[nine_k]

GPL has great provisions against hostile forks, but as is it's a bit too restrictive for games as final products.

I'd imagine that LGPL would give both an incentive to contribute to the engine, and a way to commercially release games based on it, without GPLing all the assets and all the game mechanics.

[reidrac]

LGPL isn't great for games either.

One of the most celebrated changes in SDL2 was moving from LGPL to ZLIB license. All the linking requirements of LGPL are a pain for games and distribution.

[corysama]

Then how about “GPL with the static linking exception” (used by glibc, which is statically linked by zillions of non-open softwares).

AFAICT, that license comes down to “You only need to publish changes to our GPL code, not your own code that uses our code”. So, it’s non-viral.

[reidrac]

I think you meant "Lesser GPL with the static linking exception". IIRC glibc is "stock" LGPL 2.1 without any linking exception, so I may have misunderstood your comment and you mean just LGPL.

The LGPL is not viral but it has some requirements that are inconvenient when distributing a game, specially it makes static linking impossible.

[corysama]

You are right glibc is LGPL. It's libstdc++ I was thinking of https://gcc.gnu.org/onlinedocs/libstdc++/manual/license.html

Looks like what I'm looking for can be found in MPLv2 https://www.mozilla.org/en-US/MPL/2.0/FAQ/

Ex: http://zeromq.org/area:licensing is currently LGPLw/exception, but intends to move to MPLv2 because it is legally more clear.