[R-pkg-devel] Appropriate usage of 'Suggests' -- package installed conditional on other software not found
Hi Dirk,
On Oct 3, 2019, at 10:20 AM, Dirk Eddelbuettel <edd at debian.org> wrote:
Hi John,
On 3 October 2019 at 13:56, Fox, John wrote:
| > On Oct 3, 2019, at 9:11 AM, Dirk Eddelbuettel <edd at debian.org> wrote:
| > On 3 October 2019 at 10:10, Driver, Charles wrote:
| > | I have a function that outputs / compiles some latex. To do this I use Sys.which('pdflatex') and if nothing is found, prompt the user whether to install tinytex package. So, normally I understand the use of 'Suggests' in the package description to be for when there are only certain functions / tests that require the package. In this case, the package requirement is also conditional on other software (ie a tex distribution) not being found, otherwise it is unnecessary. There are no tests or examples that depend on the package. Should tinytex be in the 'Suggests' list?
| >
| > A few suggestions:
| >
| > - IIRC CRAN Policy asks you to not have interactive prompts, and clearly
| > prohibits messing with the system. So no to the prompt to install.
|
| Can you point to where in the CRAN policies this behaviour is prohibited?
Well I hedged my bet with "IIRC".
Yes, I noticed that, but didn't want people to be potentially misled since you didn't "RC" ;)
Interactive prompts are neither explicitly allowed, nor disallowed, but the larger paragraph you quote from gives some hints. Now, turning from the 'letter of the law' to the 'spirit of the law', how many packages have you checked in the 25+ years of using R?
As it turns out, a lot, but I'm sure vastly fewer than you. The car package, e.g., has many reverse dependencies that I check before a new version of the package goes to CRAN.
How often would you have wanted an interactive prompt?
Well, never of course, but shouldn't interactive prompts only appear in interactive sessions -- e.g., enclosed in if (interactive()) {} in an example?
Moreover, I wasn't trying to argue that one *should* necessarily do this, just point out that one can in certain circumstances without violating CRAN policies. In the original context of this thread, a simple error message indicating that LaTeX is absent probably would suffice.
Best,
John
I just ran reverse depends for both Rcpp and RcppArmadillo in the last 48 hours so that is 2000+ packages -- and I am rather glad I didn't face prompts for any one of those 2000+. | The closest I can see is: "Packages should not write in the user?s home filespace (including clipboards), nor anywhere else on the file system apart from the R session?s temporary directory ... " But then, "Limited exceptions may be allowed in interactive sessions if the package obtains confirmation from the user." | | Moreover, the tinytex package does precisely these kinds of things, including installing LaTeX. And tinytex is something I keep finding problematic as it creates an obfuscation layer. There was a recent (purely latex-side) bug I fixed in one of my packages after an alert from CRAN. But the additional tinytex layer made the latex-side error incomprehensible to misleading to the point where the CRAN maintainer was mislead (as I was later). Running plain tex is better. I so wish tinytex would let me opt out and render directly via tools::texi2pdf but sadly I have no such option. I understand that tinytex seems to help on some platforms without working infrastruture; I have always had working (and extensible) texlive around due to the OS/distro I use. Anyway, this is going off-topic. It might be nice for R to offer a query whether 'is tex available?' just how capabilities() and extSoftVersion() gives hint on some other optional capabilities (which are arguably closer to its core). Dirk -- http://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org