False positives on interpolated environment variable names

[dgholz]

I have a workflow like:

on: [push]

jobs:
  example:
    runs-on: ubuntu-latest
    steps:
    - name: set output
      id: set-value
      run: |
        echo "value=key_name" >> "$GITHUB_OUTPUT"
    - name: use env var
      env:
        "${{ steps.set-value.outputs.value }}": ${{ github.repository_owner }}
      run: |
        echo "${${{ steps.set-value.outputs.value }}}"

(the actual workflow doesn't echo, it calls Bundler, which looks for environment variables with special formats to set config options)

This works fine when the workflow runs, but Actionlint reports

.github/workflows/test.yml:13:9: environment variable name "${{ steps.set-value.outputs.value }}" is invalid. '&', '=' and spaces should not be contained [env-var]
   |
13 |         "${{ steps.set-value.outputs.value }}": ${{ github.repository_owner }}
   |         ^~~~

Deleting the spaces resolves the false positive, but it reveals that Actionlint isn't handling the interpolation in the environment variable name.

[rhysd]

I didn't know that ${{ }} is available for environment variable names. Thanks for reporting this.