Comment 9 for bug 748141

It would be fine to add the currently "hidden" functionality to existing commands, perhaps under some optional switches. For example, lookup-revision and revision-info could be some special forms of output from "bzr revno" or "bzr version-info" (e.g., if the latter could accept a revisionspec as an argument).

I'm also okay with "bzr log -r ancestor:../trunk" as replacement for find-merge-base, but then please make their performance comparable, because right now find-merge-base blows "bzr log" out of the water, performance-wise. Observe:

eliz@fencepost:~/bzr/emacs/emacs-23$ time bzr log --line -r ancestor:../trunk
100531: Chong Yidong 2011-03-19 Backport fix for Bug#8219 from trunk.

real 0m13.940s
user 0m10.880s
sys 0m0.290s

eliz@fencepost:~/bzr/emacs/emacs-23$ time bzr find-merge-base . ../trunk
merge base is revision <email address hidden>

real 0m1.835s
user 0m1.730s
sys 0m0.100s

On Windows, the numbers are 20 sec and 5 sec respectively, also mostly in user-space.