git:worktrees（git 工作树）

Git Worktrees

Overview

Git worktrees enable checking out multiple branches simultaneously in separate directories, all sharing the same repository. Create a worktree instead of stashing changes or cloning separately.

Core principle: One worktree per active branch. Switch contexts by changing directories, not branches.

Core Concepts

Quick Reference

Essential Commands

Create a Worktree

# Create worktree with existing branch
git worktree add ../feature-x feature-x

# Create worktree with new branch from current HEAD
git worktree add -b new-feature ../new-feature

# Create worktree with new branch from specific commit
git worktree add -b hotfix-123 ../hotfix origin/main

# Create worktree tracking remote branch
git worktree add --track -b feature ../feature origin/feature

# Create worktree with detached HEAD (for experiments)
git worktree add --detach ../experiment HEAD~5

List Worktrees

# Simple list
git worktree list

# Verbose output with additional details
git worktree list -v

# Machine-readable format (for scripting)
git worktree list --porcelain

Example output:

/home/user/project           abc1234 [main]
/home/user/project-feature   def5678 [feature-x]
/home/user/project-hotfix    ghi9012 [hotfix-123]

Remove a Worktree

# Remove worktree (working directory must be clean)
git worktree remove ../feature-x

# Force remove (discards uncommitted changes)
git worktree remove --force ../feature-x

Move a Worktree

# Relocate worktree to new path
git worktree move ../old-path ../new-path

Lock/Unlock Worktrees

# Lock worktree (prevents pruning if on removable storage)
git worktree lock ../feature-x
git worktree lock --reason "On USB drive" ../feature-x

# Unlock worktree
git worktree unlock ../feature-x

Prune Stale Worktrees

# Remove stale worktree metadata (after manual directory deletion)
git worktree prune

# Dry-run to see what would be pruned
git worktree prune --dry-run

# Verbose output
git worktree prune -v

Repair Worktrees

# Repair worktree links after moving directories manually
git worktree repair

# Repair specific worktree
git worktree repair ../feature-x

Workflow Patterns

Pattern 1: Feature + Hotfix in Parallel

To fix a bug while feature work is in progress:

# Create worktree for hotfix from main
git worktree add -b hotfix-456 ../project-hotfix origin/main

# Switch to hotfix directory, fix, commit, push
cd ../project-hotfix
git add . && git commit -m "fix: resolve critical bug #456"
git push origin hotfix-456

# Return to feature work
cd ../project

# Clean up when done
git worktree remove ../project-hotfix

Pattern 2: PR Review While Working

To review a PR without affecting current work:

# Fetch PR branch and create worktree
git fetch origin pull/123/head:pr-123
git worktree add ../project-review pr-123

# Review: run tests, inspect code
cd ../project-review

# Return to work, then clean up
cd ../project
git worktree remove ../project-review
git branch -d pr-123

Pattern 3: Compare Implementations

To compare code across branches side-by-side:

# Create worktrees for different versions
git worktree add ../project-v1 v1.0.0
git worktree add ../project-v2 v2.0.0

# Diff, compare, or run both simultaneously
diff ../project-v1/src/module.js ../project-v2/src/module.js

# Clean up
git worktree remove ../project-v1
git worktree remove ../project-v2

Pattern 4: Long-Running Tasks

To run tests/builds in isolation while continuing development:

# Create worktree for CI-like testing
git worktree add ../project-test main

# Start long-running tests in background
cd ../project-test && npm test &

# Continue development in main worktree
cd ../project

Pattern 5: Stable Reference

To maintain a clean main checkout for reference:

# Create permanent worktree for main branch
git worktree add ../project-main main

# Lock to prevent accidental removal
git worktree lock --reason "Reference checkout" ../project-main

Pattern 6: Selective Merging from Multiple Features

To combine specific changes from multiple feature branches:

# Create worktrees for each feature to review
git worktree add ../project-feature-1 feature-1
git worktree add ../project-feature-2 feature-2

# Review changes in each worktree
diff ../project/src/module.js ../project-feature-1/src/module.js
diff ../project/src/module.js ../project-feature-2/src/module.js

# From main worktree, selectively take changes
cd ../project
git checkout feature-1 -- src/moduleA.js src/utils.js
git checkout feature-2 -- src/moduleB.js
git commit -m "feat: combine selected changes from feature branches"

# Or cherry-pick specific commits
git cherry-pick abc1234  # from feature-1
git cherry-pick def5678  # from feature-2

# Clean up
git worktree remove ../project-feature-1
git worktree remove ../project-feature-2

Comparing and Merging Changes Between Worktrees

Since all worktrees share the same Git repository, you can compare files, cherry-pick commits, and selectively merge changes between them.

Compare and Review File Changes

Since worktrees are just directories, you can compare files directly:

# Compare specific file between worktrees
diff ../project-main/src/app.js ../project-feature/src/app.js

# Use git diff to compare branches (works from any worktree)
git diff main..feature-branch -- src/app.js

# Visual diff with your preferred tool
code --diff ../project-main/src/app.js ../project-feature/src/app.js

# Compare entire directories
diff -r ../project-v1/src ../project-v2/src

Merge Only One File from a Worktree

You can selectively bring a single file from another branch using git checkout:

# In your current branch, get a specific file from another branch
git checkout feature-branch -- path/to/file.js

# Or get it from a specific commit
git checkout abc1234 -- path/to/file.js

# Get multiple specific files
git checkout feature-branch -- src/module.js src/utils.js

For partial file changes (specific hunks/lines only):

# Interactive patch mode - select which changes to take
git checkout -p feature-branch -- path/to/file.js

This prompts you to accept/reject each change hunk individually with options:

• y - apply this hunk
• n - skip this hunk
• s - split into smaller hunks
• e - manually edit the hunk

Cherry-Pick Commits from Worktrees

Cherry-picking works at the commit level. Since all worktrees share the same repository, you can cherry-pick any commit:

# Find the commit hash (from any worktree or git log)
git log feature-branch --oneline

# Cherry-pick specific commit into your current branch
git cherry-pick abc1234

# Cherry-pick multiple commits
git cherry-pick abc1234 def5678

# Cherry-pick a range of commits
git cherry-pick abc1234^..def5678

# Cherry-pick without committing (stage changes only)
git cherry-pick --no-commit abc1234

Merge Changes from Multiple Worktrees

You can merge or cherry-pick from multiple branches:

# Merge multiple branches sequentially
git merge feature-1
git merge feature-2

# Or use octopus merge for multiple branches at once
git merge feature-1 feature-2 feature-3

# Cherry-pick commits from multiple branches
git cherry-pick abc1234  # from feature-1
git cherry-pick def5678  # from feature-2

Selective Merging - Pick Which Changes to Include

Option 1: Selective File Checkout

# Get specific files from different branches
git checkout feature-1 -- src/moduleA.js
git checkout feature-2 -- src/moduleB.js
git commit -m "Merge selected files from feature branches"

Option 2: Interactive Patch Selection

# Select specific hunks from a file
git checkout -p feature-1 -- src/shared.js

Option 3: Cherry-Pick with Selective Staging

# Apply changes without committing
git cherry-pick --no-commit abc1234

# Unstage what you don't want
git reset HEAD -- unwanted-file.js
git checkout -- unwanted-file.js

# Commit only what you kept
git commit -m "Selected changes from feature-1"

Option 4: Merge with Manual Selection

# Start merge but don't auto-commit
git merge --no-commit feature-1

# Review and modify staged changes
git status
git reset HEAD -- file-to-exclude.js
git checkout -- file-to-exclude.js

# Commit your selection
git commit -m "Merge selected changes from feature-1"

Option 5: Using git restore (Git 2.23+)

# Restore specific file from another branch
git restore --source=feature-branch -- path/to/file.js

# Interactive restore with patch selection
git restore -p --source=feature-branch -- path/to/file.js

Directory Structure Conventions

Organize worktrees predictably:

~/projects/
  myproject/              # Main worktree (main/master branch)
  myproject-feature-x/    # Feature branch worktree
  myproject-hotfix/       # Hotfix worktree
  myproject-review/       # Temporary PR review worktree

Naming convention: <project>-<purpose> or <project>-<branch>

Best Practices

Common Issues and Solutions

Issue: "Branch is already checked out"

Cause: Attempting to checkout a branch that's active in another worktree.

Solution:

# Find where the branch is checked out
git worktree list

# Either work in that worktree or remove it first
git worktree remove ../other-worktree

Issue: Stale worktree after manual deletion

Cause: Deleted worktree directory without using git worktree remove.

Solution:

# Clean up stale metadata
git worktree prune

Issue: Worktree moved manually

Cause: Moved worktree directory without using git worktree move.

Solution:

# Repair the worktree links
git worktree repair
# Or specify the new path
git worktree repair /new/path/to/worktree

Issue: Worktree on removed drive

Cause: Worktree was on removable storage that's no longer connected.

Solution:

# If temporary, lock it to prevent pruning
git worktree lock ../usb-worktree

# If permanent, prune it
git worktree prune

Common Mistakes

Agent Workflow Integration

To isolate parallel agent tasks:

# Create worktree for isolated task
git worktree add -b task-123 ../project-task-123
cd ../project-task-123
# Make changes, run tests, return
cd ../project

To experiment safely with detached HEAD:

# Create detached worktree (no branch to clean up)
git worktree add --detach ../project-experiment
cd ../project-experiment
# Experiment, then discard or commit to new branch
git worktree remove --force ../project-experiment

Verification Checklist

Before using worktrees:

• Understand that branches can only be checked out in one worktree
• Know where worktrees will be created (use sibling directories)
• Plan cleanup strategy for temporary worktrees

When creating worktrees:

• Use descriptive directory names
• Verify branch is not already checked out elsewhere
• Consider using --detach for experiments

When removing worktrees:

• Commit or stash any uncommitted changes
• Use git worktree remove, not rm -rf
• Run git worktree prune if directory was deleted manually