Change PowerShell Version used in PowerShell@2 - Azure DevOps Tricks #1

Ran into a pipeline issue when using ConvertFrom-Json -Depth 20 to load a JSON file in a PowerShell@2 task in a DevOps pipeline. The -Depth parameter was throwing an error:

ConvertFrom-Json : A parameter cannot be found that matches parameter name 'Depth'

What the ConvertFrom-Json docs say?

• PowerShell 5.1
  • Doesn't list a parameter -Depth.
• PowerShell 7 (LTS)
  • -Depth: Gets or sets the maximum depth the JSON input is allowed to have. By default, it is 1024. This parameter was introduced in PowerShell 6.2.

What version of PowerShell is PowerShell@2 using?

note: this may differ depending on the Agent that is running the task.

I added a line to the script to get the version:

   Write-Host "Version: ($PSVersionTable.PSVersion)"

Output:

   Version: 5.1.17763.1852

How do we change the version?

This little snippet allows a script defined in a PowerShell@2 task to relaunch in a specific version of PowerShell.

    if ($PSVersionTable.PSVersion -lt [Version]"7.0") {
        Write-Host "Version: $($PSVersionTable.PSVersion)"
        Write-Host "Re-launching as pwsh"
        pwsh -File $MyInvocation.MyCommand.Definition
        exit
    }

Some other options if you want a specific version.

    powershell -Version 2 -File $MyInvocation.MyCommand.Definition