[R-pkg-devel] CRAN Windows failure due to old pandoc ?

[Duncan Murdoch]

On 26/09/2020 9:14 a.m., Dirk Eddelbuettel wrote:
> 
> I had a submission fail and bomb with this error on Windows:
> 
>    Flavor: r-devel-windows-ix86+x86_64
>    Check: re-building of vignette outputs, Result: WARNING
>      Error(s) in re-building vignettes:
>      --- re-building 'vignettefilename.Rmd' using rmarkdown
>      pandoc.exe: unrecognized option `--lua-filter'
>      unrecognized option `--lua-filter'
>      unrecognized option `--lua-filter'
>      Try pandoc.exe --help for more information.
>      Error: processing vignette 'vignettefilename.Rmd' failed with diagnostics:
>      pandoc document conversion failed with error 2
>      --- failed re-building 'vignettefilename.Rmd'
>      
>      SUMMARY: processing the following file failed:
>        'vignettefilename.Rmd'
>      
>      Error: Vignette re-building failed.
>      Execution halted
> 
> This looks like a host configuration problem:
> 
>    edd using rob:~$ pandoc --help | grep lua
>      -L SCRIPTPATH         --lua-filter=SCRIPTPATH
>    edd using rob:~$ pandoc --version | head -1
>    pandoc 2.9.2.1
>    edd using rob:~$
> 
> Can we expect CRAN to update its pandoc binary? Or will we have to 'for now'
> rely on 'reply-all', explaining to CRAN that the failure is from their end?
> 
> As they in the press, I had reached out to CRAN but they 'have not yet
> responded to requests for comments' as we know they're busy. Anybody seen
> this error though?

I haven't seen that one, but I regularly get errors in rgl and tables 
because of missing or insufficient pandoc on some systems.  I added 
lines like

   SystemRequirements:  pandoc (>= 1.12.3) for vignettes

to DESCRIPTION to state the Pandoc version, added rmarkdown to the 
Suggests list, and added code like this to the start of HTML vignettes:

```{r echo = FALSE}
if (!requireNamespace("rmarkdown") || 
!rmarkdown::pandoc_available("1.12.3")) {
   warning("This vignette requires pandoc version 1.12.3; code will not 
run in older versions.")
   knitr::opts_chunk$set(eval = FALSE)
}
```

This makes the test happy, though it also makes the vignette pretty 
useless on systems that don't meet the stated requirements.  Since 
SystemRequirements is free-form, I can see why CRAN doesn't do automatic 
interpretation of it, but it would be nice if they did.

Duncan Murdoch