merge: introduce 'commitinfo' in mergeresult
commitinfo will be used to pass information which is required on commit phase
from the merge phase.
One common example is, merge chooses filenode from second parent and we need to
tell commit to choose that. Right now this one and related cases are not very
neatly implement and there is no clear line on how to pass on such information.
Upcoming patches will try to work on in this area and make things easier.
Differential Revision: https://phab.mercurial-scm.org/D8742
Our full contribution guidelines are in our wiki, please see:
https://www.mercurial-scm.org/wiki/ContributingChanges
If you just want a checklist to follow, you can go straight to
https://www.mercurial-scm.org/wiki/ContributingChanges#Submission_checklist
If you can't run the entire testsuite for some reason (it can be
difficult on Windows), please at least run `contrib/check-code.py` on
any files you've modified and run `python contrib/check-commit` on any
commits you've made (for example, `python contrib/check-commit
273ce12ad8f1` will report some style violations on a very old commit).