Try env in jobs scope

Author: vkucera

.github/workflows/o2-linter.yml

@@ -4,16 +4,16 @@ name: O2 linter
 
 "on": [pull_request_target, push]
 permissions: {}
-env:
-  HEAD_BRANCH: ${{ github.event_name == 'push' && github.ref || 'refs/pull/'{{ github.event.number }}'/merge' }}
-  BASE_BRANCH: ${{ github.event_name == 'push' && 'master' || github.event.pull_request.base.ref }}
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
   cancel-in-progress: true
 
 jobs:
   o2-linter:
+    env:
+      branch_head: ${{ github.event_name == 'push' && github.ref || 'refs/pull/'{{ github.event.number }}'/merge' }}
+      branch_base: ${{ github.event_name == 'push' && 'master' || github.event.pull_request.base.ref }}
     name: O2 linter
     runs-on: ubuntu-24.04
     permissions:
@@ -22,14 +22,14 @@ jobs:
       - name: Checkout Code
         uses: actions/checkout@v4
         with:
-          ref: ${{ env.HEAD_BRANCH }}
+          ref: ${{ env.branch_head }}
           fetch-depth: 0 # needed to get the full history
       - name: Run tests
         id: linter
         run: |
           # Diff against the common ancestor of the source branch and the target branch.
-          echo "Diffing ${{ env.HEAD_BRANCH }} against ${{ env.BASE_BRANCH }}."
-          readarray -t files < <(git diff --diff-filter d --name-only origin/${{ env.BASE_BRANCH }}...)
+          echo "Diffing ${{ env.branch_head }} against ${{ env.branch_base }}."
+          readarray -t files < <(git diff --diff-filter d --name-only origin/${{ env.branch_base }}...)
           if [ ${#files[@]} -eq 0 ]; then
               echo "::notice::No files to lint."
               echo "linter_ran=0" >> "$GITHUB_OUTPUT"