Unexpected interaction between `column.major` and Date `handlers` in `as.yaml()`

[cynthiahqy]

In as.yaml(), setting column.major=FALSE appears to prevent the application of Date handlers. For a while, I thought I was specifying my handler functions incorrectly, but I don't believe that is the case. I used these references for the handlers:

• Is there a way to control how Date objects are translated? #18
• https://github.com/r-lib/ymlthis/blob/15e54ad42ab7c1c10b96490c74e63999149afac1/R/yml.R#L184-L191

I've included a minimal example showing the difference in date handling when column.major=TRUE (default) vs. when column.major=FALSE. This interaction doesn't appear when using the verbatim_logical handler, making the Date behaviour entirely unexpected.

library(yaml)
library(purrr)

## Working date handling
date_handler <- list(Date = function(x) as.character(x))
my_list <- list(date = as.Date(c("2012-10-10", "2014-03-28")))
yaml::as.yaml(my_list, handlers = date_handler)
#> [1] "date:\n- '2012-10-10'\n- '2014-03-28'\n"
## instead of a list, use tibble and df (with column.major = TRUE by default)
my_tbl <- tibble::tibble(date = as.Date(c("2012-10-10", "2014-03-28")))
yaml::as.yaml(my_tbl, handlers = date_handler) |> cat()
#> date:
#> - '2012-10-10'
#> - '2014-03-28'
## but the date_handler doesn't apply with column.major = FALSE?
yaml::as.yaml(my_tbl, handlers = date_handler, column.major = FALSE) |> cat()
#> - date: 15623.0
#> - date: 16157.0

## Same issue with data.frames
my_df <- as.data.frame(my_tbl)
yaml::as.yaml(my_df, handlers = date_handler)
#> [1] "date:\n- '2012-10-10'\n- '2014-03-28'\n"
yaml::as.yaml(my_df, handlers = date_handler, column.major = FALSE)
#> [1] "- date: 15623.0\n- date: 16157.0\n"

## What if convert the tibble to list first?
# purrr::transpose also does the weird number conversion
purrr::transpose(my_tbl)
#> [[1]]
#> [[1]]$date
#> [1] 15623
#> 
#> 
#> [[2]]
#> [[2]]$date
#> [1] 16157
# but not if you do as.list() first
as.list(my_tbl) |>
    purrr::list_transpose(simplify = FALSE)
#> [[1]]
#> [[1]]$date
#> [1] "2012-10-10"
#> 
#> 
#> [[2]]
#> [[2]]$date
#> [1] "2014-03-28"

# what about logical handlers?
my_tbl$bool <- c(TRUE, FALSE)
verbatim_logical <- function(x) {
    result <- tolower(as.logical(x))
    class(result) <- "verbatim"
    return(result)
}
yml_handlers <- c(date_handler, list(logical = verbatim_logical))
# Logical handlers work fine either way, but dates depend on column.major
my_tbl |> yaml::as.yaml(handlers = yml_handlers, column.major = FALSE)
#> [1] "- date: 15623.0\n  bool: true\n- date: 16157.0\n  bool: false\n"
my_tbl |> yaml::as.yaml(handlers = yml_handlers, column.major = TRUE)
#> [1] "date:\n- '2012-10-10'\n- '2014-03-28'\nbool:\n- true\n- false\n"

^{Created on 2024-03-18 with reprex v2.0.2}

Session info

sessioninfo::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
#>  setting  value
#>  version  R version 4.3.1 (2023-06-16)
#>  os       macOS Ventura 13.4.1
#>  system   aarch64, darwin20
#>  ui       X11
#>  language (EN)
#>  collate  en_US.UTF-8
#>  ctype    en_US.UTF-8
#>  tz       Australia/Melbourne
#>  date     2024-03-18
#>  pandoc   3.1.7 @ /opt/homebrew/bin/ (via rmarkdown)
#> 
#> ─ Packages ───────────────────────────────────────────────────────────────────
#>  package     * version date (UTC) lib source
#>  cli           3.6.1   2023-03-23 [1] CRAN (R 4.3.0)
#>  digest        0.6.33  2023-07-07 [1] CRAN (R 4.3.0)
#>  evaluate      0.21    2023-05-05 [1] CRAN (R 4.3.0)
#>  fansi         1.0.4   2023-01-22 [1] CRAN (R 4.3.0)
#>  fastmap       1.1.1   2023-02-24 [1] CRAN (R 4.3.0)
#>  fs            1.6.3   2023-07-20 [1] CRAN (R 4.3.0)
#>  glue          1.6.2   2022-02-24 [1] CRAN (R 4.3.0)
#>  htmltools     0.5.6   2023-08-10 [1] CRAN (R 4.3.0)
#>  knitr         1.43    2023-05-25 [1] CRAN (R 4.3.0)
#>  lifecycle     1.0.3   2022-10-07 [1] CRAN (R 4.3.0)
#>  magrittr      2.0.3   2022-03-30 [1] CRAN (R 4.3.0)
#>  pillar        1.9.0   2023-03-22 [1] CRAN (R 4.3.0)
#>  pkgconfig     2.0.3   2019-09-22 [1] CRAN (R 4.3.0)
#>  purrr       * 1.0.2   2023-08-10 [1] CRAN (R 4.3.0)
#>  R.cache       0.16.0  2022-07-21 [1] CRAN (R 4.3.0)
#>  R.methodsS3   1.8.2   2022-06-13 [1] CRAN (R 4.3.0)
#>  R.oo          1.25.0  2022-06-12 [1] CRAN (R 4.3.0)
#>  R.utils       2.12.2  2022-11-11 [1] CRAN (R 4.3.0)
#>  reprex        2.0.2   2022-08-17 [1] CRAN (R 4.3.0)
#>  rlang         1.1.1   2023-04-28 [1] CRAN (R 4.3.0)
#>  rmarkdown     2.24    2023-08-14 [1] CRAN (R 4.3.0)
#>  sessioninfo   1.2.2   2021-12-06 [1] CRAN (R 4.3.0)
#>  styler        1.10.1  2023-06-05 [1] CRAN (R 4.3.0)
#>  tibble        3.2.1   2023-03-20 [1] CRAN (R 4.3.0)
#>  utf8          1.2.3   2023-01-31 [1] CRAN (R 4.3.0)
#>  vctrs         0.6.3   2023-06-14 [1] CRAN (R 4.3.0)
#>  withr         2.5.0   2022-03-03 [1] CRAN (R 4.3.0)
#>  xfun          0.39    2023-04-20 [1] CRAN (R 4.3.0)
#>  yaml        * 2.3.7   2023-01-23 [1] CRAN (R 4.3.0)
#> 
#>  [1] /Library/Frameworks/R.framework/Versions/4.3-arm64/Resources/library
#> 
#> ──────────────────────────────────────────────────────────────────────────────

[dupontct]

I have replicated the issue.

When running in column.major = FALSE mode. To encode the row it picks that rows element from the each column to encode the row as a list. The problem being that when the element from the picked up the element loses it class information. Thus the element is no longer a Date but instead is a numeric (which is the base class of the Date type). That is why the Date handler doesn't do anything when column.major = FALSE. Boolean is fine because it is a intrinsic data type.

Now working on a fix.