# Commit Operations in Git
This document covers advanced commit operations beyond basic `git commit`, including partial commits, commit amendments, and commit signing.
## Table of Contents
1. [Partial Commits](#partial-commits)
2. [Amending Commits](#amending-commits)
3. [Commit Signing](#commit-signing)
4. [Advanced Commit Creation](#advanced-commit-creation)
5. [Commit Templates](#commit-templates)
## Partial Commits
### Interactive Staging (Patch Mode)
```bash
# Stage parts of files interactively
git add -p
# Options during interactive staging:
# y - stage this hunk
# n - do not stage this hunk
# q - quit; do not stage this hunk or remaining ones
# a - stage this hunk and all later hunks in the file
# d - do not stage this hunk or any later hunks in the file
# s - split the current hunk into smaller hunks
# e - manually edit the current hunk
```
### Staging Specific Lines
```bash
# Using git gui for visual selection
git gui
# Or using command line with specific hunks
git add -p file.txt
# Stage only specific lines by editing hunks
# Press 'e' to edit, then remove lines you don't want to stage
```
### Proposed MCP Tool
```yaml
tool: partial_commit_helper
parameters:
files: array[string]
selection_mode: enum["hunks", "lines", "interactive"]
auto_split: boolean
preview_changes: boolean
force_execute: boolean
```
## Amending Commits
### Basic Amendment
```bash
# Amend the last commit message
git commit --amend -m "New commit message"
# Amend the last commit, adding new changes
git add forgotten-file.txt
git commit --amend --no-edit
# Amend with editor
git commit --amend
```
### Advanced Amendment
```bash
# Amend a specific commit (not the last one)
git rebase -i HEAD~3
# Mark the commit as 'edit'
# Make changes
git commit --amend
git rebase --continue
# Amend author information
git commit --amend --author="Name <email@example.com>"
# Amend commit date
git commit --amend --date="2024-01-15T10:30:00"
```
### Proposed MCP Tool
```yaml
tool: commit_amend_helper
parameters:
target: enum["last", "specific"]
commit_ref: string (if target="specific")
amend_options:
message: string
author: object {name, email}
date: string
add_files: array[string]
preserve_timestamp: boolean
force_execute: boolean
```
## Commit Signing
### GPG Signing Setup
```bash
# List GPG keys
gpg --list-secret-keys --keyid-format=long
# Configure git to use GPG key
git config --global user.signingkey <key-id>
# Enable automatic signing
git config --global commit.gpgsign true
# Sign a specific commit
git commit -S -m "Signed commit"
```
### SSH Signing (Git 2.34+)
```bash
# Configure SSH signing
git config --global gpg.format ssh
git config --global user.signingkey ~/.ssh/id_ed25519.pub
# Create allowed signers file
echo "$(git config user.email) $(cat ~/.ssh/id_ed25519.pub)" > ~/.ssh/allowed_signers
git config --global gpg.ssh.allowedSignersFile ~/.ssh/allowed_signers
# Sign with SSH
git commit -S -m "SSH signed commit"
```
### Verification
```bash
# Verify commit signatures
git log --show-signature
# Verify specific commit
git verify-commit <commit-hash>
# Show only signed commits
git log --pretty="format:%h %G? %aN %s" --graph
```
### Proposed MCP Tool
```yaml
tool: commit_signing_manager
parameters:
action: enum["setup", "sign", "verify", "list"]
signing_method: enum["gpg", "ssh"]
key_config:
key_id: string
key_path: string (for SSH)
auto_sign: boolean
verify_options:
commits: array[string]
show_details: boolean
```
## Advanced Commit Creation
### Commit with Specific Timestamp
```bash
# Commit with custom author date
GIT_AUTHOR_DATE="2024-01-15T10:30:00" git commit -m "Message"
# Commit with both author and committer date
export GIT_AUTHOR_DATE="2024-01-15T10:30:00"
export GIT_COMMITTER_DATE="2024-01-15T10:30:00"
git commit -m "Message"
```
### Commit as Different Author
```bash
# Single commit as different author
git commit --author="Other Person <other@example.com>" -m "Message"
# Configure for multiple commits
git config user.name "Other Person"
git config user.email "other@example.com"
```
### Empty Commits
```bash
# Create empty commit (useful for triggering CI)
git commit --allow-empty -m "Trigger CI build"
# Empty commit with sign-off
git commit --allow-empty -s -m "Signed empty commit"
```
### Proposed MCP Tool
```yaml
tool: advanced_commit_creator
parameters:
message: string
commit_options:
author: object {name, email}
committer: object {name, email}
author_date: string
committer_date: string
allow_empty: boolean
sign_off: boolean
gpg_sign: boolean
stage_files: array[string]
force_execute: boolean
```
## Commit Templates
### Setting Up Templates
```bash
# Create a commit template file
cat > ~/.gitmessage << 'EOF'
# Type: feat, fix, docs, style, refactor, test, chore
# Scope: component or file name
# Subject: imperative mood, max 50 chars
# Body: explain what and why, not how
# Wrap at 72 characters
# Footer: references to issues, breaking changes
# BREAKING CHANGE: description
# Closes: #123, #456
EOF
# Configure git to use template
git config --global commit.template ~/.gitmessage
# Use template for single commit
git commit -t ~/.gitmessage
```
### Project-Specific Templates
```bash
# Set template for current repository
git config commit.template .gitmessage
# Create project template
cat > .gitmessage << 'EOF'
[JIRA-] Subject
Why:
-
What:
-
Testing:
- [ ] Unit tests pass
- [ ] Integration tests pass
- [ ] Manual testing completed
EOF
```
### Proposed MCP Tool
```yaml
tool: commit_template_manager
parameters:
action: enum["create", "apply", "list", "delete"]
template_name: string
template_content: string (for create)
scope: enum["global", "project"]
variables: object (for template substitution)
force_execute: boolean
```
## Best Practices
### 1. Atomic Commits
- Each commit should represent one logical change
- Use partial staging to separate unrelated changes
- Split large changes into multiple commits
### 2. Commit Message Quality
- Use imperative mood ("Add feature" not "Added feature")
- First line: 50 characters max
- Body: wrap at 72 characters
- Explain why, not just what
### 3. Commit Hygiene
- No commented-out code
- No debugging statements
- Run tests before committing
- Use pre-commit hooks
### 4. Security
- Never commit secrets or credentials
- Use `.gitignore` for sensitive files
- Sign commits for authenticity
- Review commits before pushing
## Common Issues and Solutions
### Issue: Committed to Wrong Branch
```bash
# Move commit to correct branch
git checkout correct-branch
git cherry-pick <commit-hash>
git checkout wrong-branch
git reset --hard HEAD~1
```
### Issue: Committed Sensitive Data
```bash
# Remove from last commit
git reset HEAD~1
# Edit files to remove sensitive data
git add .
git commit -m "Safe commit"
# For older commits, use filter-branch or BFG
```
### Issue: Forgot to Sign Commit
```bash
# Sign the last commit
git commit --amend -S --no-edit
# Sign multiple commits
git rebase -i HEAD~3 --exec 'git commit --amend -S --no-edit'
```
## Integration with Commit Helper MCP
These advanced commit operations complement the existing Commit Helper MCP:
1. **Enhanced Message Generation**: Use templates with `generate_commit_message`
2. **Partial Commit Support**: Stage specific changes before commit
3. **Signing Integration**: Automatic signing with generated messages
4. **Amendment Workflow**: Fix commits while maintaining conventions
## Proposed Workflow Enhancement
```yaml
enhanced_commit_workflow:
1. analyze_changes: Identify logical change groups
2. partial_stage: Stage related changes together
3. generate_message: Create conventional commit message
4. sign_commit: Add GPG/SSH signature
5. verify_commit: Ensure commit meets standards
6. push_changes: Safe push with lease
```
This enhanced workflow ensures high-quality, secure, and well-organized commits that follow project conventions and best practices.
