git-branch-diff

#!/usr/bin/env bash
#
# Diff between current branch and default branch
#
# Copyright 2022, Joe Block <jpb@unixorn.net>

set -o pipefail
if [[ -n "$DEBUG" ]]; then
  set -x
fi

function debug() {
  if [[ -n "$DEBUG" ]]; then
    echo "$@"
  fi
}

function echo-stderr() {
  echo "$@" 1>&2
}

function fail() {
  printf '%s\n' "$1" >&2  ## Send message to stderr. Exclude >&2 if you don't want it that way.
  exit "${2-1}"  ## Return a code specified by $2 or 1 by default.
}

function has() {
  # Check if a command is in $PATH
  which "$@" > /dev/null 2>&1
}

DEFAULT_BRANCH=$(git remote show origin | grep 'HEAD branch' | cut -d ' ' -f5)

exec git diff "${DEFAULT_BRANCH}..HEAD" "$@"