merge: pretend ancestor is local to simplify backwards and overwrite

mercurial/merge.py

@@ -133,6 +133,10 b' def manifestmerge(repo, p1, p2, pa, over'
     m2 = p2.manifest()
     ma = pa.manifest()
     backwards = (pa == p2)
+
+    if backwards or overwrite:
+        ma = m1
+
     action = []
     copy, copied, diverge = {}, {}, {}
 
@@ -209,7 +213,7 b' def manifestmerge(repo, p1, p2, pa, over'
             else: # case 4,21 A/B/B
                 act("local moved to " + f2, "m",
                     f, f2, f, fmerge(f, f2, f2), False)
-        elif f in ma:
+        elif f in ma and not n[20:]:
             if n != ma[f] and not overwrite:
                 if repo.ui.prompt(
                     _(" local changed %s which remote deleted\n"

tests/test-up-local-change.out

@@ -38,7 +38,7 b' summary: 2'
 resolving manifests
  overwrite False partial False
  ancestor 33aaa84a386b local 802f095af299+ remote 33aaa84a386b
- b: remote deleted -> r
+ b: other deleted -> r
 removing b
 0 files updated, 0 files merged, 1 files removed, 0 files unresolved
 changeset:   0:33aaa84a386b

tests/test-update-reverse.out

@@ -43,8 +43,8 b' side2'
 resolving manifests
  overwrite True partial False
  ancestor 537353581d3d local ded32b0db104+ remote 221226fb2bd8
- side2: remote deleted -> r
- side1: remote deleted -> r
+ side2: other deleted -> r
+ side1: other deleted -> r
  main: remote created -> g
 removing side1
 removing side2