find pandoc

[Liripo]

Hello:
When I use rocker docker, I have encountered the following problem.

docker run -u $UID --rm -it rocker/tidyverse:4.2 R -e 'htmlwidgets:::find_pandoc()'

The error is as follows：

> htmlwidgets:::find_pandoc()
sh: 1: //opt/pandoc/pandoc: not found
Error in system(paste(shQuote(pandoc_path), "--version"), intern = TRUE) : 
  error in running command
Calls: <Anonymous> ... get_pandoc_version -> with_pandoc_safe_environment -> force -> system
Execution halted

It was caused by

htmlwidgets/R/pandoc.R

Lines 176 to 182 in 9827b5f

	if (!is_windows())
	sources <- c(sources, path.expand("~/opt/pandoc"))
	# determine the versions of the sources
	versions <- lapply(sources, function(src) {
	if (file.exists(src))
	get_pandoc_version(src)

. I would like to ask if it is possible to judge pandoc binary files directly, not just directories？

[jcheng5]

I don't really know this code... but rmarkdown::find_pandoc seems to work (though it does take a surprising few seconds on my machine), so we probably just need to copy that over. @Liripo if you're up for making a pull request, I'd be grateful.

[Liripo]

Thanks for your reply, I will check the rmarkdown::find_pandoc and try it.