git-svn-migrate.sh

#!/bin/sh

# Copyright 2010 John Albin Wilkins.
# Available under the GPL v2 license. See LICENSE.txt.

script=`basename $0`;
usage=$(cat <<EOF_USAGE
USAGE: $script --url-file=<filename> --authors-file=<filename> [destination folder]
\n
\nFor more info, see: $script --help
EOF_USAGE
);

help=$(cat <<EOF_HELP
NAME
\n\t$script - Migrates Subversion repositories to Git
\n
\nSYNOPSIS
\n\t$script [options] [arguments]
\n
\nDESCRIPTION
\n\tThe $script utility migrates a list of Subversion
\n\trepositories to Git using the specified authors list. The
\n\turl-file and authors-file parameters are required. The
\n\tdestination folder is optional and can be specified as an
\n\targument or as a named parameter.
\n
\n\tThe following options are available:
\n
\n\t-u=<filename>, -u <filename>,
\n\t--url-file=<filename>, --url-file <filename>
\n\t\tSpecify the file containing the Subversion repository list.
\n
\n\t-a=<filename>, -a <filename>,
\n\t--authors-file=[filename], --authors-file [filename]
\n\t\tSpecify the file containing the authors transformation data.
\n
\n\t-d=<folder>, -d <folder>,
\n\t--destination=<folder>, --destination <folder>
\n\t\tThe directory where the new Git repositories should be
\n\t\tsaved. Defaults to the current directory.
\n
\n\t-i=<filename>, -i <filename>,
\n\t--ignore-file=<filename>, --ignore-file <filename>
\n\t\tThe location of a .gitignore file to add to all repositories.
\n
\n\t--no-minimize-url
\n\t\tPass the "--no-minimize-url" parameter to git-svn. See
\n\t\tgit svn --help for more info.
\n
\nBASIC EXAMPLES
\n\t# Use the long parameter names
\n\t$script --url-file=my-repository-list.txt --authors-file=authors-file.txt --destination=/var/git
\n
\n\t# Use short parameter names
\n\t$script -u my-repository-list.txt -a authors-file.txt /var/git
\n
\nSEE ALSO
\n\tfetch-svn-authors.sh
\n\tsvn-lookup-author.sh
EOF_HELP
);


# Set defaults for any optional parameters or arguments.
destination='.';
gitsvn_params='';

# Process parameters.
until [[ -z "$1" ]]; do
  option=$1;
  # Strip off leading '--' or '-'.
  if [[ ${option:0:1} == '-' ]]; then
    if [[ ${option:0:2} == '--' ]]; then
      tmp=${option:2};
    else
      tmp=${option:1};
    fi
  else
    # Any argument given is assumed to be the destination folder.
    tmp="destination=$option";
  fi
  parameter=${tmp%%=*}; # Extract option's name.
  value=${tmp##*=};     # Extract option's value.
  case $parameter in
    # Some parameters don't require a value.
    no-minimize-url ) ;;

    # If a value is expected, but not specified inside the parameter, grab the next param.
    * )
      if [[ $value == $tmp ]]; then
        if [[ ${2:0:1} == '-' ]]; then
          # The next parameter is a new option, so unset the value.
          value='';
        else
          value=$2;
          shift;
        fi
      fi
      ;;
  esac

  case $parameter in
    u )               url_file=$value;;
    url-file )        url_file=$value;;
    a )               authors_file=$value;;
    authors-file )    authors_file=$value;;
    d )               destination=$value;;
    destination )     destination=$value;;
    i )               ignore_file=$value;;
    ignore-file )     ignore_file=$value;;
    no-minimize-url ) gitsvn_params="$gitsvn_params --no-minimize-url";;

    h )               echo $help | less >&2; exit;;
    help )            echo $help | less >&2; exit;;

    * )               echo "Unknown option: $option\n$usage" >&2; exit 1;;
  esac

  # Remove the processed parameter.
  shift;
done

# Check for required parameters.
if [[ $url_file == '' || $authors_file == '' ]]; then
  echo $usage >&2;
  exit 1;
fi
# Check for valid files.
if [[ ! -f $url_file ]]; then
  echo "Specified URL file \"$url_file\" does not exist or is not a file." >&2;
  echo $usage >&2;
  exit 1;
fi
if [[ ! -f $authors_file ]]; then
  echo "Specified authors file \"$authors_file\" does not exist or is not a file." >&2;
  echo $usage >&2;
  exit 1;
fi


# Process each URL in the repository list.
pwd=`pwd`;
tmp_destination="$pwd/tmp-git-repo";
mkdir -p $destination;
destination=`cd $destination; pwd`; #Absolute path.

# Ensure temporary repository location is empty.
if [[ -e $tmp_destination ]]; then
  echo "Temporary repository location \"$tmp_destination\" already exists. Exiting." >&2;
  exit 1;
fi
while read line
do
  # Check for 2-field format:  Name [tab] URL
  name=`echo $line | awk '{print $1}'`;
  url=`echo $line | awk '{print $2}'`;
  # Check for simple 1-field format:  URL
  if [[ $url == '' ]]; then
    url=$name;
    name=`basename $url`;
  fi
  # Process each Subversion URL.
  echo >&2;
  echo "At $(date)..." >&2;
  echo "Processing \"$name\" repository at $url..." >&2;

  # Init the final bare repository.
  mkdir $destination/$name.git;
  cd $destination/$name.git;
  git init --bare;
  git symbolic-ref HEAD refs/heads/trunk;

  # Clone the original Subversion repository to a temp repository.
  cd $pwd;
  git svn clone $url --no-metadata -A $authors_file --authors-prog=./svn-lookup-author.sh --stdlayout --quiet $gitsvn_params $tmp_destination;

  # Create .gitignore file.
  echo "Converting svn:ignore properties into .gitignore." >&2;
  if [[ $ignore_file != '' ]]; then
    cp $ignore_file $tmp_destination/.gitignore;
  fi
  cd $tmp_destination;
  git svn show-ignore --id trunk >> .gitignore;
  git add .gitignore;
  git commit --author="git-svn-migrate <nobody@example.org>" -m 'Convert svn:ignore properties to .gitignore.';

  # Push to final bare repository and remove temp repository.
  git remote add bare $destination/$name.git;
  git config remote.bare.push 'refs/remotes/*:refs/heads/*';
  git push bare;
  # Push the .gitignore commit that resides on master.
  git push bare master:trunk;
  cd $pwd;
  rm -r $tmp_destination;

  # Rename Subversion's "trunk" branch to Git's standard "master" branch.
  cd $destination/$name.git;
  git branch -m trunk master;

  # Remove bogus branches of the form "name@REV".
  git for-each-ref --format='%(refname)' refs/heads | grep '@[0-9][0-9]*' | cut -d / -f 3- |
  while read ref
  do
    git branch -D "$ref";
  done

  # Convert git-svn tag branches to proper tags.
  git for-each-ref --format='%(refname)' refs/heads/tags | cut -d / -f 4 |
  while read ref
  do
    git tag -a "$ref" -m "Convert \"$ref\" to proper git tag." "refs/heads/tags/$ref";
    git branch -D "tags/$ref";
  done
done < $url_file