Misleading use of 'Open Source' wording

[benbeshara]

The website and repository claim several times that this project is capital-o Open Source (the GitHub readme even stating that MeshLib is Fully Open Source as a reason to choose this project), but a cursory reading of the license refutes this immediately.

It comes with a restricted-use trial license and is distributed with a revokable license rather than ownership of a copy (along with threats of audits for compliance). It is at best, source-available. I do note that this project was open source until February 21, 2022 when its MIT license was replaced with the current iteration. If the product is open source, then the license is simply incorrect. If the license is correct, then the project is not open source and to claim that it is as a USP is misleading to potential users.

(Clarifying that It is perfectly fine if MeshLib is not Open Source, the issue is potentially incorrect claims about it's open source status that could affect end-users who take the wording at face value. I am writing some 3D tools at the moment that I would like to at some stage distribute under an OSI open-source license that I cannot if I integrate with this library.)

[DmitryLambin]

@benbeshara MeshLib is not using misleading messaging in this case.
The library is open source in the literal sense that its source code is open and publicly available in the repository. Anyone can view the full implementation, inspect it, build it, and understand how the algorithms work. That is the meaning used on the website when stating that MeshLib is open source.
However, “open source” and “OSI-approved open source licensing” are not always the same thing. The current MeshLib license is source-available with additional usage terms, which means:

• The entire source code is accessible in the repository.
• Users can read, audit, and build the library from source.
• Commercial use and redistribution are governed by the license terms, rather than being unrestricted as in MIT/GPL-style licenses.

So to clarify the situation:

• Source availability: Yes — the full source code is open and accessible.
• OSI-approved license: No — the current license is more restrictive than typical OSI open-source licenses.
• Misleading messaging: No — the project emphasizes open access to the source code rather than claiming OSI certification.

If your goal is to distribute software under an OSI open-source license that requires fully permissive dependencies, then you are correct that integrating MeshLib may not be compatible with that licensing model.