Script to migrate releases from CHANGELOG.md to GitHub Releases

backfill-releases.sh

#!/bin/bash
# Usage: OAUTH_TOKEN="..." backfill-releases CHANGELOG.md [<project-title>]

set -e

log="${1?}"
project_name="${2}"

repo="$(git config remote.origin.url | grep -oE 'github\.com[/:][^/]+/[^/]+' | sed 's/\.git$//' | cut -d/ -f2-3)"
[ -n "${project_name}" ] || project_name="${repo#*/}"

tags=()

tag_exists() {
  local t
  if [ -z "$tags" ]; then
    tags=( $(git ls-remote --tags origin | cut -d/ -f3) )
  fi
  for t in "${tags[@]}"; do [ "$t" = "$1" ] && return 0; done
  return 1
}

extract_entry() {
  awk -v "tag=$1" '
    /^#### / {
      if ($2 == tag) {
        show = 1
        next
      }
      else if (show) exit
    }
    { if (show) print }
  ' "$log"
}

create_release() {
  ruby --disable-gems -rjson -e "
    puts JSON::generate(
      tag_name: 'v${1}',
      name: '${project_name} ${1}',
      body: ARGF.read.strip
    )
  " | curl -fsS -X POST https://api.github.com/repos/${repo}/releases \
           -H "Authorization: token ${OAUTH_TOKEN}" -d @-
}

for entry in $(grep '^#### ' "$log" | awk '{print $2}'); do
  if tag_exists "v${entry}"; then
    if extract_entry "$entry" | create_release "$entry" >/dev/null; then
      printf "."
    else
      printf "\nCreating release v${entry} failed.\n" >&2
    fi
  else
    echo "warning: no \`v${entry}' tag exists" >&2
  fi
done

printf "\n"