Github Actions reusable workflow access repo issues - github

Question

I moved some common ci work into its own repo for linting, static checks etc. Multiple repos will then use this to avoid duplication. Issue I am having is, obviously the checks need to be carried out on the repo that invokes the workflow. How is this made possible? When the common workflow is executed it has no access to the contents of the initial repo. It only checks out itself.
Example source repo:
name: Perform Pre Build Check
on:
push:
workflow_dispatch:
jobs:
checks:
uses: <org>/<common-repo>/.github/workflows/checks.yml#main
Common workflow:
name: Perform Pre-Build Checks
on:
workflow_call:
jobs:
formatting-check:
name: Formatting Check
runs-on: ubuntu-latest
steps:
- uses: actions/checkout#v2
- name: Run linting check
run: xxxxxx
- name: Install cppcheck
run: sudo apt-get -y install cppcheck
- name: Run cppcheck
run: xxxxx
continue-on-error: true

Answer 1

This is what I ended up doing. Not sure if this was right approach but it worked. Basically just passing in the repo & ref name from current repo that triggered the workflow,
Example source repo:
name: Perform Pre Build Check
on:
push:
workflow_dispatch:
jobs:
checks:
uses: <org>/<common-repo>/.github/workflows/checks.yml#main
with:
repo-name: ${{ github.GITHUB_REPOSITORY }}
ref-name: ${{ github.GITHUB_REF_NAME }}
Common workflow:
name: Perform Pre-Build Checks
on:
workflow_call:
inputs:
repo-name:
required: true
type: string
ref-name:
required: true
type: string
jobs:
formatting-check:
name: Formatting Check
runs-on: ubuntu-latest
steps:
- uses: actions/checkout#v2
with:
repository: ${{inputs.repo-name}}
ref: ${{inputs.ref-name}}
- name: Run linting check
run: xxxxxx
- name: Install cppcheck
run: sudo apt-get -y install cppcheck
- name: Run cppcheck
run: xxxxx
continue-on-error: true