Use nullrev+count instead of count-1 in a newly introduced expression.
Before that repo.changelog.tip() was used, but this yields a node.
Of course many more places should be changed like this, this was just done
as an example.
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -2195,7 +2195,7 @@ def tip(ui, repo, **opts):
Show the tip revision.
"""
- cmdutil.show_changeset(ui, repo, opts).show(repo.changelog.count()-1)
+ cmdutil.show_changeset(ui, repo, opts).show(nullrev+repo.changelog.count())
def unbundle(ui, repo, fname, **opts):
"""apply a changegroup file