copies: calculate mergecopies() based on pathcopies()

When copies are stored in changesets, we need a changeset-centric
version of mergecopies() just like we have a changeset-centric version
of pathcopies(). I think the natural way of thinking about
mergecopies() is in terms of pathcopies() from the base to each of the
commits. So if we can rewrite mergecopies() based on two such
pathcopies() calls, we'll get the changeset-centric version for
free. That's what this patch does.

A nice bonus is that it ends up being a lot simpler. mergecopies() has
accumulated a lot of technical debt over time. One good example is the
code for dealing with grafts (the "partial/incomplete/dirty"
stuff). Since pathcopies() already deals with backwards renames and
ping-pong renames, we get that for free.

I've run tests with hard-coded debug logging for "fullcopy" and while
I haven't looked at every difference it produces, all the ones I have
looked at seemed reasonable to me. I'm a little surprised that no more
tests fail when run with '--extra-config-opt
experimental.copies.read-from=compatibility' compared to before this
patch. This patch also fixes the broken cases in test-annotate.t and
test-fastannotate.t. It also enables the part of test-copies.t that
was previously disabled exactly because mergecopies() needed to get a
changeset-centric version.

One drawback of the rewritten code is that we may now make
remotefilelog prefetch more files. We used to prefetch files that were
unique to either side of the merge compared to the other. We now
prefetch files that are unique to either side of the merge compared to
the base. This means that if you added the same file to each side, we
would not prefetch it before, but we would now. Such cases are
probably quite rare, but one likely scenario where they happen is when
moving from a commit to its successor (or the other way around). The
user will probably already have the files in the cache in such cases,
so it's probably not a big deal.

Some timings for calculating mergecopies between two revisions
(revisions shown on each line, all using the common ancestor as base):

In the hg repo:
4.8 4.9: 0.21s -> 0.21s
4.0 4.8: 0.35s -> 0.63s

In and old copy of the mozilla-unified repo:
FIREFOX_BETA_60_BASE^ FIREFOX_BETA_60_BASE: 0.82s -> 0.82s
FIREFOX_NIGHTLY_59_END FIREFOX_BETA_60_BASE: 2.5s -> 2.6s
FIREFOX_BETA_59_END FIREFOX_BETA_60_BASE: 3.9s -> 4.1s
FIREFOX_AURORA_50_BASE FIREFOX_BETA_60_BASE: 31s -> 33s

So it's measurably slower in most cases. The most significant
difference is in the hg repo between revisions 4.0 and 4.8. In that
case it seems to come from the fact that pathcopies() uses
fctx.isintroducedafter() (in _tracefile), while the old mergecopies()
used fctx.linkrev() (in _checkcopies()). That results in a single call
to filectx._adjustlinkrev(), which is responsible for the entire
difference in time (in my repo). So we pay a performance penalty but
we get more correct code (see change in
test-mv-cp-st-diff.t). Deleting the "== f.filenode()" in _tracefile()
recovers the lost performance in the hg repo.

There were are few other optimizations in _checkcopies() that I could
not measure any impact from. One was from the "seen" set. Another was
from a "continue" when the file was not in the destination manifest
(corresponding to "am" in _tracefile).

Also note that merge copies are not calculated when updating with a
clean working copy, which is probably the most common case. I
therefore think the much simpler code is worth the slowdown.

Differential Revision: https://phab.mercurial-scm.org/D6255

mercurial/copies.py

@@ -373,57 +373,6 b' def _computenonoverlap(repo, c1, c2, add'
 
     return u1, u2
 
-def _makegetfctx(ctx):
-    """return a 'getfctx' function suitable for _checkcopies usage
-
-    We have to re-setup the function building 'filectx' for each
-    '_checkcopies' to ensure the linkrev adjustment is properly setup for
-    each. Linkrev adjustment is important to avoid bug in rename
-    detection. Moreover, having a proper '_ancestrycontext' setup ensures
-    the performance impact of this adjustment is kept limited. Without it,
-    each file could do a full dag traversal making the time complexity of
-    the operation explode (see issue4537).
-
-    This function exists here mostly to limit the impact on stable. Feel
-    free to refactor on default.
-    """
-    rev = ctx.rev()
-    repo = ctx._repo
-    ac = getattr(ctx, '_ancestrycontext', None)
-    if ac is None:
-        revs = [rev]
-        if rev is None:
-            revs = [p.rev() for p in ctx.parents()]
-        ac = repo.changelog.ancestors(revs, inclusive=True)
-        ctx._ancestrycontext = ac
-    def makectx(f, n):
-        if n in node.wdirfilenodeids:  # in a working context?
-            if ctx.rev() is None:
-                return ctx.filectx(f)
-            return repo[None][f]
-        fctx = repo.filectx(f, fileid=n)
-        # setup only needed for filectx not create from a changectx
-        fctx._ancestrycontext = ac
-        fctx._descendantrev = rev
-        return fctx
-    return util.lrucachefunc(makectx)
-
-def _combinecopies(copyfrom, copyto, finalcopy, diverge, incompletediverge):
-    """combine partial copy paths"""
-    remainder = {}
-    for f in copyfrom:
-        if f in copyto:
-            finalcopy[copyto[f]] = copyfrom[f]
-            del copyto[f]
-    for f in incompletediverge:
-        assert f not in diverge
-        ic = incompletediverge[f]
-        if ic[0] in copyto:
-            diverge[f] = [copyto[ic[0]], ic[1]]
-        else:
-            remainder[f] = ic
-    return remainder
-
 def mergecopies(repo, c1, c2, base):
     """
     Finds moves and copies between context c1 and c2 that are relevant for
@@ -518,6 +467,23 b' def _isfullcopytraceable(repo, c1, base)'
         return commits < sourcecommitlimit
     return False
 
+def _checksinglesidecopies(src, dsts1, m1, m2, mb, c2, base,
+                           copy, renamedelete):
+    if src not in m2:
+        # deleted on side 2
+        if src not in m1:
+            # renamed on side 1, deleted on side 2
+            renamedelete[src] = dsts1
+    elif m2[src] != mb[src]:
+        if not _related(c2[src], base[src]):
+            return
+        # modified on side 2
+        for dst in dsts1:
+            if dst not in m2:
+                # dst not added on side 2 (handle as regular
+                # "both created" case in manifestmerge otherwise)
+                copy[dst] = src
+
 def _fullcopytracing(repo, c1, c2, base):
     """ The full copytracing algorithm which finds all the new files that were
     added from merge base up to the top commit and for each file it checks if
@@ -526,168 +492,73 b' def _fullcopytracing(repo, c1, c2, base)'
     This is pretty slow when a lot of changesets are involved but will track all
     the copies.
     """
-    # In certain scenarios (e.g. graft, update or rebase), base can be
-    # overridden We still need to know a real common ancestor in this case We
-    # can't just compute _c1.ancestor(_c2) and compare it to ca, because there
-    # can be multiple common ancestors, e.g. in case of bidmerge.  Because our
-    # caller may not know if the revision passed in lieu of the CA is a genuine
-    # common ancestor or not without explicitly checking it, it's better to
-    # determine that here.
-    #
-    # base.isancestorof(wc) is False, work around that
-    _c1 = c1.p1() if c1.rev() is None else c1
-    _c2 = c2.p1() if c2.rev() is None else c2
-    # an endpoint is "dirty" if it isn't a descendant of the merge base
-    # if we have a dirty endpoint, we need to trigger graft logic, and also
-    # keep track of which endpoint is dirty
-    dirtyc1 = not base.isancestorof(_c1)
-    dirtyc2 = not base.isancestorof(_c2)
-    graft = dirtyc1 or dirtyc2
-    tca = base
-    if graft:
-        tca = _c1.ancestor(_c2)
-
-    limit = _findlimit(repo, c1, c2)
-
     m1 = c1.manifest()
     m2 = c2.manifest()
     mb = base.manifest()
 
-    # gather data from _checkcopies:
-    # - diverge = record all diverges in this dict
-    # - copy = record all non-divergent copies in this dict
-    # - fullcopy = record all copies in this dict
-    # - incomplete = record non-divergent partial copies here
-    # - incompletediverge = record divergent partial copies here
-    diverge = {} # divergence data is shared
-    incompletediverge  = {}
-    data1 = {'copy': {},
-             'fullcopy': {},
-             'incomplete': {},
-             'diverge': diverge,
-             'incompletediverge': incompletediverge,
-            }
-    data2 = {'copy': {},
-             'fullcopy': {},
-             'incomplete': {},
-             'diverge': diverge,
-             'incompletediverge': incompletediverge,
-            }
+    copies1 = pathcopies(base, c1)
+    copies2 = pathcopies(base, c2)
+
+    inversecopies1 = {}
+    inversecopies2 = {}
+    for dst, src in copies1.items():
+        inversecopies1.setdefault(src, []).append(dst)
+    for dst, src in copies2.items():
+        inversecopies2.setdefault(src, []).append(dst)
+
+    copy = {}
+    diverge = {}
+    renamedelete = {}
+    allsources = set(inversecopies1) | set(inversecopies2)
+    for src in allsources:
+        dsts1 = inversecopies1.get(src)
+        dsts2 = inversecopies2.get(src)
+        if dsts1 and dsts2:
+            # copied/renamed on both sides
+            if src not in m1 and src not in m2:
+                # renamed on both sides
+                dsts1 = set(dsts1)
+                dsts2 = set(dsts2)
+                # If there's some overlap in the rename destinations, we
+                # consider it not divergent. For example, if side 1 copies 'a'
+                # to 'b' and 'c' and deletes 'a', and side 2 copies 'a' to 'c'
+                # and 'd' and deletes 'a'.
+                if dsts1 & dsts2:
+                    for dst in (dsts1 & dsts2):
+                        copy[dst] = src
+                else:
+                    diverge[src] = sorted(dsts1 | dsts2)
+            elif src in m1 and src in m2:
+                # copied on both sides
+                dsts1 = set(dsts1)
+                dsts2 = set(dsts2)
+                for dst in (dsts1 & dsts2):
+                    copy[dst] = src
+            # TODO: Handle cases where it was renamed on one side and copied
+            # on the other side
+        elif dsts1:
+            # copied/renamed only on side 1
+            _checksinglesidecopies(src, dsts1, m1, m2, mb, c2, base,
+                                   copy, renamedelete)
+        elif dsts2:
+            # copied/renamed only on side 2
+            _checksinglesidecopies(src, dsts2, m2, m1, mb, c1, base,
+                                   copy, renamedelete)
+
+    renamedeleteset = set()
+    divergeset = set()
+    for src, dsts in diverge.items():
+        divergeset.update(dsts)
+    for src, dsts in renamedelete.items():
+        renamedeleteset.update(dsts)
 
     # find interesting file sets from manifests
     addedinm1 = m1.filesnotin(mb, repo.narrowmatch())
     addedinm2 = m2.filesnotin(mb, repo.narrowmatch())
-    bothnew = sorted(addedinm1 & addedinm2)
-    if tca == base:
-        # unmatched file from base
-        u1r, u2r = _computenonoverlap(repo, c1, c2, addedinm1, addedinm2)
-        u1u, u2u = u1r, u2r
-    else:
-        # unmatched file from base (DAG rotation in the graft case)
-        u1r, u2r = _computenonoverlap(repo, c1, c2, addedinm1, addedinm2)
-        # unmatched file from topological common ancestors (no DAG rotation)
-        # need to recompute this for directory move handling when grafting
-        mta = tca.manifest()
-        u1u, u2u = _computenonoverlap(repo, c1, c2,
-                                      m1.filesnotin(mta, repo.narrowmatch()),
-                                      m2.filesnotin(mta, repo.narrowmatch()),
-                                      debug=False)
-
-    for f in u1u:
-        _checkcopies(c1, c2, f, base, tca, dirtyc1, limit, data1)
-
-    for f in u2u:
-        _checkcopies(c2, c1, f, base, tca, dirtyc2, limit, data2)
-
-    copy = dict(data1['copy'])
-    copy.update(data2['copy'])
-    fullcopy = dict(data1['fullcopy'])
-    fullcopy.update(data2['fullcopy'])
-
-    if dirtyc1:
-        _combinecopies(data2['incomplete'], data1['incomplete'], copy, diverge,
-                       incompletediverge)
-    if dirtyc2:
-        _combinecopies(data1['incomplete'], data2['incomplete'], copy, diverge,
-                       incompletediverge)
-
-    renamedelete = {}
-    renamedeleteset = set()
-    divergeset = set()
-    for of, fl in list(diverge.items()):
-        if len(fl) == 1 or of in c1 or of in c2:
-            del diverge[of] # not actually divergent, or not a rename
-            if of not in c1 and of not in c2:
-                # renamed on one side, deleted on the other side, but filter
-                # out files that have been renamed and then deleted
-                renamedelete[of] = [f for f in fl if f in c1 or f in c2]
-                renamedeleteset.update(fl) # reverse map for below
-        else:
-            divergeset.update(fl) # reverse map for below
+    u1, u2 = _computenonoverlap(repo, c1, c2, addedinm1, addedinm2)
 
-    bothdiverge = {}
-    bothincompletediverge = {}
-    remainder = {}
-    both1 = {'copy': {},
-             'fullcopy': {},
-             'incomplete': {},
-             'diverge': bothdiverge,
-             'incompletediverge': bothincompletediverge
-            }
-    both2 = {'copy': {},
-             'fullcopy': {},
-             'incomplete': {},
-             'diverge': bothdiverge,
-             'incompletediverge': bothincompletediverge
-            }
-    for f in bothnew:
-        _checkcopies(c1, c2, f, base, tca, dirtyc1, limit, both1)
-        _checkcopies(c2, c1, f, base, tca, dirtyc2, limit, both2)
-    if dirtyc1 and dirtyc2:
-        remainder = _combinecopies(both2['incomplete'], both1['incomplete'],
-                                   copy, bothdiverge, bothincompletediverge)
-        remainder1 = _combinecopies(both1['incomplete'], both2['incomplete'],
-                                   copy, bothdiverge, bothincompletediverge)
-        remainder.update(remainder1)
-    elif dirtyc1:
-        # incomplete copies may only be found on the "dirty" side for bothnew
-        assert not both2['incomplete']
-        remainder = _combinecopies({}, both1['incomplete'], copy, bothdiverge,
-                                   bothincompletediverge)
-    elif dirtyc2:
-        assert not both1['incomplete']
-        remainder = _combinecopies({}, both2['incomplete'], copy, bothdiverge,
-                                   bothincompletediverge)
-    else:
-        # incomplete copies and divergences can't happen outside grafts
-        assert not both1['incomplete']
-        assert not both2['incomplete']
-        assert not bothincompletediverge
-    for f in remainder:
-        assert f not in bothdiverge
-        ic = remainder[f]
-        if ic[0] in (m1 if dirtyc1 else m2):
-            # backed-out rename on one side, but watch out for deleted files
-            bothdiverge[f] = ic
-    for of, fl in bothdiverge.items():
-        if len(fl) == 2 and fl[0] == fl[1]:
-            copy[fl[0]] = of # not actually divergent, just matching renames
-
-    # Sometimes we get invalid copies here (the "and not remotebase" in
-    # _checkcopies() seems suspicious). Filter them out.
-    for dst, src in fullcopy.copy().items():
-        if src not in mb:
-            del fullcopy[dst]
-    # Sometimes we forget to add entries from "copy" to "fullcopy", so fix
-    # that up here
-    for dst, src in copy.items():
-        fullcopy[dst] = src
-    # Sometimes we forget to add entries from "diverge" to "fullcopy", so fix
-    # that up here
-    for src, dsts in diverge.items():
-        for dst in dsts:
-            fullcopy[dst] = src
-
+    fullcopy = copies1.copy()
+    fullcopy.update(copies2)
     if not fullcopy:
         return copy, {}, diverge, renamedelete, {}
 
@@ -752,7 +623,7 b' def _fullcopytracing(repo, c1, c2, base)'
 
     movewithdir = {}
     # check unaccounted nonoverlapping files against directory moves
-    for f in u1r + u2r:
+    for f in u1 + u2:
         if f not in fullcopy:
             for d in dirmove:
                 if f.startswith(d):
@@ -899,99 +770,6 b' def _related(f1, f2):'
     except StopIteration:
         return False
 
-def _checkcopies(srcctx, dstctx, f, base, tca, remotebase, limit, data):
-    """
-    check possible copies of f from msrc to mdst
-
-    srcctx = starting context for f in msrc
-    dstctx = destination context for f in mdst
-    f = the filename to check (as in msrc)
-    base = the changectx used as a merge base
-    tca = topological common ancestor for graft-like scenarios
-    remotebase = True if base is outside tca::srcctx, False otherwise
-    limit = the rev number to not search beyond
-    data = dictionary of dictionary to store copy data. (see mergecopies)
-
-    note: limit is only an optimization, and provides no guarantee that
-    irrelevant revisions will not be visited
-    there is no easy way to make this algorithm stop in a guaranteed way
-    once it "goes behind a certain revision".
-    """
-
-    msrc = srcctx.manifest()
-    mdst = dstctx.manifest()
-    mb = base.manifest()
-    mta = tca.manifest()
-    # Might be true if this call is about finding backward renames,
-    # This happens in the case of grafts because the DAG is then rotated.
-    # If the file exists in both the base and the source, we are not looking
-    # for a rename on the source side, but on the part of the DAG that is
-    # traversed backwards.
-    #
-    # In the case there is both backward and forward renames (before and after
-    # the base) this is more complicated as we must detect a divergence.
-    # We use 'backwards = False' in that case.
-    backwards = not remotebase and base != tca and f in mb
-    getsrcfctx = _makegetfctx(srcctx)
-    getdstfctx = _makegetfctx(dstctx)
-
-    if msrc[f] == mb.get(f) and not remotebase:
-        # Nothing to merge
-        return
-
-    of = None
-    seen = {f}
-    for oc in getsrcfctx(f, msrc[f]).ancestors():
-        of = oc.path()
-        if of in seen:
-            # check limit late - grab last rename before
-            if oc.linkrev() < limit:
-                break
-            continue
-        seen.add(of)
-
-        # remember for dir rename detection
-        if backwards:
-            data['fullcopy'][of] = f # grafting backwards through renames
-        else:
-            data['fullcopy'][f] = of
-        if of not in mdst:
-            continue # no match, keep looking
-        if mdst[of] == mb.get(of):
-            return # no merge needed, quit early
-        c2 = getdstfctx(of, mdst[of])
-        # c2 might be a plain new file on added on destination side that is
-        # unrelated to the droids we are looking for.
-        cr = _related(oc, c2)
-        if cr and (of == f or of == c2.path()): # non-divergent
-            if backwards:
-                data['copy'][of] = f
-            elif of in mb:
-                data['copy'][f] = of
-            elif remotebase: # special case: a <- b <- a -> b "ping-pong" rename
-                data['copy'][of] = f
-                del data['fullcopy'][f]
-                data['fullcopy'][of] = f
-            else: # divergence w.r.t. graft CA on one side of topological CA
-                for sf in seen:
-                    if sf in mb:
-                        assert sf not in data['diverge']
-                        data['diverge'][sf] = [f, of]
-                        break
-            return
-
-    if of in mta:
-        if backwards or remotebase:
-            data['incomplete'][of] = f
-        else:
-            for sf in seen:
-                if sf in mb:
-                    if tca == base:
-                        data['diverge'].setdefault(sf, []).append(f)
-                    else:
-                        data['incompletediverge'][sf] = [of, f]
-                    return
-
 def duplicatecopies(repo, wctx, rev, fromrev, skiprev=None):
     """reproduce copies from fromrev to rev in the dirstate
 

tests/test-annotate.t

@@ -273,37 +273,10 b' annotate after merge with -l'
   > EOF
   $ hg ci -mc -d '3 0'
   created new head
-BROKEN: 'a' was copied to 'b' on both sides. We should not get a merge conflict here
   $ hg merge
   merging b
-  warning: conflicts while merging b! (edit, then use 'hg resolve --mark')
-  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
-  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
-  [1]
-  $ cat b
-  <<<<<<< working copy: b80e3e32f75a - test: c
-  a
-  z
-  a
-  ||||||| base
-  =======
-  a
-  a
-  a
-  b4
-  c
-  b5
-  >>>>>>> merge rev:    64afcdf8e29e - test: mergeb
-  $ cat <<EOF > b
-  > a
-  > z
-  > a
-  > b4
-  > c
-  > b5
-  > EOF
-  $ hg resolve --mark -q
-  $ rm b.orig
+  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
+  (branch merge, don't forget to commit)
   $ echo d >> b
   $ hg ci -mmerge2 -d '4 0'
 

tests/test-commit-amend.t

@@ -787,12 +787,11 b' Amend a merge changeset (with renames du'
 Update to p1 with 'aaa' modified. 'aaa' was renamed from 'aa' in p2. 'aa' exists
 in p1 too, but it was recorded as copied from p2.
   $ echo modified >> aaa
-BROKEN: should not be follow the rename back to 'aa' here, since the rename
-happened compared to p2
   $ hg co -m '.^' -t :merge3
-  merging aaa and aa to aa
-  warning: conflicts while merging aa! (edit, then use 'hg resolve --mark')
-  0 files updated, 0 files merged, 1 files removed, 1 files unresolved
+  file 'aaa' was deleted in other [destination] but was modified in local [working copy].
+  What do you want to do?
+  use (c)hanged version, (d)elete, or leave (u)nresolved? u
+  1 files updated, 0 files merged, 1 files removed, 1 files unresolved
   use 'hg resolve' to retry unresolved file merges
   [1]
   $ hg co -C tip

tests/test-copies.t

@@ -549,9 +549,6 b' test reflect that for this particular ca'
 
 Grafting revision 4 on top of revision 2, showing that it respect the rename:
 
-TODO: Make this work with copy info in changesets (probably by writing a
-changeset-centric version of copies.mergecopies())
-#if no-changeset
   $ hg up 2 -q
   $ hg graft -r 4 --base 3 --hidden
   grafting 4:af28412ec03c "added d, modified b" (tip)
@@ -560,15 +557,14 b' changeset-centric version of copies.merg'
   $ hg l -l1 -p
   @  5 added d, modified b
   |  b1
-  ~  diff -r 5a4825cc2926 -r 94a2f1a0e8e2 b1
+  ~  diff -r 5a4825cc2926 -r 94a2f1a0e8e2 b1 (no-changeset !)
+  ~  diff -r f5474f5023a8 -r ef7c02d69f3d b1 (changeset !)
      --- a/b1	Thu Jan 01 00:00:00 1970 +0000
      +++ b/b1	Thu Jan 01 00:00:00 1970 +0000
      @@ -1,1 +1,2 @@
       b
      +baba
   
-#endif
-
 Test to make sure that fullcopytracing algorithm don't fail when both the merging csets are dirty
 (a dirty cset is one who is not the descendant of merge base)
 -------------------------------------------------------------------------------------------------

tests/test-fastannotate-hg.t

@@ -273,37 +273,10 b' annotate after merge with -l'
   > EOF
   $ hg ci -mc -d '3 0'
   created new head
-BROKEN: 'a' was copied to 'b' on both sides. We should not get a merge conflict here
   $ hg merge
   merging b
-  warning: conflicts while merging b! (edit, then use 'hg resolve --mark')
-  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
-  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
-  [1]
-  $ cat b
-  <<<<<<< working copy: b80e3e32f75a - test: c
-  a
-  z
-  a
-  ||||||| base
-  =======
-  a
-  a
-  a
-  b4
-  c
-  b5
-  >>>>>>> merge rev:    64afcdf8e29e - test: mergeb
-  $ cat <<EOF > b
-  > a
-  > z
-  > a
-  > b4
-  > c
-  > b5
-  > EOF
-  $ hg resolve --mark -q
-  $ rm b.orig
+  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
+  (branch merge, don't forget to commit)
   $ echo d >> b
   $ hg ci -mmerge2 -d '4 0'
 

tests/test-graft.t

@@ -75,6 +75,8 b' Specifying child as --base revision fail'
 
   $ hg graft -r 2 --base 3
   grafting 2:5c095ad7e90f "2"
+  note: possible conflict - c was deleted and renamed to:
+   a
   note: graft of 2:5c095ad7e90f created no changes to commit
 
 Can't continue without starting:
@@ -220,6 +222,9 b' Graft out of order, skipping a merge and'
   committing changelog
   updating the branch cache
   grafting 5:97f8bfe72746 "5"
+    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
+     src: 'c' -> dst: 'b' 
+    checking for directory renames
   resolving manifests
    branchmerge: True, force: True, partial: False
    ancestor: 4c60f11aa304, local: 6b9e5368ca4e+, remote: 97f8bfe72746
@@ -233,6 +238,9 b' Graft out of order, skipping a merge and'
   $ HGEDITOR=cat hg graft 4 3 --log --debug
   scanning for duplicate grafts
   grafting 4:9c233e8e184d "4"
+    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
+     src: 'c' -> dst: 'b' 
+    checking for directory renames
   resolving manifests
    branchmerge: True, force: True, partial: False
    ancestor: 4c60f11aa304, local: 1905859650ec+, remote: 9c233e8e184d
@@ -1129,7 +1137,6 b' and A.3 with a local content change to b'
   grafting 2:f58c7e2b28fa "C0"
   merging f1e and f1b to f1e
   merging f2a and f2c to f2c
-  merging f5b and f5a to f5a
 
 Test the cases A.1 (f4x) and A.7 (f3x).
 

tests/test-mv-cp-st-diff.t

@@ -1688,13 +1688,8 b' Check debug output for copy tracing'
 Check that merging across the rename works
 
   $ echo modified >> renamed
-BROKEN: This should propagate the change to 'f'
   $ hg co -m 4
-  file 'renamed' was deleted in other [destination] but was modified in local [working copy].
-  What do you want to do?
-  use (c)hanged version, (d)elete, or leave (u)nresolved? u
-  1 files updated, 0 files merged, 0 files removed, 1 files unresolved
-  use 'hg resolve' to retry unresolved file merges
-  [1]
+  merging renamed and f to f
+  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
 
   $ cd ..

tests/test-rename-merge2.t

@@ -433,6 +433,9 b' m "um a c" "um x c" " " "10 do merg'
   --------------
   test L:nc a b R:up b   W:       - 12 merge b no ancestor
   --------------
+    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
+     src: 'a' -> dst: 'b' 
+    checking for directory renames
   resolving manifests
    branchmerge: True, force: False, partial: False
    ancestor: 924404dff337, local: 86a2aa42fc76+, remote: af30c7647fc7
@@ -469,6 +472,9 b' m "um a c" "um x c" " " "10 do merg'
   --------------
   test L:up b   R:nm a b W:       - 13 merge b no ancestor
   --------------
+    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
+     src: 'a' -> dst: 'b' 
+    checking for directory renames
   resolving manifests
    branchmerge: True, force: False, partial: False
    ancestor: 924404dff337, local: 59318016310c+, remote: bdb19105162a
@@ -506,6 +512,9 b' m "um a c" "um x c" " " "10 do merg'
   --------------
   test L:nc a b R:up a b W:       - 14 merge b no ancestor
   --------------
+    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
+     src: 'a' -> dst: 'b' 
+    checking for directory renames
   resolving manifests
    branchmerge: True, force: False, partial: False
    ancestor: 924404dff337, local: 86a2aa42fc76+, remote: 8dbce441892a
@@ -543,6 +552,9 b' m "um a c" "um x c" " " "10 do merg'
   --------------
   test L:up b   R:nm a b W:       - 15 merge b no ancestor, remove a
   --------------
+    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
+     src: 'a' -> dst: 'b' 
+    checking for directory renames
   resolving manifests
    branchmerge: True, force: False, partial: False
    ancestor: 924404dff337, local: 59318016310c+, remote: bdb19105162a
@@ -580,6 +592,9 b' m "um a c" "um x c" " " "10 do merg'
   --------------
   test L:nc a b R:up a b W:       - 16 get a, merge b no ancestor
   --------------
+    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
+     src: 'a' -> dst: 'b' 
+    checking for directory renames
   resolving manifests
    branchmerge: True, force: False, partial: False
    ancestor: 924404dff337, local: 86a2aa42fc76+, remote: 8dbce441892a
@@ -617,6 +632,9 b' m "um a c" "um x c" " " "10 do merg'
   --------------
   test L:up a b R:nc a b W:       - 17 keep a, merge b no ancestor
   --------------
+    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
+     src: 'a' -> dst: 'b' 
+    checking for directory renames
   resolving manifests
    branchmerge: True, force: False, partial: False
    ancestor: 924404dff337, local: 0b76e65c8289+, remote: 4ce40f5aca24
@@ -653,6 +671,9 b' m "um a c" "um x c" " " "10 do merg'
   --------------
   test L:nm a b R:up a b W:       - 18 merge b no ancestor
   --------------
+    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
+     src: 'a' -> dst: 'b' 
+    checking for directory renames
   resolving manifests
    branchmerge: True, force: False, partial: False
    ancestor: 924404dff337, local: 02963e448370+, remote: 8dbce441892a
@@ -695,6 +716,9 b' m "um a c" "um x c" " " "10 do merg'
   --------------
   test L:up a b R:nm a b W:       - 19 merge b no ancestor, prompt remove a
   --------------
+    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
+     src: 'a' -> dst: 'b' 
+    checking for directory renames
   resolving manifests
    branchmerge: True, force: False, partial: False
    ancestor: 924404dff337, local: 0b76e65c8289+, remote: bdb19105162a