merge: introduce hasconflicts() on mergeresult object

This and upcoming patches will improve the mergeresult object making it more
powerful and provide clean APIs for various things. Doing this will clean up the
core merge code which is present in `update()` a bit.

Differential Revision: https://phab.mercurial-scm.org/D8816

mercurial/merge.py

@@ -581,6 +581,21 b' class mergeresult(object):'
     def setactions(self, actions):
         self._actions = actions
 
+    def hasconflicts(self):
+        """ tells whether this merge resulted in some actions which can
+        result in conflicts or not """
+        for _f, (m, _unused, _unused) in pycompat.iteritems(self._actions):
+            if m not in (
+                mergestatemod.ACTION_GET,
+                mergestatemod.ACTION_KEEP,
+                mergestatemod.ACTION_EXEC,
+                mergestatemod.ACTION_REMOVE,
+                mergestatemod.ACTION_PATH_CONFLICT_RESOLVE,
+            ):
+                return True
+
+        return False
+
 
 def manifestmerge(
     repo,
@@ -1809,17 +1824,10 b' def update('
         actionbyfile = mresult.actions
 
         if updatecheck == UPDATECHECK_NO_CONFLICT:
-            for f, (m, args, msg) in pycompat.iteritems(actionbyfile):
-                if m not in (
-                    mergestatemod.ACTION_GET,
-                    mergestatemod.ACTION_KEEP,
-                    mergestatemod.ACTION_EXEC,
-                    mergestatemod.ACTION_REMOVE,
-                    mergestatemod.ACTION_PATH_CONFLICT_RESOLVE,
-                ):
-                    msg = _(b"conflicting changes")
-                    hint = _(b"commit or update --clean to discard changes")
-                    raise error.Abort(msg, hint=hint)
+            if mresult.hasconflicts():
+                msg = _(b"conflicting changes")
+                hint = _(b"commit or update --clean to discard changes")
+                raise error.Abort(msg, hint=hint)
 
         # Prompt and create actions. Most of this is in the resolve phase
         # already, but we can't handle .hgsubstate in filemerge or