Rule request: AvoidUsingOutNull

Summary of the new feature

I want PSScriptAnalyzer to flag uses of Out-Null for output suppression so that I can maintain consistent code style and potentially gain minor performance improvements.

Currently, many PowerShell scripts use | Out-Null to suppress command output, but there are alternative approaches like [void], > $null, or assignment to $null that are stylistically preferred by many developers. While the performance difference is minimal, having a consistent approach to output suppression improves code readability and maintainability.

Proposed technical implementation details (optional)

• Rule Name: AvoidUsingOutNull
• Severity: Information (since this is primarily a style preference)
• Category: Style
• Detection: Flag any pipeline that ends with | Out-Null
• Suggested alternatives:
  • [void](command)
  • command > $null
  • $null = command
• Example violation: Get-Process | Out-Null
• Example fix: [void](Get-Process) or Get-Process > $null

The rule should provide informational messages suggesting these alternatives while acknowledging that this is primarily a stylistic choice rather than a critical performance issue.

What is the latest version of PSScriptAnalyzer at the point of writing

1.24.0

Locate comparable PSScriptAnalyzer rules and their tests, then inspect how rule names, severities, categories, diagnostics, and pipeline patterns are represented. Done means pipelines ending in Out-Null produce an informational Style diagnostic with suggested alternatives, while other output-suppression forms remain unaffected.