merge: fix spurious merges for copies in linear updates

We make better use of contexts to accurately identify copies that
don't need merges.

Add a simple test and update other tests.

mercurial/merge.py

@@ -8,7 +8,7 b''
 from node import *
 from i18n import gettext as _
 from demandload import *
-demandload(globals(), "errno util os tempfile")
+demandload(globals(), "errno util os tempfile context")
 
 def filemerge(repo, fw, fo, wctx, mctx):
     """perform a 3-way merge in the working directory
@@ -123,6 +123,14 b' def findcopies(repo, m1, m2, ma, limit):'
                 f = dirname(f)
         return d
 
+    wctx = repo.workingctx()
+
+    def makectx(f, n):
+        if len(n) == 20:
+            return repo.filectx(f, fileid=n)
+        return wctx.filectx(f)
+    ctx = util.cachefunc(makectx)
+
     def findold(fctx):
         "find files that path was copied from, back to linkrev limit"
         old = {}
@@ -160,7 +168,7 b' def findcopies(repo, m1, m2, ma, limit):'
             # named changed on only one side?
             if ca.path() == c.path() or ca.path() == c2.path():
                 fullcopy[c.path()] = of # remember for dir rename detection
-                if c == c2: # no merge needed, ignore copy
+                if c == ca or c2 == ca: # no merge needed, ignore copy
                     continue
                 copy[c.path()] = of
 
@@ -171,13 +179,11 b' def findcopies(repo, m1, m2, ma, limit):'
     if not m1 or not m2 or not ma:
         return {}
 
-    dcopies = repo.dirstate.copies()
     u1 = nonoverlap(m1, m2, ma)
     u2 = nonoverlap(m2, m1, ma)
-    ctx = util.cachefunc(lambda f, n: repo.filectx(f, fileid=n[:20]))
 
     for f in u1:
-        checkcopies(ctx(dcopies.get(f, f), m1[f]), m2)
+        checkcopies(ctx(f, m1[f]), m2)
 
     for f in u2:
         checkcopies(ctx(f, m2[f]), m1)

tests/test-merge-local.out

@@ -21,7 +21,7 b' merging zzz1_merge_ok'
 merging zzz1_merge_ok failed!
 merging zzz2_merge_bad
 merging zzz2_merge_bad failed!
-3 files updated, 0 files merged, 1 files removed, 2 files unresolved
+3 files updated, 0 files merged, 2 files removed, 2 files unresolved
 There are unresolved merges with locally modified files.
 You can redo the full merge using:
   hg update 0
@@ -40,7 +40,7 b' merge: warning: conflicts during merge'
 merging zzz1_merge_ok
 merging zzz2_merge_bad
 merging zzz2_merge_bad failed!
-3 files updated, 1 files merged, 1 files removed, 1 files unresolved
+3 files updated, 1 files merged, 2 files removed, 1 files unresolved
 There are unresolved merges with locally modified files.
 You can finish the partial merge using:
   hg update 0
@@ -59,7 +59,7 b' M zzz1_merge_ok'
 M zzz2_merge_bad
 # local merge without conflicts
 merging zzz1_merge_ok
-4 files updated, 1 files merged, 1 files removed, 0 files unresolved
+4 files updated, 1 files merged, 2 files removed, 0 files unresolved
 --- a/zzz1_merge_ok
 +++ b/zzz1_merge_ok
 +new last line

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-dir-merge.out

@@ -10,39 +10,33 b' resolving manifests'
  overwrite None partial False
  ancestor f9b20c0d4c51 local ce36d17b18fb+ remote 55119e611c80
  a/c: remote renamed directory to b/c -> d
- a/a: remote moved to b/a -> m
- a/b: remote moved to b/b -> m
-copying a/a to b/a
+ a/b: other deleted -> r
+ a/a: other deleted -> r
+ b/a: remote created -> g
+ b/b: remote created -> g
 removing a/a
-copying a/b to b/b
 removing a/b
 moving a/c to b/c
-3 files updated, 0 files merged, 0 files removed, 0 files unresolved
+getting b/a
+getting b/b
+3 files updated, 0 files merged, 2 files removed, 0 files unresolved
 (branch merge, don't forget to commit)
 a/* b/a b/b b/c
 M b/a
-  a/a
 M b/b
-  a/b
 A b/c
   a/c
 R a/a
 R a/b
 R a/c
-2 files updated, 0 files merged, 1 files removed, 0 files unresolved
+0 files updated, 0 files merged, 1 files removed, 0 files unresolved
 resolving manifests
  overwrite None partial False
  ancestor f9b20c0d4c51 local 55119e611c80+ remote ce36d17b18fb
- b/a: local moved to a/a -> m
- b/b: local moved to a/b -> m
  None: local renamed directory to b/c -> d
 getting a/c to b/c
-3 files updated, 0 files merged, 0 files removed, 0 files unresolved
+1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 (branch merge, don't forget to commit)
 a/* b/a b/b b/c
-M b/a
-  a/a
-M b/b
-  a/b
 A b/c
   a/c

tests/test-rename-dir-merge2.out

@@ -10,11 +10,9 b' adding manifests'
 adding file changes
 added 1 changesets with 1 changes to 1 files (+1 heads)
 (run 'hg heads' to see heads, 'hg merge' to merge)
-merging a/f and b/f
-1 files updated, 1 files merged, 0 files removed, 0 files unresolved
+2 files updated, 0 files merged, 1 files removed, 0 files unresolved
 (branch merge, don't forget to commit)
 M b/f
-  a/f
 A b/aa/g
   a/aa/g
 R a/aa/g

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 to b -> 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 to a -> 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: other deleted -> r
  rev: versions differ -> m
- a: remote moved to b -> 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 to a -> 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
 --------------
 
 --------------