Concatenating s2 vectors does not call `new_s2_geography()`

[tzakharko]

Since s2 vectors inherit from wk_vctr and not vctrs_vctr, vec_restore() is never called on the concatenation result. The consequence is that the ALTREP class is not properly set up and the concatenated s2 geography vectors can't be serialized. In addition, c.wk_vctr sets additional attributes like crs and geodesic, creating an asymmetry with "regular" s2 vectors that don't have these attributes.

I am wondering whether the original idea was to make s2 geography vctrs vectors, but was then abandoned for some reason?

[paleolimbot]

We should probably add c.s2_geography to get around this! s2 (and wk) vectors are vctrs vectors in the sense that they work in tibbles and vec_c() and other places; however, they don't inherit from vctrs_vctr (to avoid a required dependency on vctrs).

[tzakharko]

Thanks! Would this do the trick?

#' @export
c.s2_geography <- function(...) {
  new_s2_geography(unlist(lapply(list(...), as_s2_geography)))
}

[paleolimbot]

I think so!