3 ms·

It's a plugin, not a modification of WordPress. Wordpresses license is irrelevant.

viraptor 2y ago
Plugins as code that is integrated with WP are still required to be GPL-compatible. Unless you want to connect to your plugin through some layer of networking and a GPL licensed proxy, your plugins need to be open as well. Specifically running something as basic as register_activation_hook() means you're linking with WP-provided code.
jazzyjackson 2y ago
Whether a plugin is standalone or a combined program (and therefore a derivation) is apparently a matter of debate. Sounds like if you so much as use a data structure defined by WordPress, then by distributing your software you're really distributing a modified version of WordPress. [My read of 0] This is intuitive enough for me, if you can't use my plugin without WordPress, then really what I'm shipping is WordPress + my changes. However, some plugins are distributed with a "split license", the php that integrated with WordPress is GPLd, but JavaScript, css, other assets are under a different license. [1] I don't think this has been tested in court one way or another. Matt of course considers this heresy [2] [0] https://www.gnu.org/licenses/gpl-faq.en.html#GPLPlugins https://www.gnu.org/licenses/gpl-faq.en.html#GPLPlugins [1] https://www.contentpowered.com/blog/wordpress-plugins-free-gpl/ https://www.contentpowered.com/blog/wordpress-plugins-free-g... [2] https://ma.tt/2015/07/licenses-going-dutch/?utm_source=perplexity https://ma.tt/2015/07/licenses-going-dutch/?utm_source=perpl...
- dragonwriter 2y ago
  > Sounds like if you so much as use a data structure defined by WordPress, then by distributing your software you're really distributing a modified version of WordPress. Given that reimplementing an API for interoperability is at least sometimes not a violation of copyright (see, e.g., Oracle v. Google), using a datastructure defined in a piece of software providing a plugin API to interoperate with it cannot make the resulting software exist only as a combination with the software providing the API, since it relies only on some software providing the same API, not necessarily the particular software that originally provided the API.
kmeisthax 2y ago
The GPL is strategically ambiguous as to the meaning of the word "program" and "combine". The licensing terms could be taken to be relative to UNIX concepts like processes, since Stallman had a very UNIX-centric worldview; but the FSF has been very clear that they consider "program" to be more expansive a definition than that[0]. While there are some cases in which two GPL programs could be said to live in the same address space[1] (or PHP interpreter), WordPress plugins are very much designed to integrate with WordPress and modify its behavior. From a copyright perspective, that smells awfully like a derivative work, and thus all the usual GPL licensing language and copyleft would apply here. Ergo, I'm writing these opinions under the assumption that WordPress plugins have to also be GPL. [0] For example, they consider proxying out to a separate network service to not escape the bounds of a GPL "Program". [1] It's very rare nowadays to see separate programs live in the same address space. Classic Mac OS did this; but I don't think anyone is going to take someone to court over retrocomputing hobbyist software. Linus argues that you can have proprietary kernel modules as long as they only touch user-mode API stuff, but that's because they have a specific licensing exception that makes the UAPI outside the bounds of the GPL copyleft. The web is the only place where you could have GPL Programs coexist within the same isolation boundary.

Plugins as code that is integrated with WP are still required to be GPL-compatible. Unless you want to connect to your plugin through some layer of networking and a GPL licensed proxy, your plugins need to be open as well. Specifically running something as basic as register_activation_hook() means you're linking with WP-provided code.

jazzyjackson 2y ago

Whether a plugin is standalone or a combined program (and therefore a derivation) is apparently a matter of debate. Sounds like if you so much as use a data structure defined by WordPress, then by distributing your software you're really distributing a modified version of WordPress. [My read of 0] This is intuitive enough for me, if you can't use my plugin without WordPress, then really what I'm shipping is WordPress + my changes. However, some plugins are distributed with a "split license", the php that integrated with WordPress is GPLd, but JavaScript, css, other assets are under a different license. [1] I don't think this has been tested in court one way or another. Matt of course considers this heresy [2] [0] https://www.gnu.org/licenses/gpl-faq.en.html#GPLPlugins https://www.gnu.org/licenses/gpl-faq.en.html#GPLPlugins [1] https://www.contentpowered.com/blog/wordpress-plugins-free-gpl/ https://www.contentpowered.com/blog/wordpress-plugins-free-g... [2] https://ma.tt/2015/07/licenses-going-dutch/?utm_source=perplexity https://ma.tt/2015/07/licenses-going-dutch/?utm_source=perpl...

dragonwriter 2y ago
> Sounds like if you so much as use a data structure defined by WordPress, then by distributing your software you're really distributing a modified version of WordPress. Given that reimplementing an API for interoperability is at least sometimes not a violation of copyright (see, e.g., Oracle v. Google), using a datastructure defined in a piece of software providing a plugin API to interoperate with it cannot make the resulting software exist only as a combination with the software providing the API, since it relies only on some software providing the same API, not necessarily the particular software that originally provided the API.

kmeisthax 2y ago

The GPL is strategically ambiguous as to the meaning of the word "program" and "combine". The licensing terms could be taken to be relative to UNIX concepts like processes, since Stallman had a very UNIX-centric worldview; but the FSF has been very clear that they consider "program" to be more expansive a definition than that[0]. While there are some cases in which two GPL programs could be said to live in the same address space[1] (or PHP interpreter), WordPress plugins are very much designed to integrate with WordPress and modify its behavior. From a copyright perspective, that smells awfully like a derivative work, and thus all the usual GPL licensing language and copyleft would apply here. Ergo, I'm writing these opinions under the assumption that WordPress plugins have to also be GPL. [0] For example, they consider proxying out to a separate network service to not escape the bounds of a GPL "Program". [1] It's very rare nowadays to see separate programs live in the same address space. Classic Mac OS did this; but I don't think anyone is going to take someone to court over retrocomputing hobbyist software. Linus argues that you can have proprietary kernel modules as long as they only touch user-mode API stuff, but that's because they have a specific licensing exception that makes the UAPI outside the bounds of the GPL copyleft. The web is the only place where you could have GPL Programs coexist within the same isolation boundary.