The TeX Live inclusion policy

TeX Live takes almost all of the material it includes from CTAN, but not everything that goes to CTAN gets into TeX Live. That’s because CTAN will take anything TeX-related, but TeX Live is ‘free as in speech’ and that means that some things are not suitable for inclusion.

Packages are removed from time to time license reasons: they are not actually free, so can’t stay. However,  a few packages have been removed from TeX Live they did not fit in with the policy for inclusion in TeX Live for other reasons. That has caused a bit more surprise, and some questions have come up about it.So I thought it would be useful to summarise the TeX Live situation as I understand it.

The clearest case is material where the license is not ‘free’ (as defined by Debian): anything without a free license cannot go into TeX Live. Perhaps the next clearest case is support for commercial fonts. To use a font with pdfLaTeX, it’s necessary to have the correct support files. Quite often, these are sent to CTAN with a free license, but don’t go into TeX Live. Without the fonts themselves you can’t use the support material, so it’s only practically useful if you are happy to buy the non-free fonts.

Life is more complicated in the cases that have come up recently, where things are less clear cut. AS many readers will know, the PDF specification is nowadays an ISO standard, and there are several PDF viewer implementations with free licenses. However, there are two caveats to this. First, Adobe have published extensions to the ISO version of the PDF specification. Secondly, creating a PDF viewer does not mean that every possible PDF feature is implemented. Why is this relevant to TeX Live? Well, there are several packages on CTAN, for example media9, which use PDF features which are either not part of the ISO standard PDF specification or which are only available in Adobe Reader. These have been removed from TeX Live as the conclusion is that they only have real functionality along with a non-free product. (There seems to be some confusion as to whether any of the free viewers may support at least some of the necessary PDF features: I can’t find a definite answer.)

That judgement is complicated: this case is not the same as the font situation. The PDFs produced by for example media9 are still viewable with free readers, they just don’t have all of the bells and whistles available. It’s also the case that if we look back in time a little, PDFs were only viewable using Adobe Reader, but that did not stop the development of  pdfTeX, hyperref and so on. On the other hand, the TeX Live developers already do a great deal of hard work, and it’s not unreasonable for them to set a policy that they are comfortable with: after all, it’s a labour of love. I think that the policy is reasonably clear, although tracking what is practically implemented, as opposed to what is legally allowed, is rather likely to change over time.

 

11 thoughts on “The TeX Live inclusion policy

  1. As I already wrote in the mentioned thread I really don’t understand the decision to remove media9. Not that it will actually have a big impact, I just think that the reasoning behind is really strange.

    Fact is that most people who use (La)TeX to produce a document for print will, at one point or another, use a commercial product . To insist on a some kind of hypothetical workflow completely based on free tools is out of touch with reality IMO (there’s also a very basic logical inconsistency here: I will always need a commercial, non-free software to run the Mac and Windows binary which are part of TL).

    Of course, in the end it’s the maintainers who decide, but I also don’t understand why they would adopt a policy which actually increases their work since, as you write, they now have to track what can and can’t be done with free tools.

    I simply don’t see any positive effect coming from such a policy – neither for the users nor for the maintainers, neither on a practical level nor on some principle. What can actually be gained from such a policy?

  2. I’d agree that having a policy based on what is implemented is more work than one based on what is technically possible or legally allowed (both of which change only slowly). As I’ve indicated, actually getting a clear answer on what is and is not implemented in free PDF viwers is not so easy!

    I guess that many of the TeX Live developers do have workflows that are ‘free-only’, which does not necessarily fit in with the situation for users.

  3. Obviously, the focus of TeX Live is not Windows, but rather Linux (Debian). Thus, I can’t see a logical inconsistency in the TeX Live policy. It’s simply necessary.

  4. TeX Live is not focussed just on Debian, or even just on Linux: as they say on their website ‘[TeX Live] provides a comprehensive TeX system with binaries for most flavors of Unix, including GNU/Linux, and also Windows’.

    I’m also not quite sure what you mean by ‘It’s simply necessary’, as the TeX Live licensing page says ‘the material in TeX Live should not require nonfree software to be useful’, an additional statement beyond those related to licensing.

  5. Thanks for a mostly correct post :).

    1. We don’t follow Debian guidelines. We follow GNU guidelines. But even there, I don’t promise to blindly follow every decision by rms. See tug.org/texlive/copying.html.

    2. In the event that PDF movies were not implemented by a free reader, media9 *is* the same case as free support for proprietary fonts. The package would have no purpose except to be used with nonfree software.

    3. However, happily, James Cloos pointed out that apparently some kind of movie support has been implemented in poppler(?) or at least okular. See the latest msgs in the thread. Therefore I will be restoring the PDF movie packages soon.

    4. As for why we do any of this (Simon’s question) — well, we simply have a philosophical/moral/ethical belief in free software. There’s no use in debating it here. I’m well aware most of the people in the world don’t, and they are welcome to do as they please.

    karl

  6. Thanks for the reply. I leave the difference between Debian and FSF ‘free’ to the legal experts!

    The reason I see the font case differently from the movie one is that the the font support material requires commercial material that can’t be reimplemented (as font metrics never match exactly, even for ‘clones’). On the other hand, there is as I understand it no restriction on implementing movie support in a free PDF viewer: it’s purely a question of someone doing it. So the latter case can be altered by ‘free’ programmers, but the former one cannot. I of course realise that this is a philosophical point!

    I’m please to here that the movie packages will return. Have you actually pinned down a free PDF viewer that can do this (as in ‘seen it work’)?

  7. @Karl: If that moral believe is the overall guiding principle of TL, I really don’t understand how the Win and Mac distributions come into play. Something just doesn’t add up here.

  8. @Lars: You definitely need non-free software to run the Win and Mac binaries. Therefore these binaries are a clear violation of this guiding principle.

    Obviously, I’m not saying there shouldn’t be distributions for Mac and Win. It just seems to me that the interpretation of what Karl calls “philosophical/moral/ethical belief in free software” is somewhat arbitrary and, as is my impression from the discussion, primarily directed against Adobe.

  9. @Simon: The fact that you can use TeX Live without any non-free software does not imply that this has to be possible on any operating system.

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