyle.xml" {
	Import-Module PSScriptAnalyzer

	# Run the linter, producing a list of result objects.
	$Results = Invoke-ScriptAnalyzer `
			-Path "${PSScriptRoot}" `
			-CustomRulePath "${PSScriptRoot}/.lint-rules" `
			-RecurseCustomRulePath `
			-IncludeDefaultRules `
			-ReportSummary `
			-Recurse

	# Get the total count of errors in the results.
	$ErrorCount = ${Results} `
		| Where-Object { ${_}.Severity -eq [DiagnosticSeverity]::Error } `
		| Measure-Object

	# Cannot have any errors at all
	Assert-Build `
		-Condition ( ${ErrorCount}.Count -eq 0 ) `
		-Message "Cannot have any linting errors. $(${ErrorCount}.Count) errors found."

	# Group results again by file to work better in the report.
	$FileResults = ${Results} | Group-Object `
		-Property ScriptName `
		-AsHashTable

	# Write a checkstyle-formatted report to disk.
	# https://github.com/PowerShell/PSScriptAnalyzer/issues/1296
	$XmlWriter = New-Object System.Xml.XmlTextWriter("${Outputs}", $Null)
	try {
		$XmlWriter.Formatting = 'Indented'
		$XmlWriter.Indentation = 1
		$XmlWriter.IndentChar = "`t"
		$XmlWriter.WriteStartDocument()
		$XmlWriter.WriteStartElement("checkstyle")
		$XmlWriter.WriteAttributeString("version", "1.0.0")
		foreach ($FileResult in (${FileResults} ?? @{}).GetEnumerator()) {
			$XmlWriter.WriteStartElement("file")
			$XmlWriter.WriteAttributeString("name", ${FileResult}.Name)
			foreach ($Result in ${FileResult}.Value) {
				$XmlWriter.WriteStartElement("error")
				$XmlWriter.WriteAttributeString("line", ${Result}.Line)
				$XmlWriter.WriteAttributeString("column", ${Result}.Column)
				$XmlWriter.WriteAttributeString("severity", ${Result}.Severity)
				$XmlWriter.WriteAttributeString("message", ${Result}.Message)
				$XmlWriter.WriteAttributeString("source", ${Result}.RuleName)
				$XmlWriter.WriteEndElement()
			}
			$XmlWriter.WriteEndElement()
		}
		$XmlWriter.WriteEndElement()
		$XmlWriter.WriteEndDocument()
		$XmlWriter.Flush()
	} finally {
		$XmlWriter.Close()
	}

}