Completing Racket’s relicensing effort

posted by Sam Tobin-Hochstadt, with help from Sage Gerard and Joel Dueck and Matthew Flatt and the Software Freedom Conservancy, especially Pamela Chestek

With the upcoming Racket 7.5 release, almost all of Racket, including the core Racket CS binary, the standard library, and the packages provided with the main distribution, are available under a permissive license, either the Apache 2.0 License or the MIT License. You can read the details of the new license in the GitHub repository. This has been a long process, beginning in 2017, and we’re grateful to all the contributors to Racket, including those from very long ago, who gave permission for the re-licensing. More than 350 contributors to Racket responded; many of the responses can be seen in this GitHub issue.

Why relicense?

Racket has long been a part of the free software community, and we value both that community and the ability to build on other free software. However, two factors mean have made our previous license, the GNU LGPL, less of a good fit going forward. First, it is unclear how to apply the LGPL’s statement about dynamic linking to a language like Racket, where macro expansion can copy code from libraries to applications, and where applications are typically bundled with the Racket runtime and libraries. Second, some organizations unfortunately are unwilling to use software licensed under any variant of the GPL. Since we want to provide a clear license and to promote the use of Racket everywhere, a new, more-permissive license is the right choice for Racket.

What is available under the new license?

In the soon-to-be-released Racket 7.5, the Racket CS binary, and any Racket code in the Minimal Racket distribution, is available under both the Apache 2.0 and MIT licenses. Additionally, almost all of the packages distributed with the full Racket distribution are available under these licenses. The exceptions are “slatex”, “srfi-doc”, “swindle”, “r5rs-doc”, “r6rs-doc”, and “r6rs-std-doc” as well as “string-constants-lib” which is discussed below; see the LICENSE files available in those individual packages for details. The traditional Racket binary itself, as well as other executables such as the DrRacket binary, continues to include code from several libraries distributed under the LGPL and is thus still distributed with that license; we do not anticipate this changing.

Additionally, packages that include the compiled version of native libraries such as Gtk which themselves are licensed under the LGPL retain that license.

Some packages did not complete the re-licensing process until after the release process for Racket 7.5 began; those packages will ship with new licenses in Racket 7.6.

Is there anything remaining to re-license?

We’ve completed the re-licensing for all code that we planned to cover. However, some translations (part of the “string-constants-lib” package) have authors that are unknown or have not responded to us. This does not affect the licensing of any programs using Racket unless they depend on or derive from those translations directly.

Did anyone say no?

Two people declined to re-license their contributions to Racket. We therefore removed their contributions and, where appropriate, replaced them with new code and/or documentation.