merge: fix --preview to show all nodes that will be merged (
issue2043).
Formerly, it omitted nodes that were not descendants of the least
common ancestor of the two merge parents, even though those nodes
contribute to the merge. The new algorithm uses revlog.findmissing()
instead of ancestor() + nodesbetween().
#!/bin/sh
set -e
mkdir test
cd test
echo foo>foo
hg init
hg addremove
hg commit -m "1"
hg verify
hg clone . ../branch
cd ../branch
hg co
echo bar>>foo
hg commit -m "2"
cd ../test
hg pull ../branch
hg verify
hg co
cat foo
hg manifest --debug