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

[luke-tierney at uiowa.edu]

On Wed, 7 Feb 2018, Martin Maechler wrote:

>>>>>> Gábor Csárdi <csardi.gabor at gmail.com>
>>>>>>     on Tue, 6 Feb 2018 19:26:55 -0800 writes:
>
>    > codetools is a recommended package, and it is part of most R
>    > installations. builder.r-hub.io is a bit more strict, it does have the
>    > recommended packages, on some builders at least, so codetools might be
>    > missing.
>
>    > Gabor
>
> hmm... but a package maintainer has to also add recommended
> packages to 'Suggests' if they are needed in the vignette (e.g.)
>
>
>    > On Tue, Feb 6, 2018 at 7:22 PM, David Scott <d.scott at auckland.ac.nz> wrote:
>    >> On a package I help maintain, we had a note from Kurt about a warning when
>    >> building vignettes on R-devel.
>    >>
>    >> It was
>    >>
>    >> Warning: You used a knitr feature that depends on the digest package.
>    >>
>    >> Checking the location of the error and googling it, I am pretty certain it
>    >> comes from cache = true for a chunk in the vignette.
>    >>
>    >> Adding digest as suggested package, I got no warning from winbuilder using
>    >> R-devel, but submitting to https://builder.r-hub.io gave me a new warning
>    >> from codetools at the same location as previously. Like digest, codetools is
>    >> suggested by knitr.
>

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.

Best,

luke

> well, but  "suggests of suggests are not suggests":
> If your vignette really needs codetools you (your package
> DESCRIPTION) need to suggest it yourself.
>
>    >> Any advice? One thought is just take off cache = true.
>
> well, yes ;-) ..
> Seriously, of course rather fix the problem, which must be
> fixable relatively easily.
>
> Martin
>
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-- 
Luke Tierney
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
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