Opaque error from `parameters()` with `new_*_param(..., label = NULL)`

[owenjonesuob]

We can specify a new parameter with new_quant_param() or new_qual_param().

The docs state that label is an optional parameter:

dials/R/constructors.R

Lines 34 to 36 in 210055f

	#' @param label An optional named character string that can be used for
	#' printing and plotting. The name should match the object name (e.g.
	#' `"mtry"`, `"neighbors"`, etc.)

But if no label is specified, we get an opaque error when handing our new parameter to parameters():

library(dials)
#> Loading required package: scales

with_label <- function() new_quant_param(
  values = 1,
  label = c("with_label" = "Here is a label")
)


sans_label <- function() new_quant_param(
  values = 1
)


parameters(with_label())
#> Collection of 1 parameters for tuning
#> 
#>  identifier       type    object
#>  with_label with_label nparam[+]

parameters(sans_label())
#> Error in `purrr::map_chr()`:
#> ℹ In index: 1.
#> Caused by error:
#> ! Result must be length 1, not 0.

^{Created on 2024-09-02 with reprex v2.1.1}

Session info

sessioninfo::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
#>  setting  value
#>  version  R version 4.3.2 (2023-10-31)
#>  os       Amazon Linux 2023.5.20240708
#>  system   x86_64, linux-gnu
#>  ui       X11
#>  language (EN)
#>  collate  C.UTF-8
#>  ctype    C.UTF-8
#>  tz       Europe/London
#>  date     2024-09-02
#>  pandoc   3.1.11 @ /usr/lib/rstudio-server/bin/quarto/bin/tools/x86_64/ (via rmarkdown)
#> 
#> ─ Packages ───────────────────────────────────────────────────────────────────
#>  package     * version date (UTC) lib source
#>  cli           3.6.3   2024-06-21 [1] CRAN (R 4.3.2)
#>  colorspace    2.1-1   2024-07-26 [2] CRAN (R 4.3.2)
#>  dials       * 1.3.0   2024-07-30 [2] CRAN (R 4.3.2)
#>  DiceDesign    1.10    2023-12-07 [2] CRAN (R 4.3.2)
#>  digest        0.6.36  2024-06-23 [2] CRAN (R 4.3.2)
#>  dplyr         1.1.4   2023-11-17 [2] CRAN (R 4.3.2)
#>  evaluate      0.24.0  2024-06-10 [2] CRAN (R 4.3.2)
#>  fansi         1.0.6   2023-12-08 [2] CRAN (R 4.3.2)
#>  fastmap       1.2.0   2024-05-15 [2] CRAN (R 4.3.2)
#>  fs            1.6.4   2024-04-25 [2] CRAN (R 4.3.2)
#>  generics      0.1.3   2022-07-05 [2] CRAN (R 4.3.2)
#>  glue          1.7.0   2024-01-09 [2] CRAN (R 4.3.2)
#>  hardhat       1.4.0   2024-06-02 [2] CRAN (R 4.3.2)
#>  htmltools     0.5.8.1 2024-04-04 [2] CRAN (R 4.3.2)
#>  knitr         1.48    2024-07-07 [2] CRAN (R 4.3.2)
#>  lifecycle     1.0.4   2023-11-07 [2] CRAN (R 4.3.2)
#>  magrittr      2.0.3   2022-03-30 [2] CRAN (R 4.3.2)
#>  munsell       0.5.1   2024-04-01 [2] CRAN (R 4.3.2)
#>  pillar        1.9.0   2023-03-22 [2] CRAN (R 4.3.2)
#>  pkgconfig     2.0.3   2019-09-22 [2] CRAN (R 4.3.2)
#>  purrr         1.0.2   2023-08-10 [2] CRAN (R 4.3.2)
#>  R6            2.5.1   2021-08-19 [2] CRAN (R 4.3.2)
#>  reprex        2.1.1   2024-07-06 [2] CRAN (R 4.3.2)
#>  rlang         1.1.4   2024-06-04 [2] CRAN (R 4.3.2)
#>  rmarkdown     2.27    2024-05-17 [2] CRAN (R 4.3.2)
#>  rstudioapi    0.16.0  2024-03-24 [2] CRAN (R 4.3.2)
#>  scales      * 1.3.0   2023-11-28 [2] CRAN (R 4.3.2)
#>  sessioninfo   1.2.2   2021-12-06 [2] CRAN (R 4.3.2)
#>  tibble        3.2.1   2023-03-20 [2] CRAN (R 4.3.2)
#>  tidyselect    1.2.1   2024-03-11 [2] CRAN (R 4.3.2)
#>  utf8          1.2.4   2023-10-22 [2] CRAN (R 4.3.2)
#>  vctrs         0.6.5   2023-12-01 [2] CRAN (R 4.3.2)
#>  withr         3.0.1   2024-07-31 [2] CRAN (R 4.3.2)
#>  xfun          0.46    2024-07-18 [2] CRAN (R 4.3.2)
#>  yaml          2.3.10  2024-07-26 [2] CRAN (R 4.3.2)
#> 
#>  [1] /home/owen10004/efs/R/x86_64-amazon-linux-gnu-library/4.3
#>  [2] /usr/lib64/R/site-library
#>  [3] /usr/lib64/R/library
#> 
#> ──────────────────────────────────────────────────────────────────────────────

It's because the label is used within parameters() to construct the parameter names:

dials/R/parameters.R

Line 39 in 210055f

elem_name <- purrr::map_chr(x, ~ names(.x$label))

[hfrick]

Thanks @owenjonesuob ! 🙏