fix #2308: don't trim trailing spaces escaped by \

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: knitr
 Type: Package
 Title: A General-Purpose Package for Dynamic Report Generation in R
-Version: 1.45.6
+Version: 1.45.7
 Authors@R: c(
     person("Yihui", "Xie", role = c("aut", "cre"), email = "[email protected]", comment = c(ORCID = "0000-0003-0645-5666")),
     person("Abhraneel", "Sarma", role = "ctb"),

NEWS.md

@@ -16,6 +16,8 @@
 
 - The `family` argument was not passed to the `pdf` device (thanks, @sebkopf, rstudio/rmarkdown#2526).
 
+- Trailing spaces escaped by `\` should not be trimmed in `kable()` (thanks, @mjsmith037, #2308).
+
 ## MAJOR CHANGES
 
 - Unbalanced chunk delimiters (fences) in R Markdown documents are no longer allowed, as announced two years ago at <https://yihui.org/en/2021/10/unbalanced-delimiters/> (#2306). This means the opening delimiter must strictly match the closing delimiter, e.g., if a code chunk starts with four backticks, it must also end with four; or if a chunk header is indented by two spaces, the closing fence must be indented by exactly two spaces. For authors who cannot update their R Markdown documents for any reason at the moment, setting `options(knitr.unbalanced.chunk = TRUE)` (e.g., in `.Rprofile`) can temporarily prevent **knitr** from throwing an error, but it is strongly recommended that you fix the problems as soon as possible, because this workaround will be removed in future.

R/table.R

@@ -153,7 +153,8 @@ kable = function(
   n = nrow(x)
   x = replace_na(to_character(x), is.na(x))
   if (!is.matrix(x)) x = matrix(x, nrow = n)
-  x = trimws(x)
+  # trim white spaces except those escaped by \ at the end (#2308)
+  x = gsub('^\\s+|(?<!\\\\)\\s+$', '', x, perl = TRUE)
   colnames(x) = col.names
   if (format != 'latex' && length(align) && !all(align %in% c('l', 'r', 'c')))
     stop("'align' must be a character vector of possible values 'l', 'r', and 'c'")

tests/testit/test-table.R

@@ -111,6 +111,17 @@ x\\\\
 \\end{tabular}')
 })
 
+assert('kable() does not trim escaped spaces at the end', {
+  (kable2(data.frame(x = '\\ '), 'latex', escape =FALSE ) %==% '
+\\begin{tabular}{l}
+\\hline
+x\\\\
+\\hline
+\\ \\\\
+\\hline
+\\end{tabular}')
+})
+
 assert('kable() escapes HTML special characters by default', {
   (kable2(data.frame(x = c('10<>', '5&2'), y = c('3>8', '"40"')), 'html') %==%
      '<table>\n <thead>\n  <tr>\n   <th style="text-align:left;"> x </th>\n   <th style="text-align:left;"> y </th>\n  </tr>\n </thead>\n<tbody>\n  <tr>\n   <td style="text-align:left;"> 10&lt;&gt; </td>\n   <td style="text-align:left;"> 3&gt;8 </td>\n  </tr>\n  <tr>\n   <td style="text-align:left;"> 5&amp;2 </td>\n   <td style="text-align:left;"> &quot;40&quot; </td>\n  </tr>\n</tbody>\n</table>')