[Blikkentrekker]

Copyleft doesn't work well with Rust's ecosystem of many small crates and heavy reliance on libraries alongside static linking.

If one library be GPLv2 and the other GPLv3 they couldn't be used together in one project. LGPL solves nothing because it's all statically linked anyway. And yes, one could licence under both under the user's choice but then GPLv4 comes out and the process repeats itself, and yes one could use GPLv2+ but people aren't exactly willing to licence under a licence that doesn't yet exist and put blind faith into whoever writes it.

Using anything but a permissive licence is a good way to ensure no one will lose your library and someone will just re-implement it under a permissive licence.

C is a completely different landscape. Libraries are larger and the wheel is re-invented more often and most of all dynamic linking is used a lot so the LGPL solves a lot.

[F3nd0]

Correct me if I'm wrong, but I think all of these are solved problems.

LGPL should only pose a problem if you explicitly want your program to be used with non-free software. And then only if said non-free software doesn't give you a way to rebuild it yourself, should you want to modify the LGPL program. (So not a problem for open-core or public-source projects, either.)

If, for some reason, you insist on allowing static linking for all the projects, I think the MPL allows this. (People often seem to think of the LGPL, but it's not the only weak-copyleft licence around.)

Otherwise, when releasing your project under GPLv3+, you don't have to put blind faith into the FSF; you can designate a proxy which will decide whether the new version should be allowed for your project or not. This proxy can be yourself, or it can be a different organisation you choose to trust. Plus, I'm pretty sure the GPL allows you to make linking exceptions of your liking.

[Blikkentrekker]

> LGPL should only pose a problem if you explicitly want your program to be used with non-free software. And then only if said non-free software doesn't give you a way to rebuild it yourself, should you want to modify the LGPL program. (So not a problem for open-core or public-source projects, either.)

No, just if you want it to be used with anything that isn't that exact same GPL licence.

> Otherwise, when releasing your project under GPLv3+, you don't have to put blind faith into the FSF; you can designate a proxy which will decide whether the new version should be allowed for your project or not. This proxy can be yourself, or it can be a different organisation you choose to trust. Plus, I'm pretty sure the GPL allows you to make linking exceptions of your liking.

That's the same as just licencing under the GPLv3 and later retroactively deciding to also give the GPLv4 option when liking that licence. The issue is, what if you don't? Then your code can't be combined with any GPLv4 library.

The simple reality is that crates that have incompatible licences, and GPLv2 and GPLv3 are incompatible, cannot be used together in one distributed project without committing copyright infringement. The thing with MIT is that it's compatible with about every single licence out there.