TYPO3 Core

The idea/problem behind this patch request is the fact that there are quite a bunch of legally unclear extensions out there ...
There are people which do not include the GPL header in the top of class files - either by intention or by mistake.

I do not know which legal impact it has upon a TYPO3 installation at a whole if there are extensions installed which do not comply to the GPL.

As far as my current understanding is concerned a TYPO3 extension requires to be GPL ... But what happens if it is not? In other software projects (Linux distributions, etc.), the Linux kernel, etc. this "taints" the whole setup.

I guess it would be somewhat similar in a TYPO3 instance.

I do not know if there are any TYPO3 "clones" out there which try to resemble the TYPO3 extension API. But just in such a hypothetical case "they" could legally use TYPO3 CMS extensions as they are GPL licensed while installing their extensions in TYPO3 would eventually violate TYPO3 CMS legal requirements and or break their legal requirements because they would be "forced" to GPL their work.

By current understanding a TYPO3 CMS extension requires to be licensed under the GPL or LGPL at a version of 2 or later

And in general, this also is not true. MIT license is compatible with GPL and TYPO3 itself used MIT code.
Therefore Extensions licensed as MIT are valid to be installed with TYPO3.

However all Extensions on TER must be GPL as written in the ToS of TER.

Besides that, license check should not be done during installation, but during upload to TER or separately in a license check module (reports) or something similar.

why shouldn't I be allowed to install any package I want on my server?

It is just about knowing that you are tainting your system with non-GPL software.

Bernhard Kraft wrote:

It is just about knowing that you are tainting your system with non-GPL software.

That might be useful to know, however this IMHO should not be done during installation, but needs a separate check

I veto Helmuts postings.

Of course it is allowed to install non-GPL extensions. As previously mentioned it is only forbidden to upload non-GPL extensions to the official TER. But this is also not checked.

I will create a separate issue for this.

So I should not be allowed to upload a non-GPL extension to TER. This is explained somewhere - but there is no technical check/reason against it. So if I not place the "This software is GPL" header in my file headings and have not a "license" => "GPLv2" in my ext_emconf or composer.json I will still be able to upload it to TER. There is a German Sprichwort: "Wo kein Kläger da kein Richter".

Meaning that if no one cares about whether all software in TER is GPL there could be some non-GPL extensions lurking around.

So we have two frontiers:
1. Take care only GPL extensions get uploaded to TER.
2. Notify a user when he is installing non-GPL software.

The checkbox that has to be clicked before the upload states:

I confirm that my extension contains only GPL v2 or any later version compliant code.

So there is no need to stick to GPLv2 due to the "any later" part and there is no need to stick to GPL at all due to the term "compliant".
Which is why some themes we did based on theme_bootstrap are using MIT license and are still legally published to the TER.

Please discuss topics like this with the licensing team first, since we are using our own tracker here on forge.