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
hg init a
cd a
touch empty1
hg add empty1
hg commit -m 'add empty1' -d '1000000 0'
touch empty2
hg add empty2
hg commit -m 'add empty2' -d '1000000 0'
hg up -C 0
touch empty3
hg add empty3
hg commit -m 'add empty3' -d '1000000 0'
hg heads
hg merge 1
# before changeset 05257fd28591, we didn't notice the
# empty file that came from rev 1.
hg status
hg commit -m merge -d '1000000 0'
hg manifest --debug tip