Script to permit to rcheckin a git repository to a newly created TFVC repository with git-tfs

replace_root.sh

#Script to permit to rcheckin a git repository to a newly created TFVC repository with git-tfs
#adaptation from my answer: http://stackoverflow.com/questions/645450/insert-a-commit-before-the-root-commit-in-git/30558271#30558271
#usage: pass to the script (1) the url of the tfs server, (2) the tfs path in the repository, (3) the changeset id
#../replace_root.sh "https://urlOfYourTfs/DefaultCollection" "$/EmptyTfs/Trunk" 21

# Command to get Changeset ID
# tf history "$/EmptyTfs/Trunk" /collection:"https://urlOfYourTfs/DefaultCollection" /noprompt /stopafter:1

# Clean up any previous attempt
rm -rf ./.git/refs/replace
git checkout master
git branch -D new-root

tfsServer=$1
tfsPath=$2
tfsChangesetId=$3

gitTfsMetadata="git-tfs-id: [$tfsServer]$tfsPath;C$tfsChangesetId"
echo "Creating a root commit with git-tfs metadatas:"
echo $gitTfsMetadata

root_commit_sha=$(git rev-list --max-parents=0 HEAD)
echo "root_commit_sha=" $root_commit_sha
git checkout --force --orphan new-root
"C:\Program Files\Git\usr\bin\find.exe" . -path ./.git -prune -o -exec rm -rf {} \; 2> /dev/null
git add -A
GIT_COMMITTER_DATE="2000-01-01T12:00:00" git commit --date==2000-01-01T12:00:00 --allow-empty -m "$gitTfsMetadata"
new_root_commit_sha=$(git rev-parse HEAD)

echo "The commit '$new_root_commit_sha' will be added before existing root commit '$root_commit_sha'..."

parent="parent $new_root_commit_sha"
replacement_commit=$(
 git cat-file commit $root_commit_sha | sed "s/author/$parent\nauthor/" | git hash-object -t commit -w --stdin
) || return 3
git replace "$root_commit_sha" "$replacement_commit"

read -r -p "Apply changes? [y/N] " response
response=${response,,} #tolower
if [[ $response =~ ^(yes|y)$ ]]
then
    git filter-branch -- --all
    rm -rf ./.git/refs/original
    rm -rf ./.git/refs/replace
    git checkout -f master
    git branch -D new-root

    git tfs bootstrap
else
    echo "Aborting! Feel free to run it again after you've verified your changes."
fi