powershell/PSUseUsingScopeModifierInNewRunspaces

powershell/PSUseUsingScopeModifierInNewRunspaces is a PSScriptAnalyzer diagnostic emitted by tally for PowerShell snippets embedded in Dockerfiles.

Property	Value
Severity	Warning
Category	PSScriptAnalyzer
Auto-fix	No

Description

If a scriptblock is intended to be run in a new runspace, variables inside it should use the $using: scope modifier, or be initialized within the scriptblock. This applies to:

Invoke-Command- Only with the ComputerName or Session parameter.
Workflow { InlineScript {} }
Foreach-Object - Only with the Parallel parameter
Start-Job
Start-ThreadJob
The Script resource in DSC configurations, specifically for the GetScript, TestScript and SetScript properties.

How to Fix

Within the ScriptBlock, instead of just using a variable from the parent scope, you have to add the using: scope modifier to it.

Examples

Problematic code

$var = 'foo'
1..2 | ForEach-Object -Parallel { $var }

Correct code

$var = 'foo'
1..2 | ForEach-Object -Parallel { $using:var }

More correct examples

$bar = 'bar'
Invoke-Command -ComputerName 'foo' -ScriptBlock { $using:bar }

$bar = 'bar'
$s = New-PSSession -ComputerName 'foo'
Invoke-Command -Session $s -ScriptBlock { $using:bar }

# Remark: Workflow is supported on Windows PowerShell only
Workflow {
    $foo = 'foo'
    InlineScript { $using:foo }
}

$foo = 'foo'
Start-ThreadJob -ScriptBlock { $using:foo }
Start-Job -ScriptBlock {$using:foo }

Source

This rule documentation is adapted from Microsoft’s PSScriptAnalyzer documentation for UseUsingScopeModifierInNewRunspaces, licensed under CC BY 4.0.

​Description

​How to Fix

​Examples

​Problematic code

​Correct code

​More correct examples

​Source