[R-pkg-devel] R-devel warning: You used a knitr feature that depends on the digest package.

[Dirk Eddelbuettel]

On 7 February 2018 at 15:03, luke-tierney at uiowa.edu wrote:
| The problem is that this is an indirect dependency with knitr needing
| digest and codetools to implement a feature (cacheing) that is being
| asked for. And there is no obvious way (to me at least) of finding out
| that these are needed for this feature. If knitr marked these as
| Depends rather than Suggests there would be no problem. Depends seems
| more in line with the extensions manual that Suggests in this case.

There are more examples.  A vignette of mine used a popular plotting package
and some its standard examples -- which deploy mgcv::gam() to smooth, and of
course without testing if mgcv was available.  Which promptly blows up in a
stringent CRAN test of vignette dependencies.

Something used _unconditionally_ is not a Suggests.

Dirk

-- 
http://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org