ARM Template deployment returing a value that I dont expect - azure

Question

I am working on writing some Powershell that I am going to use in Azure DevOPS pipelines. This is to create an AppServiceplan. I have included the code below. I have used this same basic template to deploy a few other things and I have not run into this problem before.
This piece of the code $appSP = Get-AzAppServicePlan -Name $appServicePlanName -ResourceGroupName $rgname does not return a value, which is expected because this is the first time running it, yet its triggering this piece of code Write-verbose "AppService Plan '$appServicePlanName' already exists."
So it seems that even though the Get-AzAppServicePlan appears to be blank, maybe its returning some sort of object that I cant see?
Any ideas?
function Assert-AppServicePlan {
<#
.SYNOPSIS
This function will ensure that specified AppServicePlan exists.
.DESCRIPTION
Function will check if specified Azure AppServicePlan exists, and if not - it will be created.
Will return AppServicePLan object or, in case of error, $null.
.PARAMETER appServicePlanName
App Service Plan to be checked or created.
.PARAMETER rgName
Resource Group.
.PARAMETER SKU
SKU for App Service Plan. Default is P2V2.
.EXAMPLE
Assert-AppServicePlan -appServicePlansName "BARF" -rgName "MyResourceGroup" -SKU "F1" -verbose
#>
param(
[Parameter(Mandatory = $true)][ValidateNotNullorEmpty()][string]$appServicePlanName,
[Parameter(Mandatory = $true)][ValidateNotNullorEmpty()][string]$rgName,
[Parameter(Mandatory = $true)][ValidateNotNullorEmpty()][string]$SKU
);
$appSP = Get-AzAppServicePlan -Name $appServicePlanName -ResourceGroupName $rgname
if ($notPresent)
{
Write-Verbose "App Service Plan '$appServicePlanName' doesn't exist. Creating it."
try
{
$appSP = New-AzResourceGroupDeployment -ResourceGroupName `
$rgname -TemplateFile .\templates\appserviceplan.json `
-TemplateParameterFile .\templates\appserviceplan.parameters.json `
-ErrorAction Stop
}
catch
{
Write-verbose "Error while creating App Service Plan."
Write-Error $_
}
}
else
{
Write-verbose "AppService Plan '$appServicePlanName' already exists."
}
return $appSP
}

Answer 1

The Get-AzAppServicePlan cmdlet returns the App Service Plan object if found in the specified resource group, else nothing. So, it would be sufficient to check on this result in your if condition.
Another case where the result might mislead returning null is when you query under an incorrect PS context or a different Subscription (locally). However, since you intend to run this as part of Azure DevOps pipelines, the Service connection used by the task would ensure it.

Answer 2

Just another suggestion, you can use ErrorVariable
Get-AzAppServicePlan -Name $appServicePlanName -ResourceGroupName $rgname -ErrorAction Silentlycontinue -ErrorVariable notPresent
if ($notPresent)
{
#create something
}
else {
#exits
}