Bug: `xportr_metadata` replaces metadata with default arguments

[André Veríssimo]

What happened?

xportr_metadata will always replace the metadata attribute even if the default parameters are given (as it's NULL)

See example.

Possible solution (replicate domain setting)

diff --git a/R/metadata.R b/R/metadata.R
index df206ef..baa0905 100644
--- a/R/metadata.R
+++ b/R/metadata.R
@@ -44,12 +44,15 @@ xportr_metadata <- function(.df, metadata = NULL, domain = NULL) {
   if (is.null(metadata) && is.null(domain)) {
     stop("Must provide either metadata or domain argument")
   }
-  ## Common section to detect domain from argument or attribute
+  ## Common section to detect default arguments
 
   domain <- get_domain(.df, domain)
   if (!is.null(domain)) attr(.df, "_xportr.df_arg_") <- domain
 
+  metadata <- metadata %||% attr(.df, "_xportr.df_metadata_")
+  if (!is.null(metadata)) attr(.df, "_xportr.df_arg_") <- metadata
+
   ## End of common section
 
-  structure(.df, `_xportr.df_metadata_` = metadata)
+  .df
 }

Session Information

No response

Reproducible Example

library(xportr)

metadata <- data.frame(
  dataset = "test",
  variable = c("Subj", "Param", "Val", "NotUsed"),
  type = c("numeric", "character", "numeric", "character"),
  format = NA,
  order = c(1, 3, 4, 2)
)

adlb <- data.frame(
  Subj = as.character(123, 456, 789),
  Different = c("a", "b", "c"),
  Val = c("1", "2", "3"),
  Param = c("param1", "param2", "param3")
)

adlb_with_metadata <- adlb |>
  xportr_metadata(metadata) |>
  xportr_metadata(domain = "test")
  
attr(adlb_with_metadata, "_xportr.df_metadata_")
#> NULL

^{Created on 2024-01-23 with reprex v2.0.2}