[Rd] Implications of a Dependency on a GPLed Package

[Matthew Dowle]

Christian,

In my mind, rightly or wrongly, it boils down to these four points :

1. CRAN policy excludes closed source packages; i.e., every single 
package on CRAN includes its C code, if any. If an R package included a 
.dll or .so which linked at C level to R, and that was being distributed 
without providing the source, then that would be a clear breach of R's 
GPL. But nobody is aware of any such package. Anyone who is aware of 
that should let the R Foundation know. Whether or not the GPL applies to 
R only interpreted code (by definition you cannot "close-source" 
interpreted code) is important too, but not as important as distribution 
of closed source binaries linking to R at C level.

2. Court cases would never happen unless two lawyers disagreed. Even 
then two judges can disagree (otherwise appeals would never be 
successful).

3. There are two presidents of the R Foundation. And it appears they 
disagree. Therefore it appears very unlikely that the R Foundation would 
bring a GPL case against anyone. Rather, it seems to be up to the 
community to decide for themselves. If you don't mind about close source 
non free software linking to R at C level then buy it (if that exists), 
if you don't, don't.

4. As a package author it is entirely up to you how to approach this 
area. Yes, seek legal advice. And I'd suggest seeking the advice of 
several lawyers, not just one. Then follow the advice that you like the 
best.

Matthew