apache license 2.0 for consideration

Roy T. Fielding fielding at apache.org
Tue Feb 24 00:51:28 UTC 2004

Hello Eben,

Thanks for responding -- I do find your messages to be a great help
in understanding license issues.

On Monday, February 23, 2004, at 10:58  AM, Eben Moglen wrote:
> Since you forwarded me the beginning of your list's thread on ASL2 and
> GPL2 I have been preparing the analysis you quite rightly sought.  I
> regret that the statement at gnu.org was, and is, inadequate to
> explain FSF's concerns; you have correctly inferred that I did not
> write it.
> Today's statement by the Apache Foundation raises a new question for
> me, about which I had assumed that careful reading of your license
> would provide an answer, but which I answered for myself--after such a
> reading--differently than the Apache Foundation statement.

I'll assume you are referring to the statement at


> I hope we can clarify both our views quickly, to avoid the public row
> that seems (unnecessarily so far as I can see) to be developing.  For
> this purpose, I need to ask the question raised by today's statement:
>   A developer, X, adds GPL'd code to Apache, and distributes the 
> combination.
>   The combined code, including the GPL'd code itself, practices the
>   teaching of a patent, P, licensed under ASL2.  A user, Y, asserts a
>   defensive patent claim of infringement by Apache.  Is the license to
>   practice patent P in the GPL'd code added to Apache by X withdrawn or
>   in force?  Is the license as to the ASL code combined with the GPL
>   code withdrawn or in force?
> I have been assuming, on the basis of the license text, which seemed
> clear to me, that the answer is "withdrawn/withdrawn."  Your statement
> of today asserting GPL compatibility suggests that the answer must be
> "in force/in force."  Can you help?

That is a very complex set of issues.  First, the patent is not only
licensed under the ASL2 -- it is actually licensed by the contributor
to the ASF and any recipient of the ASF's software as part of their
contribution. The Apache License makes the recipient aware of that
license and the condition of reciprocity (as accepted by our
community of contributors) under which that license was granted.
The ASF does not have the right to sublicense any such patent;
we merely pass the license along from the contributors.

Therefore, assuming that the patent was infringed by a contribution
made by the owner of that patent to an ASL2 product, the license
remains in force regardless of what other code/license terms are
added to make up derivative works.  The contributor's patent license
is withdrawn from Y upon the claim of infringement (upon Y claiming
that Y owns a patent that has not been licensed to Apache).  Thus,
your interpretation is mostly correct in that the answer to both
of your questions is "withdrawn from Y".

A second issue, however, is that the GPL does not allow redistribution
of the combination if a patent does exist and is not available free
to everyone.  Again, the ASL2 has no impact here, since a separate
license to the patent may exist outside of the ASL2's required license.
For example, if a company says "this patent may be freely used within
any product distributed under the GPL or the Apache License", then a
user would still retain rights to use under the GPL even if the Apache
License termination clause is triggered.  That is because the 
is passive -- it only matters if the user has no rights aside from those
given by the ASL2.

So, there may be a case where a given software product may be
incompatible with the GPL, whether or not it is licensed under the
ASL2, simply because an enforced patent exists within that product
and has not been licensed (as might be the case for patented
technology that was independently invented for Apache, or for which
the "inventor" failed to reference the existing prior art).
I hope you agree that, in such a case, it is the product that is
incompatible with the GPL and not the generic licensing terms.
It is the GPL's own restrictions on redistributing works covered
by an enforced patent that cause the combination to be
non-distributable, and that is true even if the patent was
infringed by the GPL part of the code (e.g., combining two
independent products into one product may cause a new infringement
even if neither one infringed separately).

As we said in our statement, the ASF does not knowingly distribute
patented technology unless it is licensed free for everyone (not
just under the ASL2).  The purpose of the patent license in ASL2
is to protect our users against deliberate contributions of
patented technology that are later enforced against the end-user.
Since nobody knows when a patent is infringed until the patent
is approved and enforced, usually years after it was introduced,
our contributors have agreed to work together on a royalty-free
basis for anything they might contribute, provided that the
people benefiting from that broad license are also willing to
license their patents in the same work (or at least agree not
to enforce them on that work).  I believe that is the same
spirit in which the GPL says that one cannot distribute as GPL
a Program or Derived Work that is covered by a patent with terms
more restrictive than the GPL.

I hope that helps,

Roy T. Fielding, co-founder, The Apache Software Foundation
                  (fielding at apache.org)  <http://roy.gbiv.com/>

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