Licensing for cxx-kde-frameworks (Rust bridge for KF6)

[Neal Gompa]

On Sun, Nov 3, 2024 at 6:23 PM Darshan Phaldesai
<dev.darshanphaldesai at gmail.com> wrote:
>
> On 03/11/24 3:06 pm, Neal Gompa wrote:
>
> > On Sun, Nov 3, 2024 at 4:30 PM Darshan Phaldesai
> > <dev.darshanphaldesai at gmail.com> wrote:
> >> On 31/10/24 5:47 am, Sune Vuorela wrote:
> >>
> >>> On 2024-10-30, Darshan Phaldesai <dev.darshanphaldesai at gmail.com> wrote:
> >>>> Few considerations:
> >>>> First, I plan to include bridges for most libraries needed for
> >>>> application development and so need to consider their licenses as well.
> >>>> Second, This project will only hold the "bridge" code and thus users
> >>>> will still need to install the libraries. I don't think this should
> >>>> cause any license violations but the bridge code is based of the method
> >>>> signatures of the original libraries.
> >>>> Third, Upstream `cxx-qt` project uses Apache-2.0+MIT and I planned to do
> >>>> the same but KDE's Licensing policy doesn't mention any thing about
> >>>> Apache-2.0.
> >>> I'd say just stick the same license on it as the KDE Frameworks in
> >>> question.
> >>> Given they are a directly derived work and also uses the KDE Frameworks
> >>> underneath, giving any other license is just going to be confusing for
> >>> the people involved.
> >>>
> >>> The app developers needs to deal with (l)gpl licenses anyway.
> >>>
> >>> /Sune
> >> Now that I think about it, this might the best way to maintain license
> >> compatibility. Individual bridges can be licensed depending on their
> >> counterparts.
> >>
> >> I will make this change. Thank you.
> > It's not that simple. The reason I suggested MPL-2.0 is because
> > LGPL-2.1-or-later is effectively the same as GPL-2.0-or-later with
> > Rust because it's statically linked.
> >
> > MPL-2.0 preserves the copyleft at a per source file level, but allows
> > the binary artifact to have a composition of compatible licenses
> > (including the GNU ones). This is the least messy for Rust bindings to
> > LGPL libraries.
>
> While most rust executables are statically linked, I am not sure whether
> this is the case when using `cxx-qt`. This is what running file command
> on `kontrast-rs` (a sample rust app that uses cxx-kde-frameworks) produces
>
>  > kontrast-rs: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV),
> dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for
> GNU/Linux 4.4.0, BuildID[xxHash]=9e033617833656c9, not stripped.
>
> `ldd` also confirms this. I might be totally wrong as I know very less
> about this.
> If the final binaries are dynamically linked, the restrictions that you
> mention still apply ?
>

It does, because the *Rust parts* are statically linked, but the
*C/C++ parts* are dynamically linked.



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