git-branch-changes

git-branch-changes.sh

#!/bin/bash
#
# git-branch-changes - Show changes between current branch and main/master with filtering
#
# This script helps you:
# 1. View the diff between your current branch and main/master
# 2. Filter out specific files or patterns using grep
# 3. Focus on relevant changes by excluding files like README.md, etc.
#
# This is an enhanced version of the 'bc' alias from .gitconfig:
# bc = "!f() { git diff $(git merge-base $(git show-ref --verify --quiet refs/heads/main && echo main || echo master) HEAD) HEAD; }; f"

set -e  # Exit on error

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[0;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Function to print error messages
error() {
  echo -e "${RED}ERROR: $1${NC}" >&2
  exit 1
}

# Function to print warning messages
warn() {
  echo -e "${YELLOW}WARNING: $1${NC}" >&2
}

# Function to print info messages
info() {
  echo -e "${BLUE}INFO: $1${NC}" >&2
}

# Function to print success messages
success() {
  echo -e "${GREEN}SUCCESS: $1${NC}" >&2
}

# Function to show usage
show_usage() {
  echo "Usage: git branch-changes [options] [exclude_pattern1] [exclude_pattern2] ..."
  echo "Show changes between current branch and main/master with filtering"
  echo ""
  echo "Options:"
  echo "  -b, --base <branch>  Specify base branch (default: main or master)"
  echo "  -c, --copy           Copy output to clipboard (requires pbcopy)"
  echo "  -n, --name-only      Show only names of changed files"
  echo "  -d, --debug          Show debug information"
  echo "  -h, --help           Show this help message"
  echo ""
  echo "Arguments:"
  echo "  exclude_pattern      Pattern(s) of files to exclude from diff (e.g., '*.md')"
  echo ""
  echo "Description:"
  echo "  This command shows the diff between your current branch and the main/master branch,"
  echo "  with the ability to exclude files matching specified patterns."
  echo ""
  echo "Examples:"
  echo "  # Show all changes between current branch and main/master"
  echo "  git branch-changes"
  echo ""
  echo "  # Show changes excluding markdown files"
  echo "  git branch-changes '*.md'"
  echo ""
  echo "  # Show changes excluding multiple patterns"
  echo "  git branch-changes '*.md' '*.json' 'docs/*'"
  echo ""
  echo "  # Show changes against a specific base branch"
  echo "  git branch-changes -b develop"
  echo ""
  echo "  # Show only names of changed files, excluding markdown files"
  echo "  git branch-changes -n '*.md'"
  echo ""
  echo "  # Copy changes to clipboard, excluding markdown and JSON files"
  echo "  git branch-changes -c '*.md' '*.json'"
}

# Process options
base_branch=""
copy_to_clipboard=false
name_only=false
debug_mode=false

while [[ $# -gt 0 ]]; do
  case "$1" in
    -b|--base)
      base_branch="$2"
      shift 2
      ;;
    -c|--copy)
      copy_to_clipboard=true
      shift
      ;;
    -n|--name-only)
      name_only=true
      shift
      ;;
    -d|--debug)
      debug_mode=true
      shift
      ;;
    -h|--help)
      show_usage
      exit 0
      ;;
    -*)
      error "Unknown option: $1"
      show_usage
      exit 1
      ;;
    *)
      break
      ;;
  esac
done

# Determine base branch if not specified
if [ -z "$base_branch" ]; then
  if git show-ref --verify --quiet refs/heads/main; then
    base_branch="main"
  elif git show-ref --verify --quiet refs/heads/master; then
    base_branch="master"
  else
    error "Could not determine main branch. Please specify with -b option."
  fi
fi

# Get the merge base
merge_base=$(git merge-base "$base_branch" HEAD)
if [ $? -ne 0 ]; then
  error "Failed to find merge base with branch '$base_branch'"
fi

# Process exclude patterns
exclude_patterns=("$@")
if [ ${#exclude_patterns[@]} -gt 0 ]; then
  info "Excluding patterns: ${exclude_patterns[*]}"
fi

# Handle name-only mode
if $name_only; then
  # Get list of changed files
  files=$(git diff --name-only "$merge_base" HEAD)

  # If no files, exit
  if [ -z "$files" ]; then
    info "No changes detected between current branch and $base_branch"
    echo ""
    exit 0
  fi

  # Filter out excluded files
  if [ ${#exclude_patterns[@]} -gt 0 ]; then
    # Create a temporary file for grep
    temp_exclude=$(mktemp)

    # Build grep pattern for all exclude patterns
    for pattern in "${exclude_patterns[@]}"; do
      echo "$pattern" >> "$temp_exclude"
    done

    # Filter files using grep
    filtered_files=$(echo "$files" | grep -v -f "$temp_exclude" || echo "")

    # Clean up
    rm "$temp_exclude"

    # Use filtered files
    files="$filtered_files"
  fi

  # Output the result
  if [ -z "$files" ]; then
    info "No files match after applying filters"
    echo ""
    exit 0
  fi

  if $copy_to_clipboard; then
    if ! command -v pbcopy &> /dev/null; then
      error "pbcopy command not found. Cannot copy to clipboard."
    fi
    echo "$files" | pbcopy
    info "Filtered file list copied to clipboard"
  else
    echo "$files"
  fi

  exit 0
fi

# Handle full diff mode
# Get the list of changed files
changed_files=$(git diff --name-only "$merge_base" HEAD)

# If no files, exit
if [ -z "$changed_files" ]; then
  info "No changes detected between current branch and $base_branch"
  echo ""
  exit 0
fi

# Debug output
if $debug_mode; then
  info "All changed files (first 10):"
  echo "$changed_files" | head -n 10 >&2
  total_files=$(echo "$changed_files" | wc -l | tr -d ' ')
  if [ $total_files -gt 10 ]; then
    info "... and $((total_files - 10)) more files"
  fi
fi

# If no exclude patterns, just run the diff command
if [ ${#exclude_patterns[@]} -eq 0 ]; then
  diff_output=$(git diff "$merge_base" HEAD)
else
  # Filter out files matching exclude patterns
  filtered_files=""

  # Process each file
  while IFS= read -r file; do
    exclude=false

    # Check if file matches any exclude pattern
    for pattern in "${exclude_patterns[@]}"; do
      # Convert glob pattern to shell pattern
      if [[ "$file" == *$pattern ]]; then
        exclude=true
        if $debug_mode; then
          info "Excluding file: $file"
        fi
        break
      fi
    done

    # If file doesn't match any pattern, include it
    if ! $exclude; then
      filtered_files+="$file"$'\n'
      if $debug_mode; then
        info "Including file: $file"
      fi
    fi
  done <<< "$changed_files"

  # Remove trailing newline
  filtered_files=${filtered_files%$'\n'}

  # If no files left after filtering, exit
  if [ -z "$filtered_files" ]; then
    info "No files match after applying filters"
    echo ""
    exit 0
  fi

  # Get diff for only the filtered files
  # Convert the file list to space-separated for git diff
  file_args=$(echo "$filtered_files" | tr '\n' ' ')

  # Get the diff for only these files
  diff_output=$(git diff "$merge_base" HEAD -- $file_args)

  # If debug mode is enabled, show more information about the diff
  if $debug_mode; then
    # Check if there are any actual changes in the filtered files
    if [ -z "$diff_output" ]; then
      info "No actual changes found in the filtered files"
      info "This means the only files with changes are the ones you excluded"
    else
      info "Found changes in the filtered files"
    fi
  fi
fi

# Output the result
if [ -z "$diff_output" ]; then
  info "No changes after applying filters"
  echo ""
  exit 0
fi

if $copy_to_clipboard; then
  if ! command -v pbcopy &> /dev/null; then
    error "pbcopy command not found. Cannot copy to clipboard."
  fi
  echo "$diff_output" | pbcopy
  info "Filtered changes copied to clipboard"
else
  echo "$diff_output"
fi

exit 0