commit-msg

#!/bin/bash
# To use this hook, place it in .git/hooks for your repo
# The file must be named "commit-msg" (no extension)
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# Color codes
red='\033[0;31m'
yellow='\033[0;33m'
blue='\033[0;34m'
green='\033[0;32m'
NC='\033[0m'
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
# Utilities
print_newline_if_needed(){
  if [ "${errs_found}" -gt 0 ] || [ "${warns_found}" -gt 0 ]; then
    echo -e
  fi
}

print_length_error(){
  # $1 should be the line number in text, e.g., "second"
  # $2 should be the requirement in text, e.g., "be blank"
  # $3 should be the line passed through
  print_newline_if_needed
  echo -e "${red}The ${1} line of your commit message must ${2}.${NC}"
  echo -e "  Your ${1} line has ${yellow}${#3}${NC} characters: ${yellow}${3}${NC}"
}

print_result(){
  # $1 should be the error or warning counter, e.g., "${errs_found}"
  # $2 should be what to print if the counter is 0
  # $3 should be what to print if the counter is 1
  # $4 should be what to print for all other counter values
  case "${1}" in
  0)
    print_newline_if_needed
    echo -e "${2}"
    ;;
  1)
    print_newline_if_needed
    echo -e "${3}"
    ;;
  *)
    print_newline_if_needed
    echo -e "${4}"
    ;;
esac
}
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# Conventional Commit Checker
line_number=-1
errs_found=0
warns_found=0

if ! [ -f "${1}" ]; then
  echo -e "${red}No such file or directory \"${1}\". Try again with a valid file.${NC}"
  ((errs_found++))
fi

while read -r line; do
  # Skip comments
  if [ "${line:0:1}" = "#" ]; then
    continue
  fi

  ((line_number++))

  # Linewise requirements
  case ${line_number} in
    0)
      downcase_line=$(echo "$line" | tr '[:upper:]' '[:lower:]')

      if ! [[ ${downcase_line} =~ ^((build|chore|ci|docs|feat|fix|perf|refactor|style|test|wip)(\([a-zA-Z0-9]+\))?(!)?: [^ ]+.*$) ]]; then
        if [ "${downcase_line:0:7}" = "fixup! " ]; then
          echo -e "${yellow}Conventional commit message check skipped on fixup commits.${NC}"
          break;
        elif [[ "${downcase_line:0:6}" = "merge " ]]; then
          echo -e "${yellow}Conventional commit first-line check skipped on merge commits.${NC}"
          continue;
        elif [[ "${downcase_line:0:7}" = "revert " ]]; then
          echo -e "${yellow}Conventional commit first-line check skipped on revert commits.${NC}"
          continue;
        fi
        print_newline_if_needed
        echo -e "${red}Please use conventional commit messages:"
        echo -e "  ${yellow}fix${green}(parser)${NC}: ${blue}properly handle new lines${NC}"
        echo -e "  ${yellow}^┬^${green}^──┬───^${NC}  ${blue}^───────────────────────^ ─> Summary in present tense.${NC}"
        echo -e "  ${yellow} │ ${green}   └─> [optional]: Scope of the commit.${NC}"
        echo -e "  ${yellow} └─> Type: build, chore, ci, docs, feat, fix, perf, refactor, style, test, wip.${NC}"
        ((errs_found++))
      fi

      if [ ${#line} -gt 50 ]; then
        print_length_error "first" "be 50 characters or fewer" "${line}"
        ((errs_found++))
      fi
      ;;
    1)
      if [[ ${#line} -gt 0 ]]; then
        print_length_error "second" "be blank" "${line}"
        ((errs_found++))
      fi
      ;;
    *)
      if [ ${#line} -gt 72 ]; then
        if [ ${warns_found} -eq 0 ]; then
          print_newline_if_needed
          echo -e "${yellow}Human readable lines in commit message body should be 72 characters or shorter.${NC}"
          echo -e "${yellow}If lines violate this warning, use git commit --amend to fix them.${NC}"
        fi
        echo -e "  Line #$((line_number+1)) has ${yellow}${#line}${NC} characters: ${yellow}${line}${NC}"
        ((warns_found++))
      fi
      ;;
  esac
done < "${1}"

print_result "${warns_found}" \
             "" \
             "${yellow}${warns_found} warning detected with your commit message.\n\
Please fix it using git commit --amend.${NC}" \
             "${yellow}${warns_found} warnings detected with your commit message.\n\
Please fix them using git commit --amend.${NC}"

print_result "${errs_found}" \
             "${green}\xE2\x9C\x94${NC} commit message follows conventional commits syntax." \
             "${red}${errs_found} issue detected with your commit message. \
Please fix it and try again.${NC}" \
             "${red}${errs_found} issues detected with your commit message. \
Please fix these and try again.${NC}"

exit "${errs_found}"
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