[Rd] Accessing data files w/ --use-zip-data

[Jeff Gentry]

I have encountered an issue while preparing some of the Bioconductor
packages for our upcoming release, and Duncan Murdoch suggested that I
bring one of the related points up here.

The background is that we are building our packages under Windows with
"Rcmd install --build" which will flag the zip options.  When the total
size of files in <pkg>\data are over a certain threshold of size (100k
IIRC) the will be zipped in a file named Rdata.zip to save space.  So far,
so good.

The problem arose in that at least one of the packages in the BioC suite
is directly acccessing files in the data directory and not going through
the data() command or related functions - and in this case the package
authors are doing it in .First.lib() which causes the package loading to
fail.

The issue that Duncan suggested I raise is whether or not it should be
considered accepted behaviour for a package author to be accessing files
in <pkg>\data (at this time I don't know the reasoning behind the specific
example here, I just know that that's what they've done) or if this should
be considered a Bad Thing.

Thanks
-Jeff