OK; I've been chewing and debating on this with several folks, in
several fora, for some time. Here are the facts as I've been able to
determine them so far; at least some of them will be stupidly obvious
to most of you. Please tear them apart as indicated.
+ The R community is much sysadmin-y and progammer-y than other
language communities. Several positions about correctness which
lots of admins take as Truth (i.e. dependency cycle == BAD) they
find to be more of an aesthetic call. This is reasonable.
+ Different repositories in the R community have independant lives and
attitudes. There is modest competition and grumbling between
maintainers associated with different repos.
+ Package dependencies cross repo boundaries; sticking with the
'Better' repositories just won't work, and discussion of these
variations tends to make R folks testy.
conclusion: The goal of evolving the R packages into a DAG is a
+ There are four classes of dependency in R-package land: Requires,
Imports, Suggests, and Enhances.
+ Requires and Imports are required to load the package. 
+ Suggests may be required to fully CMD CHECK the package 
+ The need for suggests at CMD CHECK can be deactivated by build
config file. 
+ Many of the dependency cycles can be avoided if we ignore Suggests
as an RPM dependency.
Now, on to opinion:
+ We would like all official packages to have passed a full R CMD CHECK
+ We would like an absolute minimum of manual special case handling.
It may not be possible to make that amount zero.
So: Here's my suggested procedure for building any single package,
gangked from a message I sent to R-core:
1) Express binary package dependencies according to Depends and Imports.
I'll call this the 'narrow dependency graph'.
2) As part of the binary package build process, run CHECK
with R_CHECK_FORCE_SUGGESTS = false.
I'll pull nomenclature out of my ear and call these "built" but not
3) Build all binary packages which are downstream according to all of
Depends, Imports, Suggests, and Extends. I'll call this the 'broad
4) Install all the packages in the broad dependency graph.
5) for each package in the broad graph, run CHECK with
Then the affected packages are "checked". Perhaps this can be noted
with a signature.
- Allen S. Rout