Use tib_spec attribute in untibblify() (#291)

* Initial plan

* Use tib_spec attribute in untibblify() (#235)

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Co-authored-by: jonthegeek <33983824+jonthegeek@users.noreply.github.com>

* Use get_spec(x) as default for spec argument

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Co-authored-by: jonthegeek <33983824+jonthegeek@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: jonthegeek <33983824+jonthegeek@users.noreply.github.com>

Author: Copilot

NEWS.md

@@ -1,5 +1,6 @@
 # tibblify (development version)
 
+* `untibblify()` now automatically uses the `tib_spec` attribute when present, so tibblified objects can be round-tripped without explicitly passing the spec (#235).
 * `parse_openapi_spec()` supports many more fields and works for many more APIs (#190, #200, @jonthegeek and @mgirlich).
 * The underlying C implementation has been updated to better comply with R's C API. We also fixed various bugs during this update (#203, #204, #222).
 * Documentation of all functions has been updated for clarity (#228, #245, #246).

R/untibblify.R

@@ -4,7 +4,8 @@
 #' into a nested list.
 #'
 #' @param x A data frame or an object.
-#' @param spec Optional. A spec object which was used to create `x`.
+#' @param spec Optional. A spec object which was used to create `x`. Defaults
+#'   to the spec stored as the `tib_spec` attribute of `x`, if present.
 #'
 #' @return A nested list.
 #' @export
@@ -18,7 +19,7 @@
 #'   )
 #' )
 #' untibblify(x)
-untibblify <- function(x, spec = NULL) {
+untibblify <- function(x, spec = get_spec(x)) {
   call <- current_call()
 
   if (is.data.frame(x)) {
@@ -33,15 +34,6 @@ untibblify <- function(x, spec = NULL) {
 }
 
 untibblify_df <- function(x, spec, call) {
-  if (is.null(spec)) {
-    idx <- seq_len(vctrs::vec_size(x))
-    out <- purrr::map(
-      idx,
-      ~ untibblify_row(vctrs::vec_slice(x, .x), spec, call)
-    )
-    return(out)
-  }
-
   idx <- seq_len(vctrs::vec_size(x))
   purrr::map(idx, ~ untibblify_row(vctrs::vec_slice(x, .x), spec, call))
 }
@@ -50,7 +42,6 @@ untibblify_row <- function(x, spec, call) {
   if (!is.null(spec)) {
     x <- apply_spec_renaming(x, spec)
   }
-  # browser()
 
   out <- as.list(x)
   fields <- spec$fields

man/dot-pkg_abort.Rd

@@ -186,6 +186,17 @@ test_that("can rename according to spec (#49)", {
   )
 })
 
+test_that("uses tib_spec attribute when no spec provided (#235)", {
+  input <- list(
+    list(x = 1, y = "a"),
+    list(x = 2, y = "b")
+  )
+  spec <- tspec_df(x2 = tib_int("x"), y2 = tib_chr("y"))
+  tibbed <- tibblify(input, spec)
+
+  expect_equal(untibblify(tibbed), input)
+})
+
 test_that("checks input (#49)", {
   expect_snapshot({
     (expect_error(untibblify(1:3)))