tests/test-race

branch heads: fix regression introduced in e67e5b60e55f (issue1726)

For merge nodes it is not adequate to only check a single possible
branch head for whether it is an ancestor of the latest head, but it
needs to be done for each possible branch head.

#!/bin/sh

mkdir t
cd t
hg init
echo a > a
hg add a
hg commit -m test

# do we ever miss a sub-second change?
for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20; do
    hg co -qC 0
    echo b > a
    hg st
done