auto name tag with a specified rule

auto-tag.sh

#!/usr/bin/env bash

f() {
  # 获取当前仓库最新的状态，避免本地 tag 列表不是最新的
  # https://stackoverflow.com/questions/8943693/can-git-operate-in-silent-mode
  # https://stackoverflow.com/questions/1204190/does-git-fetch-tags-include-git-fetch
  # https://stackoverflow.com/questions/16678072/can-we-set-a-git-default-to-fetch-all-tags-during-a-remote-pull
  git fetch --tags --prune --prune-tags --quiet

  local latestTag
  # https://stackoverflow.com/questions/1404796/how-can-i-get-the-latest-tag-name-in-current-branch-in-git
  # https://stackoverflow.com/questions/14273531/how-to-sort-git-tags-by-version-string-order-of-form-rc-x-y-z-w
  latestTag=$(git tag -l rc* --sort=v:refname | tail -1)

  if [[ "$latestTag" =~ ^(rc)([0-9]{4}[0-9]{2}[0-9]{2})_([0-9]+)(_.*)?$ ]]; then
    local now
    # https://stackoverflow.com/questions/1401482/yyyy-mm-dd-format-date-in-shell-script
    now=$(date '+%Y%m%d')
    # 获取 tag 里面的日期
    local fullDate="${BASH_REMATCH[2]}"
    # 获取 tag 里面的版本号
    local version="${BASH_REMATCH[3]}"

    local finalDate
    local finalVersion
    if (( now > fullDate )); then
      finalDate="$now"
      finalVersion='1'
    else
      finalDate="$fullDate"
      finalVersion="$((version + 1))"
    fi
    
    local finalTag="${BASH_REMATCH[1]}${finalDate}_${finalVersion}${BASH_REMATCH[4]}"
    
    git tag "$finalTag"
    echo "tag: $finalTag"
  else
    git tag "$@"
  fi
}