bereniketech/git-worktrees

Git Worktrees

---

1. Overview

Git worktrees create isolated workspaces sharing the same repository, allowing work on multiple branches simultaneously without switching.

Rule: Systematic directory selection + safety verification = reliable isolation.

---

2. Directory Selection

Follow this priority order:

Check Existing Directories

ls -d .worktrees 2>/dev/null     # Preferred (hidden)
ls -d worktrees 2>/dev/null      # Alternative

If found, use that directory. If both exist, .worktrees wins.

Check CLAUDE.md

grep -i "worktree.*director" CLAUDE.md 2>/dev/null

If preference specified, use it without asking.

Ask User

If no directory exists and no CLAUDE.md preference:

No worktree directory found. Where should I create worktrees?

1. .worktrees/ (project-local, hidden)
2. A custom global location

Which would you prefer?

---

3. Safety Verification

For Project-Local Directories (.worktrees or worktrees)

Rule: Verify directory is ignored before creating worktree.

git check-ignore -q .worktrees 2>/dev/null || git check-ignore -q worktrees 2>/dev/null

If NOT ignored: add appropriate line to .gitignore, commit the change, then proceed. This prevents accidentally committing worktree contents to the repository.

For Global Directories

No .gitignore verification needed — outside project entirely.

---

4. Creation Steps

Detect Project Name

project=$(basename "$(git rev-parse --show-toplevel)")

Create Worktree

# Create worktree with new branch
git worktree add "$LOCATION/$BRANCH_NAME" -b "$BRANCH_NAME"
cd "$LOCATION/$BRANCH_NAME"

Run Project Setup

Auto-detect and run appropriate setup:

# Node.js
if [ -f package.json ]; then npm install; fi
# Rust
if [ -f Cargo.toml ]; then cargo build; fi
# Python
if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
if [ -f pyproject.toml ]; then poetry install; fi
# Go
if [ -f go.mod ]; then go mod download; fi

Verify Clean Baseline

Run tests to ensure worktree starts clean:

npm test / cargo test / pytest / go test ./...

If tests fail, report failures and ask whether to proceed or investigate. If tests pass, report ready.

Report Location

Worktree ready at <full-path>
Tests passing (<N> tests, 0 failures)
Ready to implement <feature-name>

---

5. Quick Reference

| Situation | Action | |-----------|--------| | .worktrees/ exists | Use it (verify ignored) | | worktrees/ exists | Use it (verify ignored) | | Both exist | Use .worktrees/ | | Neither exists | Check CLAUDE.md → Ask user | | Directory not ignored | Add to .gitignore + commit | | Tests fail during baseline | Report failures + ask | | No package.json/Cargo.toml | Skip dependency install |

---

6. Common Mistakes

• Skipping ignore verification — Worktree contents get tracked, pollute git status. Always use git check-ignore before creating project-local worktree.
• Assuming directory location — Creates inconsistency, violates project conventions. Follow priority: existing > CLAUDE.md > ask.
• Proceeding with failing tests — Can't distinguish new bugs from pre-existing issues. Report failures, get explicit permission to proceed.
• Hardcoding setup commands — Breaks on projects using different tools. Auto-detect from project files.

---

7. Red Flags

Never:

• Create worktree without verifying it's ignored (project-local)
• Skip baseline test verification
• Proceed with failing tests without asking
• Assume directory location when ambiguous

Always:

• Follow directory priority: existing > CLAUDE.md > ask
• Verify directory is ignored for project-local
• Auto-detect and run project setup
• Verify clean test baseline