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From Marvin Humphrey <>
Subject Re: Podling Graduation Rally
Date Tue, 21 Feb 2017 18:25:02 GMT
On Tue, Feb 21, 2017 at 6:31 AM, John D. Ament <> wrote:

> So are we saying that the code modifications are sub-licensed? Or
> re-licensed?

Think of each file as the result of layering changesets on top of each
other.  Each changeset has its own copyright holder and each copyright
holder grants a license.

When all changesets have the same license, then the end product has
uniform licensing, even though many entities hold continue to hold

However, it is also possible that changesets may be granted under
different licenses -- in which case, the end product has heterogeneous
licensing.  It may not be possible to slice up the file into code blocks
which are under one license exclusively. Instead, if you want clean
divisions by license you have to go back to the changesets.

For BSD-2-clause files which came in with MADlib but were not relicensed
(because not all authors participated in the SGA), we are saying that
changesets submitted after arrival at the ASF shall be under Apache-2.0.

PS: This workflow is not possible when the first license has reciprocity
    requirements (i.e. it's a "copyleft" license like GPL or MPL),
    because a key condition of such licenses is that the copyright
    holder for subsequent changesets must make them available under the
    original license.  However, BSD licenses do not impose such a
    restriction, so it's valid to create an ALv2 changeset to apply on
    top of a BSD file.

Marvin Humphrey

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