avoid unnecessary copy merges

mercurial/merge.py

@@ -139,6 +139,8 b' def findcopies(repo, m1, m2, ma, limit):'
         ''' check if an apparent pair actually matches '''
         c2 = ctx(f2, man[f2])
         ca = c.ancestor(c2)
+        if c == ca or c2 == ca:
+            return
         if ca and ca.path() == c.path() or ca.path() == c2.path():
             copy[c.path()] = f2
             copy[f2] = c.path()

tests/test-merge8.out

@@ -6,5 +6,4 b' adding manifests'
 adding file changes
 added 2 changesets with 2 changes to 1 files
 (run 'hg update' to get a working copy)
-merging a and b
-0 files updated, 1 files merged, 0 files removed, 0 files unresolved
+1 files updated, 0 files merged, 1 files removed, 0 files unresolved

tests/test-rename-merge2.out

@@ -88,15 +88,14 b' resolving manifests'
  overwrite None partial False
  ancestor 924404dff337 local 94b33a1b7f2d+ remote 735846fee2d7
  rev: versions differ -> m
- a: remote copied -> m
-copying a to b
+ b: remote created -> g
+getting b
 merging rev
 my rev@94b33a1b7f2d+ other rev@735846fee2d7 ancestor rev@924404dff337
 1 files updated, 1 files merged, 0 files removed, 0 files unresolved
 (branch merge, don't forget to commit)
 --------------
 M b
-  a
 C a
 --------------
 
@@ -106,16 +105,14 b' test L:nc a b R: W: - 6 not'
 resolving manifests
  overwrite None partial False
  ancestor 924404dff337 local ac809aeed39a+ remote 97c705ade336
- b: local copied -> m
  rev: versions differ -> m
 merging rev
 my rev@ac809aeed39a+ other rev@97c705ade336 ancestor rev@924404dff337
-1 files updated, 1 files merged, 0 files removed, 0 files unresolved
+0 files updated, 1 files merged, 0 files removed, 0 files unresolved
 (branch merge, don't forget to commit)
 --------------
-M b
-  a
 C a
+C b
 --------------
 
 --------------
@@ -124,17 +121,17 b' test L: R:nm a b W: - 7 get'
 resolving manifests
  overwrite None partial False
  ancestor 924404dff337 local 94b33a1b7f2d+ remote e03727d2d66b
- a: remote moved -> m
+ a: other deleted -> r
  rev: versions differ -> m
-copying a to b
+ b: remote created -> g
 removing a
+getting b
 merging rev
 my rev@94b33a1b7f2d+ other rev@e03727d2d66b ancestor rev@924404dff337
-1 files updated, 1 files merged, 0 files removed, 0 files unresolved
+1 files updated, 1 files merged, 1 files removed, 0 files unresolved
 (branch merge, don't forget to commit)
 --------------
 M b
-  a
 --------------
 
 --------------
@@ -143,15 +140,13 b' test L:nm a b R: W: - 8 not'
 resolving manifests
  overwrite None partial False
  ancestor 924404dff337 local ecf3cb2a4219+ remote 97c705ade336
- b: local moved -> m
  rev: versions differ -> m
 merging rev
 my rev@ecf3cb2a4219+ other rev@97c705ade336 ancestor rev@924404dff337
-1 files updated, 1 files merged, 0 files removed, 0 files unresolved
+0 files updated, 1 files merged, 0 files removed, 0 files unresolved
 (branch merge, don't forget to commit)
 --------------
-M b
-  a
+C b
 --------------
 
 --------------