How does using a LGPL gem affect the MIT licensed application

lgpllicensingmit-licenseruby

I am developing an open source ruby application under the MIT license. I am using this license because I don't want to place any restrictions on the users of the application. Also I can actually read and understand this license.

I recently started using another ruby gem in my project (require "somegem"). This ruby gem is under the LGPL license.

Do I have to change anything about my project because I am using this other ruby gem that is licensed with LGPL? My project does not contain the source code for the other gem and it is not shipped with my project. It is simply listed as a dependency so that ruby gems will install it and my project will call into it from my code.

Additionally, it would be helpful to know if there are any licenses I need to "watch out for" because using them would affect the license of my project.

There are some other post about this topic but phrased in different ways. Since I find this license stuff tricky I am hoping to get a answer directed at my situation.

Thank you,
Corsen

Best Answer

It does not affect

LGPL — stands for Lesser GPL (used to mean Library GPL). The significant difference with GPL is, that it doesn't impose the license on software using the library. Only if you'd modify the library or directly include parts of the code in your software, then your code would have to be LGPL. On the other hand if you're just using gem in your app, it's perfectly fine to keep your app with any license you please.

The mentioned part of LGPL:

A program that contains no derivative of any portion of the Library, but is designed to work with the Library by being compiled or linked with it, is called a "work that uses the Library". Such a work, in isolation, is not a derivative work of the Library, and therefore falls outside the scope of this License.