how to use semverDiff expression properly?

[jessebot]

Hoi friends!

I'll get right to it. I want to use semverDiff to open PRs labeled with the semver type. I want to do the following in my ClusterPromotionTask:

spec:
  steps:
    ... other steps cut for brevity
    # parse the plugin repo's current Chart.yaml appVersion
    - uses: yaml-parse
      as: parse-old-chart-yaml
      config:
        path: ./src/${{ vars.chartPath }}/Chart.yaml
        outputs:
          - name: appVersion
            fromExpression: appVersion

    # update the plugin repo's Chart.yaml appVersion to the Chart.yaml version upstream
    - uses: yaml-update
      as: update-appversion
      config:
        path: ./src/${{ vars.chartPath }}/Chart.yaml
        updates:
          - key: appVersion
            value: ${{ chartFrom(vars.chartRepo, warehouse(vars.warehouseName)).Version }}

    # parse the plugin repo's new Chart.yaml appVersion
    - uses: yaml-parse
      as: parse-new-chart-yaml
      config:
        path: ./src/${{ vars.chartPath }}/Chart.yaml
        outputs:
          - name: appVersion
            fromExpression: appVersion

    # get semver type (major, minor, or patch)
    - uses: compose-output
      as: semver
      config:
        semverType: ${{ semverDiff(task.outputs['parse-old-chart-yaml'].appVersion, task.outputs['parse-new-chart-yaml'].appVersion) }}

Basically, all I want to do is check the semver update type, and use that in a PR in a further down step, but the semverDiff never works and I don't know why, because when I look in the GUI, I see that both yaml-parse steps are working fine:

However I keep getting this error:

an unrecoverable error occurred: failed to get step config: reflect: call of reflect.Value.Call on zero Value (1:2) | semverDiff(task.outputs['parse-old-chart-yaml'].appVersion, task.outputs['parse-new-chart-yaml'].appVersion) | .^

To give a bit more clarity, I went ahead and added a step before the compose-output step with the semverDiff call that looks like this:

    # testing yaml parse outputs
    - uses: compose-output
      as: testing-outputs
      config:
        oldOutput: ${{ task.outputs['parse-old-chart-yaml'].appVersion }}
        newOutput: ${{ task.outputs['parse-new-chart-yaml'].appVersion }}

And that seems to be working as well:

And I don't know why I get that error or how to solve it. Perhaps it is a bug?

If anyone has any advice, I'm happy to take it, or provide any other info you need! 💙

Update

Wait, there's a chance it was broken because I was using 1.7.2! Trying with 1.7.3 now!

[jessebot]

yep, this was me on the wrong version of kargo. Please feel free to ignore this one. Anyone else lost, make sure you're using Kargo 1.7.3 and up to use the semverDiff expression!