merge: replace a repo.lookup('.') by more typical repo['.'].node()
The `repo.lookup('.')` form comes from b3311e26f94f (merge: fix
--preview to show all nodes that will be merged (issue2043).,
2010-02-15). I don't know why that commit changed from `repo['.']`,
but I don't think there's any reason to do that. Note that performance
should not be a reason (anymore?), because repo.lookup() is
implemented by first creating a context object.
Differential Revision: https://phab.mercurial-scm.org/D7998
--- a/mercurial/commands.py Fri Jan 24 16:07:42 2020 -0800
+++ b/mercurial/commands.py Fri Jan 24 15:18:19 2020 -0800
@@ -4881,7 +4881,7 @@
if opts.get(b'preview'):
# find nodes that are ancestors of p2 but not of p1
- p1 = repo.lookup(b'.')
+ p1 = repo[b'.'].node()
p2 = node
nodes = repo.changelog.findmissing(common=[p1], heads=[p2])