Why is Powershell 7 (pwsh.exe) NOT outputting the full error when we have a $null passed to a non-null parameter? And how can I configure my Powershell 7 on my Windows 10 box to fully report it?

Given this script:

param(
  [Parameter()]
  $Adventurer = "Bilbo"
)

$ErrorActionPreference = 'Stop'
#Requires -Version 7

function Get-SpyResult($FileName) {
  $profile = Get-Item $FileName
  # ...
}

$x = Get-SpyResult $Adventurer
# ...
Write-Host "If this worked, we would get here."

We can observe the following:

PS C:temp> $PSVersionTable.PSVersion.ToString()
7.4.1
PS C:temp> .here_be_dragons.ps1 "Someone"
Get-Item: C:temphere_be_dragons.ps1:10
Line |
  10 |    $profile = Get-Item $FileName
     |               ~~~~~~~~~~~~~~~~~~
     | Cannot find path 'C:tempSomeone' because it does not exist.
PS C:temp>
PS C:temp> .here_be_dragons.ps1 $Null
here_be_dragons.ps1: Cannot bind argument to parameter 'Path' because it is null.
PS C:temp> # Why ??
PS C:temp>
PS C:temp> $Error[0]
Get-Item: C:temphere_be_dragons.ps1:10
Line |
  10 |    $profile = Get-Item $FileName
     |                        ~~~~~~~~~
     | Cannot bind argument to parameter 'Path' because it is null.

PS C:temp>

As you can see, Cannot find path is reported with a stack trace.

But Cannot bind argument to parameter is not properly reported, you have to resolve the error object manually.

Now, by inspecting the error objects, we can get a clue:

When it works, we have this:

_> $Error[0].GetType()

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     False    ActionPreferenceStopException            System.Management.Automation.RuntimeException

For the $null mess we have:

_> $Error[0].GetType()

IsPublic IsSerial Name                                     BaseType
-------- -------- ----                                     --------
True     False    ErrorRecord                              System.Object

The actual error objects seem to be generated differently. But that still doesn’t explain what this is all about and how I can get my scripts to always report a stack trace.