That's interesting, wouldn't that mean that the licenses themselves aren't in some sense 'legal' in the EU? How does the GPL prevent this from invalidating down the whole license?

That's surprising, considering the virality is part of the license text, not the law; does the law prohibit that clause?

Here's a good explanation: https://joinup.ec.europa.eu/collection/eupl/news/why-viral-l...

The short answer is that there are certain protections that ensure interoperability, and that linking to software does not make it a derivative work.

That's an interesting analysis.

That directive is usually understood to be about reverse engineering in order to build compatible software: "to obtain the necessary information to achieve the interoperability of an independently created program with other programs" being a key bit.

It's not immediately clear to me - a programmer but not a lawyer - that this has any bearing on whether linking creates a derivative work.

Have any other experts, or courts, weighed in on whether this analysis is sound?