Add prepare job to set OS list for CI workflow

Author: epernod

.github/workflows/ci.yml

@@ -21,6 +21,21 @@ on:
 
 
 jobs:
+  prepare:
+    runs-on: ubuntu-latest
+    outputs:
+      os_list: ${{ steps.set.outputs.os_list }}
+    steps:
+      - id: set
+        run: |
+          if [[ "${{ github.event_name }}" == "pull_request" ]] ||
+             [[ "${{ github.event_name }}" == "push" && "${{ github.ref }}" != refs/tags/v* ]] ||
+             [[ "${{ github.event_name }}" == "workflow_dispatch" && "${{ inputs.full_build }}" != "true" ]]; then
+            echo 'os_list=["ubuntu-22.04","windows-2022"]' >> $GITHUB_OUTPUT
+          else
+            echo 'os_list=["ubuntu-22.04","windows-2022","macos-14"]' >> $GITHUB_OUTPUT
+          fi
+
   build-and-test:
     name: Run on ${{ matrix.os }} with SOFA ${{ matrix.sofa_branch }} / MeshRefinement=${{ matrix.with_mesh_refinement }}
 
@@ -43,13 +58,7 @@ jobs:
       fail-fast: false
 
       matrix:
-        os: ${{ fromJSON(
-          (github.event_name == 'pull_request' ||
-           (github.event_name == 'push' && !startsWith(github.ref, 'refs/tags/v')) ||
-           (github.event_name == 'workflow_dispatch' && inputs.full_build != 'true'))
-          && '["ubuntu-22.04","windows-2022"]'
-          || '["ubuntu-22.04","windows-2022","macos-14"]'
-        ) }}
+        os: ${{ fromJSON(needs.prepare.outputs.os_list) }}
 
         sofa_branch: [master]
         with_mesh_refinement: [ON, OFF]