Passing an alternative PDK image does not work

[fraenki]

So I've tried to use the pdk "nightly" image...

       - name: Run pdk validate
         uses: puppets-epic-show-theatre/action-pdk-validate@v1.1.0
         with:
           pdk-image: puppet/pdk:nightly
           puppet-version: ${{ matrix.puppet_version }}

...but unfortunately, the GitHub Action still uses the "latest" image. From the GitHub Actions logs:

...
Download action repository 'puppets-epic-show-theatre/action-pdk-validate@v1.1.0' (SHA:4536bf103a3c2b92ddee02dfceab99a27ef2e83f)
...
Build container for action use: '/home/runner/work/_actions/puppets-epic-show-theatre/action-pdk-validate/v1.1.0/Dockerfile'.
  /usr/bin/docker build -t a5c76b:ebfbbc0bea1d492c8f1f5190da4765ee -f "/home/runner/work/_actions/puppets-epic-show-theatre/action-pdk-validate/v1.1.0/Dockerfile" "/home/runner/work/_actions/puppets-epic-show-theatre/action-pdk-validate/v1.1.0"
Sending build context to Docker daemon  41.98kB
  
Step 1/5 : ARG PDKIMAGE=puppet/pdk:latest
Step 2/5 : FROM $PDKIMAGE
latest: Pulling from puppet/pdk
...

So it looks like that pdk-image parameter does nothing. Or am I doing something wrong?

[fraenki]

@cdenneen You've contributed the pdk-image functionality, maybe you could comment on this issue? Thanks :)

[vaxvms]

I think it has never and ever worked PDFIMAGE is an ARG and not an ENV so you have to use --build-arg to use in at container build time.

According to https://github.com/orgs/community/discussions/25241 this is not supported as-is