Can a Mercurial fork change its license to AGPL?

[Adrian Buehlmann]

On 2015-02-28 03:08, Mads Kiilerich wrote:
> http://hg.quicksilver-vcs.org/quicksilver/rev/ab8914b3657e is more 
> problematic as it obfuscates the original license (even though they take 
> care to preserve attribution and copyright).

http://www.gnu.org/licenses/gpl.html says

"Notwithstanding any other provision of this License, you have
permission to link or combine any covered work with a work licensed
under version 3 of the GNU Affero General Public License into a single
combined work, and to convey the resulting work."

What Arc Riley did with that commit there appears not just to be
"linking" or "combining". It looks like he replaced GPL2 headers in
sources with AGPL headers, which I fail to see how that would be
compatible with the GPL.

That being said, it doesn't look like anything actually interesting
seems to have happened with that "fork" yet, except for renaming the
mercurial directory in the tree to quicksilver 3 months ago.

FWIW, quicksilver appears already left behind today with respect to
Mercurial and it will most likely get into even more serious licensing
problems in case it will try to pull and merge current Mercurial code
changes.

So far, that fork looks prematurely dead already anyway.