Hi Ole: Thanks for getting in touch with us concerning the Debian packaging of PLplot. Andrew Ross (who at one time maintained Debian packaging of PLplot) is our only Debian packaging expert. But he has been inactive in PLplot development for a while now so it is likely our help to you will be limited to making upstream changes to minimize the number of patches you have to apply and also making upstream changes to straighten out any licensing uncertainties (see below).
On 2017-07-11 09:43+0200 Ole Streicher wrote:
The other point is already older, but a show-stopper: PLplot uses a few old libraries from Pavel Sakov (CSIRO Marine Research), in lib/csa and lib/nn. These libraries have a license that is not free (in the sense of the Debian Free Software Guidelines [3]), and they are incompatible to the LGPL of plplot. I already wrote an E-mail to the mail address given in the README to ask him for a license change, but I am not sure whether Pavel's address is still valid. There was already some discussion on Debian mailing lists about that topic 9 years ago [4], but I couldn't find a (follow-up) discussion on the plplot-devel mailing list. Was there any discussion, and what is your opinion about that license?
Your help with solving this licensing uncertainty (which I have not been too concerned about before due to historical reassurances from Rafael Laboissiere) would be much appreciated. When this topic first came up soon after we starting using stripped versions of Pavel's csa and nn libraries back in 2003 Rafael Laboissiere (who was a fanatic about free software licensing) contacted Pavel privately and afterward assured us the licensing issue was settled (I think by getting Pavel's OK to relicense our stripped version of his work under the LGPL, but I am by no means sure about that). However, after that reassurance Rafael never changed our lib/nn/README and lib/csa/README files to reflect whatever that 2003+ agreement with Pavel was. Therefore, I agree, the issue is at least formally still with us. And since then Rafael has completely dropped out of the Debian world and the free software world (including PLplot) after supporting both so strongly for so many years. So Rafael is no longer a good contact concerning this situation. Do you know how to extract e-mail contact information from github? If so, Pavel is active on github and apparently still working on the full versions of both nn and csa. (see <https://github.com/sakov?tab=overview&from=2017-05-01&to=2017-05-31&utf8=%E2%9C%93>) Apparently there is licensing text for the full modern versions of nn and csa at <https://github.com/sakov/nn-c/blob/master/nn/LICENSE> and <https://github.com/sakov/csa-c/blob/master/csa/LICENSE>. I am not a license lawyer, but the latter looks like a simple free software license to me. If you agree, and, better yet, if you can identify what free license it is (some form of BSD??), then it is likely it is license that you will be able to immediately identify as consistent with Debian's DFSG. In which case, it should be a simple matter regardless of whatever agreement he made with Rafael in 2003+ to convince Pavel to license our stripped version for both nn and csa that we adopted in 2003 under that same free software license. One minor complication is that the modern nn license text which is otherwise completely compatible with the modern csa license text has an additional note on the end as follows: Note: this software makes use of the Triangle software, which is non-free for commercial use. See the triangle.c and triangle.h files for details. Our own file, lib/nn/README refers to this same "triangle" issue in a different way. However, I don't think we have to be concerned about that issue in the slightest since our stripped version lib/nn contains no triangle.c or triangle.h and lib/nn/delaunay.c contains the following comment line // Adapted for use with Qhull instead of "triangle". which I traced back using git blame --follow to b583d184 (Joao Cardoso 2003-03-02 02:04:52 +0000 20) * Adapted for use with Qhull instead of "triangle" The associated commit message for b583d184 was Add a striped version of Pavel Sakov nn library to support Delaunay linear interpolation and Natural Neighbors interpolation for plgridata(). Note, although apparently Joao was smart enough to get rid of the dependence on "triangle", he has long since retired from the free software world so he is also not a good contact concerning this situation. In sum, I think to deal with this licensing issue, the following 4 steps are needed: 1. Identify the modern full csa licensing from the above text. In the following steps I assume you will be able to identify it as a well-known free software license that is already known to be compatible with the DFSG. 2. Find a modern e-mail address for Pavel (surely github provides that in some way, but I cannot find it). 3. Ask Pavel to allow us to relicense the stripped version of nn and csa that we adopted in 2003 (and which does not depend on the proprietary triangle software due to Joao's further modifications) with the free software license you have identified in the first step above. Alternatively, if it turns out the above modern licensing text for csa is not DFSG compatible, then ask Pavel to relicense our stripped version under the LGPL. Frankly, I would be surprised if he objected to either request, but to be clear I prefer the license above (if suitable) for our stripped version just to be consistent with the modern nn and csa licensing as much as possible (i.e., with the triangle note dropped). 4. Upstream change: Remove the misleading lib/nn/README and lib/csa/README files and replace those with lib/nn/LICENSE and lib/csa/LICENSE which are both consistent with the text in <https://github.com/sakov/csa-c/blob/master/csa/LICENSE> (or the LGPL if your research shows the above modern license is not DFSG compatible). If you are willing to deal with the first two of these issues I am willing to deal with the third and fourth, but if you would also like to follow through with the third as well (quoting any part of this e-mail you feel is relevant) that would be even more helpful! In sum, I am looking forward with your help to finishing the above steps to remove completely the licensing uncertainty for these two PLplot libraries. Alan __________________________ Alan W. Irwin Astronomical research affiliation with Department of Physics and Astronomy, University of Victoria (astrowww.phys.uvic.ca). Programming affiliations with the FreeEOS equation-of-state implementation for stellar interiors (freeeos.sf.net); the Time Ephemerides project (timeephem.sf.net); PLplot scientific plotting software package (plplot.sf.net); the libLASi project (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net); and the Linux Brochure Project (lbproject.sf.net). __________________________ Linux-powered Science __________________________ ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
