Context

1. I want to use a parameter passed via command line to initialize some properties which are used in multiple tasks, instead of initializing them in each task.
   Invoke-psake script.ps1 -parameters @{"baseDir" = "...some_path_here..."}

2. And I want to validate that parameter first.

Example

Properties {
$reusedPath = Join-Path $baseDir "smth"
}

Task Default -Depends Validate, TaskDB, TaskServer

Task Validate {
Assert (![string]::IsNullOrEmpty($baseDir)) '$baseDir was null or empty'
Assert (Test-Path $baseDir) "`$baseDir does not exist"
}

Task TaskDB {
$x = Join-Path $reusedPath "smth1"
}

Task TaskServer {
$x = Join-Path $reusedPath "smth2"
}

Problem

Properties are initialized before any task. So my validation task doesn't do any work at all. For instance, if I don't pass $baseDir as a parameter or leave it empty, I will not reach Validate task. It will fail on a step of Properties initialization ($reusedPath = Join-Path $baseDir "smth") with really not informative error:
~~~~~~~~~~~ [<<==>>] Exception: Cannot bind argument to parameter 'Path' because it is null.

Question

Is there way to validate parameters before Properties initialization? Or is there other way how to achieve the same goal?

Environment

• Module version used: 4.7.0
• Operating System and PowerShell version: Windows 10, PowerShel 5.1