git

Git 高级工作流

掌握高级 Git 技巧，保持提交历史整洁、高效协作，并自信地应对各种情况。

何时使用此技能

• 合并前清理提交历史
• 在分支间应用特定提交
• 找出引入错误的提交
• 同时开发多个功能
• 从 Git 操作失误或提交丢失中恢复
• 管理复杂的分支工作流
• 准备整洁的 PR 以供审查
• 同步已分叉的分支

核心概念

1. 交互式变基

交互式变基是编辑 Git 历史的瑞士军刀。

常见操作：

• pick：保留提交原样
• reword：修改提交说明
• edit：修改提交内容
• squash：与前一个提交合并
• fixup：类似于 squash，但丢弃提交说明
• drop：彻底删除提交

基本用法：

# Rebase last 5 commits
git rebase -i HEAD~5

# Rebase all commits on current branch
git rebase -i $(git merge-base HEAD main)

# Rebase onto specific commit
git rebase -i abc123

2. 挑选提交

将特定提交从一个分支应用到另一个分支，而不合并整个分支。

# Cherry-pick single commit
git cherry-pick abc123

# Cherry-pick range of commits (exclusive start)
git cherry-pick abc123..def456

# Cherry-pick without committing (stage changes only)
git cherry-pick -n abc123

# Cherry-pick and edit commit message
git cherry-pick -e abc123

3. Git 二分查找

通过二分查找提交历史，找到引入错误的提交。

# Start bisect
git bisect start

# Mark current commit as bad
git bisect bad

# Mark known good commit
git bisect good v1.0.0

# Git will checkout middle commit - test it
# Then mark as good or bad
git bisect good  # or: git bisect bad

# Continue until bug found
# When done
git bisect reset

自动二分查找：

# Use script to test automatically
git bisect start HEAD v1.0.0
git bisect run ./test.sh

# test.sh should exit 0 for good, 1-127 (except 125) for bad

4. 工作树

无需暂存或切换分支，即可同时处理多个分支。

# List existing worktrees
git worktree list

# Add new worktree for feature branch
git worktree add ../project-feature feature/new-feature

# Add worktree and create new branch
git worktree add -b bugfix/urgent ../project-hotfix main

# Remove worktree
git worktree remove ../project-feature

# Prune stale worktrees
git worktree prune

5. Reflog

你的安全网——跟踪所有引用的移动，包括已删除的提交。

# View reflog
git reflog

# View reflog for specific branch
git reflog show feature/branch

# Restore deleted commit
git reflog
# Find commit hash
git checkout abc123
git branch recovered-branch

# Restore deleted branch
git reflog
git branch deleted-branch abc123

实用工作流

工作流 1：PR 前清理功能分支

# Start with feature branch
git checkout feature/user-auth

# Interactive rebase to clean history
git rebase -i main

# Example rebase operations:
# - Squash "fix typo" commits
# - Reword commit messages for clarity
# - Reorder commits logically
# - Drop unnecessary commits

# Force push cleaned branch (safe if no one else is using it)
git push --force-with-lease origin feature/user-auth

工作流 2：将热修复应用到多个版本

# Create fix on main
git checkout main
git commit -m "fix: critical security patch"

# Apply to release branches
git checkout release/2.0
git cherry-pick abc123

git checkout release/1.9
git cherry-pick abc123

# Handle conflicts if they arise
git cherry-pick --continue
# or
git cherry-pick --abort

工作流 3：查找错误的引入位置

# Start bisect
git bisect start
git bisect bad HEAD
git bisect good v2.1.0

# Git checks out middle commit - run tests
npm test

# If tests fail
git bisect bad

# If tests pass
git bisect good

# Git will automatically checkout next commit to test
# Repeat until bug found

# Automated version
git bisect start HEAD v2.1.0
git bisect run npm test

工作流 4：多分支开发

# Main project directory
cd ~/projects/myapp

# Create worktree for urgent bugfix
git worktree add ../myapp-hotfix hotfix/critical-bug

# Work on hotfix in separate directory
cd ../myapp-hotfix
# Make changes, commit
git commit -m "fix: resolve critical bug"
git push origin hotfix/critical-bug

# Return to main work without interruption
cd ~/projects/myapp
git fetch origin
git cherry-pick hotfix/critical-bug

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

工作流 5：从操作失误中恢复

# Accidentally reset to wrong commit
git reset --hard HEAD~5  # Oh no!

# Use reflog to find lost commits
git reflog
# Output shows:
# abc123 HEAD@{0}: reset: moving to HEAD~5
# def456 HEAD@{1}: commit: my important changes

# Recover lost commits
git reset --hard def456

# Or create branch from lost commit
git branch recovery def456

高级技巧

变基与合并策略

何时使用变基：

• 推送前清理本地提交
• 保持功能分支与 main 同步
• 创建线性历史，便于审查

何时使用合并：

• 将已完成的功能集成到 main
• 保留协作过程的完整历史
• 他人正在使用的公共分支

# Update feature branch with main changes (rebase)
git checkout feature/my-feature
git fetch origin
git rebase origin/main

# Handle conflicts
git status
# Fix conflicts in files
git add .
git rebase --continue

# Or merge instead
git merge origin/main

自动压缩工作流

在变基期间自动压缩修正提交。

# Make initial commit
git commit -m "feat: add user authentication"

# Later, fix something in that commit
# Stage changes
git commit --fixup HEAD  # or specify commit hash

# Make more changes
git commit --fixup abc123

# Rebase with autosquash
git rebase -i --autosquash main

# Git automatically marks fixup commits

拆分提交

将一个提交拆分为多个逻辑清晰的提交。

# Start interactive rebase
git rebase -i HEAD~3

# Mark commit to split with 'edit'
# Git will stop at that commit

# Reset commit but keep changes
git reset HEAD^

# Stage and commit in logical chunks
git add file1.py
git commit -m "feat: add validation"

git add file2.py
git commit -m "feat: add error handling"

# Continue rebase
git rebase --continue

部分挑选提交

仅从某个提交中挑选特定文件。

# Show files in commit
git show --name-only abc123

# Checkout specific files from commit
git checkout abc123 -- path/to/file1.py path/to/file2.py

# Stage and commit
git commit -m "cherry-pick: apply specific changes from abc123"

最佳实践

1. 始终使用 --force-with-lease：比 --force 更安全，可防止覆盖他人的工作
2. 仅变基本地提交：不要变基已推送并共享的提交
3. 使用描述性提交说明：未来的你会感谢现在的你
4. 保持提交原子性：每个提交都应只包含一个逻辑更改
5. 强制推送前进行测试：确保重写历史没有造成问题
6. 留意 Reflog：记住，Reflog 是你 90 天内的安全网
7. 高风险操作前创建分支：复杂变基前先创建备份分支

# Safe force push
git push --force-with-lease origin feature/branch

# Create backup before risky operation
git branch backup-branch
git rebase -i main
# If something goes wrong
git reset --hard backup-branch

常见陷阱

• 变基公共分支：会导致协作者遇到历史冲突
• 不带租约强制推送：可能覆盖队友的工作
• 在变基中丢失工作：仔细解决冲突，并在变基后进行测试
• 忘记清理工作树：遗留的工作树会占用磁盘空间
• 实验前未备份：始终创建安全分支
• 在工作目录不干净时进行二分查找：开始二分查找前先提交或暂存更改

恢复命令

# Abort operations in progress
git rebase --abort
git merge --abort
git cherry-pick --abort
git bisect reset

# Restore file to version from specific commit
git restore --source=abc123 path/to/file

# Undo last commit but keep changes
git reset --soft HEAD^

# Undo last commit and discard changes
git reset --hard HEAD^

# Recover deleted branch (within 90 days)
git reflog
git branch recovered-branch abc123

资源

• references/git-rebase-guide.md：深入了解交互式变基
• references/git-conflict-resolution.md：高级冲突解决策略
• references/git-history-rewriting.md：安全地重写 Git 历史
• assets/git-workflow-checklist.md：PR 前清理检查清单
• assets/git-aliases.md：适用于高级工作流的实用 Git 别名
• scripts/git-clean-branches.sh：清理已合并和过期的分支

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注意事项

• git pull --rebase 会改写共享分支上的本地提交——同事拉取该分支时会看到“已强制推送”警告，尽管你并未推送。
• git rebase --onto X Y..HEAD 的语义：Y 不包含在内；从 Y 开始变基意味着从 Y+1 开始，而不是 Y。默认行为可能令人意外。
• 在构建不稳定时使用 git bisect：误报的“坏”结果会破坏二分查找路径；它给出的答案在输入条件下从技术上来说是正确的。
• git reflog 默认会过期——分支记录为 90 天，HEAD 记录为 30 天。对于重要分支，请设置 gc.reflogExpire=never。
• 使用 git cherry-pick 时不加 -x：新提交中不会记录源 SHA，导致来源信息丢失。-x 会在提交消息中添加 (cherry picked from <sha>)。
• git diff --no-index a b：可以比较 Git 仓库之外的两个文件，但遇到符号链接和大小写不敏感的文件系统时，路径语义会变得古怪。