open-pr Skill

1#!/usr/bin/env bash2# Pick the remote branch the current branch most likely forked from.3# Supports telescoped/stacked PRs by scanning all origin/* ancestors.4set -euo pipefail5 6current_branch=$(git branch --show-current)7head_tip=$(git rev-parse HEAD)8best=""9min_commits=99999910best_is_feature=011 12is_trunk() {13  case "$1" in14    main | next) return 0 ;;15    *) return 1 ;;16  esac17}18 19normalize_branch_name() {20  local name=$121  name=${name#origin/}22  name=${name#remotes/origin/}23  echo "${name}"24}25 26branch_exists_on_origin() {27  git rev-parse --verify "origin/$1" >/dev/null 2>&128}29 30is_valid_base() {31  local branch=$132  local ref="origin/${branch}"33 34  [ "${branch}" != "${current_branch}" ] || return 135  branch_exists_on_origin "${branch}" || return 136 37  local branch_tip38  branch_tip=$(git rev-parse "${ref}")39  [ "${branch_tip}" != "${head_tip}" ] || return 140  git merge-base --is-ancestor "${ref}" HEAD 2>/dev/null41}42 43commit_count_since() {44  git rev-list --count "origin/$1..HEAD"45}46 47consider() {48  local branch=$149  local commit_count=$250 51  if ! is_valid_base "${branch}"; then52    return53  fi54 55  local is_feature=056  is_trunk "${branch}" || is_feature=157 58  if [ -z "${best}" ]; then59    best=${branch}60    min_commits=${commit_count}61    best_is_feature=${is_feature}62    return63  fi64 65  if [ "${commit_count}" -lt "${min_commits}" ]; then66    best=${branch}67    min_commits=${commit_count}68    best_is_feature=${is_feature}69    return70  fi71 72  if [ "${commit_count}" -gt "${min_commits}" ]; then73    return74  fi75 76  # Tie: prefer telescoped parent over trunk, then next over main.77  if [ "${best_is_feature}" -eq 0 ] && [ "${is_feature}" -eq 1 ]; then78    best=${branch}79    best_is_feature=${is_feature}80    return81  fi82 83  if [ "${best_is_feature}" -eq 1 ] && [ "${is_feature}" -eq 0 ]; then84    return85  fi86 87  if [ "${branch}" = "next" ]; then88    best=${branch}89    best_is_feature=${is_feature}90  fi91}92 93try_explicit_base() {94  local branch=$195  branch=$(normalize_branch_name "${branch}")96  consider "${branch}" "$(commit_count_since "${branch}")"97}98 99# 1. Tracked upstream (set when branching with -u or --track)100if upstream=$(git rev-parse --abbrev-ref '@{upstream}' 2>/dev/null); then101  try_explicit_base "${upstream}"102fi103 104# 2. Reflog: most recent branch we checked out from105if [ -z "${best}" ]; then106  while IFS= read -r line; do107    if [[ ${line} =~ checkout:\ moving\ from\ (.+)\ to\ ${current_branch} ]]; then108      try_explicit_base "${BASH_REMATCH[1]}"109      break110    fi111    if [[ ${line} =~ branch:\ Created\ from\ (.+) ]]; then112      try_explicit_base "${BASH_REMATCH[1]}"113      break114    fi115  done < <(git reflog show --format='%gs' "${current_branch}" 2>/dev/null || true)116fi117 118# 3. Scan all origin/* branches — closest strict ancestor wins119while IFS= read -r ref; do120  branch=${ref#origin/}121 122  if [ "${branch}" = "HEAD" ] || [ "${branch}" = "${current_branch}" ]; then123    continue124  fi125 126  if ! is_valid_base "${branch}"; then127    continue128  fi129 130  consider "${branch}" "$(commit_count_since "${branch}")"131done < <(git for-each-ref --format='%(refname:short)' refs/remotes/origin/)132 133if [ -z "${best}" ]; then134  best="next"135fi136 137echo "${best}"138