ReturnCorrectTypesForDSCFunctions

Severity Level: Information

Description

The functions in DSC resources have specific return objects.

For non-class based resources:

• Set-TargetResource must not return any value.
• Test-TargetResource must return a boolean.
• Get-TargetResource must return a hash table.

For class based resources:

• Set must not return any value.
• Test must return a boolean.
• Get must return an instance of the DSC class.

How

Ensure that each function returns the correct type.

Example 1

Wrong

function Get-TargetResource
{
    param
    (
        [parameter(Mandatory = $true)]
        [String]
        $Name
    )
    ...
}

function Set-TargetResource
{
    param
    (
        [parameter(Mandatory = $true)]
        [String]
        $Name
    )
    ...
}

function Test-TargetResource
{
    param
    (
        [parameter(Mandatory = $true)]
        [String]
        $Name
    )
    ...
}

Correct

function Get-TargetResource
{
    [OutputType([Hashtable])]
    param
    (
        [parameter(Mandatory = $true)]
        [String]
        $Name
    )
    ...
}

function Set-TargetResource
{
    param
    (
        [parameter(Mandatory = $true)]
        [String]
        $Name
    )
    ...
}

function Test-TargetResource
{
    [OutputType([System.Boolean])]
    param
    (
        [parameter(Mandatory = $true)]
        [String]
        $Name
    )
    ...
}

Example 2

Wrong

[DscResource()]
class MyDSCResource
{
    [DscProperty(Key)]
    [string] $Name

    [String] Get()
    {
        ...
    }

    [String] Set()
    {
        ...
    }

    [bool] Test()
    {
        ...
    }
}

Correct

[DscResource()]
class MyDSCResource
{
    [DscProperty(Key)]
    [string] $Name

    [MyDSCResource] Get()
    {
        ...
    }

    [void] Set()
    {
        ...
    }

    [bool] Test()
    {
        ...
    }
}