[R-pkg-devel] Problem persists, was Re: Problem compressing vignettes for CRAN

On Sun, 8 Oct 2023 16:47:41 +0100

Following on from Ivan's advice I have now installed qpdf and
Ghostview. I have checked that they are both on my path by typing
their name at the command line and verifying they open.

I then built the package with the --compress-vignettes=both and then
checked it with --as-cran I still get a complaint that it needs qpdf
to check compression.

While running R, does Sys.which('qpdf') return the path to qpdf.exe?
Does Sys.getenv('PATH') match your expectations?

I notice that in the Writing R Extensions manual in section 1.6.1 it
states "The full path to the qpdf command can be supplied as
environment variable R_QPDF ..."

Is that a typo for "must be supplied"?

Well, R tries to resolve the path to qpdf.exe using Sys.which(), so it
must work if it's on the %PATH%, but if all else fails, setting this
environment variable should help.

If it is where can I find the answers to questions about how R
accepts Windows paths? Do I need to enclose parts of names containing
spaces in "" signs?

It always depends on how the final command line is built by a
particular function, but it should work by taking plain file paths
without any escaping and quotation. The directory separators shouldn't
matter either.

(tools::compactPDF uses system2(), so it quotes the path to the
executable by itself.)

Does it mean the path up to, in this case, bin or must I include
qpdf.exe after it?

It must be the full path to the executable, including the final
qpdf.exe.

I assume I do not need to do anything special to get it to find
Ghostscript?

tools::compactPDF() expects gswin64c.exe or gswin32c.exe on the PATH.
If it's not there, R_GSCMD must be set to the full path to the
executable. Judging by the NOTE you've received, it's Ghostscript that
performed most of the compaction in your case.

Best regards,
Ivan