merge-base analog for Mercurial and bzr (to find common ancestors as possible for a merge)?

Question

Git have merge-base command that show common ancestors of two or more branches.

What analog for Mercurial and bzr?

Answer 1

For Bazaar:

bzr find-merge-base /path/to/branch1 /path/to/branch2

(This command is hidden from the main set of commands that you can obtain with bzr help commands. Use bzr help hidden-commands to see other hidden commands).

Answer 2

Use revsets:

"ancestor(single, single)"
      Greatest common ancestor of the two changesets.

$ hg log -r 'ancestor(rev1, rev2)'

Answer 3

For Mercurial:

hg debugancestor rev1 rev2