changelog: refuse to add revisions with empty usernames An empty username or a username with a "\n" will make the revision text contain two "\n\n" sequences -> corrupt repository. The problem is that changelog.read expects to find exactly one "\n\n" separator and thus cannot unpack the revision.

#!/bin/sh

hg init
echo "nothing" > a
hg add a
hg commit -m ancestor -d "1000000 0"
echo "something" > a
hg commit -m branch1 -d "1000000 0"
hg co 0
echo "something else" > a
hg commit -m branch2 -d "1000000 0"
hg merge 1
hg id
cat a
hg status