worktree-parallel-dev

name	worktree-parallel-dev
description	Run parallel Thingino tasks/agents in isolated git worktrees with correct submodule, patch, and dl-cache setup.
license	MIT

worktree-parallel-dev

Use this skill when work should happen on a separate branch without disturbing the main checkout — parallel agent sessions, an urgent fix while a long task is in flight, or risky experiments that need cheap teardown.

Model: one task, one branch, one worktree, one agent.

When to use

• The user asks for parallel work streams or multiple simultaneous agents.
• A hotfix is needed while the current tree has in-progress work (no stashing).
• A task is exploratory and may be abandoned (delete the worktree, keep the tree clean).
• A long build (30+ min) must not be interrupted by branch switching.

Workflow

1. Create a worktree from the main checkout (never bare git worktree add — the helper also inits the buildroot submodule, applies the buildroot override patches from package/all-patches/buildroot/, and shares the dl/ cache):
   • scripts/worktree.sh create <branch> [base]
   • Created at ../<repo-name>-<branch-with-dashes>/ (no spaces allowed in path).
2. Work inside the worktree only. Always pass CAMERA= explicitly:
   • cd ../<repo>-<branch> then CAMERA=<camera> make fast
   • Output is isolated: output/<branch>/<camera>-.../ inside the worktree.
3. Commit checkpoints, then sync at the end of each significant session:
   • scripts/worktree.sh sync (rebases onto origin/master, re-syncs buildroot submodule, re-applies patches)
   • Push with git push --force-with-lease after a sync rebase.
4. Protect a worktree during long builds:
   • git worktree lock <path> --reason "build running" / git worktree unlock <path>
5. Cleanup after the PR merges (from the main checkout, user-confirmed):
   • scripts/worktree.sh remove <branch> — deletes the directory (incl. its output/), preserves the branch. Never remove a worktree unless the user asked for it or approved it.

Hard rules for agents

• Never run make update in a feature worktree. It git pull --rebases the current branch. Use scripts/worktree.sh sync instead.
• Never touch files in another worktree. Each worktree is foreign territory.
• A branch can be checked out in only one worktree at a time (fatal: '<branch>' is already checked out means someone owns it — do not force).
• Do not share overrides/<pkg>/ source checkouts between worktrees; give each worktree its own clone and local.mk entry if an override is needed.
• Container builds (build-container.sh) break in linked worktrees (the .git gitfile points to an unmounted host path) — build on the host in worktrees.

Notes

• Shared across worktrees automatically: git history, dl cache (symlinked), ccache (~/.buildroot-ccache), toolchain bundles (in dl).
• Not carried into a new worktree (gitignored): local.mk, user/, overrides/, .selected_camera — set up per worktree only if the task needs them.
• Full onboarding doc: docs/worktrees.md in the firmware repo.