gbr

#!/bin/bash
set -eo pipefail

BOLD=$(tput bold)
NORMAL=$(tput sgr0)

usage() {
  echo "Rename the 'master' branch for an entire account at once."
  echo ""
  echo "This tool will find all repositories on GitHub belonging to an account that:"
  echo ""
  echo "  - aren't forks"
  echo "  - aren't archived or disabled"
  echo "  - have their default branch set to 'master'"
  echo ""
  echo "It will then rename the master branch to 'main' by default, and set that as the"
  echo "default branch on GitHub instead of 'master'."
  echo ""
  echo "By default, the 'master' branch will be left untouched to prevent any accidental"
  echo "data loss. If you'd like to delete those branches, set the '--delete' flag."
  echo ""
  echo "You must choose to either do a dry run ('--dry-run') or force the changes"
  echo "('--force'). You must also specify one of '--org' or '--user' (but not both) to"
  echo "select the account to collect repositories from."
  echo ""
  echo "${BOLD}USAGE${NORMAL}"
  echo "  $(basename "$0") [flags]"
  echo ""
  echo "${BOLD}FLAGS${NORMAL}"
  echo "  -u, --user string         The username to collect repositories in"
  echo "  -o, --org string          The organization to collect repositories in"
  echo "  -t, --team string         The team within the organization (optional)"
  echo "  -b, --new-branch string   The new name for the master branch (defaults to"
  echo "                              'main')"
  echo "  -d, --delete              Delete the master branch from GitHub"
  echo "  -n, --dry-run             Report what will happen, without making any changes"
  echo "                               on GitHub"
  echo "  -f, --force               Run for real, making changes on GitHub"
  echo "  -l, --list                Print a list of all GitHub repositories that would"
  echo "                               be changed and exit (implies a dry run)"
  exit 1
}

if [ $# -lt 2 ]; then
  usage
fi

ORG=
TEAM=
USER=
NEW_BRANCH=main
DELETE=0
DRY_RUN=0
FORCE=0
LIST_ONLY=0

while [ $# -gt 0 ] ; do
  case $1 in
    -u | --user)
      USER="$2"
      ;;
    -o | --org)
      ORG="$2"
      ;;
    -t | --team)
      TEAM="$2"
      ;;
    -b | --new-branch)
      NEW_BRANCH="$2"
      ;;
    -d | --delete)
      DELETE=1
      ;;
    -n | --dry-run)
      DRY_RUN=1
      ;;
    -f | --force)
      FORCE=1
      ;;
    -l | --list)
      LIST_ONLY=1
      DRY_RUN=1
      ;;
  esac
  shift
done

if [ "$FORCE" -ne 1 ] && [ "$DRY_RUN" -ne 1 ]; then
  usage
fi

if [ "$FORCE" -eq 1 ] && [ "$DRY_RUN" -eq 1 ]; then
  usage
fi

if [ "$LIST_ONLY" -eq 1 ] && [ "$DRY_RUN" -ne 1 ]; then
  usage
fi

if [ -z "$USER" ] && [ -z "$ORG" ]; then
  usage
fi

if [ -n "$USER" ] && [ -n "$ORG" ]; then
  usage
fi

if [ -z "$ORG" ] && [ -n "$TEAM" ]; then
  usage
fi

if [ -n "$USER" ] && [ -n "$TEAM" ]; then
  usage
fi

REPOS_ENDPOINT=
ACCOUNT=

if [ -n "$USER" ]; then
  REPOS_ENDPOINT="users/$USER/repos"
  ACCOUNT=$USER
elif [ -n "$ORG" ] && [ -n "$TEAM" ]; then
  REPOS_ENDPOINT="orgs/$ORG/teams/$TEAM/repos"
  ACCOUNT=$ORG
else
  REPOS_ENDPOINT="orgs/$ORG/repos"
  ACCOUNT=$ORG
fi

if [ -n "$TEAM" ]; then
  echo "${BOLD}==> Collecting relevant repositories for '$ORG/$TEAM'...${NORMAL}"
else
  echo "${BOLD}==> Collecting relevant repositories for '$ACCOUNT'...${NORMAL}"
fi

PARAMS="?per_page=100"
REPOS=

while [ -n "$PARAMS" ]; do
  RESPONSE=$(gh api "$REPOS_ENDPOINT$PARAMS" --include)

  BODY=$(echo "$RESPONSE" | tail -1)

  REPOS+=$(
    echo "$BODY" |
    jq "
      map(
        select(
          .fork == false and
          .archived == false and
          .disabled == false and
          .default_branch == \"master\"
        ) |
        {
          id: .id,
          name: .name,
          full_name: .full_name
        }
      )[]
    "
  )

  set +o pipefail

  # shellcheck disable=SC1004
  PARAMS=$(
    echo "$RESPONSE" |
    grep -F Link: |
    sed 's/Link: //' |
    sed 's/, /\
/g' |
    grep -F 'rel="next"' |
    grep -o '\?.*>' |
    sed -e 's/>$//'
  )

  set -o pipefail
done

if [ -z "$REPOS" ]; then
  echo "No relevant repositories found."
  exit
fi

if [ "$LIST_ONLY" -eq 1 ]; then
  echo "$REPOS" | jq -r '.full_name'
  exit
fi

TMP_DIR=/tmp/gbr/$ACCOUNT

echo "${BOLD}==> (Re)creating '$TMP_DIR'...${NORMAL}"

rm -rf "$TMP_DIR"
mkdir -p "$TMP_DIR"
cd "$TMP_DIR"

FAILED_RENAMES=()
FAILED_DELETIONS=()

for REPO in $(echo "$REPOS" | jq '.name' | sed 's/"//g'); do
  {
    echo "${BOLD}==> Updating '$ACCOUNT/$REPO'...${NORMAL}"

    git clone "git@github.com:$ACCOUNT/$REPO.git" "$TMP_DIR/$REPO"

    cd "$TMP_DIR/$REPO"

    echo "${BOLD}Setting '$NEW_BRANCH' to point to the head of 'master'...${NORMAL}"

    git checkout -B "$NEW_BRANCH" origin/master --no-track

    if [ "$DRY_RUN" -ne 1 ]; then
      git push --set-upstream origin "$NEW_BRANCH"
      git remote set-head origin "$NEW_BRANCH"
    fi

    echo "${BOLD}Changing default branch to '$NEW_BRANCH'...${NORMAL}"

    if [ "$DRY_RUN" -ne 1 ]; then
      gh api repos/:owner/:repo \
        --method PATCH \
        --raw-field default_branch="$NEW_BRANCH" \
        >/dev/null
    fi

    echo "${BOLD}Changing open pull request target branches to '$NEW_BRANCH'...${NORMAL}"

    for PR in $(gh pr list --base master --limit 9999 | cut -f 1); do
      if [ "$DRY_RUN" -ne 1 ]; then
        gh api "repos/:owner/:repo/pulls/$PR" \
          --method PATCH \
          --raw-field base="$NEW_BRANCH" \
          >/dev/null
      fi

      echo -n "."
    done

    echo ""

    if [ "$DELETE" -eq 1 ]; then
      echo "${BOLD}Deleting 'master'...${NORMAL}"

      if [ "$DRY_RUN" -ne 1 ]; then
        git push origin --delete master || FAILED_DELETIONS+=("$REPO")
      fi
    fi
  } || FAILED_RENAMES+=("$REPO")
done

echo "Done!"

if [ ${#FAILED_RENAMES[@]} -gt 0 ]; then
  echo ""
  echo "${BOLD}NOTE${NORMAL}"
  echo ""
  echo "Failed to rename the 'master' branch for the following repositories:"
  echo ""

  for REPO in "${FAILED_RENAMES[@]}"; do
    echo "  $ACCOUNT/$REPO"
  done

  echo ""
  echo "Manual intervention is required."
fi

if [ ${#FAILED_DELETIONS[@]} -gt 0 ]; then
  echo ""
  echo "${BOLD}NOTE${NORMAL}"
  echo ""
  echo "Failed to delete the 'master' branch from the following repositories:"
  echo ""

  for REPO in "${FAILED_DELETIONS[@]}"; do
    echo "  $ACCOUNT/$REPO"
  done

  echo ""
  echo "Manual intervention is required."
fi

echo ""
echo "${BOLD}NOTE${NORMAL}"
echo ""
echo "Any CI or other code that relies on branch names will need to be updated manually."