Block branch creation and deletion on public repo (place in .git/hooks/)

pre-push

#!/bin/sh

# An example hook script to verify what is about to be pushed.  Called by "git
# push" after it has checked the remote status, but before anything has been
# pushed.  If this script exits with a non-zero status nothing will be pushed.
#
# This hook is called with the following parameters:
#
# $1 -- Name of the remote to which the push is being done
# $2 -- URL to which the push is being done
#
# If pushing without using a named remote those arguments will be equal.
#
# Information about the commits which are being pushed is supplied as lines to
# the standard input in the form:
#
#   <local ref> <local sha1> <remote ref> <remote sha1>
#
# This sample shows how to prevent push of commits where the log message starts
# with "WIP" (work in progress).

remote="$1"
url="$2"

z40=0000000000000000000000000000000000000000

is_nodejs_remote=`echo $url | grep -c /nodejs/`

while read local_ref local_sha remote_ref remote_sha
do
	if [ "$local_sha" = $z40 ]
	then
		# Handle delete
    if [ $is_nodejs_remote -gt 0 ]
    then
      echo "canceling delete of $url:$remote_ref"
      exit 1
    fi
	else
		if [ "$remote_sha" = $z40 ]
		then
			# New branch, examine all commits
			range="$local_sha"
      if [ $is_nodejs_remote -gt 0 ]
      then
        echo "canceling create of $url:$remote_ref"
        exit 1
      fi
		else
			# Update to existing branch, examine new commits
			range="$remote_sha..$local_sha"
		fi

		# Check for WIP commit
		commit=`git rev-list -n 1 --grep '^WIP' "$range"`
		if [ -n "$commit" ]
		then
			echo >&2 "Found WIP commit in $local_ref, not pushing"
			exit 1
		fi
	fi
done

exit 0