copies: return None instead of ChangingFiles when relevant

If they are not relevant data, they are no need to fetch them.

Differential Revision: https://phab.mercurial-scm.org/D9140

mercurial/changelog.py

@@ -599,7 +599,7 class changelog(revlog.revlog):
         l = [hex(manifest), user, parseddate] + sortedfiles + [b"", desc]
         text = b"\n".join(l)
         return self.addrevision(
-            text, transaction, len(self), p1, p2, sidedata=sidedata
+            text, transaction, len(self), p1, p2, sidedata=sidedata, flags=flags
         )
 
     def branchinfo(self, rev):

mercurial/copies.py

@@ -24,6 +24,8 from . import (
 
 from .utils import stringutil
 
+from .revlogutils import flagutil
+
 
 def _filter(src, dst, t):
     """filters out invalid copies after chaining"""
@@ -179,6 +181,9 def _revinfo_getter(repo):
     """
     cl = repo.changelog
     parents = cl.parentrevs
+    flags = cl.flags
+
+    HASCOPIESINFO = flagutil.REVIDX_HASCOPIESINFO
 
     changelogrevision = cl.changelogrevision
 
@@ -213,7 +218,10 def _revinfo_getter(repo):
         e = merge_caches.pop(rev, None)
         if e is not None:
             return e
-        value = (p1, p2, changelogrevision(rev).changes)
+        changes = None
+        if flags(rev) & HASCOPIESINFO:
+            changes = changelogrevision(rev).changes
+        value = (p1, p2, changes)
         if p1 != node.nullrev and p2 != node.nullrev:
             # XXX some case we over cache, IGNORE
             merge_caches[rev] = value
@@ -293,12 +301,15 def _combine_changeset_copies(
             copies = {}
         for i, c in enumerate(children[r]):
             p1, p2, changes = revinfo(c)
+            childcopies = {}
             if r == p1:
                 parent = 1
+                if changes is not None:
                 childcopies = changes.copied_from_p1
             else:
                 assert r == p2
                 parent = 2
+                if changes is not None:
                 childcopies = changes.copied_from_p2
             if not alwaysmatch:
                 childcopies = {
@@ -313,6 +324,7 def _combine_changeset_copies(
                         source = prev[1]
                     newcopies[dest] = (c, source)
                 assert newcopies is not copies
+            if changes is not None:
             for f in changes.removed:
                 if f in newcopies:
                     if newcopies is copies:
@@ -373,13 +385,21 def _merge_copies_dict(minor, major, isa
             # than the branch point or there is a merge
             if new_tt == other_tt:
                 minor[dest] = value
-            elif value[1] is None and dest in changes.salvaged:
+            elif (
+                changes is not None
+                and value[1] is None
+                and dest in changes.salvaged
+            ):
                 pass
-            elif other[1] is None and dest in changes.salvaged:
+            elif (
+                changes is not None
+                and other[1] is None
+                and dest in changes.salvaged
+            ):
                 minor[dest] = value
             elif not isancestor(new_tt, other_tt):
                 minor[dest] = value
-            elif dest in changes.merged:
+            elif changes is not None and dest in changes.merged:
                 minor[dest] = value