Setting tags on release [-1] ##[error]Cannot read property 'join' of null

[lachlann562]

I've been fighting with the following error:

Setting tags on release [-1]
##[error]Cannot read property 'join' of null

My yaml:

    - task: tagBuildOrRelease@0
      displayName: 'Tag build with ${{artifact.artifact}}'
      inputs:
        type: 'build'
        tags: "${{artifact.artifact}}"

I have ultimately found the root cause, it didn't handle the "type" being lower case "build" instead of "Build"
I think it didn't match build, so it defaulted to "release" as i noticed in the diagnostics that release was empty and i eventually noticed the "setting tags on release [-1]"

it would be nice if the "type" was case insensitive as it took over an our of debugging to realize what had happened. i assumed it was a problem with the tag i was trying to create, not that it didn't know which TYPE of tag to create.