We are writing on behalf of the R Foundation, to clarify our position on
the licenses under which developers may distribute R packages.
Readers should also see FAQ 2.11: this message is not legal advice,
which we never offer. Readers should also be aware that besides
the R Foundation, R has many other copyright holders, listed in the
copyright notices in the source. Each of those copyright holders may
have a different opinion on the issues discussed here.
We welcome packages that extend the capabilities of R, and believe
that their value to the community is increased if they can be offered
with open-source licenses. At the same time, we have no desire to
discourage other license forms that developers feel are required. Of
course, such licenses as well as the contents of the package and the
way in which it is distributed must respect the rights of the copyright
holders and the terms of the R license.
When we think that a package is in violation of these rights, we
contact the author directly, and so far package authors have always agreed to
comply with our license (or convinced us that they are already in compliance).
We have no desire to be involved in legal actions---our interest is in providing
good software. However, everyone should understand that there are conceivable
circumstances in which we would be obliged to take action. Our experience to
date and the assurances of some fine commercial developers make us optimistic
that these circumstances will not arise.