copies: avoid early return in _combine_changeset_copies

We have to change how we deal with matching (see next changeset) and that
processing is common. So we shuffle things around before doing the semantic
change for clarity.

Differential Revision: https://phab.mercurial-scm.org/D9584

mercurial/copies.py

@@ -357,10 +357,10 b' def _combine_changeset_copies('
     alwaysmatch = match.always()
 
     if rustmod is not None and alwaysmatch:
-        return rustmod.combine_changeset_copies(
+        final_copies = rustmod.combine_changeset_copies(
             list(revs), children_count, targetrev, revinfo, isancestor
         )
-
+    else:
     isancestor = cached_is_ancestor(isancestor)
 
     all_copies = {}
@@ -368,7 +368,6 b' def _combine_changeset_copies('
     for current_rev in revs:
         p1, p2, changes = revinfo(current_rev)
         current_copies = None
-
         # iterate over all parents to chain the existing data with the
         # data from the parent → child edge.
         for parent, parent_rev in ((1, p1), (2, p2)):
@@ -422,7 +421,6 b' def _combine_changeset_copies('
                                 # could be avoided.
                                 newcopies = copies.copy()
                             newcopies[f] = (current_rev, None)
-
             # check potential need to combine the data from another parent (for
             # that child). See comment below for details.
             if current_copies is None: