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Perhaps this is an esoteric question, since I will never distribute the code in question and I can fairly easily avoid using GPL code, but I'm curious and it's bugging me--but not enough to consult a lawyer. What is more, I think I am more interested in the morality of this issue than the legality.

I have a program that I use under the CDDL. The program had a pretty small user base to start with and the creators now offer a later version, which is closed source. Thus I have no interest in contributing my minor modification back to the project. For my use only, I would like to include a single module that is GPL to avoid a small amount of tedious coding.

If I were to distribute the result, it is clearly a violation of the terms per various sources such as the FSF's comments on GNU GPL and CDDL.

If I have correctly tracked the source of the incompatibility back to the MPL from the link from wikipedia, all of the issues seem to arise with clauses that occur with distribution. This would imply to me that I can legally modify and combine GPL and CDDL, but cannot legally distribute the combination.

Setting aside the legality, does anyone see any moral issues with making a minor tweak to a program for my own use that introduces this incompatibility for distribution?

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Talking to my wife, I realized this topic is not esoteric as many people do not distribute server-side software and may combine licenses. Presumably they consult lawyers... – sage Jun 17 '11 at 1:18

I think that if you don't distribute, then the whole thing is moot.

If your patch is indeed small, and you would like to share it with the community but don't want to hassle with conflicting licenses, you might consider just declaring it Public Domain and be done with it. Yes, the closed-sourcers may grab it and use it, but that's just negative karma for them.

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You could also use a BSD license - that makes anyone who uses it give you credit and include your copyright notice. – Demetri Dec 18 '13 at 23:45

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