mergestate: store about files resolved in favour of other
Committing a merge sometimes wrongly creates a new filenode where it can re-use
an existing one. This happens because the commit code does it's own calculation
and does not know what happened on merge.
This starts storing information in mergestate about files which were
automatically merged and the other/remote version of file was used.
We need this information at commit to pick the filenode parent for the new
This issue was found by Pierre-Yves David and idea to store the relevant parts
in mergestate is also suggested by him.
Somethings which can be further investigated are:
- refactoring of commit logic more to depend on this information
- maybe a more generic solution?
Differential Revision: https://phab.mercurial-scm.org/D8392