mergestate: replace `addmergedother()` with generic `addcommitinfo()` (API)

Storing that a file is resolved for the other parent while merging is just one
case of things we will like to store in the mergestate. There are more which we
will like to store.

This patch replaces `addmergedother()` with a much more generic
`addcommitinfo()`. Doing this, we also blinding stores the same key value pair
generated by the merge code instead of touching them.

Differential Revision: https://phab.mercurial-scm.org/D8923

mercurial/merge.py

@@ -1367,8 +1367,7 b' def applyupdates('
     for f, op in pycompat.iteritems(mresult.commitinfo):
         # the other side of filenode was choosen while merging, store this in
         # mergestate so that it can be reused on commit
-        if op[b'filenode-source'] == b'other':
-            ms.addmergedother(f)
+        ms.addcommitinfo(f, op)
 
     moves = []
 

mercurial/mergestate.py

@@ -592,8 +592,10 b' class mergestate(object):'
         self._state[path] = [MERGE_RECORD_UNRESOLVED_PATH, frename, forigin]
         self._dirty = True
 
-    def addmergedother(self, path):
-        self._stateextras[path] = {b'filenode-source': b'other'}
+    def addcommitinfo(self, path, data):
+        """ stores information which is required at commit
+        into _stateextras """
+        self._stateextras[path].update(data)
         self._dirty = True
 
     def __contains__(self, dfile):