How infectious is the GPL? Battle of words between WordPress and Thesis

Matt Mullenweg, the creator of WordPress, is engaged in a battle of words with the maker of one of its premium themes, Chris Pearson, who runs DIYthemes and offers the Thesis theme on a paid-for basis. I listened to their discussion on Mixergy; it is ill-tempered particularly on Pearson’s side.

The issue boils down to this. WordPress is licensed under the GPL, which provides that if you derive a new work from an existing GPL-licensed work, the GPL applies to your new work as well.

Pearson argues, I think, that his work is not so tightly linked to WordPress that the GPL applies. “Thesis does not inherit anything from WordPress” he says.

Mullenweg says that the way themes interact with WordPress is such that all themes much be GPL. “If you build something on top of it, it should be GPL” he says.

Pearson is refusing to license his theme under the GPL. What is to be done – would Mullenweg go to court to protect the GPL?

“You want us to sue you? That would break my heart.” he says. Then later, “I really hope it doesn’t come to that.” Then, “If people decide the GPL doesn’t apply, it’s a serious step for open source.”

Disclosure: this site runs on WordPress and I regard Mullenweg as one of the heroes of open source. Like the Apache web server (also in action here), WordPress is among the greatest achievements of the open source community.

I have no legal expertise; though I know a little about how WordPress works. Themes link very tightly with WordPress and in most cases are built by modifying an existing GPL theme; but I guess if you could show that Pearson’s work does not do this but merely runs on WordPress, as opposed to modifying it, he may have a case. That’s the argument Michael Wasylik makes here. On the other hand, did Pearson really create his theme without including any tiny bit of GPL code?

Another factor: if you choose to build an extension to a platform like WordPress, it is arguably unwise to do something counter to the strong wishes of its founder. There are ethical as well as legal aspects to this.

It is an important discussion for the open source community.

8 thoughts on “How infectious is the GPL? Battle of words between WordPress and Thesis”

  1. “The issue boils down to this. WordPress is licensed under the GPL, which provides that if you derive a new work from an existing GPL-licensed work, the GPL applies to your new work as well.”

    It means a derived version of WordPress (Pearson shipping his OWN WordPress) has to be GPL, not that a plugin loaded on top of an existing WordPress has to be GPL.

  2. I am confused about Stephane’s comment and your agreement to that comment Tim. The issue is certainly about if a loaded plugin needs to be GPL because the framework that loads it is GPL. In eclipse for instance plugins are considered deratives, OSGi framework like knopflerfish use BSD instead.

    It makes me wonder what kind of wurm hole that would be opened up if all plugins are, by definition, whatever that definition is, seen as derative works. What is a plugin? A binary in a linux system? Linux kernel modules anyone? Why isn’t a HTML page a plugin to Apache? It surely is mixed in memory with Apache to produce a page that is, if apache so chooses, inseperable from Apache for all intents and purposes. I was actually surprised when I read the legal advice Matt has received. GPL is about distribution freedoms, it is at its core. CSS and Javascript were not seen as GPL required because they are read as data, however so is a WordPress plugin, it is certainly easy to argue that point, to draw that the line is truly a tough thing to do. Chris (Thesis) isn’t restricting those at all. Matt takes the moral high ground and states they are all nice and cosher, but that fact of the matter is, this is severely complicated and it does not seem fair to use the bully force of the web to resolve GPL issues. I really wish more court cases would happen so we get some clarification.

    If the deciding factor is that any php code in a wordpress is a plugin, which means it is GPL, then all that is required is to disconnect yourself from PHP by providing a GPL plugin to wordpress that makes sure to read your plugin as data (whatever that means). Fine, let’s establish data.

    It all gets truly confusing incredibly fast, the GPL license is just too difficult to work with, so if you chose to work with it you might as well put your own stuff under GPL too.

    gcc compiled binaries? If the libraries and code produced by gcc weren’t under an exception they would be GPL too, so clearly(?) the source file is derative work when it passes through the gcc compiler.

    If you want it is much like an HTML page, compiled by a framework and distributed to a client which diplays it. So what makes an HTML page more data, less dervived than a source file? It is definitely combined with HTTP headers before it is sent to the client. Luckily Apache is not GPL, but it is APL, what does that mean to the content on this website?

    Also Tim, it doesn’t matter if Chris used a tiny bit of GPL code or not, by just using wordpress as a framework Matt is stating that it makes your theme GPL period. It seems to me this should make all content in wordpress GPL too, at least, as I have tried to illustrate above, data needs to be defined.

    GPLv3 of gcc excplicitly removes the option above, make a PHP plugin that makes it possible to escape GPL for a gcc plugin. What is data, what is a plugin…

    We need more court cases and more guidance, it cannot be a morale or ethical debate, if it is, we don’t even need licenses, just some statements of intents and everyone will live happily ever after.

    The problem with software is that copying is trivial and comes at zero cost and effort.

    I would vote for a FOSS license where the licensee is allowed to use and modify any software he has a license too, that would include for instance windows, but not allowed to freely distribute it, unless it means transferring the license to someone else requiring you to get a new one. That would be true individual freedom, I can do what I want with what I have, even resell it for any amount I chose, even 0, while still protecting what needs to be protected against in all economics, theft.

    Instead we have GPL…

  3. Niclas

    Thanks for the interesting comment.

    I am confused about Stephane’s comment and your agreement to that comment Tim. The issue is certainly about if a loaded plugin needs to be GPL because the framework that loads it is GPL.

    Again, I picked my words carefully. I tried to make the same distinction Stephane is making; but as to whether or not that makes a WordPress theme (if it does not itself use GPL code) fall outside the GPL, that is something which is not clear to me and I suspect needs testing.


  4. I have never tried to build a wordpress plugin, so I am a uncharted terratories, but my question is, can you build and distribute a wordpress plugin without a single file from wordpress itself? If so you are merely implementing a specification and if you are you are certainly not under GPL. Someone else could build a wordpress engine that calls the same spec and it would be able to use that plugin. OSGi is a perfect example of such a spec.

    You as a theme developer does not decide which framework the enduser uses, you never distributed a framework to them, never packaged it, all you did was make a couple of files available for download for a fee that wordpress happens to be able to make sense of. But then again the enduser might have a wordpressNoGpl framework that he is actually running this plugin in, or he might not, or he might just like to use your theme as a base for his work (unless you prohibit it).

    Let’s for arguments sake say it was the other way around, a proprietary wordpress exists, with plenty of theme plugins, the license for those plugin does not fall under the proprietary license, there is just no way it would, unless you state in the license that you cannot run plugin X unless it is XXX, but GPL does not give you the right to impose such a restriction on the enduser, so you would need another license, this is why they talk about memory entanglement, as GPL is not compatible with restricting the end user freedom, you need thus to impose restrictios on the authors instead. A windows DLL falls under the windows license in the applications you distribute? Even when run in wine?.

    So now mr GPL comes along, he builds wordpress GPL (plugin spec was open so he could do that), people start running their plugins that used to run in proprietary wordpress are now all plugins GPL? Are now all windows programs run under Wine GPL? The enduser decides were to run them, not the author.

    Again GPL is all about distribution rights and for some weird reason we bring in technical mumbo jumbo about what is in computer memory and what not (see legal advice). If that was the case then a GPL computer would make all in its memory GPL just because an enduser ran it there.

    See the complications here…endlessly confusiong.

    Just as much as it would be nice as an author to have everyone follow your will of your GPL stuff, you also needs to be prepared to see this happens as you actually agreed to GPL which gives you no power to control its uses or who distributes it to whom and where.

    How can a theme be a derived work from wordpress? Does it make any chances to wordpress source code? If it doesn’t I don’t see how the GPLv3 authors can define a modified version as such, and only if you “convery” such a version you actually need to “convery” your work under GPL.

    What wordpress could do is make a block to load thesis, then thesis would have to dervive a new wordpress without that block and distribute that wordpress under GPL, but still not his theme.

    I just get awfully tired of GPL and its issues, it is a company nightmare to use GPL and try to straighten out your compliance. That is why most companies just don’t allow GPL. Sadly though most developer’s doesn’t understand or care about the complications that come by including GPL source code into their projects.

    Use a BSD and Apache license, MIT or even Microsoft’s…

  5. I think that the way I come at issues like this is whether I think that the product on offer would actually save me time and money if I bought it at the price offered. If Thesis is very well designed and has several good selling points, then what’s to stop its author making some money from it, especially given that this shows that they have a right to profit from their effort? After all, it’s ultimately your choice. If you think you can do better yourself (and feel strongly that it should be free) then there’s nothing to stop you from writing your own theme.

  6. @Clyde

    The impression I get is that users are happy enough with Thesis and its value to them. The question though is whether the Thesis folk are being fair/legal/honourable with respect to WordPress.


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