Re: [Haskell-cafe] [Cabal-devel] Cabal license combinations
Chris Smith cdsm...@gmail.com writes: actually matter. The instant anyone actually compiles an application that uses your library, however indirectly, they are bound by the terms There are other uses for code than compilation. Let's say I wrote a wrapper for a proprietary library that connects to Oracle databases. Any program using this would likely be undistributable. Still, having the wrapper free would allow porting it to a free database back end or using it for teaching, so there's always added value in added freedom. So this may be a problem for distributions, which ship compiled and linked binaries. But generally not for authors, darcs repositories or Hackage, which only ship source code. Of course it is a concern for authors! I don't think you are contradicting me here. My point is that authors are not likely to be liable or bound by other's licenses - whether they are concerned or not, is up to them. The reasonable expectation in Haskell is that they'll probably statically link; and you should read licenses of your dependencies, and carefully choose dependencies, accordingly. I think usability goes way beyond redistributability, but I guess we should just agree to disagree on this. IMO, the important thing is that cabal avoids imposing legal straightjackets on authors, and that it avoids making legal interpretations. Echoing facts from cabal files is okay, but drawing legal conclusions based on these facts should be the responsibility (i.e. both obligation and liability) of the individual user. -k -- If I haven't seen further, it is by standing in the footprints of giants ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [Cabal-devel] Cabal license combinations
Dan Knapp dan...@gmail.com writes: There is a legal distinction between static and dynamic linking, Well, the obvious distinction is that a dynamically linked executable doesn't actually contain any code from its libraries, while a statically linked one does. In particular, they assert that you are legally creating a derived work if you statically link with their library, and that your library, even if it's just a thin bindings wrapper, must therefore comply by their license terms. I disagree - the linked executable must, but not the wrapper by itself. It's source code, i.e. text, thus a creative work, and therefore covered by copyright - on its own. Of course, Haskell on most platforms and default configurations links everything statically! So this may be a problem for distributions, which ship compiled and linked binaries. But generally not for authors, darcs repositories or Hackage, which only ship source code. I guess you could conceivably say that compiling downloaded source code constitutes copying, and is thus limited under copyright. But I think all the relevant licenses would be considered to allow this. So I believe this means that you have to comply by the licenses of all your dependencies! If, and only if, you wish to distribute the final executable. I think it would be a very useful and valuable thing for Cabal to detect this situation and warn appropriately! Yes. At least, it'd be nice if Cabal would tell you about the licenses involved. But I'd let people do their own interpretations, that's too much of a minefield. -k -- If I haven't seen further, it is by standing in the footprints of giants ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [Cabal-devel] Cabal license combinations
On 9 February 2011 23:35, Dan Knapp dan...@gmail.com wrote: [SNIP] I believe this means that if we have a package named hs-save-the-whales that is under the GPL, and a front-end package hs-redeem-them-for-valuable-cash-prizes which makes use of the functionality in hs-save-the-whales, the front-end MUST be offered under the GPL, and, additionally, CANNOT be offered under BSD (I think). If you incorporate GPL code into a binary you want to distribute you have to comply with the GPL. Static linking a GPL library will incorporate GPL code into your binary, ergo you have to comply with the GPL. If you write a client of a GPL library and you want to distribute it, your client can be any GPL compatible license - it does not have to be GPL. Should you distribute a compiled binary you have to comply with the GPL and any additional terms brought in by your GPL-compatible license. Its that simple - until there is a court ruling to decide otherwise. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [Cabal-devel] Cabal license combinations
On Wed, 2011-02-09 at 18:35 -0500, Dan Knapp wrote:
I haven't heard anyone mention this yet, and it's a biggie, so I
guess I'd better de-lurk and explain it. The issue is this: There is
a legal distinction between static and dynamic linking, or at least
some licenses (the GPL is the one I'm aware of) believe that there is.
In particular, they assert that you are legally creating a derived
work if you statically link with their library, and that your
library, even if it's just a thin bindings wrapper, must therefore
comply by their license terms. They make no such claim for dynamic
linking.
I think you're in danger of adding confusion rather than removing it.
The LGPL provides some alternative terms for dynamic linking but you
still must comply with the license.
Of course, Haskell on most platforms and default configurations
links everything statically! So I believe this means that you have to
comply by the licenses of all your dependencies!
You always have to do that.
Now, there's a difference between complying by those licenses and
being under them yourself, but for example I believe this means that
if we have a package named hs-save-the-whales that is under the GPL,
and a front-end package hs-redeem-them-for-valuable-cash-prizes
which makes use of the functionality in hs-save-the-whales, the
front-end MUST be offered under the GPL, and, additionally, CANNOT be
offered under BSD (I think).
No, that is wrong. There is no difference between GPL code depending on
BSD code and BSD code depending on GPL code. The direction of the
dependency is irrelevant. In both cases the end user/distributor must
comply with both licenses.
I think it would be a very useful and valuable thing for Cabal to
detect this situation and warn appropriately! Contamination by
undesired licenses is a serious flaw in the packaging of a package; it
just happens to be a legal flaw rather than a technical one. Indeed,
I would argue that this is far more important than any hypothetical
per-file licensing.
We are already working on a feature that will show the full set of
licenses that the end user must comply with (a patch has been submitted
and it's been through one round of review so far). In your example that
would mean you expect the set to be {BSD} but the tool will show you
that it is in fact {BSD, GPL}. You can then use that as your warning
that the set of licenses is not what you expected.
The tool will not claim that {BSD, GPL} is wrong, because it isn't! What
is wrong is expectations not matching reality, and hopefully that's what
the tool can help with.
Duncan
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Re: [Haskell-cafe] [Cabal-devel] Cabal license combinations
On 10.02.11 12:12, Duncan Coutts wrote:
We are already working on a feature that will show the full set of
licenses that the end user must comply with (a patch has been submitted
and it's been through one round of review so far). In your example that
would mean you expect the set to be {BSD} but the tool will show you
that it is in fact {BSD, GPL}. You can then use that as your warning
that the set of licenses is not what you expected.
that would be quite useful for those who want to distribute executables!
may i also suggest the following feature: collect all the copyright notices and
license files from each dependency (many licenses require those to be displayed
and distributed along with the executable) and optionally bundle them with the
applicaton's data-files? i briefly looked into this, but couldn't find a way to
retrieve the installed License-File from ~/.cabal using Cabal. doing this by
hand turns out to be quite tedious when there are many dependencies ...
sk
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Re: [Haskell-cafe] [Cabal-devel] Cabal license combinations
On Thu, 2011-02-10 at 12:44 +0100, Stefan Kersten wrote:
On 10.02.11 12:12, Duncan Coutts wrote:
We are already working on a feature that will show the full set of
licenses that the end user must comply with (a patch has been submitted
and it's been through one round of review so far). In your example that
would mean you expect the set to be {BSD} but the tool will show you
that it is in fact {BSD, GPL}. You can then use that as your warning
that the set of licenses is not what you expected.
that would be quite useful for those who want to distribute executables!
may i also suggest the following feature: collect all the copyright notices
and
license files from each dependency (many licenses require those to be
displayed
and distributed along with the executable) and optionally bundle them with the
applicaton's data-files? i briefly looked into this, but couldn't find a way
to
retrieve the installed License-File from ~/.cabal using Cabal. doing this by
hand turns out to be quite tedious when there are many dependencies ...
Right, that feature was also in the patch. From experience I know that
this would indeed be very useful (I've also had to do it manually).
Duncan
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Re: [Haskell-cafe] [Cabal-devel] Cabal license combinations
On Thu, 2011-02-10 at 08:59 +0100, Ketil Malde wrote: I disagree - the linked executable must, but not the wrapper by itself. It's source code, i.e. text, thus a creative work, and therefore covered by copyright - on its own. You're certainly right from a legal standpoint. But being right doesn't actually matter. The instant anyone actually compiles an application that uses your library, however indirectly, they are bound by the terms of the underlying library as well. So your bindings are effectively covered by the underlying license anyway (unless you're choosing a license for the sake of people who will never produce any usable end result...) Sure you could attach yet another license; but unless you deliberately intend to be even more restrictive, there's no reason whatsoever to license the thin bindings layer differently from the library it is binding to. Doing so would just be potentially misleading people about the licenses they need to comply with, especially when the bindings are to libraries that are not packaged with Cabal and do not have a uniform place to record their license terms. So this may be a problem for distributions, which ship compiled and linked binaries. But generally not for authors, darcs repositories or Hackage, which only ship source code. Of course it is a concern for authors! Do you really think authors write libraries, and then just don't care whether potential users can actually use them? If you don't expect anyone to ever link a program, even indirectly, against your library, then you probably shouldn't have bothered distributing it; but if you do expect that, then you typically make choices when developing an application based on what rights you want *those* people to have. The reasonable expectation in Haskell is that they'll probably statically link; and you should read licenses of your dependencies, and carefully choose dependencies, accordingly. -- Chris Smith ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [Cabal-devel] Cabal license combinations
On Thu, Feb 10, 2011 at 10:04 AM, Chris Smith cdsm...@gmail.com wrote: On Thu, 2011-02-10 at 08:59 +0100, Ketil Malde wrote: I disagree - the linked executable must, but not the wrapper by itself. It's source code, i.e. text, thus a creative work, and therefore covered by copyright - on its own. You're certainly right from a legal standpoint. But being right doesn't actually matter. The instant anyone actually compiles an application that uses your library, however indirectly, they are bound by the terms of the underlying library as well. So your bindings are effectively covered by the underlying license anyway (unless you're choosing a license for the sake of people who will never produce any usable end result...) The vast majority of Open Source licenses in use only restrict the publication of the work or derived works, not compilation. So no, the instant of compilation is not when the transitive dependencies kick in, it is the publication of compiled binaries, which in my mind is a pretty specialized case. Antoine ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] [Cabal-devel] Cabal license combinations
On 10 Feb 2011, at 17:38, Antoine Latter wrote: So no, the instant of compilation is not when the transitive dependencies kick in, it is the publication of compiled binaries, which in my mind is a pretty specialized case. This is possibly the most important point to emphasise, of which many people seem unaware. If you expect to receive an open source application from someone else as source code, and build it yourself, then almost by the definition of Open Source, you are already in compliance with all licences. It is only those, comparatively few, people who build binaries and give them to other people *as binaries* who even need to think about licensing issues. Regards, Malcolm ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
