Git Repository

Git Repository Management Skill

This skill provides comprehensive guidance on repository management strategies, branching models, repository organization patterns, and scaling git for large teams and codebases.

When to Use

Activate this skill when:

• Setting up new repository structure
• Choosing branching strategy
• Managing monorepo vs polyrepo
• Organizing multi-project repositories
• Implementing submodule or subtree strategies
• Scaling git for large teams
• Migrating repository structures
• Establishing team workflows

Branching Strategies

Git Flow

Branch Structure:

• main (or master) - Production releases only
• develop - Integration branch for next release
• feature/* - Feature development branches
• release/* - Release preparation branches
• hotfix/* - Emergency production fixes

Workflow:

# Feature Development
git checkout develop
git checkout -b feature/user-authentication
# Work on feature...
git commit -m "feat: add JWT authentication"
git checkout develop
git merge --no-ff feature/user-authentication
git branch -d feature/user-authentication

# Release Preparation
git checkout develop
git checkout -b release/v1.2.0
# Bump version, update changelog, final testing...
git commit -m "chore: prepare release v1.2.0"

# Deploy Release
git checkout main
git merge --no-ff release/v1.2.0
git tag -a v1.2.0 -m "Release version 1.2.0"
git checkout develop
git merge --no-ff release/v1.2.0
git branch -d release/v1.2.0
git push origin main develop --tags

# Hotfix
git checkout main
git checkout -b hotfix/security-patch
git commit -m "fix: patch security vulnerability"
git checkout main
git merge --no-ff hotfix/security-patch
git tag -a v1.2.1 -m "Hotfix v1.2.1"
git checkout develop
git merge --no-ff hotfix/security-patch
git branch -d hotfix/security-patch
git push origin main develop --tags

Best For:

• Scheduled releases
• Multiple production versions
• Large teams with QA process
• Products with maintenance windows
• Enterprise software

Drawbacks:

• Complex workflow
• Long-lived branches
• Potential merge conflicts
• Delayed integration

GitHub Flow

Branch Structure:

• main - Production-ready code (always deployable)
• feature/* - All feature and fix branches

Workflow:

# Create Feature Branch
git checkout main
git pull origin main
git checkout -b feature/add-api-logging

# Develop Feature
git commit -m "feat: add structured logging middleware"
git push -u origin feature/add-api-logging

# Open Pull Request on GitHub
# Review, discuss, CI passes

# Merge and Deploy
# Merge PR on GitHub
# Automatic deployment from main

# Cleanup
git checkout main
git pull origin main
git branch -d feature/add-api-logging

Best For:

• Continuous deployment
• Small to medium teams
• Web applications
• Rapid iteration
• Cloud-native applications

Drawbacks:

• Requires robust CI/CD
• No release staging
• Less structured than Git Flow

Trunk-Based Development

Branch Structure:

• main (or trunk) - Single source of truth
• Short-lived feature branches (< 2 days, optional)
• Feature flags for incomplete work

Workflow:

# Direct Commit to Main (Small Changes)
git checkout main
git pull origin main
# Make small change...
git commit -m "fix: correct validation logic"
git push origin main

# Short-Lived Branch (Larger Changes)
git checkout -b optimize-query
# Work for < 1 day
git commit -m "perf: optimize database query"
git push -u origin optimize-query
# Immediate PR, quick review, merge same day

# Feature Flags for Incomplete Features
git checkout main
git commit -m "feat: add payment gateway (behind feature flag)"
# Feature disabled in production until complete
git push origin main

Best For:

• High-velocity teams
• Continuous integration
• Automated testing
• Feature flag infrastructure
• DevOps culture

Drawbacks:

• Requires discipline
• Needs comprehensive tests
• Feature flag management
• Higher deployment frequency

Release Branch Strategy

Branch Structure:

• main - Current development
• release/v* - Long-lived release branches
• feature/* - Feature branches

Workflow:

# Create Release Branch
git checkout -b release/v1.0 main
git push -u origin release/v1.0

# Continue Development on Main
git checkout main
# Work on v2.0 features...

# Backport Fixes to Release
git checkout release/v1.0
git cherry-pick abc123  # Fix from main
git push origin release/v1.0
git tag -a v1.0.5 -m "Patch release v1.0.5"
git push origin v1.0.5

# Multiple Release Maintenance
git checkout release/v0.9
git cherry-pick def456
git tag -a v0.9.8 -m "Security patch v0.9.8"

Best For:

• Multiple product versions
• Long-term support releases
• Enterprise customers
• Regulated industries

Drawbacks:

• Maintenance overhead
• Complex cherry-picking
• Diverging codebases

Feature Branch Workflow

Branch Structure:

• main - Stable production code
• feature/* - Feature branches from main
• bugfix/* - Bug fix branches

Workflow:

# Feature Development
git checkout main
git checkout -b feature/payment-integration

# Long-Running Feature (Sync with Main)
git fetch origin
git rebase origin/main
# Or merge
git merge origin/main

# Complete Feature
git push origin feature/payment-integration
# Create pull request
# After review and approval, merge to main

Best For:

• Medium-sized teams
• Code review processes
• Parallel feature development
• Quality gates before merge

Repository Organization

Monorepo

Structure:

monorepo/
├── .git/
├── services/
│   ├── api/
│   ├── web/
│   └── worker/
├── packages/
│   ├── shared-utils/
│   ├── ui-components/
│   └── api-client/
├── tools/
│   ├── build-tools/
│   └── scripts/
└── docs/

Advantages:

• Single source of truth
• Shared code visibility
• Atomic cross-project changes
• Unified versioning
• Simplified dependency management
• Consistent tooling

Disadvantages:

• Large repository size
• Slower clone/fetch
• Complex CI/CD
• Access control challenges
• Tooling requirements

Implementation:

# Initialize Monorepo
git init
mkdir -p services/api services/web packages/shared-utils

# Workspace Setup (Node.js example)
cat > package.json << EOF
{
  "name": "monorepo",
  "private": true,
  "workspaces": [
    "services/*",
    "packages/*"
  ]
}
EOF

# Sparse Checkout (Partial Clone)
git clone --filter=blob:none --no-checkout <url>
cd repo
git sparse-checkout init --cone
git sparse-checkout set services/api packages/shared-utils
git checkout main

# Build Only Changed Packages
git diff --name-only HEAD~1 | grep "^services/api" && cd services/api && npm run build

Tools:

• Bazel - Build system for large monorepos
• Nx - Monorepo build system (Node.js)
• Lerna - JavaScript monorepo management
• Turborepo - High-performance build system
• Git-subtree - Merge external repositories

Polyrepo

Structure:

organization/
├── api-service/       (separate repo)
├── web-app/           (separate repo)
├── mobile-app/        (separate repo)
├── shared-utils/      (separate repo)
└── documentation/     (separate repo)

Advantages:

• Clear ownership boundaries
• Independent versioning
• Smaller repository size
• Granular access control
• Flexible CI/CD
• Team autonomy

Disadvantages:

• Dependency version conflicts
• Cross-repo changes are complex
• Duplicated tooling/config
• Harder to refactor across repos

Implementation:

# Template Repository
git clone git@github.com:org/template-service.git new-service
cd new-service
rm -rf .git
git init
git remote add origin git@github.com:org/new-service.git

# Shared Configuration
# Use git submodules or packages
git submodule add git@github.com:org/shared-config.git config

Monorepo vs Polyrepo Decision Matrix

Submodule Management

Basic Submodules

# Add Submodule
git submodule add https://github.com/org/shared-lib.git libs/shared

# Clone with Submodules
git clone --recurse-submodules <url>

# Initialize After Clone
git submodule init
git submodule update

# Update Submodule
cd libs/shared
git pull origin main
cd ../..
git add libs/shared
git commit -m "chore: update shared library"

# Update All Submodules
git submodule update --remote --merge

# Remove Submodule
git submodule deinit libs/shared
git rm libs/shared
rm -rf .git/modules/libs/shared

Submodule Strategies

Pinned Version Strategy:

# Submodule points to specific commit
# Manual updates with testing
git submodule update --remote libs/shared
# Test changes...
git add libs/shared
git commit -m "chore: update shared-lib to v1.2.3"

Auto-Update Strategy:

# CI automatically updates submodules
# .github/workflows/update-submodules.yml
name: Update Submodules
on:
  schedule:
    - cron: '0 0 * * 0'  # Weekly
jobs:
  update:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
        with:
          submodules: true
      - run: git submodule update --remote
      - run: git commit -am "chore: update submodules"
      - run: git push

Nested Submodules

# Add Nested Submodule
cd libs/framework
git submodule add https://github.com/org/utils.git utils

# Update Recursively
git submodule update --init --recursive

# Run Command in All Submodules
git submodule foreach 'git checkout main'
git submodule foreach 'git pull'
git submodule foreach --recursive 'echo $name: $(git rev-parse HEAD)'

Subtree Management

Git Subtree vs Submodule

Subtree Advantages:

• Simpler for contributors
• No separate clone steps
• Part of main repository history
• No broken references

Subtree Disadvantages:

• More complex to update
• Pollutes main history
• Larger repository

Subtree Operations

# Add Subtree
git subtree add --prefix=libs/shared https://github.com/org/shared.git main --squash

# Update Subtree
git subtree pull --prefix=libs/shared https://github.com/org/shared.git main --squash

# Push Changes Back to Subtree
git subtree push --prefix=libs/shared https://github.com/org/shared.git feature-branch

# Split Subtree (Extract to New Repo)
git subtree split --prefix=libs/shared -b shared-lib-branch
git push git@github.com:org/new-shared-lib.git shared-lib-branch:main

Subtree Workflow

# Setup Remote for Easier Management
git remote add shared-lib https://github.com/org/shared.git

# Add Subtree with Remote
git subtree add --prefix=libs/shared shared-lib main --squash

# Pull Updates
git fetch shared-lib
git subtree pull --prefix=libs/shared shared-lib main --squash

# Contribute Back
git subtree push --prefix=libs/shared shared-lib feature-branch

Repository Templates

GitHub Template Repository

# Create Template Structure
mkdir -p .github/workflows
cat > .github/workflows/ci.yml << EOF
name: CI
on: [push, pull_request]
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - run: make test
EOF

# Template Files
touch .gitignore README.md LICENSE CONTRIBUTING.md
mkdir -p docs src tests

# Mark as Template on GitHub Settings
# Use template to create new repositories

Cookiecutter Template

# Install Cookiecutter
pip install cookiecutter

# Create from Template
cookiecutter https://github.com/org/project-template.git

# Template Structure
project-template/
├── cookiecutter.json
└── {{cookiecutter.project_name}}/
    ├── .git/
    ├── src/
    ├── tests/
    └── README.md

Large Repository Management

Partial Clone

# Blobless Clone (No file contents initially)
git clone --filter=blob:none <url>

# Treeless Clone (Even more minimal)
git clone --filter=tree:0 <url>

# Shallow Clone (Limited History)
git clone --depth 1 <url>

# Shallow Clone with Single Branch
git clone --depth 1 --single-branch --branch main <url>

Sparse Checkout

# Enable Sparse Checkout
git sparse-checkout init --cone

# Specify Directories
git sparse-checkout set src/api src/shared

# Add More Directories
git sparse-checkout add docs

# List Current Sparse Checkout
git sparse-checkout list

# Disable Sparse Checkout
git sparse-checkout disable

Git LFS (Large File Storage)

# Install Git LFS
git lfs install

# Track Large Files
git lfs track "*.psd"
git lfs track "*.zip"
git lfs track "data/**"

# Track Files in .gitattributes
cat .gitattributes
# *.psd filter=lfs diff=lfs merge=lfs -text

# Clone with LFS
git clone <url>
cd repo
git lfs pull

# Migrate Existing Files to LFS
git lfs migrate import --include="*.zip"

Repository Splitting

Extract Subdirectory to New Repo

# Using git filter-repo (recommended)
git filter-repo --path services/api --path-rename services/api:

# Result: New repo with only services/api content and history

# Using git subtree
git subtree split --prefix=services/api -b api-service
mkdir ../api-service
cd ../api-service
git init
git pull ../original-repo api-service

Merge Multiple Repos

# Add Remote
git remote add project-b ../project-b

# Fetch History
git fetch project-b

# Merge with Unrelated Histories
git merge --allow-unrelated-histories project-b/main

# Move Files to Subdirectory
mkdir project-b
git mv * project-b/
git commit -m "chore: organize project-b into subdirectory"

Repository Maintenance

Regular Maintenance Tasks

# Optimize Repository
git gc --aggressive

# Prune Unreachable Objects
git prune --expire now

# Verify Integrity
git fsck --full

# Repack Repository
git repack -a -d --depth=250 --window=250

# Update Server Info (for dumb HTTP)
git update-server-info

Automation Script

#!/bin/bash
# repo-maintenance.sh

echo "Starting repository maintenance..."

# Fetch all branches
git fetch --all --prune

# Clean up stale branches
git branch -vv | grep ': gone]' | awk '{print $1}' | xargs -r git branch -D

# Garbage collection
git gc --auto

# Verify integrity
git fsck --full --strict

echo "Maintenance complete!"

Scheduled Maintenance

# .github/workflows/maintenance.yml
name: Repository Maintenance
on:
  schedule:
    - cron: '0 2 * * 0'  # Weekly at 2 AM Sunday
jobs:
  maintain:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
        with:
          fetch-depth: 0
      - name: Run Maintenance
        run: |
          git gc --aggressive
          git prune --expire now
          git fsck --full

Access Control and Permissions

Branch Protection Rules

# Example Configuration
protected_branches:
  main:
    required_pull_request_reviews:
      required_approving_review_count: 2
      dismiss_stale_reviews: true
      require_code_owner_reviews: true
    required_status_checks:
      strict: true
      contexts:
        - continuous-integration
        - security-scan
    enforce_admins: true
    restrictions:
      users: []
      teams: [core-team]

CODEOWNERS File

# .github/CODEOWNERS

# Global owners
*                    @org/core-team

# Service owners
/services/api/       @org/backend-team
/services/web/       @org/frontend-team
/services/mobile/    @org/mobile-team

# Specific files
/docs/               @org/documentation-team
/.github/            @org/devops-team
/security/           @org/security-team @org/lead-architect

# Require multiple reviews
/packages/shared/    @org/core-team @org/architecture-team

Migration Strategies

SVN to Git

# Create Authors File
svn log --quiet | grep "^r" | awk '{print $3}' | sort -u > authors.txt

# Edit authors.txt:
# john = John Doe <john@example.com>

# Convert Repository
git svn clone <svn-url> --authors-file=authors.txt --stdlayout repo

# Convert Tags and Branches
cd repo
git for-each-ref --format="%(refname:short)" refs/remotes/tags | \
  cut -d / -f 3 | xargs -I {} git tag {} refs/remotes/tags/{}

# Push to Git
git remote add origin <git-url>
git push -u origin --all
git push origin --tags

Mercurial to Git

# Using hg-git
hg bookmark -r default main
hg push git+ssh://git@github.com/org/repo.git

# Using fast-export
git clone https://github.com/frej/fast-export.git
mkdir git-repo && cd git-repo
git init
../fast-export/hg-fast-export.sh -r ../hg-repo
git checkout HEAD

Best Practices

1. Choose Appropriate Strategy: Match branching model to team size and deployment frequency
2. Document Workflows: Keep team documentation current
3. Automate Maintenance: Regular repository health checks
4. Use Branch Protection: Enforce code review and CI
5. Clear Ownership: Define code owners for all areas
6. Regular Cleanup: Remove stale branches and merged features
7. Monitor Repository Size: Use LFS for large files
8. Template Repositories: Standardize new project structure
9. Access Control: Implement principle of least privilege
10. Migration Planning: Test migrations thoroughly before production

Resources

Additional repository management resources are available in the assets/ directory:

• templates/ - Repository structure templates
• scripts/ - Automation and maintenance scripts
• workflows/ - CI/CD workflow examples

See references/ directory for:

• Branching strategy comparison guides
• Monorepo tool documentation
• Enterprise git patterns
• Repository scaling strategies

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