"Error in .f(.x[[i]], ...) : object 'values_1' not found" should be updated to more readable error

[MadhulikaTanuboddi]

Run the following example where in one of the footnotes section, we are trying to add a footnote to a column named "valuer" that does not exist in the table

library(gt)
library(tidyverse)

# Create a table with footnotes in various cell types
tbl <-
  dplyr::tribble(
    ~date,        ~rowname,  ~value_1,  ~value_2,
    "2018-02-10", "1",       20.4,      361.1,
    "2018-02-10", "2",       10.9,      743.3,
    "2018-02-10", "3",       34.6,      344.7,
    "2018-02-10", "4",        8.3,      342.3,
    "2018-02-11", "5",       28.3,      234.9,
    "2018-02-11", "6",       75.5,      190.9,
    "2018-02-11", "7",       63.1,        2.3,
    "2018-02-11", "8",       25.8,      184.3,
    "2018-02-11", "9",        5.2,      197.2,
    "2018-02-11", "10",      55.3,      284.6
  )

# Create a display table
footnotes_tbl <-
  gt(data = tbl, groupname_col = "date") %>%
  tab_spanner(
    label = "values",
    columns = starts_with("value")
  ) %>%
  tab_footnote(
    footnote = "This is an even smaller number.",
    locations = cells_body(columns = vars(value_1), rows = 9)
  ) %>%
  tab_footnote(
    footnote = "This is a small number.",
    locations = cells_body(columns = vars(value_1), rows = 4)
  ) %>%
  tab_footnote(
    footnote = "First data cell.",
    locations = cells_body(columns = "valuer", rows = 1)
  ) %>%
  tab_footnote(
    footnote = "The first row group",
    locations = cells_row_groups(groups = ends_with("10"))
  ) %>%
  tab_footnote(
    footnote = "Two sets of values",
    locations = cells_column_spanners(spanners = starts_with("val"))
  ) %>%
  tab_footnote(
    footnote = "A stub cell.",
    locations = cells_stub(rows = 1)
  ) %>%
  tab_footnote(
    footnote = md("`value_1` is the first column of values."),
    locations = cells_column_labels(columns = vars(value_1))
  )

footnotes_tbl

Expected: Readable error saying valuer does not exist
Actual: Error in .f(.x[[i]], ...) : object 'values_1' not found. "Error in f.." does not make sense here

[rich-iannone]

Running this code now (in the dev version) provides a slightly better error thanks to our better use of tidyselect:

Error: Can't subset columns that don't exist.
x Column `valuer` doesn't exist.

It can still be argued that a better, more descriptive error message can still be provided by gt.