Evaluating Azure Devops Expressions within Powershell - powershell

Question

I want to be able to invoke the Counter expression within a template but I am unsure how to do so; my current template yml file looks like this:
parameters:
- name: major
type: string
default: '1'
- name: minor
type: string
default: '0'
steps:
- task: PowerShell#2
displayName: Set NuGet package version
inputs:
targetType: 'inline'
script: |
$isMain = ('$(Build.SourceBranch)' -eq 'refs/heads/main')
$minor = ${{ parameters.minor }}
$revision1 = $[counter($minor, 1)]
Write-Host $revision
exit 0
But I get:
The term '$[counter' is not recognized as the name of a cmdlet, function, script file, or operable
program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
I am guessing there is way I can invoke the function via Powershell.
The reason for me wanting to do this in the template as opposed to passing it in as a parameter from the consumer of the template is because seemingly parameters are not evaluated when passed into a template.

Answer 1

Evaluating Azure Devops Expressions within Powershell
Just as Daniel said that:
The powershell script you're trying to run is getting finalized
during compile time. This line: $revision1 = $[counter($minor, 1)]
cannot possibly work. You are trying to take the results of a
powershell script expression and use it in a YAML function.
That is reason why it is not work for you.
And personally think you can go the easier way, just define the variable in the main YAML file：
azure-pipelines.yml：
variables:
- name: minor
value: 0
- name: revision1
value: $[counter(variables['minor'], 0)]
stages:
- stage: Run
jobs:
- job:
steps:
- template: Template.yml
And we could use the the Counter in the template directly:
Template.yml:
steps:
- task: PowerShell#2
displayName: Set NuGet package version
inputs:
targetType: 'inline'
script: |
Write-Host '$(revision1)'
The test result: