powershell/PSAvoidDefaultValueSwitchParameter

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

Property	Value
Severity	Warning
Category	PSScriptAnalyzer
Default	Disabled in tally
Auto-fix	No

tally disables this rule by default for Dockerfile RUN snippets because a RUN executes statements inline rather than defining cmdlets, parameters, or modules with external callers. Re-enable it with include = ["powershell/PSAvoidDefaultValueSwitchParameter"] or by setting rules.powershell.PSAvoidDefaultValueSwitchParameter.severity = "warning" in .tally.toml.

Description

If your parameter takes only true and false, define the parameter as type [Switch]. PowerShell treats a switch parameter as true when it’s used with a command. If the parameter isn’t included with the command, PowerShell considers the parameter to be false. Don’t define [Boolean] parameters. You shouldn’t define a switch parameter with a default value of $true because this isn’t the expected behavior of a switch parameter.

How

Change the default value of the switch parameter to be $false or don’t provide a default value. Write the logic of the script to assume that the switch parameter default value is $false or not provided.

Examples

Problematic code

function Test-Script
{
    [CmdletBinding()]
    Param
    (
        [String]
        $Param1,

        [switch]
        $Switch=$True
    )
    ...
}

Correct code

function Test-Script
{
    [CmdletBinding()]
    Param
    (
        [String]
        $Param1,

        [switch]
        $Switch
    )

    begin {
        # Ensure that the $Switch is set to false if not provided
        if (-not $PSBoundParameters.ContainsKey('Switch')) {
            $Switch = $false
        }
    }
    ...
}

More information

Strongly Encouraged Development Guidelines

Source

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

powershell/PSAvoidDefaultValueForMandatoryParameter

powershell/PSAvoidExclaimOperator

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​Description

​How

​Examples

​Problematic code

​Correct code

​More information

​Source

Description

How

Examples

Problematic code

Correct code

More information

Source