Python SURFEX software license check

Checked with Lourens Veen. Question and response are copied below. Bottom line is, we're free to proceed as usual, but have to pay attention to providing modifications of SURFEX under the CECILL-C license.

Regarding the python scripts, requesting the author to place these under a CECILL-C license seems the best solution.

Response################### Hi Meiert and Ou,

Yes, the CeCILL licenses are a set of open source/free software licenses made in France.

The background is that some large organisations there liked the idea of Free software, but didn't like the existing ((L)GPLv2 at the time) licenses because their wording is based on US law. The Anglosaxon legal tradition differs from the continental European one in various respects (in particular here European "author's rights" vs. Anglosaxon "copyright" and differences in consumer protection law that affect the warranty disclaimer). So they basically made their own versions of the GPL, LGPL and a permissive license, worded to match French law, and explicitly governed by it.

The Free Software Foundation, when it made the GPLv3 and the LGPLv3, talked to very many lawyers and even non-lawyers around the world to get their feedback on aspects related to international law, and that was included into the GPLv3. So to some extent, these licenses (and also the EU Public Licenses, which are similar but Italian) are now obsolete, because the (L)GPL has been internationalised.

Of course, once you have them, you'll never get rid of them, so here we are 🙂. CeCILL-C is a weak copyleft license like the LGPL and the MPL, which we are fine with to have as a dependency. Your interpretation of it is entirely correct, and it's our policy to license our own work under the Apache License 2.0 (which you can do here), and to contribute to existing projects under their existing license (which matches your point 2.), so you're all good to go.

Good luck with the project!

Best,

Lourens

Question############################ Hi Lourens,

Here I am again with another license question =). In the vegetation water dynamics project we are working together with partners from TUDelft making use of the established SURFEX modelling and data assimilation framework (developed by Meteo-France and the scientific community). Surfex has been licensed (the exceptions mentioned are not used within the project) and is available under a CECILL-C license, apparently a French equivalent of the L-GPL license (although it isn’t clear to me which version of L-GPL).

I just wanted to briefly check 2 things with you:

If my understanding is correct, the project can make use of the unmodified software freely, specifically also including it in derivative software provided under a different license (e.g. Apache 2.0), provided the SURFEX component is provided under the CECILL-C license.

If we end up wanting/needing to modify (parts of) the SURFEX software, the modified components must be made available under the CECILL-C license. Any derivative software can again be licensed under a different license provided the (modified) SURFEX component is made available under the CECILL-C license.

Could you please confirm or correct my/our interpretation at your earliest convenience?

Thanks in advance, Meiert

NLeSC / team-atlas

Python SURFEX software license check #270