merge topics (two heads)

[Uwe Brauer]

Hi 

Please look at the following script

hg init
echo "First" > test.org
hg add test.org
hg commit -u "Bernhard Riemann <bernhard.riemann at gmail.com>" -m "First"
echo "Second" >> test.org
hg commit -u "Bernhard Riemann <bernhard.riemann at gmail.com>" -m "Second"
echo "Third" >> test.org
hg commit -u "Bernhard Riemann <bernhard.riemann at gmail.com>" -m "Third"
echo "Forth" >> test.org
hg commit  -m "Fourth"
hg topics NewTopic
echo "Fifth" >> test.org
hg commit  -m "Fifth"
echo "Six" >> test.org
hg commit  -m "Six"
hg log -G
hg heads

changeset:   5:ab935cede9ba
tag:         tip
topic:       NewTopic
user:        Uwe Brauer <oub at mat.ucm.es>
date:        Fri Oct 25 20:54:22 2019 +0200
summary:     Six

changeset:   3:c5dc6239ac03
user:        Uwe Brauer <oub at mat.ucm.es>
date:        Fri Oct 25 20:54:21 2019 +0200
summary:     Fourth

So they are two heads, but I receive
 hg up -r
 hg merge NewTopic


abort: nothing to merge


So I am puzzled.

Uwe Brauer