github context is not accessible from step.uses

Describe the bug It is not possible to use github context in jobs.<job_id>.steps[*].uses.

To Reproduce create workflow which uses github context within uses:

name: ci
on: [push, pull_request]
jobs:
  my_job:
    runs-on: ubuntu-latest
    steps:
      - name: this repo action
        uses: ${{ github.repository }}@${{ github.sha }}        

Expected behavior github.repository and github.sha are substituted with correspoonding values.

Runner Version and Platform

public runner

What’s not working?

github context variable substitution

Job Log Output

The workflow is not valid. .github/workflows/ci.yml (Line: 17, Col: 15): Unrecognized named-value: 'github'. Located at position 1 within expression: github.repository 

Runner and Worker’s Diagnostic Logs

https://github.com/myci-actions/add-deb-repo/actions/runs/469160309

[TingluoHuang]

We don’t support expression in those place, you need to checkout the repo to use local action.

- uses: actions/checkout@v2
- uses: ./

[TingluoHuang]

We want the YAML file readable at some level, so we don’t open expressions for every part of the YAML file.

You can make a feature request at https://github.community/c/code-to-cloud/github-actions/41

The runner repo might not be a good place for this kind of question, it doesn’t understand YAML at all, the service parses the YAML and validates against a defined schema. 😄