[License-discuss] Fwd: Yet another question about using libraries with different licensed in OSS

Alex Rousskov rousskov at measurement-factory.com
Wed Jan 18 22:06:29 UTC 2017

On 01/18/2017 02:00 PM, Massimo Zaniboni wrote:
> On 18/01/2017 21:30, Alex Rousskov wrote:
>> AFAIK, neither GPL nor Apache license actually _require_ this. You may
>> have missed the "END OF TERMS AND CONDITIONS" markers when reading the
>> corresponding web pages.

> 1) I'm consulting https://www.apache.org/licenses/LICENSE-2.0
> "You must cause any modified files to carry prominent notices stating
> that You changed the files;"

A single prominent notice for a collection of changed files satisfies
that requirement. It is normally expressed via implications of various
"This Software contains code originally written by X and licensed under
Y" notices.  The change notice does not have to go inside the changed
file itself. Otherwise, there would be no legal way to delete an old
licensed file while preserving its code in other/new files!

> [https://www.apache.org/licenses/LICENSE-2.0#apply] there is the
> boilerplate notice, and also if the text is not 100% clear, it seems
> that it must be added to every source code file.

That Appendix text is not normative because it comes after the END OF
TERMS AND CONDITIONS marker. It is a good suggestion, but it is not a
part of the Apache licensing terms.

> 2) In https://www.gnu.org/licenses/gpl.html it says explicitely
> "How to Apply These Terms to Your New Programs

That text is not normative because it comes after the END OF TERMS AND

> Also because a file is a strong container of source code, and so it
> is 100% clear who are the authors, and which license is applied to the
> code.

Using those suggested boilerplates does not make it 100% clear who the
authors are:

* Did the listed person A author function X or was it the listed author
B? Or do they both hold joint copyright? Or is it their employer(s)?

* If somebody removes (or does not add) an author's name, for any
reason, that author is still the author of her code.

* If somebody adds the wrong author name, for any reason, that person
does not magically become the author of somebody else code.

Similar file scoping problems apply to licenses, especially when a
project mixes different ones.

That 100% clarity via boilerplates is an illusion that gets
progressively more expensive to support in active open source projects
with a non-trivial number of authors. Fortunately, there is no need to
pay that price in most cases.


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