upstream-zulip/tools/deploy-branch

#!/usr/bin/env bash
set -euo pipefail

function error_out() {
    echo -en '\e[0;31m'
    echo "$1"
    echo -en '\e[0m'
    exit 1
}

[ -z "$(git status --porcelain --untracked-files=no)" ] || error_out "Working directory or index not clean"

old_ref=$(git rev-list --max-count=1 HEAD)
branch=${1-}
[ -z "$branch" ] && error_out "You must specify a branch name to deploy"

branch_ref=$(git rev-list --max-count=1 "$branch") || error_out "Unknown branch: $branch"

if [ "$old_ref" == "$branch_ref" ]; then
    new_ref=main
else
    if ref_name=$(git describe --all --exact "$old_ref"); then
        new_ref=$(echo "$ref_name" | perl -pe 's{^(heads|remotes)/}{}')
    else
        new_ref=$old_ref
    fi
fi

git fetch -p

git rebase origin/main "$branch" || error_out "Rebase onto origin/main failed"

git push . HEAD:main
git push origin main || error_out "Push of main to origin/main failed"

git checkout "$new_ref"
git branch -D "$branch"
git push origin ":$branch"