histedit: abort if there are multiple roots in "--outgoing" revisions Before this patch, if there are multiple roots in "--outgoing" revisions, result of "histedit --outgoing" depends on the parent of the working directory. It succeeds only when the parent of the working directory is a descendant of the oldest root in "--outgoing" revisions, and fails otherwise. It seems to be ambiguous and difficult for users. This patch makes "histedit --outgoing" abort if there are multiple roots in "--outgoing" revisions always.

discovery: abort also when pushing multiple headed new branch Before this patch, pushing with --new-branch permits to create multiple headed branch on the destination repository. But permitting to create new branch should be different from permitting to create multiple heads on branch. This patch prevents from careless pushing multiple headed new branch, and requires --force to push such branch forcibly.