formulas don't work with brmsformula objects produced by `bf()`

[jsocolar]

We fail in a few places, including:

• in validate_params_individually we have

  assertthat::assert_that(
  inherits(f_det, "formula"),
  msg = formula_error("detection")
  )

  • in validate_unit_formula_variables we have

    stats::terms(f_occ)

  • in is_flocker_formula we have

    is_flocker_formula <- function (x) {
    is_formula(x) & as.character(x)[1] == "~" & length(x) == 2
    }

More importantly, inside flock_ we have things like

if (!is.null(f_occ)) {
    f_occ_txt <- paste0(deparse(f_occ), collapse = "")
    f_occ_use <- stats::as.formula(paste0("occ ", f_occ_txt))
  }

Can we come up with a slick fix?