Branch Rename Skill

Overview

This skill intelligently analyzes the differences between the current branch and the base branch (typically origin/main), then generates and applies a descriptive branch name following conventional commit conventions. The generated name uses kebab-case and accurately reflects the nature of the changes.

Naming Convention

Format

<type>/<description>

Branch Type Prefixes

Description Guidelines

• Kebab-case: lowercase words separated by hyphens
• Length: 20 characters or less (excluding prefix)
• Imperative mood: "add" not "added", "fix" not "fixed"
• Specific: Clearly describes the primary change
• Concise: No unnecessary words

Good examples:

• feat/oauth-login ✓
• fix/race-condition ✓
• docs/quick-start ✓

Bad examples:

• feat/AddOAuthLogin ✗ (not kebab-case)
• fix/fixed-the-race-condition-in-auth ✗ (too long, past tense)
• docs/documentation-updates ✗ (redundant)

Workflow

1. Verify Git Repository Status

Check if we're in a valid git repository:

git rev-parse --git-dir 2>&1

Expected output:

• Success: .git or path to git directory
• Failure: "not a git repository" error

Check current branch:

git branch --show-current

If detached HEAD state:

Error: Cannot rename branch - currently in detached HEAD state

You are not on any branch. To create a new branch from current state:
  git checkout -b <branch-name>

If on protected branch (main/master/develop):

Warning: You are on the protected branch '[branch-name]'

Creating new branches from protected branches is recommended:
  git checkout -b <new-branch-name>

Proceed with rename anyway? [y/n]

2. Identify Base Branch

Attempt to find the base branch in order of preference:

# Try origin/main
git rev-parse --verify origin/main 2>/dev/null

# If not found, try origin/master
git rev-parse --verify origin/master 2>/dev/null

# If not found, try local main
git rev-parse --verify main 2>/dev/null

# If not found, try local master
git rev-parse --verify master 2>/dev/null

Store the first successful result as BASE_BRANCH

If no base branch found:

Error: Cannot determine base branch

None of the following branches exist:
  - origin/main
  - origin/master
  - main
  - master

Please specify the base branch manually or create one.

3. Analyze Changes

Fetch comprehensive change information:

# Summary of changed files
git diff $BASE_BRANCH...HEAD --stat

# Detailed line-by-line changes
git diff $BASE_BRANCH...HEAD

# Commit messages on this branch
git log $BASE_BRANCH..HEAD --oneline

# Number of commits
git rev-list --count $BASE_BRANCH..HEAD

If no changes detected:

No changes detected between current branch and $BASE_BRANCH

This branch is either:
  - Fully merged into $BASE_BRANCH
  - Has no commits
  - Is synchronized with $BASE_BRANCH

No rename needed.

Parse the data to extract:

• List of modified files with paths
• Number of insertions and deletions
• Commit messages for context
• File patterns (identify directories/modules)

4. Determine Branch Type

Apply pattern matching logic:

File-based Detection

# Documentation changes
if files match: *.md, docs/*, README*
  → type: docs

# Test files
if files match: *test.*, *spec.*, __tests__/*, tests/*
  → type: test

# CI/CD configurations
if files match: .github/workflows/*, .gitlab-ci.yml, Jenkinsfile
  → type: ci

# Build configurations
if files match: package.json, Gemfile, requirements.txt, *.config.js
  → type: build

# Style/formatting
if files match: .prettierrc, .eslintrc, .editorconfig
  → type: style

Content-based Detection

# Analyze diff and commit messages for keywords

# New features (keyword presence in diffs/commits)
if contains: "add", "implement", "create", "new"
  → type: feat

# Bug fixes
if contains: "fix", "bug", "issue", "resolve", "correct"
  → type: fix

# Refactoring
if contains: "refactor", "restructure", "extract", "move", "rename"
  → type: refactor

# Performance
if contains: "optimize", "performance", "faster", "cache", "speed"
  → type: perf

# Default fallback
if no clear pattern:
  → type: chore

Multiple Types

If changes span multiple types:

1. Count file changes per type
2. Select the type with most changes
3. If tie, prioritize: feat > fix > refactor > others

5. Generate Description

Extract meaningful description from changes:

1. Identify primary module/component:

   # From file paths: src/auth/login.ts → "auth"
   # From multiple files in same dir → use directory name
   

2. Extract action from commits:

   # From commit messages like "Add OAuth support"
   # Extract: "oauth-support"
   

3. Combine module + action:

   # If module: "auth", action: "oauth"
   # Result: "auth-oauth"
   
   # If action already includes module context
   # Result: just use action
   

4. Sanitize description:

   # Convert to lowercase
   description=$(echo "$description" | tr '[:upper:]' '[:lower:]')
   
   # Replace spaces/underscores with hyphens
   description=$(echo "$description" | tr ' _' '-')
   
   # Remove special characters
   description=$(echo "$description" | sed 's/[^a-z0-9-]//g')
   
   # Remove consecutive hyphens
   description=$(echo "$description" | sed 's/--*/-/g')
   
   # Trim to 20 characters
   description=${description:0:20}
   
   # Remove trailing hyphen if present
   description=${description%-}
   

Examples of description generation:

6. Construct New Branch Name

Combine type and description:

new_branch="${type}/${description}"

Validate the name:

# Check length (should be reasonable, typically < 50 chars total)
if [ ${#new_branch} -gt 50 ]; then
  # Truncate description further
fi

# Check for existing branch with same name
if git show-ref --verify --quiet "refs/heads/$new_branch"; then
  # Append number: feat/user-auth-2
  suffix=2
  while git show-ref --verify --quiet "refs/heads/${new_branch}-${suffix}"; do
    ((suffix++))
  done
  new_branch="${new_branch}-${suffix}"
fi

7. Check Current Branch Name

Compare with existing name:

current_branch=$(git branch --show-current)

# If already follows convention and is accurate
if [[ "$current_branch" =~ ^(feat|fix|docs|style|refactor|perf|test|build|ci|chore)/ ]]; then
  # Extract current description
  current_desc=${current_branch#*/}

  # Check similarity with generated description
  if [ "$current_desc" == "$description" ]; then
    echo "Current branch name is already appropriate: $current_branch"
    echo "No rename needed."
    exit 0
  fi
fi

8. Rename Branch

Perform the rename operation:

old_branch=$(git branch --show-current)

# Rename the branch
git branch -m "$old_branch" "$new_branch"

Verify the rename:

# Check new branch name
if [ "$(git branch --show-current)" == "$new_branch" ]; then
  echo "✓ Branch renamed successfully"
else
  echo "✗ Branch rename failed"
  exit 1
fi

9. Display Results and Instructions

Show summary:

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Branch Renamed Successfully
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Old name: [old_branch]
New name: [new_branch]

Reason: [Brief explanation of type and description choice]

Changes analyzed:
  - [X] files modified
  - [Y] insertions, [Z] deletions
  - [N] commits

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

If branch was previously pushed to remote:

⚠ Remote Branch Update Required

This branch was previously pushed to remote as '[old_branch]'.
To update the remote:

1. Push the new branch:
   git push -u origin [new_branch]

2. Delete the old remote branch:
   git push origin --delete [old_branch]

3. (Optional) Update any open pull requests to point to new branch

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Check if branch has remote tracking:

# Check for remote tracking branch
if git rev-parse --abbrev-ref --symbolic-full-name @{u} 2>/dev/null; then
  # Remote tracking exists, show update instructions
fi

Examples

Example 1: Feature Addition

Scenario:

• Current branch: feature-branch
• Changes: Added user authentication with OAuth

Commands executed:

git diff origin/main...HEAD --stat
# Output: src/auth/oauth.ts | 120 +++++++
#         src/auth/login.ts  |  45 +++

git log origin/main..HEAD --oneline
# Output: a1b2c3d Add OAuth authentication
#         b2c3d4e Implement login flow

Analysis:

• Type: feat (new functionality)
• Primary module: auth
• Action: oauth-login
• Description: oauth-login (16 chars)

Result:

Old: feature-branch
New: feat/oauth-login

Reason: Detected new authentication feature in auth module

Example 2: Bug Fix

Scenario:

• Current branch: bugfix
• Changes: Fixed null pointer exception in payment processing

Commands executed:

git diff origin/main...HEAD --stat
# Output: src/payment/process.ts | 8 ++--

git log origin/main..HEAD --oneline
# Output: c3d4e5f Fix null pointer in payment processor

Analysis:

• Type: fix (bug fix keywords)
• Primary module: payment
• Issue: null-pointer
• Description: payment-null-ptr (17 chars)

Result:

Old: bugfix
New: fix/payment-null-ptr

Reason: Detected bug fix in payment processing module

Example 3: Documentation

Scenario:

• Current branch: update-docs
• Changes: Updated API documentation

Commands executed:

git diff origin/main...HEAD --stat
# Output: docs/api/v2.md      | 200 +++++++++++++
#         docs/guides/auth.md |  50 ++++

git log origin/main..HEAD --oneline
# Output: d4e5f6a Update API v2 documentation
#         e5f6g7h Add authentication guide

Analysis:

• Type: docs (documentation files)
• Focus: api-v2
• Description: api-v2-guide (12 chars)

Result:

Old: update-docs
New: docs/api-v2-guide

Reason: Detected documentation updates for API v2

Example 4: Refactoring

Scenario:

• Current branch: cleanup
• Changes: Extracted validation logic into utilities

Commands executed:

git diff origin/main...HEAD --stat
# Output: src/utils/validation.ts | 150 ++++++++++++++
#         src/components/Form.tsx  |  80 ++------

git log origin/main..HEAD --oneline
# Output: f6g7h8i Extract validation to utility module
#         g7h8i9j Simplify form component

Analysis:

• Type: refactor (code restructuring)
• Module: validation
• Action: extract-validation
• Description: validation-utils (16 chars)

Result:

Old: cleanup
New: refactor/validation-utils

Reason: Detected refactoring of validation logic into utils

Example 5: Multiple Change Types

Scenario:

• Current branch: various-updates
• Changes: Added feature, fixed bugs, updated docs

Commands executed:

git diff origin/main...HEAD --stat
# Output: src/auth/oauth.ts   | 120 +++++++  (new file)
#         src/payment/fix.ts  |   8 +-    (bug fix)
#         docs/readme.md      |  10 +      (docs)

git log origin/main..HEAD --oneline
# Output: h8i9j0k Add OAuth authentication (major)
#         i9j0k1l Fix payment bug         (minor)
#         j0k1l2m Update readme            (minor)

Analysis:

• Mixed types: feat (120 lines), fix (8 lines), docs (10 lines)
• Primary type: feat (most significant change)
• Focus: oauth from largest change
• Description: oauth-auth (10 chars)

Result:

Old: various-updates
New: feat/oauth-auth

Reason: Primary change is new OAuth authentication feature
        (Also includes minor bug fix and doc update)

Technical Requirements

Required Tools

Minimum Versions

• Git: 2.0 or higher (for git diff ... syntax)
• Bash: 4.0 or higher

Git Configuration

No special configuration required, but recommended:

# Set default branch name (optional)
git config --global init.defaultBranch main

Best Practices

1. Run before pushing: Rename branches early before pushing to remote
2. One focus per branch: Branches with mixed purposes are harder to name
3. Keep descriptions clear: Prioritize clarity over brevity
4. Follow team conventions: Adjust type prefixes if team uses different standards
5. Update PR titles: If PR exists, update title to match new branch name
6. Communicate changes: Inform team members if renaming shared branches

Limitations

1. Single branch focus: Best results when branch has one primary purpose
2. 20-character limit: Very long descriptions get truncated
3. English descriptions: Generated names are in English
4. No semantic analysis: Cannot understand complex business logic
5. Pattern-based: Relies on file patterns and keywords
6. Local operation: Does not automatically update remote branches

Error Handling

Common Errors and Solutions

Error: Not a git repository

• Cause: Current directory is not a git repository
• Solution: Navigate to git repository or run git init

Error: Detached HEAD state

• Cause: Not on any branch (e.g., checked out specific commit)
• Solution: Create new branch with git checkout -b <name>

Error: Cannot determine base branch

• Cause: No main/master branch exists
• Solution: Create base branch or specify manually

Error: No changes detected

• Cause: Branch is synchronized with base or has no commits
• Solution: No action needed, branch is up to date

Error: Branch name already exists

• Cause: Generated name conflicts with existing branch
• Solution: Tool automatically appends number (e.g., feat/auth-2)

Error: Invalid ref format

• Cause: Generated name contains invalid characters
• Solution: Tool sanitizes automatically, but check for edge cases

Advanced Features

Custom Base Branch

Allow user to specify different base branch:

# Compare against different branch
git diff custom-base...HEAD --stat

Interactive Mode

Confirm before renaming:

Generated branch name: feat/oauth-login

Current: feature-branch
New:     feat/oauth-login

Proceed with rename? [y/n]

Dry Run Mode

Show what would happen without actually renaming:

# Simulate rename
echo "Would rename: $old_branch → $new_branch"
# Skip actual git branch -m command

Preserve Remote Connection

Automatically update remote tracking after rename:

git branch -m "$old_branch" "$new_branch"
git push origin -u "$new_branch"
git push origin --delete "$old_branch"

References

• Git Branch Documentation: https://git-scm.com/docs/git-branch
• Conventional Commits: https://www.conventionalcommits.org/
• Git Best Practices: https://www.git-scm.com/book/en/v2/Distributed-Git-Contributing-to-a-Project

Notes

• Branch renaming is a local operation by default
• Remote branches must be updated separately if already pushed
• Pull requests may need manual update after branch rename
• Team members should be notified of branch name changes
• Consider branch protection rules when renaming
• Some CI/CD systems may be configured for specific branch names