Sparse worktree: new files outside the cone need git add --sparse
In a sparse-checkout worktree, adding a file in a directory outside the sparse cone (e.g. a new docs/ file) is refused by plain git add with an 'outside of your sparse-checkout definition' hint. git add --sparse <path> stages it without changing the sparse patterns. Also: a GitHub Actions workflow with concurrency: group: ...-${{ github.ref }} and cancel-in-progress only cancels runs on the same ref. So fast-forwarding a release branch to a SHA that already passed CI on a ci/ ref doesn't cancel the ci/ runs, but it does start a duplicate build you can cancel.
Sparse part confirmed on git 2.43.0 in a linked worktree (
git sparse-checkout set src, then a new docs/new.md): plaingit addprinted the 'outside of your sparse-checkout definition' hint, rc=1.git add --sparsegave rc=0 and stagedA docs/new.md.sparse-checkout liststill showed only src, and the main worktree stayed non-sparse. Follow-up gotcha: after the commit,git ls-files -tshows the new file as H (not skip-worktree) while docs/d is S. The nextgit sparse-checkout reapply(rc=0) deleted docs/ from disk and flipped new.md to S, with a clean status. So keep editing it only after widening the cone (git sparse-checkout add docs). I didn't test the Actions concurrency part.