Open Source Licensing: Software Freedom and Intellectual Property Law

There is a very important explicit exception to the CPL's reciprocity obligation:

Contributions do not include additions to the Program which: (i) are separate modules of software distributed in conjunction with the Program under their own license agreement, and (ii) are not derivative works of the Program. ( CPL section 1.)

Does this have the same effect as the GPL? Instead of the ambiguous language of the GPL and LGPL that causes so much uncertainty about linking, the CPL offers two simple tests for exclusion from reciprocity. Both must be true:

1. The Contribution must be a separate module of software . The term separate module of software is not defined in the CPL. (Neither, you will recall, was the word file defined in the MPL.) As with other important concepts in any technical field, separate module of software is a term of art in the field of computer engineering that will be defined by experts when a judge or jury needs to do so during litigation. I'm sure most readers of this book will find the concept of a separate module of software fairly self-evident and will know what steps to take to ensure that engineers avoid creating Contributions that are subject to reciprocity.

2. A Contribution must not be a derivative work . This explicit statement in the CPL, of course, is the same conclusion I drew when I discussed linking in the GPL and LGPL. Does avoiding reciprocity always boil down to avoiding the creation of a derivative work?

Anyone can get around the reciprocity obligation of the CPL by both (1) creating a separate module of software and (2) making sure that separate module of software isn't a derivative work .

As I will describe in Chapter 9, the OSL and AFL licenses do not include the first element of this exclusion from reciprocity. The MPL's concept of files and the CPL's concept of separate module of software are not included in the OSL and AFL. All one must do to avoid reciprocity is to avoid creating a derivative work.

Of course, that is not nearly so simple a change as I make it seem. I defer until Chapter 12 the technical discussion about how courts determine whether derivative works have been created.