hg2git.sh

#!/bin/bash
#
# Converts mercurial repostories to git repositories.
# Requires git-remote-hg from https://github.com/felipec/git-remote-hg.
#

if [ $# -lt 2 ] || [ $# -gt 3 ]
  then
  echo "Usage: ${0} <url> <local_directory> [user_map]"
  echo "Where"
  echo "  url is the url of a mercurial repository"
  echo "  local_directory is a directory to put the bare git repository in"
  echo "  user_map is the path to a file containing hg to git user mappings in CSV"
  echo "    eg:"
  echo "    User Name,[email protected],[email protected]"
  exit
fi

URL="${1}"
LOCAL_DIR="${2}"
USER_MAP="${3}"

# Clone from remote mercurial to local bare git (using --mirror)
git clone --mirror "hg::${URL}" "${LOCAL_DIR}" || exit $?
git -C "${LOCAL_DIR}" --bare gc --aggressive || exit $?  # Recommended by git-remote-hg

# Rewrite history to map mercurial usernames to git usernames and email
# addresses
# Copied from https://gist.github.com/octocat/0831f3fbd83ac4d46451
# This needs to be done in a bare git repository
if [ "${USER_MAP}" ] && [ -f "${USER_MAP}" ]
  then
  export correct_name
  export old_email
  export correct_email
  grep -v "^#" "${USER_MAP}" | \
  while IFS=',' read correct_name old_email correct_email
    do
    git -C "${LOCAL_DIR}" --bare filter-branch --env-filter '

    if [ "${GIT_COMMITER_EMAIL}" = "${old_email}" ]
      then
      export GIT_COMMITER_NAME="${correct_name}"
      export GIT_COMMITER_EMAIL="${correct_email}"
    fi
    if [ "${GIT_AUTHOR_EMAIL}" = "${old_email}" ]
      then
      export GIT_AUTHOR_NAME="${correct_name}"
      export GIT_AUTHOR_EMAIL="${correct_email}"
    fi
    ' --force --tag-name-filter cat -- --branches --tags || exit $?
  done
fi

# Rename branches from "branches/${branch}" to "${branch}"
git -C "${LOCAL_DIR}" --bare branch -a | \
grep branches | \
while read branch
  do
  git -C "${LOCAL_DIR}" --bare branch -m ${branch} ${branch//branches\/} || exit $?
done