Re: License of that GNAT patch ?

[Georg Bauhaus <rm.dash-bauhaus@futureapps.de>]

On 06.10.11 09:40, Ludovic Brenta wrote:

> This is allowed.  The whole point of free software is that people can
> change it.  I still don't understand what you are driving at.

Indeed. Change it with the proviso that .... Not just change it.


>> What if there is no assignment of copyright to settle ownership
>> of this new work?
> 
> In this case, the copyright on the derivative work belongs to all
> contributors and you enter license hell as Linux illustrates.

I wanted to emphasize ownership issues.


>> If this isn't a a legal issue, wow, then I imagine that any Ada shop
>> can take whatever they need from the whole of the FSF Ada body,
>> modify it in whichever way they like,
> 
> Yes
> 
>> and distribute binaries
>> made from the result, without any obligation regarding sources.
> 
> This is true only of the subset of the Ada sources that are covered by
> the GPLv3 with Runtime Library Exception.

I doubt that said exception allows the creation and distribution
of derivative works, including substantial changes to said library
itself, with additional permissions added again, but without agreement
on additional permissions.  The exception says it is about linking
and such only, not changing.

>> (They have been patching sources to which a linking exception applies...
>> I can't help but think that a linking permission does not imply
>> more far reaching permissions.)
>> Sounds like a general presumption in the sense of weakening copyleft,
> 
> Are you trying to say that the Runtime Library Exception weakens the
> GPL? 

No, quite the opposite. Roughly speaking, the Runtime Library
Exception enforces the GPL by being an exception, saying you
have "exceptional rights" only in certain circumstances.
For example, when yours is an Eligible Compilation Process.

I'm saying that thinking that exceptions allow others to change
the software and re-apply the exception is (a) something the
Java classpath exception talks about, but (b) neither the GMGPL nor
the GPL Runtime Exception talk about: do the same exceptional
permissions apply if you *change* the GPLed work to which the
exception (expressly for linking and such) applies.
 The GPLv3 says something about the *removal* of additional
permissions. When it talks about *adding* additional
permissions, then only for the material that some someone has
added. In the non-Java case, one cannot simply add permissions to
the entire patched work unless there is permission to do so, that's
my point (and question). And since said exceptions say: *this*
software, not any changed software...

My understanding is that, in general, if you instantiate or link
units from, e.g., GMGPLed software, you can distribute closed source
products. If you change GMGPLed software, you cannot do the same,
because that is not what the exceptional permission says.

Yannick said,

"the patch contains no license information, and I would like to know
 how I should handle such a case and any future similar cases.
 The GNAT compiler I use is one with the GCC Runtime Exception,
 which I wish to preserve."

I don't see how the GCC Runtime Exception can be re-applied by
anyone to any changed runtime without agreements.

My comment, admittedly, tries to be more general:

If B takes A's software and that software carries a linking(!) exception,
then B modifies A's software,
then B sends the modified software to C (but not to A and no assignment),
then C produces proprietary software P,
then C distributes P in closed source form,
then everything that the GPL is about is ineffective and IMHO not the
intent of an exceptional permission to link A's software as is.

All of this hinges on whether or not the GCC Runtime Exception
allows, without copyright assignment, linking privately *changed*
runtimes into proprietary binary products and distributing closed
source only.  I don't think so, and be stunned if I'm wrong.