column_spec() fails at single-row headerless tables in latex format.

[famuvie]

Admittedly a corner case, but specifying a column width with column_spec() errors for headerless tables with a single row in LaTeX format.

Minimal reproducible example below.

library(kableExtra)

dat <- data.frame(x = 1, y = 1)
dat <- setNames(dat, NULL)

kbl(dat, format = "latex") |> 
  column_spec(2, latex_column_spec = "l")
#> Error in if (bold) {: missing value where TRUE/FALSE needed

^{Created on 2021-10-04 by the reprex package (v2.0.1)}

I skimmed the code and I suspect that the issue is in column_spec_latex(), where it gets a sequence of rows as: rows <- seq(1 + off, nrows). With nrows = 1L (correct) and off = 1 as well, it yields rows = c(2, 1) and fails in the subsequent loop through the rows when it starts processing row number 2 which does not exist.

But I'm not sure what a proper fix would be, since I don't know the role played by off in the general case.

I suspect this is related with #613.

Best wishes.