[Rd] Copyright versus Licenses

[Bryan McLellan]

My company recently started using a R library from RCRAN that is
licensed under the LGPL Version 2 or greater per the DESCRIPTION file,
but contains no copy of the LGPL notice, or any copyright notice. I've
grown accustomed to paying attention to copyright and licensing as a
Debian package maintainer, and sent the author of the package an email
expressing my concern. The author believed that assigning themselves
copyright was incompatible with licensing the library under the terms
of the LGPL. I disagree, and further contend that without copyright
notice, the [copyright] license loses a certain degree of
applicability, as it becomes inconclusive as to who is licensing the
software under the terms of the LGPL. Not knowing who I was, the
library author asked me to start a discussion of the subject on this
list, presumably so they could see the opinions of others that they
trust.

The LGPL itself [1], in the final section entitled "How to Apply These
Terms to Your New Libraries", the license provides a template for
adding to the top of each source code file that contains a copyright
line, a general notice regarding the lack of warranty, and information
on where to obtain a full copy of the license. The GPL HOWTO [2]
expresses similar instructions for the inclusion of a copyright line
with the license. I know that R distributes copies of common licenses
under 'share/licenses' in the R source. Debian does as well in
'/usr/share/common-licenses/' for the purpose of not having to include
the full LICENSE and/or COPYING file with every package that uses a
common open source license, allowing the use of verbage such as "The
Debian packaging is © 2010 [author] and is licensed under the Apache
License version 2.0. On debian and derived systems, see
`/usr/share/common-licenses/Apache-2.0' for the complete text." The R
manual for writing extensions suggests a similar approach to avoiding
duplication in Section 1.1 [3].

The R manual for writing extensions also mentions [4] in Section 1.1.1
the optional use of a Copyright field in the DESCRIPTION file,
separate from the License field. As this section implies that the
DESCRIPTION file format is based on the debian control file format, I
assume the goal is to keep these lines simple, generally under 80
characters do to average terminal width. As such, I don't assume this
field is recommended for complete copyright information for a library
with multiple contributors. The aforementioned article does not
specify where a developer should alternately put copyright
information, perhaps assuming one would add it to each source code
file as is recommended by GNU.

In closing, do the R developers believe that including a Copyright
notice is imperative with a Copyright License?

If so, what advice do they have for those writing and contributing
open source R libraries as to where this notice should go?

Should that information perhaps be added to the R manual for extensions?

Bryan McLellan

[1] http://www.gnu.org/licenses/lgpl-2.1.txt
[2] http://www.gnu.org/licenses/gpl-howto.html
[3] http://cran.r-project.org/doc/manuals/R-exts.html#Package-structure
[4] http://cran.r-project.org/doc/manuals/R-exts.html#The-DESCRIPTION-file