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Ticket UUID: e14d152114efee10394a7e0b4b1c0478efff52c5
Title: bundled zlib documentation is under a potentially non-free license
Type: Bug Version: 8.6
Submitter: andrewsh Created on: 2017-03-06 18:02:33
Subsystem: 57. zlib Assigned To: jan.nijtmans
Priority: 5 Medium Severity: Minor
Status: Closed Last Modified: 2017-03-07 11:12:07
Resolution: Fixed Closed By: jan.nijtmans
    Closed on: 2017-03-07 11:12:07

Tcl redistributes the sources of zlib under `tcl/compat/zlib`.

As Simon Josefsson points out in <>, the zlib RFCs are under a potentially non-free license (due not allowing modifications and commercial use, depending on the interpretation). It doesn’t seem to be necessary to ship the RFCs with Tcl, so it’s probably best to resolve the issue by simply removing them.


User Comments: jan.nijtmans added on 2017-03-07 11:11:53:
Even though I'm not convinced, I know how difficult it is to convince lawyers that they are wrong. ;-) And - since it's incredible easy to remove those files from the distribution, let's just take the easiest road .... Done now in core-8-6-branch and trunk.

andrewsh added on 2017-03-07 10:10:13:
It doesn't explicitly allow redistribution with a fee, which make it not possible to include it in commercially-sold software packages, such as commercial Linux distributions.

It is true Tcl itself probably won't violate the license, but it forces downstreams such as Linux distributions to repackage the tarballs to remove RFCs which distro's users may not be able to legally redistribute. Instead of adding more work for downstreams it's better to remove them from Tcl distribution. There isn't a single reason to ship them, is there?

jan.nijtmans added on 2017-03-07 09:05:18:
Actually, I don't think this is a problem at all! Tcl's re-distribution is not commercial, and no modification is made to any of the text. So, I don't see at all how Tcl could possible violate this license by re-distributing the rfc's.

I checked the license text, I don't see anywhere that commercial use (of the rfc texts) is forbidden, only that re-distribution is allowed without fee.