Port tags arranged in SVN directories to annotated tags in GIT

port_tags_dir2git.sh

#!/usr/local/bin/bash

# Prerequisites:
# 1. Clone two instances of the same repo into primary_repo and backup_repo
# 2. On primary_repo, rebase where necessary (or git filter-repo)

if [ "$#" -ne 2 ]; then
  printf 'Usage:   %s <primary_repo> <tags_path>\n' "$0"
  printf 'Example: %s /freshports/primary_repo /freshports/backup_repo/path/to/tags\n' "$0"
  exit 1
fi

PRIMARY_REPO="$1"
TAGS_PATH="$2"
PARENT_DIR=$(pwd)

cd "${TAGS_PATH}"
declare -A datetimes
declare -A messages

# here, parse out all the tags and their respective timestamps/messages
for tag in $(ls); do
  tag_log="$(git log -n 1 --pretty=format:"%ad %s" --date=iso $tag)"
  tag_date=$(echo $tag_log | cut -d' ' -f1,2,3)
  tag_msg=$(echo $tag_log | cut -d' ' -f4- | sed "s/^'//;s/'$//")
  datetimes[$tag]="${tag_date}"
  messages[$tag]="${tag_msg}"
done

cd "${PARENT_DIR}" && cd "${PRIMARY_REPO}"

declare -A commits

# here, figure out which commits line up with the tags
for tag in "${!datetimes[@]}"; do
  commit=$(git log --until="${datetimes[$tag]}" -n 1 --author-date-order --pretty=format:"%h")
  commits[$commit]="${tag}"
  printf '%s (%s): %s: %s\n' "${tag}" "${commit}" "${datetimes[$tag]}" "${messages[$tag]}"
done

# go ahead and apply the annotated tag
for commit in "${!commits[@]}"; do
  tag="${commits[$commit]}"
  git checkout $commit
  git tag -a "${tag}" -m "${messages[$tag]}"
done