Re: [Jython-dev] Jython license and GPL incompatibility

[<bc...@wo...>]

[Ben Burton]

>> - ReadlineConsole is neither GPL or LGPL
>
>http://www.bablokb.de/java/readline.html, first paragraph: "It is distributed 
>under the LGPL."  Although there should be no problem linking LGPL stuff with 
>jython, it's the GPLed libreadline.so that gets linked along with it that 
>concerns me.

No. The LGPL covers the Readline.java class and friends. It does not
cover ReadlineConsole.java. That file is clearly based on a copy of some
CNRI software and I don't believe Bablok have ever tried to put LGPL on
something that was initially written by CNRI.

It may not change the issue much but it does add another degree of
separation.

>> So in the distributed form, jython doesn't links with any (L)GPL code.
>> If anyone installs bablok's Readline class and libreadline and changes
>> the python.console option they are creating a derivative work which they
>> do not have the right to distribute.
>
>So what's to stop me taking the GPLed fastlib.so, making a new proprietary 
>library superfastlib.so that links to fastlib.so but contains my 
>modifications, and then selling superfastlib.so but requiring users to 
>download fastlib.so themselves; thus I'm not distributing the GPLed code 
>myself but I still get the benefit of having a proprietary derivative work as 
>such.

Note that we does not *require* people to download a GPL library. Jython
works completely fine without.

>i.e. I believe the claim you make defeats the purpose of GPLing a library.  
>Of course I could be very much mistaken.  I am not at all well versed in 
>licensing details.  I don't say any of this because I am confident that I'm 
>correct; I merely say it for the purpose of opening (what I believe is 
>necessary) discussion on the issues.
>
>http://www.fsf.org/copyleft/gpl-faq.html#GPLPluginsInNF
>
>This also suggests to me that the readline plugin to Jython cannot be used, 
>i.e. sure, you can distribute support for the plugin but nobody should be 
>allowed to use it (and hence there's no reason to distribute support for it).

I though GPL only covered copying, distribution and modification.
Maybe changing the python.console property is considered a modification?

>> I have somehow considered ReadlineConsole to be similar to CPython-2.0's
>> readline.c file. In itself readline.c did not require CPython to be GPL
>> compatible.
>
>As I understand it, at least the debian python2 release disabled readline 
>support because of the GPL-incompatibility issue.

Right. The same would surely be necesary in the case of Jython. There is
absolutely no way a binary readline <-> jython combination could be
released. Did the debian release include the source for readline.c? If
it did then jython can surely include the source for
ReadlineConsole.java.

Maybe the binary version of ReadlineConsole.class is a violation of GPL.
I'm not sure how GPL view the way java compiles and links between
classes. Would using reflection to find and call two functions named
"Readline.readline" and "Readline.initReadline" also be a violation?

>IANAL, in fact I know very little about legal matters; these are just my 
>thoughts that I'm throwing in.  If you like I can raise the issue on 
>deb...@li... and see what they have to say.

I dunno. I'm not familiar with the S/N level on debian-legal. Also, I'm
not all that interested in whether debian can include jython. I'm more
interested in whether jython can include ReadlineConsole. I don't know
if debian-legal is the right place to ask that question.

regards,
finn