release-kit 0.2.1

#!/usr/bin/env sh
# Retire every long-lived branch besides the trunk, now that the trunk is the
# default, so exactly one permanent branch remains. Idempotent: an absent
# candidate is the desired state. Refuses when a candidate is not an ancestor
# of the trunk, so a repository whose work still sits on an old branch cannot
# lose it to a mistyped setup.
set -eu
: "${RK_REPO:?rk sets this; run this script through rk setup}"
: "${RK_TRUNK_BRANCH:?rk sets this; run this script through rk setup}"

project="$(printf '%s' "$RK_REPO" | sed 's|/|%2F|g')"

# The forge CLI may pretty-print JSON; stripping whitespace makes every
# pattern below hold for the compact and the pretty form alike, and no
# value a pattern touches can carry whitespace of its own.
compact() { tr -d ' \t\r\n'; }

for candidate in main develop; do
  if [ "$candidate" = "$RK_TRUNK_BRANCH" ]; then
    continue
  fi
  if glab api "projects/$project/repository/branches/$candidate" >/dev/null 2>&1; then
    # Commits reachable from the candidate and not from the trunk; an empty
    # list means the candidate is an ancestor and holds nothing of its own.
    # The comparison is captured first and fails closed: a comparison that
    # cannot be read must never read as an empty one, because the next line
    # deletes.
    if ! compare="$(glab api "projects/$project/repository/compare?from=$RK_TRUNK_BRANCH&to=$candidate")"; then
      echo "FAIL the comparison of $candidate and $RK_TRUNK_BRANCH could not be read" >&2
      echo 'remediation: check authentication and rerun' >&2
      exit 1
    fi
    ahead="$(printf '%s' "$compare" | grep -c '"short_id"' || true)"
    if [ "$ahead" = "0" ]; then
      glab api -X DELETE "projects/$project/repository/branches/$candidate" >/dev/null
      echo "ok $candidate deleted"
    else
      echo "FAIL $candidate is not an ancestor of $RK_TRUNK_BRANCH; deleting it would lose work" >&2
      echo 'remediation: merge or move the work first, then rerun' >&2
      exit 1
    fi
  fi
done

echo 'check: prints nothing for the retired branches'
for candidate in main develop; do
  glab api "projects/$project/repository/branches/$candidate" 2>/dev/null | compact | grep -o "\"name\":\"$candidate\"" || true
done
echo 'ok single-trunk'