Warning when querying an s-attribute which is not available in subcorpus

[ChristophLeonhardt]

In the following chunk I try to identify which types of named entities occur in a particular paragraph. In this case, the paragraph does not contain any named entities. This is returned by s_attributes() as "character(0)". I assume that this is okay. However, s_attributes() also prints a warning message each time this happens.

library(polmineR)
paragraph <- corpus("GERMAPARL2") |>
  subset(protocol_date == "1949-09-07") |>
  split(s_attribute = "p_type", values = FALSE) |>
  _[[2]]

s_attributes(paragraph, "ne_type")

character(0)
Warning message:
In check_strucs(corpus = corpus, s_attribute = s_attribute, strucs = struc, :
struc vector has length 0

I assume that this warning message is there because there probably are scenarios in which missing struc vectors have potentially negative implications. However, in this case, I would think that s_attributes() does what it is supposed to do?

So, from a user perspective, what should I make of this warning? Maybe it should be more telling? On another note, if the object is not a single subcorpus but a subcorpus bundle, this warning might be shown a lot of times. This can be irritating if returning "character(0)" is, in fact, correct behavior of s_attributes().