message: Add error messages for improperly configured buckets
diff: @@ -89,7 +89,23 @@ fn publish_script(user: &GlobalUser, target: &Target) -> Result<(), failure::Err
  fn upload_buckets(target: &Target, user: &GlobalUser) -> Result<(), failure::Error> {
  for namespace in &target.kv_namespaces() {
  if let Some(bucket) = &namespace.bucket {
  + if bucket.is_empty() {
  + failure::bail!(
  + "{} You need to specify a bucket directory in your wrangler.toml",
  + emoji::WARN
  + )
  + }
  let path = Path::new(&bucket);
  + if !path.exists() {
  + if let Some(path_str) = path.to_str() {
  + failure::bail!(
  + "{} could not find a directory for bucket \"{}\"",
  + emoji::WARN,
  + path_str
  + )
  + }
  + failure::bail!("{} bucket path is not valid UTF-8")
  + }
  kv::bucket::sync(target, user.to_owned(), &namespace.id, path, false)?;
  }
  }
  