G'day. The question of licensing for code derived from a sample contained in the flymake manual came up, and I wanted to follow up to ensure appropriate compliance with the license terms.
This is copied to the FSF licensing team, as I strongly suspect they are appropriate to correct any misapprehensions that I have about the licenses, their application, or the other questions at hand.
The source in question is here:
That manual is licensed under the GFDL, appropriately. The code, I think, is sufficiently large and involved that it can't be reused arbitrarily as "fair use", or any other general licensing exception.
Now, I'm pretty certain the intent was that this code could be reused for the purpose of developing flymake backends, and it is a copy of code that was under the GPL prior to inclusion – although it is not directly including that code, and has extended the commentary.
The manual in question, the GFDL itself, and the GNU/FSF FAQ about licensing provide no exceptions for the case of relicensing the sample code that I am able to find.
As far as I can tell, this means that anything derived from that sample code would also be covered by the GFDL, including the provisions for invariant sections, which do not really make sense in the context of "I wrote a flymake backend."
On checking, none of the other Emacs manuals seem to have any documented exception to the GFDL for sample code either; the Emacs manual mentions the GPL, but only in the context of Emacs itself, noting the manual is undir the GFDL.
Would it be appropriate to extend the documentation to explicitly permit reuse of the sample code in the Emacs flymake manual, or all Emacs manuals, under the same license as Emacs itself? That is, sample code could be used under the GFDL *or* the GPLv3 (at this time).
If I have missed something, and I am definitely not an IP licensing lawyer, please let me know, and I'll be very happy to be corrected. :)
Thanks for your time.