#!/bin/bash
# git-svn-switch
# by Justen Hyde based on this blog post:
#
# http://translate.org.za/blogs/wynand/en/content/changing-your-svn-repository-address-git-svn-setup
#
# Use at your own risk. For the love of cthulhu, back
# your repo up before letting this loose on it.
 
if [ $# -ne 1 ]
then
  echo "Usage: `basename $0` {new subversion url}"
  exit -1
fi
 
if [[ $1 = "--help" || $1 = "-h" ]]
then
  echo
  echo "Usage: `basename $0` {new subversion url}"
  echo
  echo " Changes the url of the subversion repository a git-svn repo is connected to."
  echo " Analogous to svn switch. Potentially a weapon of mass destruction. Use with care."
  echo " Run this from within your git repo. You only need one argument: the new url of the svn repo."
  echo " git-svn-switch will attempt to verify that the url is at least a svn repo before starting the switch"
  echo " but don't depend on it to stop you from doing summat daft."
  echo
  exit 1
fi
 
# get the current subversion url
SRC=`git svn info --url`
if [ -n "$SRC" ]
then
  FROM=`echo $SRC | sed "s|/trunk||"`
  REPO=`svn info $1`
  echo "Checking $REPO is actually a subversion repository..."
  if [ -n "$REPO" ]
  then
    echo "The new URL looks valid."
    echo "Rewriting the git history with the new url..."
    SED_FILTER="sed 's;git-svn-id: "$FROM";git-svn-id: "$1";g'"
    git gc
    git filter-branch --msg-filter "$SED_FILTER" $(cat .git/packed-refs | awk '// {print $2}' | grep -v 'pack-refs')
#Couple of pointless checkouts - on some repos the log changes seem to need flushing by an operation like this
    git checkout trunk
    git checkout master
    echo "Rebuild git-svn internals and updating the repo"
    rm -rf .git/svn
    sed -i~ 's|'$FROM'|'$1'|g' .git/config
    git svn rebase
  else
    echo "Error: $1 Does not appear to be a subversion repository."
  fi
else
  echo "Error: This doesn't appear to be a git working directory, or it's a git repo that hasn't been created using a git-svn bridge"
fi