[Docs] Azure Devops - Fetch Depth

[dazinator]

For Azure devops build pipelines created later than a certain date, they started doing shallow clone's and subsequently this means the following gitversion AzDO tasks fail.

   - task: gitversion/setup@0
      displayName: Install GitVersion
      inputs:
        versionSpec: '5.11.1'

    - task: gitversion/execute@0
      displayName: Determine Version
      inputs:      

There is a gitversion docs page for configuring the different build servers but nothing about this for azure devops that I could see.

The important piece of info is here: https://learn.microsoft.com/en-us/azure/devops/pipelines/yaml-schema/steps-checkout?view=azure-pipelines#shallow-fetch

It basically boils down to this, you need to add an intial checkout task to your yaml pipeline to control checkout behaviour and explicit set fetch depth to 0 (which means it won't do shallow fetch).

 steps:     
    # this is rewquired for gitversion
    - checkout: self
      fetchDepth: 0
      clean: true