Re: How to (radically) fork an LGPL project?

[Martin Dickopp]

Barry Margolin <barmar@alum.mit.edu> writes:

> In article <5TYzc.188756$WA4.48243@twister.nyc.rr.com>,
>  Kenny Tilton <ktilton@nyc.rr.com> wrote:
>
>> I have taken an LGPL project and made radical changes incompatible with
>> large wadges of the original. I understand a couple of things:
>> 
>> 1. my version is a derived work still bound by the LGPL. No problemo.
>> 
>> 2. I must make clear that I have made (extensive) modifications so no
>> one blames any one but me for any problems with the modified lib.
>> 
>> My question is a simple one: how do I do this? It seems strange leaving
>> the poor originator's name in the copyright notice at the top of my
>> nonsense. So I am inclined to do something like (in brief):
>> 
>> "Copyright (c) 2004 by Kenny
>> 
>> "A work derived from XYZ, Copyright (c) 2003 by Joe. All blame goes to
>> kenny, all credit goes to Joe."

A statement to the effect of "all blame goes to me, all credit goes to
him" is not required by the LGPL, but if you want to include such a line
as a courtesy to the original author, you can of course do so.

>> otoh, it seems strange claiming copyright when 50% of the code is
>> largely untouched. (40% of the original is replaced with my original
>> code, 10% is Joe's code somewhat modified.)

It is not a question of "claiming" copyright.  As soon as you make any
non-trivial changes, you hold the copyright to the code written by you.
If it is 90%, 50%, or 1% doesn't matter.

> IANAL, but I suggest a combined copyright:
>
> Copyright (c) 2004 by Kenny, Joe

IANAL either, but it is my understanding that the years matter.
Therefore, I suggest two copyright statements:

    Copyright (C) 2004 Kenny
    Copyright (C) 2003 Joe

Martin