copies: detect case when a merge decision overwrite previous data

We now detect and record when a merge case required special logic (eg: thing
that append during the merge, ambiguity leading to picking p1 data, etc) and we
explicitly mark the result as superseding the previous data.

This fixes the family of test we previously added.

Differential Revision: https://phab.mercurial-scm.org/D9613

mercurial/copies.py

@@ -1,1269 +1,1281 b''
 # coding: utf8
 # copies.py - copy detection for Mercurial
 #
 # Copyright 2008 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from __future__ import absolute_import
 
 import collections
 import os
 
 from .i18n import _
 from .node import (
     nullid,
     nullrev,
 )
 
 from . import (
     match as matchmod,
     pathutil,
     policy,
     pycompat,
     util,
 )
 
 
 from .utils import stringutil
 
 from .revlogutils import (
     flagutil,
     sidedata as sidedatamod,
 )
 
 rustmod = policy.importrust("copy_tracing")
 
 
 def _filter(src, dst, t):
     """filters out invalid copies after chaining"""
 
     # When _chain()'ing copies in 'a' (from 'src' via some other commit 'mid')
     # with copies in 'b' (from 'mid' to 'dst'), we can get the different cases
     # in the following table (not including trivial cases). For example, case 6
     # is where a file existed in 'src' and remained under that name in 'mid' and
     # then was renamed between 'mid' and 'dst'.
     #
     # case src mid dst result
     #   1   x   y   -    -
     #   2   x   y   y   x->y
     #   3   x   y   x    -
     #   4   x   y   z   x->z
     #   5   -   x   y    -
     #   6   x   x   y   x->y
     #
     # _chain() takes care of chaining the copies in 'a' and 'b', but it
     # cannot tell the difference between cases 1 and 2, between 3 and 4, or
     # between 5 and 6, so it includes all cases in its result.
     # Cases 1, 3, and 5 are then removed by _filter().
 
     for k, v in list(t.items()):
         if k == v:  # case 3
             del t[k]
         elif v not in src:  # case 5
             # remove copies from files that didn't exist
             del t[k]
         elif k not in dst:  # case 1
             # remove copies to files that were then removed
             del t[k]
 
 
 def _chain(prefix, suffix):
     """chain two sets of copies 'prefix' and 'suffix'"""
     result = prefix.copy()
     for key, value in pycompat.iteritems(suffix):
         result[key] = prefix.get(value, value)
     return result
 
 
 def _tracefile(fctx, am, basemf):
     """return file context that is the ancestor of fctx present in ancestor
     manifest am
 
     Note: we used to try and stop after a given limit, however checking if that
     limit is reached turned out to be very expensive. we are better off
     disabling that feature."""
 
     for f in fctx.ancestors():
         path = f.path()
         if am.get(path, None) == f.filenode():
             return path
         if basemf and basemf.get(path, None) == f.filenode():
             return path
 
 
 def _dirstatecopies(repo, match=None):
     ds = repo.dirstate
     c = ds.copies().copy()
     for k in list(c):
         if ds[k] not in b'anm' or (match and not match(k)):
             del c[k]
     return c
 
 
 def _computeforwardmissing(a, b, match=None):
     """Computes which files are in b but not a.
     This is its own function so extensions can easily wrap this call to see what
     files _forwardcopies is about to process.
     """
     ma = a.manifest()
     mb = b.manifest()
     return mb.filesnotin(ma, match=match)
 
 
 def usechangesetcentricalgo(repo):
     """Checks if we should use changeset-centric copy algorithms"""
     if repo.filecopiesmode == b'changeset-sidedata':
         return True
     readfrom = repo.ui.config(b'experimental', b'copies.read-from')
     changesetsource = (b'changeset-only', b'compatibility')
     return readfrom in changesetsource
 
 
 def _committedforwardcopies(a, b, base, match):
     """Like _forwardcopies(), but b.rev() cannot be None (working copy)"""
     # files might have to be traced back to the fctx parent of the last
     # one-side-only changeset, but not further back than that
     repo = a._repo
 
     if usechangesetcentricalgo(repo):
         return _changesetforwardcopies(a, b, match)
 
     debug = repo.ui.debugflag and repo.ui.configbool(b'devel', b'debug.copies')
     dbg = repo.ui.debug
     if debug:
         dbg(b'debug.copies:    looking into rename from %s to %s\n' % (a, b))
     am = a.manifest()
     basemf = None if base is None else base.manifest()
 
     # find where new files came from
     # we currently don't try to find where old files went, too expensive
     # this means we can miss a case like 'hg rm b; hg cp a b'
     cm = {}
 
     # Computing the forward missing is quite expensive on large manifests, since
     # it compares the entire manifests. We can optimize it in the common use
     # case of computing what copies are in a commit versus its parent (like
     # during a rebase or histedit). Note, we exclude merge commits from this
     # optimization, since the ctx.files() for a merge commit is not correct for
     # this comparison.
     forwardmissingmatch = match
     if b.p1() == a and b.p2().node() == nullid:
         filesmatcher = matchmod.exact(b.files())
         forwardmissingmatch = matchmod.intersectmatchers(match, filesmatcher)
     if repo.ui.configbool(b'devel', b'copy-tracing.trace-all-files'):
         missing = list(b.walk(match))
         # _computeforwardmissing(a, b, match=forwardmissingmatch)
         if debug:
             dbg(b'debug.copies:      searching all files: %d\n' % len(missing))
     else:
         missing = _computeforwardmissing(a, b, match=forwardmissingmatch)
         if debug:
             dbg(
                 b'debug.copies:      missing files to search: %d\n'
                 % len(missing)
             )
 
     ancestrycontext = a._repo.changelog.ancestors([b.rev()], inclusive=True)
 
     for f in sorted(missing):
         if debug:
             dbg(b'debug.copies:        tracing file: %s\n' % f)
         fctx = b[f]
         fctx._ancestrycontext = ancestrycontext
 
         if debug:
             start = util.timer()
         opath = _tracefile(fctx, am, basemf)
         if opath:
             if debug:
                 dbg(b'debug.copies:          rename of: %s\n' % opath)
             cm[f] = opath
         if debug:
             dbg(
                 b'debug.copies:          time: %f seconds\n'
                 % (util.timer() - start)
             )
     return cm
 
 
 def _revinfo_getter(repo, match):
     """returns a function that returns the following data given a <rev>"
 
     * p1: revision number of first parent
     * p2: revision number of first parent
     * changes: a ChangingFiles object
     """
     cl = repo.changelog
     parents = cl.parentrevs
     flags = cl.flags
 
     HASCOPIESINFO = flagutil.REVIDX_HASCOPIESINFO
 
     changelogrevision = cl.changelogrevision
 
     if rustmod is not None:
 
         def revinfo(rev):
             p1, p2 = parents(rev)
             if flags(rev) & HASCOPIESINFO:
                 raw = changelogrevision(rev)._sidedata.get(sidedatamod.SD_FILES)
             else:
                 raw = None
             return (p1, p2, raw)
 
     else:
 
         def revinfo(rev):
             p1, p2 = parents(rev)
             if flags(rev) & HASCOPIESINFO:
                 changes = changelogrevision(rev).changes
             else:
                 changes = None
             return (p1, p2, changes)
 
     return revinfo
 
 
 def cached_is_ancestor(is_ancestor):
     """return a cached version of is_ancestor"""
     cache = {}
 
     def _is_ancestor(anc, desc):
         if anc > desc:
             return False
         elif anc == desc:
             return True
         key = (anc, desc)
         ret = cache.get(key)
         if ret is None:
             ret = cache[key] = is_ancestor(anc, desc)
         return ret
 
     return _is_ancestor
 
 
 def _changesetforwardcopies(a, b, match):
     if a.rev() in (nullrev, b.rev()):
         return {}
 
     repo = a.repo().unfiltered()
     children = {}
 
     cl = repo.changelog
     isancestor = cl.isancestorrev
 
     # To track rename from "A" to B, we need to gather all parent → children
     # edges that are contains in `::B` but not in `::A`.
     #
     #
     # To do so, we need to gather all revisions exclusive¹ to "B" (ie¹: `::b -
     # ::a`) and also all the "roots point", ie the parents of the exclusive set
     # that belong to ::a. These are exactly all the revisions needed to express
     # the parent → children we need to combine.
     #
     # [1] actually, we need to gather all the edges within `(::a)::b`, ie:
     # excluding paths that leads to roots that are not ancestors of `a`. We
     # keep this out of the explanation because it is hard enough without this special case..
 
     parents = cl._uncheckedparentrevs
     graph_roots = (nullrev, nullrev)
 
     ancestors = cl.ancestors([a.rev()], inclusive=True)
     revs = cl.findmissingrevs(common=[a.rev()], heads=[b.rev()])
     roots = set()
     has_graph_roots = False
 
     # iterate over `only(B, A)`
     for r in revs:
         ps = parents(r)
         if ps == graph_roots:
             has_graph_roots = True
         else:
             p1, p2 = ps
 
             # find all the "root points" (see larger comment above)
             if p1 != nullrev and p1 in ancestors:
                 roots.add(p1)
             if p2 != nullrev and p2 in ancestors:
                 roots.add(p2)
     if not roots:
         # no common revision to track copies from
         return {}
     if has_graph_roots:
         # this deal with the special case mentionned in the [1] footnotes. We
         # must filter out revisions that leads to non-common graphroots.
         roots = list(roots)
         m = min(roots)
         h = [b.rev()]
         roots_to_head = cl.reachableroots(m, h, roots, includepath=True)
         roots_to_head = set(roots_to_head)
         revs = [r for r in revs if r in roots_to_head]
 
     if repo.filecopiesmode == b'changeset-sidedata':
         # When using side-data, we will process the edges "from" the children.
         # We iterate over the childre, gathering previous collected data for
         # the parents. Do know when the parents data is no longer necessary, we
         # keep a counter of how many children each revision has.
         #
         # An interresting property of `children_count` is that it only contains
         # revision that will be relevant for a edge of the graph. So if a
         # children has parent not in `children_count`, that edges should not be
         # processed.
         children_count = dict((r, 0) for r in roots)
         for r in revs:
             for p in cl.parentrevs(r):
                 if p == nullrev:
                     continue
                 children_count[r] = 0
                 if p in children_count:
                     children_count[p] += 1
         revinfo = _revinfo_getter(repo, match)
         return _combine_changeset_copies(
             revs, children_count, b.rev(), revinfo, match, isancestor
         )
     else:
         # When not using side-data, we will process the edges "from" the parent.
         # so we need a full mapping of the parent -> children relation.
         children = dict((r, []) for r in roots)
         for r in revs:
             for p in cl.parentrevs(r):
                 if p == nullrev:
                     continue
                 children[r] = []
                 if p in children:
                     children[p].append(r)
         x = revs.pop()
         assert x == b.rev()
         revs.extend(roots)
         revs.sort()
 
         revinfo = _revinfo_getter_extra(repo)
         return _combine_changeset_copies_extra(
             revs, children, b.rev(), revinfo, match, isancestor
         )
 
 
 def _combine_changeset_copies(
     revs, children_count, targetrev, revinfo, match, isancestor
 ):
     """combine the copies information for each item of iterrevs
 
     revs: sorted iterable of revision to visit
     children_count: a {parent: <number-of-relevant-children>} mapping.
     targetrev: the final copies destination revision (not in iterrevs)
     revinfo(rev): a function that return (p1, p2, p1copies, p2copies, removed)
     match: a matcher
 
     It returns the aggregated copies information for `targetrev`.
     """
 
     alwaysmatch = match.always()
 
     if rustmod is not None:
         final_copies = rustmod.combine_changeset_copies(
             list(revs), children_count, targetrev, revinfo, isancestor
         )
     else:
         isancestor = cached_is_ancestor(isancestor)
 
         all_copies = {}
         # iterate over all the "children" side of copy tracing "edge"
         for current_rev in revs:
             p1, p2, changes = revinfo(current_rev)
             current_copies = None
             # iterate over all parents to chain the existing data with the
             # data from the parent → child edge.
             for parent, parent_rev in ((1, p1), (2, p2)):
                 if parent_rev == nullrev:
                     continue
                 remaining_children = children_count.get(parent_rev)
                 if remaining_children is None:
                     continue
                 remaining_children -= 1
                 children_count[parent_rev] = remaining_children
                 if remaining_children:
                     copies = all_copies.get(parent_rev, None)
                 else:
                     copies = all_copies.pop(parent_rev, None)
 
                 if copies is None:
                     # this is a root
                     newcopies = copies = {}
                 elif remaining_children:
                     newcopies = copies.copy()
                 else:
                     newcopies = copies
                 # chain the data in the edge with the existing data
                 if changes is not None:
                     childcopies = {}
                     if parent == 1:
                         childcopies = changes.copied_from_p1
                     elif parent == 2:
                         childcopies = changes.copied_from_p2
 
                     if childcopies:
                         newcopies = copies.copy()
                         for dest, source in pycompat.iteritems(childcopies):
                             prev = copies.get(source)
                             if prev is not None and prev[1] is not None:
                                 source = prev[1]
                             newcopies[dest] = (current_rev, source)
                         assert newcopies is not copies
                     if changes.removed:
                         for f in changes.removed:
                             if f in newcopies:
                                 if newcopies is copies:
                                     # copy on write to avoid affecting potential other
                                     # branches.  when there are no other branches, this
                                     # could be avoided.
                                     newcopies = copies.copy()
                                 newcopies[f] = (current_rev, None)
                 # check potential need to combine the data from another parent (for
                 # that child). See comment below for details.
                 if current_copies is None:
                     current_copies = newcopies
                 else:
                     # we are the second parent to work on c, we need to merge our
                     # work with the other.
                     #
                     # In case of conflict, parent 1 take precedence over parent 2.
                     # This is an arbitrary choice made anew when implementing
                     # changeset based copies. It was made without regards with
                     # potential filelog related behavior.
                     assert parent == 2
                     current_copies = _merge_copies_dict(
-                        newcopies, current_copies, isancestor, changes
+                        newcopies,
+                        current_copies,
+                        isancestor,
+                        changes,
+                        current_rev,
                     )
             all_copies[current_rev] = current_copies
 
         # filter out internal details and return a {dest: source mapping}
         final_copies = {}
         for dest, (tt, source) in all_copies[targetrev].items():
             if source is not None:
                 final_copies[dest] = source
     if not alwaysmatch:
         for filename in list(final_copies.keys()):
             if not match(filename):
                 del final_copies[filename]
     return final_copies
 
 
 # constant to decide which side to pick with _merge_copies_dict
 PICK_MINOR = 0
 PICK_MAJOR = 1
 PICK_EITHER = 2
 
 
-def _merge_copies_dict(minor, major, isancestor, changes):
+def _merge_copies_dict(minor, major, isancestor, changes, current_merge):
     """merge two copies-mapping together, minor and major
 
     In case of conflict, value from "major" will be picked.
 
     - `isancestors(low_rev, high_rev)`: callable return True if `low_rev` is an
                                         ancestors of `high_rev`,
 
     - `ismerged(path)`: callable return True if `path` have been merged in the
                         current revision,
 
     return the resulting dict (in practice, the "minor" object, updated)
     """
     for dest, value in major.items():
         other = minor.get(dest)
         if other is None:
             minor[dest] = value
         else:
-            pick = _compare_values(changes, isancestor, dest, other, value)
-            if pick == PICK_MAJOR:
+            pick, overwrite = _compare_values(
+                changes, isancestor, dest, other, value
+            )
+            if overwrite:
+                if pick == PICK_MAJOR:
+                    minor[dest] = (current_merge, value[1])
+                else:
+                    minor[dest] = (current_merge, other[1])
+            elif pick == PICK_MAJOR:
                 minor[dest] = value
     return minor
 
 
 def _compare_values(changes, isancestor, dest, minor, major):
     """compare two value within a _merge_copies_dict loop iteration
 
-    return pick
+    return (pick, overwrite).
 
     - pick is one of PICK_MINOR, PICK_MAJOR or PICK_EITHER
+    - overwrite is True if pick is a return of an ambiguity that needs resolution.
     """
     major_tt, major_value = major
     minor_tt, minor_value = minor
 
     if major_tt == minor_tt:
         # if it comes from the same revision it must be the same value
         assert major_value == minor_value
-        return PICK_EITHER
+        return PICK_EITHER, False
     elif (
         changes is not None
         and minor_value is not None
         and major_value is None
         and dest in changes.salvaged
     ):
         # In this case, a deletion was reverted, the "alive" value overwrite
         # the deleted one.
-        return PICK_MINOR
+        return PICK_MINOR, True
     elif (
         changes is not None
         and major_value is not None
         and minor_value is None
         and dest in changes.salvaged
     ):
         # In this case, a deletion was reverted, the "alive" value overwrite
         # the deleted one.
-        return PICK_MAJOR
+        return PICK_MAJOR, True
     elif isancestor(minor_tt, major_tt):
         if changes is not None and dest in changes.merged:
             # change to dest happened on the branch without copy-source change,
             # so both source are valid and "major" wins.
-            return PICK_MAJOR
+            return PICK_MAJOR, True
         else:
-            return PICK_MAJOR
+            return PICK_MAJOR, False
     elif isancestor(major_tt, minor_tt):
         if changes is not None and dest in changes.merged:
             # change to dest happened on the branch without copy-source change,
             # so both source are valid and "major" wins.
-            return PICK_MAJOR
+            return PICK_MAJOR, True
         else:
-            return PICK_MINOR
+            return PICK_MINOR, False
     elif minor_value is None:
         # in case of conflict, the "alive" side wins.
-        return PICK_MAJOR
+        return PICK_MAJOR, True
     elif major_value is None:
         # in case of conflict, the "alive" side wins.
-        return PICK_MINOR
+        return PICK_MINOR, True
     else:
         # in case of conflict where both side are alive, major wins.
-        return PICK_MAJOR
+        return PICK_MAJOR, True
 
 
 def _revinfo_getter_extra(repo):
     """return a function that return multiple data given a <rev>"i
 
     * p1: revision number of first parent
     * p2: revision number of first parent
     * p1copies: mapping of copies from p1
     * p2copies: mapping of copies from p2
     * removed: a list of removed files
     * ismerged: a callback to know if file was merged in that revision
     """
     cl = repo.changelog
     parents = cl.parentrevs
 
     def get_ismerged(rev):
         ctx = repo[rev]
 
         def ismerged(path):
             if path not in ctx.files():
                 return False
             fctx = ctx[path]
             parents = fctx._filelog.parents(fctx._filenode)
             nb_parents = 0
             for n in parents:
                 if n != nullid:
                     nb_parents += 1
             return nb_parents >= 2
 
         return ismerged
 
     def revinfo(rev):
         p1, p2 = parents(rev)
         ctx = repo[rev]
         p1copies, p2copies = ctx._copies
         removed = ctx.filesremoved()
         return p1, p2, p1copies, p2copies, removed, get_ismerged(rev)
 
     return revinfo
 
 
 def _combine_changeset_copies_extra(
     revs, children, targetrev, revinfo, match, isancestor
 ):
     """version of `_combine_changeset_copies` that works with the Google
     specific "extra" based storage for copy information"""
     all_copies = {}
     alwaysmatch = match.always()
     for r in revs:
         copies = all_copies.pop(r, None)
         if copies is None:
             # this is a root
             copies = {}
         for i, c in enumerate(children[r]):
             p1, p2, p1copies, p2copies, removed, ismerged = revinfo(c)
             if r == p1:
                 parent = 1
                 childcopies = p1copies
             else:
                 assert r == p2
                 parent = 2
                 childcopies = p2copies
             if not alwaysmatch:
                 childcopies = {
                     dst: src for dst, src in childcopies.items() if match(dst)
                 }
             newcopies = copies
             if childcopies:
                 newcopies = copies.copy()
                 for dest, source in pycompat.iteritems(childcopies):
                     prev = copies.get(source)
                     if prev is not None and prev[1] is not None:
                         source = prev[1]
                     newcopies[dest] = (c, source)
                 assert newcopies is not copies
             for f in removed:
                 if f in newcopies:
                     if newcopies is copies:
                         # copy on write to avoid affecting potential other
                         # branches.  when there are no other branches, this
                         # could be avoided.
                         newcopies = copies.copy()
                     newcopies[f] = (c, None)
             othercopies = all_copies.get(c)
             if othercopies is None:
                 all_copies[c] = newcopies
             else:
                 # we are the second parent to work on c, we need to merge our
                 # work with the other.
                 #
                 # In case of conflict, parent 1 take precedence over parent 2.
                 # This is an arbitrary choice made anew when implementing
                 # changeset based copies. It was made without regards with
                 # potential filelog related behavior.
                 if parent == 1:
                     _merge_copies_dict_extra(
                         othercopies, newcopies, isancestor, ismerged
                     )
                 else:
                     _merge_copies_dict_extra(
                         newcopies, othercopies, isancestor, ismerged
                     )
                     all_copies[c] = newcopies
 
     final_copies = {}
     for dest, (tt, source) in all_copies[targetrev].items():
         if source is not None:
             final_copies[dest] = source
     return final_copies
 
 
 def _merge_copies_dict_extra(minor, major, isancestor, ismerged):
     """version of `_merge_copies_dict` that works with the Google
     specific "extra" based storage for copy information"""
     for dest, value in major.items():
         other = minor.get(dest)
         if other is None:
             minor[dest] = value
         else:
             new_tt = value[0]
             other_tt = other[0]
             if value[1] == other[1]:
                 continue
             # content from "major" wins, unless it is older
             # than the branch point or there is a merge
             if (
                 new_tt == other_tt
                 or not isancestor(new_tt, other_tt)
                 or ismerged(dest)
             ):
                 minor[dest] = value
 
 
 def _forwardcopies(a, b, base=None, match=None):
     """find {dst@b: src@a} copy mapping where a is an ancestor of b"""
 
     if base is None:
         base = a
     match = a.repo().narrowmatch(match)
     # check for working copy
     if b.rev() is None:
         cm = _committedforwardcopies(a, b.p1(), base, match)
         # combine copies from dirstate if necessary
         copies = _chain(cm, _dirstatecopies(b._repo, match))
     else:
         copies = _committedforwardcopies(a, b, base, match)
     return copies
 
 
 def _backwardrenames(a, b, match):
     if a._repo.ui.config(b'experimental', b'copytrace') == b'off':
         return {}
 
     # Even though we're not taking copies into account, 1:n rename situations
     # can still exist (e.g. hg cp a b; hg mv a c). In those cases we
     # arbitrarily pick one of the renames.
     # We don't want to pass in "match" here, since that would filter
     # the destination by it. Since we're reversing the copies, we want
     # to filter the source instead.
     f = _forwardcopies(b, a)
     r = {}
     for k, v in sorted(pycompat.iteritems(f)):
         if match and not match(v):
             continue
         # remove copies
         if v in a:
             continue
         r[v] = k
     return r
 
 
 def pathcopies(x, y, match=None):
     """find {dst@y: src@x} copy mapping for directed compare"""
     repo = x._repo
     debug = repo.ui.debugflag and repo.ui.configbool(b'devel', b'debug.copies')
     if debug:
         repo.ui.debug(
             b'debug.copies: searching copies from %s to %s\n' % (x, y)
         )
     if x == y or not x or not y:
         return {}
     if y.rev() is None and x == y.p1():
         if debug:
             repo.ui.debug(b'debug.copies: search mode: dirstate\n')
         # short-circuit to avoid issues with merge states
         return _dirstatecopies(repo, match)
     a = y.ancestor(x)
     if a == x:
         if debug:
             repo.ui.debug(b'debug.copies: search mode: forward\n')
         copies = _forwardcopies(x, y, match=match)
     elif a == y:
         if debug:
             repo.ui.debug(b'debug.copies: search mode: backward\n')
         copies = _backwardrenames(x, y, match=match)
     else:
         if debug:
             repo.ui.debug(b'debug.copies: search mode: combined\n')
         base = None
         if a.rev() != nullrev:
             base = x
         copies = _chain(
             _backwardrenames(x, a, match=match),
             _forwardcopies(a, y, base, match=match),
         )
     _filter(x, y, copies)
     return copies
 
 
 def mergecopies(repo, c1, c2, base):
     """
     Finds moves and copies between context c1 and c2 that are relevant for
     merging. 'base' will be used as the merge base.
 
     Copytracing is used in commands like rebase, merge, unshelve, etc to merge
     files that were moved/ copied in one merge parent and modified in another.
     For example:
 
     o          ---> 4 another commit
     |
     |   o      ---> 3 commit that modifies a.txt
     |  /
     o /        ---> 2 commit that moves a.txt to b.txt
     |/
     o          ---> 1 merge base
 
     If we try to rebase revision 3 on revision 4, since there is no a.txt in
     revision 4, and if user have copytrace disabled, we prints the following
     message:
 
     ```other changed <file> which local deleted```
 
     Returns a tuple where:
 
     "branch_copies" an instance of branch_copies.
 
     "diverge" is a mapping of source name -> list of destination names
     for divergent renames.
 
     This function calls different copytracing algorithms based on config.
     """
     # avoid silly behavior for update from empty dir
     if not c1 or not c2 or c1 == c2:
         return branch_copies(), branch_copies(), {}
 
     narrowmatch = c1.repo().narrowmatch()
 
     # avoid silly behavior for parent -> working dir
     if c2.node() is None and c1.node() == repo.dirstate.p1():
         return (
             branch_copies(_dirstatecopies(repo, narrowmatch)),
             branch_copies(),
             {},
         )
 
     copytracing = repo.ui.config(b'experimental', b'copytrace')
     if stringutil.parsebool(copytracing) is False:
         # stringutil.parsebool() returns None when it is unable to parse the
         # value, so we should rely on making sure copytracing is on such cases
         return branch_copies(), branch_copies(), {}
 
     if usechangesetcentricalgo(repo):
         # The heuristics don't make sense when we need changeset-centric algos
         return _fullcopytracing(repo, c1, c2, base)
 
     # Copy trace disabling is explicitly below the node == p1 logic above
     # because the logic above is required for a simple copy to be kept across a
     # rebase.
     if copytracing == b'heuristics':
         # Do full copytracing if only non-public revisions are involved as
         # that will be fast enough and will also cover the copies which could
         # be missed by heuristics
         if _isfullcopytraceable(repo, c1, base):
             return _fullcopytracing(repo, c1, c2, base)
         return _heuristicscopytracing(repo, c1, c2, base)
     else:
         return _fullcopytracing(repo, c1, c2, base)
 
 
 def _isfullcopytraceable(repo, c1, base):
     """Checks that if base, source and destination are all no-public branches,
     if yes let's use the full copytrace algorithm for increased capabilities
     since it will be fast enough.
 
     `experimental.copytrace.sourcecommitlimit` can be used to set a limit for
     number of changesets from c1 to base such that if number of changesets are
     more than the limit, full copytracing algorithm won't be used.
     """
     if c1.rev() is None:
         c1 = c1.p1()
     if c1.mutable() and base.mutable():
         sourcecommitlimit = repo.ui.configint(
             b'experimental', b'copytrace.sourcecommitlimit'
         )
         commits = len(repo.revs(b'%d::%d', base.rev(), c1.rev()))
         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 src not in mb:
         # Work around the "short-circuit to avoid issues with merge states"
         # thing in pathcopies(): pathcopies(x, y) can return a copy where the
         # destination doesn't exist in y.
         pass
     elif mb[src] != m2[src] and not _related(c2[src], base[src]):
         return
     elif mb[src] != m2[src] or mb.flags(src) != m2.flags(src):
         # modified on side 2
         for dst in dsts1:
             copy[dst] = src
 
 
 class branch_copies(object):
     """Information about copies made on one side of a merge/graft.
 
     "copy" is a mapping from destination name -> source name,
     where source is in c1 and destination is in c2 or vice-versa.
 
     "movewithdir" is a mapping from source name -> destination name,
     where the file at source present in one context but not the other
     needs to be moved to destination by the merge process, because the
     other context moved the directory it is in.
 
     "renamedelete" is a mapping of source name -> list of destination
     names for files deleted in c1 that were renamed in c2 or vice-versa.
 
     "dirmove" is a mapping of detected source dir -> destination dir renames.
     This is needed for handling changes to new files previously grafted into
     renamed directories.
     """
 
     def __init__(
         self, copy=None, renamedelete=None, dirmove=None, movewithdir=None
     ):
         self.copy = {} if copy is None else copy
         self.renamedelete = {} if renamedelete is None else renamedelete
         self.dirmove = {} if dirmove is None else dirmove
         self.movewithdir = {} if movewithdir is None else movewithdir
 
     def __repr__(self):
         return '<branch_copies\n  copy=%r\n  renamedelete=%r\n  dirmove=%r\n  movewithdir=%r\n>' % (
             self.copy,
             self.renamedelete,
             self.dirmove,
             self.movewithdir,
         )
 
 
 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
     this file was copied from another file.
 
     This is pretty slow when a lot of changesets are involved but will track all
     the copies.
     """
     m1 = c1.manifest()
     m2 = c2.manifest()
     mb = base.manifest()
 
     copies1 = pathcopies(base, c1)
     copies2 = pathcopies(base, c2)
 
     if not (copies1 or copies2):
         return branch_copies(), branch_copies(), {}
 
     inversecopies1 = {}
     inversecopies2 = {}
     for dst, src in copies1.items():
         inversecopies1.setdefault(src, []).append(dst)
     for dst, src in copies2.items():
         inversecopies2.setdefault(src, []).append(dst)
 
     copy1 = {}
     copy2 = {}
     diverge = {}
     renamedelete1 = {}
     renamedelete2 = {}
     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:
                         copy1[dst] = src
                         copy2[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:
                     copy1[dst] = src
                     copy2[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, copy1, renamedelete1
             )
         elif dsts2:
             # copied/renamed only on side 2
             _checksinglesidecopies(
                 src, dsts2, m2, m1, mb, c1, base, copy2, renamedelete2
             )
 
     # find interesting file sets from manifests
     cache = []
 
     def _get_addedfiles(idx):
         if not cache:
             addedinm1 = m1.filesnotin(mb, repo.narrowmatch())
             addedinm2 = m2.filesnotin(mb, repo.narrowmatch())
             u1 = sorted(addedinm1 - addedinm2)
             u2 = sorted(addedinm2 - addedinm1)
             cache.extend((u1, u2))
         return cache[idx]
 
     u1fn = lambda: _get_addedfiles(0)
     u2fn = lambda: _get_addedfiles(1)
     if repo.ui.debugflag:
         u1 = u1fn()
         u2 = u2fn()
 
         header = b"  unmatched files in %s"
         if u1:
             repo.ui.debug(
                 b"%s:\n   %s\n" % (header % b'local', b"\n   ".join(u1))
             )
         if u2:
             repo.ui.debug(
                 b"%s:\n   %s\n" % (header % b'other', b"\n   ".join(u2))
             )
 
         renamedeleteset = set()
         divergeset = set()
         for dsts in diverge.values():
             divergeset.update(dsts)
         for dsts in renamedelete1.values():
             renamedeleteset.update(dsts)
         for dsts in renamedelete2.values():
             renamedeleteset.update(dsts)
 
         repo.ui.debug(
             b"  all copies found (* = to merge, ! = divergent, "
             b"% = renamed and deleted):\n"
         )
         for side, copies in ((b"local", copies1), (b"remote", copies2)):
             if not copies:
                 continue
             repo.ui.debug(b"   on %s side:\n" % side)
             for f in sorted(copies):
                 note = b""
                 if f in copy1 or f in copy2:
                     note += b"*"
                 if f in divergeset:
                     note += b"!"
                 if f in renamedeleteset:
                     note += b"%"
                 repo.ui.debug(
                     b"    src: '%s' -> dst: '%s' %s\n" % (copies[f], f, note)
                 )
         del renamedeleteset
         del divergeset
 
     repo.ui.debug(b"  checking for directory renames\n")
 
     dirmove1, movewithdir2 = _dir_renames(repo, c1, copy1, copies1, u2fn)
     dirmove2, movewithdir1 = _dir_renames(repo, c2, copy2, copies2, u1fn)
 
     branch_copies1 = branch_copies(copy1, renamedelete1, dirmove1, movewithdir1)
     branch_copies2 = branch_copies(copy2, renamedelete2, dirmove2, movewithdir2)
 
     return branch_copies1, branch_copies2, diverge
 
 
 def _dir_renames(repo, ctx, copy, fullcopy, addedfilesfn):
     """Finds moved directories and files that should move with them.
 
     ctx: the context for one of the sides
     copy: files copied on the same side (as ctx)
     fullcopy: files copied on the same side (as ctx), including those that
               merge.manifestmerge() won't care about
     addedfilesfn: function returning added files on the other side (compared to
                   ctx)
     """
     # generate a directory move map
     invalid = set()
     dirmove = {}
 
     # examine each file copy for a potential directory move, which is
     # when all the files in a directory are moved to a new directory
     for dst, src in pycompat.iteritems(fullcopy):
         dsrc, ddst = pathutil.dirname(src), pathutil.dirname(dst)
         if dsrc in invalid:
             # already seen to be uninteresting
             continue
         elif ctx.hasdir(dsrc) and ctx.hasdir(ddst):
             # directory wasn't entirely moved locally
             invalid.add(dsrc)
         elif dsrc in dirmove and dirmove[dsrc] != ddst:
             # files from the same directory moved to two different places
             invalid.add(dsrc)
         else:
             # looks good so far
             dirmove[dsrc] = ddst
 
     for i in invalid:
         if i in dirmove:
             del dirmove[i]
     del invalid
 
     if not dirmove:
         return {}, {}
 
     dirmove = {k + b"/": v + b"/" for k, v in pycompat.iteritems(dirmove)}
 
     for d in dirmove:
         repo.ui.debug(
             b"   discovered dir src: '%s' -> dst: '%s'\n" % (d, dirmove[d])
         )
 
     movewithdir = {}
     # check unaccounted nonoverlapping files against directory moves
     for f in addedfilesfn():
         if f not in fullcopy:
             for d in dirmove:
                 if f.startswith(d):
                     # new file added in a directory that was moved, move it
                     df = dirmove[d] + f[len(d) :]
                     if df not in copy:
                         movewithdir[f] = df
                         repo.ui.debug(
                             b"   pending file src: '%s' -> dst: '%s'\n"
                             % (f, df)
                         )
                     break
 
     return dirmove, movewithdir
 
 
 def _heuristicscopytracing(repo, c1, c2, base):
     """Fast copytracing using filename heuristics
 
     Assumes that moves or renames are of following two types:
 
     1) Inside a directory only (same directory name but different filenames)
     2) Move from one directory to another
                     (same filenames but different directory names)
 
     Works only when there are no merge commits in the "source branch".
     Source branch is commits from base up to c2 not including base.
 
     If merge is involved it fallbacks to _fullcopytracing().
 
     Can be used by setting the following config:
 
         [experimental]
         copytrace = heuristics
 
     In some cases the copy/move candidates found by heuristics can be very large
     in number and that will make the algorithm slow. The number of possible
     candidates to check can be limited by using the config
     `experimental.copytrace.movecandidateslimit` which defaults to 100.
     """
 
     if c1.rev() is None:
         c1 = c1.p1()
     if c2.rev() is None:
         c2 = c2.p1()
 
     changedfiles = set()
     m1 = c1.manifest()
     if not repo.revs(b'%d::%d', base.rev(), c2.rev()):
         # If base is not in c2 branch, we switch to fullcopytracing
         repo.ui.debug(
             b"switching to full copytracing as base is not "
             b"an ancestor of c2\n"
         )
         return _fullcopytracing(repo, c1, c2, base)
 
     ctx = c2
     while ctx != base:
         if len(ctx.parents()) == 2:
             # To keep things simple let's not handle merges
             repo.ui.debug(b"switching to full copytracing because of merges\n")
             return _fullcopytracing(repo, c1, c2, base)
         changedfiles.update(ctx.files())
         ctx = ctx.p1()
 
     copies2 = {}
     cp = _forwardcopies(base, c2)
     for dst, src in pycompat.iteritems(cp):
         if src in m1:
             copies2[dst] = src
 
     # file is missing if it isn't present in the destination, but is present in
     # the base and present in the source.
     # Presence in the base is important to exclude added files, presence in the
     # source is important to exclude removed files.
     filt = lambda f: f not in m1 and f in base and f in c2
     missingfiles = [f for f in changedfiles if filt(f)]
 
     copies1 = {}
     if missingfiles:
         basenametofilename = collections.defaultdict(list)
         dirnametofilename = collections.defaultdict(list)
 
         for f in m1.filesnotin(base.manifest()):
             basename = os.path.basename(f)
             dirname = os.path.dirname(f)
             basenametofilename[basename].append(f)
             dirnametofilename[dirname].append(f)
 
         for f in missingfiles:
             basename = os.path.basename(f)
             dirname = os.path.dirname(f)
             samebasename = basenametofilename[basename]
             samedirname = dirnametofilename[dirname]
             movecandidates = samebasename + samedirname
             # f is guaranteed to be present in c2, that's why
             # c2.filectx(f) won't fail
             f2 = c2.filectx(f)
             # we can have a lot of candidates which can slow down the heuristics
             # config value to limit the number of candidates moves to check
             maxcandidates = repo.ui.configint(
                 b'experimental', b'copytrace.movecandidateslimit'
             )
 
             if len(movecandidates) > maxcandidates:
                 repo.ui.status(
                     _(
                         b"skipping copytracing for '%s', more "
                         b"candidates than the limit: %d\n"
                     )
                     % (f, len(movecandidates))
                 )
                 continue
 
             for candidate in movecandidates:
                 f1 = c1.filectx(candidate)
                 if _related(f1, f2):
                     # if there are a few related copies then we'll merge
                     # changes into all of them. This matches the behaviour
                     # of upstream copytracing
                     copies1[candidate] = f
 
     return branch_copies(copies1), branch_copies(copies2), {}
 
 
 def _related(f1, f2):
     """return True if f1 and f2 filectx have a common ancestor
 
     Walk back to common ancestor to see if the two files originate
     from the same file. Since workingfilectx's rev() is None it messes
     up the integer comparison logic, hence the pre-step check for
     None (f1 and f2 can only be workingfilectx's initially).
     """
 
     if f1 == f2:
         return True  # a match
 
     g1, g2 = f1.ancestors(), f2.ancestors()
     try:
         f1r, f2r = f1.linkrev(), f2.linkrev()
 
         if f1r is None:
             f1 = next(g1)
         if f2r is None:
             f2 = next(g2)
 
         while True:
             f1r, f2r = f1.linkrev(), f2.linkrev()
             if f1r > f2r:
                 f1 = next(g1)
             elif f2r > f1r:
                 f2 = next(g2)
             else:  # f1 and f2 point to files in the same linkrev
                 return f1 == f2  # true if they point to the same file
     except StopIteration:
         return False
 
 
 def graftcopies(wctx, ctx, base):
     """reproduce copies between base and ctx in the wctx
 
     Unlike mergecopies(), this function will only consider copies between base
     and ctx; it will ignore copies between base and wctx. Also unlike
     mergecopies(), this function will apply copies to the working copy (instead
     of just returning information about the copies). That makes it cheaper
     (especially in the common case of base==ctx.p1()) and useful also when
     experimental.copytrace=off.
 
     merge.update() will have already marked most copies, but it will only
     mark copies if it thinks the source files are related (see
     merge._related()). It will also not mark copies if the file wasn't modified
     on the local side. This function adds the copies that were "missed"
     by merge.update().
     """
     new_copies = pathcopies(base, ctx)
     parent = wctx.p1()
     _filter(parent, wctx, new_copies)
     # Extra filtering to drop copy information for files that existed before
     # the graft. This is to handle the case of grafting a rename onto a commit
     # that already has the rename. Otherwise the presence of copy information
     # would result in the creation of an empty commit where we would prefer to
     # not create one.
     for dest, __ in list(new_copies.items()):
         if dest in parent:
             del new_copies[dest]
     for dst, src in pycompat.iteritems(new_copies):
         wctx[dst].markcopied(src)

rust/hg-core/src/copy_tracing.rs

@@ -1,815 +1,871 b''
 use crate::utils::hg_path::HgPath;
 use crate::utils::hg_path::HgPathBuf;
 use crate::Revision;
 use crate::NULL_REVISION;
 
 use im_rc::ordmap::DiffItem;
 use im_rc::ordmap::Entry;
 use im_rc::ordmap::OrdMap;
 
 use std::cmp::Ordering;
 use std::collections::HashMap;
 use std::convert::TryInto;
 
 pub type PathCopies = HashMap<HgPathBuf, HgPathBuf>;
 
 type PathToken = usize;
 
 #[derive(Clone, Debug, PartialEq, Copy)]
 struct TimeStampedPathCopy {
     /// revision at which the copy information was added
     rev: Revision,
     /// the copy source, (Set to None in case of deletion of the associated
     /// key)
     path: Option<PathToken>,
 }
 
 /// maps CopyDestination to Copy Source (+ a "timestamp" for the operation)
 type TimeStampedPathCopies = OrdMap<PathToken, TimeStampedPathCopy>;
 
 /// hold parent 1, parent 2 and relevant files actions.
 pub type RevInfo<'a> = (Revision, Revision, ChangedFiles<'a>);
 
 /// represent the files affected by a changesets
 ///
 /// This hold a subset of mercurial.metadata.ChangingFiles as we do not need
 /// all the data categories tracked by it.
 /// This hold a subset of mercurial.metadata.ChangingFiles as we do not need
 /// all the data categories tracked by it.
 pub struct ChangedFiles<'a> {
     nb_items: u32,
     index: &'a [u8],
     data: &'a [u8],
 }
 
 /// Represent active changes that affect the copy tracing.
 enum Action<'a> {
     /// The parent ? children edge is removing a file
     ///
     /// (actually, this could be the edge from the other parent, but it does
     /// not matters)
     Removed(&'a HgPath),
     /// The parent ? children edge introduce copy information between (dest,
     /// source)
     Copied(&'a HgPath, &'a HgPath),
 }
 
 /// This express the possible "special" case we can get in a merge
 ///
 /// See mercurial/metadata.py for details on these values.
 #[derive(PartialEq)]
 enum MergeCase {
     /// Merged: file had history on both side that needed to be merged
     Merged,
     /// Salvaged: file was candidate for deletion, but survived the merge
     Salvaged,
     /// Normal: Not one of the two cases above
     Normal,
 }
 
 type FileChange<'a> = (u8, &'a HgPath, &'a HgPath);
 
 const EMPTY: &[u8] = b"";
 const COPY_MASK: u8 = 3;
 const P1_COPY: u8 = 2;
 const P2_COPY: u8 = 3;
 const ACTION_MASK: u8 = 28;
 const REMOVED: u8 = 12;
 const MERGED: u8 = 8;
 const SALVAGED: u8 = 16;
 
 impl<'a> ChangedFiles<'a> {
     const INDEX_START: usize = 4;
     const ENTRY_SIZE: u32 = 9;
     const FILENAME_START: u32 = 1;
     const COPY_SOURCE_START: u32 = 5;
 
     pub fn new(data: &'a [u8]) -> Self {
         assert!(
             data.len() >= 4,
             "data size ({}) is too small to contain the header (4)",
             data.len()
         );
         let nb_items_raw: [u8; 4] = (&data[0..=3])
             .try_into()
             .expect("failed to turn 4 bytes into 4 bytes");
         let nb_items = u32::from_be_bytes(nb_items_raw);
 
         let index_size = (nb_items * Self::ENTRY_SIZE) as usize;
         let index_end = Self::INDEX_START + index_size;
 
         assert!(
             data.len() >= index_end,
             "data size ({}) is too small to fit the index_data ({})",
             data.len(),
             index_end
         );
 
         let ret = ChangedFiles {
             nb_items,
             index: &data[Self::INDEX_START..index_end],
             data: &data[index_end..],
         };
         let max_data = ret.filename_end(nb_items - 1) as usize;
         assert!(
             ret.data.len() >= max_data,
             "data size ({}) is too small to fit all data ({})",
             data.len(),
             index_end + max_data
         );
         ret
     }
 
     pub fn new_empty() -> Self {
         ChangedFiles {
             nb_items: 0,
             index: EMPTY,
             data: EMPTY,
         }
     }
 
     /// internal function to return an individual entry at a given index
     fn entry(&'a self, idx: u32) -> FileChange<'a> {
         if idx >= self.nb_items {
             panic!(
                 "index for entry is higher that the number of file {} >= {}",
                 idx, self.nb_items
             )
         }
         let flags = self.flags(idx);
         let filename = self.filename(idx);
         let copy_idx = self.copy_idx(idx);
         let copy_source = self.filename(copy_idx);
         (flags, filename, copy_source)
     }
 
     /// internal function to return the filename of the entry at a given index
     fn filename(&self, idx: u32) -> &HgPath {
         let filename_start;
         if idx == 0 {
             filename_start = 0;
         } else {
             filename_start = self.filename_end(idx - 1)
         }
         let filename_end = self.filename_end(idx);
         let filename_start = filename_start as usize;
         let filename_end = filename_end as usize;
         HgPath::new(&self.data[filename_start..filename_end])
     }
 
     /// internal function to return the flag field of the entry at a given
     /// index
     fn flags(&self, idx: u32) -> u8 {
         let idx = idx as usize;
         self.index[idx * (Self::ENTRY_SIZE as usize)]
     }
 
     /// internal function to return the end of a filename part at a given index
     fn filename_end(&self, idx: u32) -> u32 {
         let start = (idx * Self::ENTRY_SIZE) + Self::FILENAME_START;
         let end = (idx * Self::ENTRY_SIZE) + Self::COPY_SOURCE_START;
         let start = start as usize;
         let end = end as usize;
         let raw = (&self.index[start..end])
             .try_into()
             .expect("failed to turn 4 bytes into 4 bytes");
         u32::from_be_bytes(raw)
     }
 
     /// internal function to return index of the copy source of the entry at a
     /// given index
     fn copy_idx(&self, idx: u32) -> u32 {
         let start = (idx * Self::ENTRY_SIZE) + Self::COPY_SOURCE_START;
         let end = (idx + 1) * Self::ENTRY_SIZE;
         let start = start as usize;
         let end = end as usize;
         let raw = (&self.index[start..end])
             .try_into()
             .expect("failed to turn 4 bytes into 4 bytes");
         u32::from_be_bytes(raw)
     }
 
     /// Return an iterator over all the `Action` in this instance.
     fn iter_actions(&self, parent: Parent) -> ActionsIterator {
         ActionsIterator {
             changes: &self,
             parent: parent,
             current: 0,
         }
     }
 
     /// return the MergeCase value associated with a filename
     fn get_merge_case(&self, path: &HgPath) -> MergeCase {
         if self.nb_items == 0 {
             return MergeCase::Normal;
         }
         let mut low_part = 0;
         let mut high_part = self.nb_items;
 
         while low_part < high_part {
             let cursor = (low_part + high_part - 1) / 2;
             let (flags, filename, _source) = self.entry(cursor);
             match path.cmp(filename) {
                 Ordering::Less => low_part = cursor + 1,
                 Ordering::Greater => high_part = cursor,
                 Ordering::Equal => {
                     return match flags & ACTION_MASK {
                         MERGED => MergeCase::Merged,
                         SALVAGED => MergeCase::Salvaged,
                         _ => MergeCase::Normal,
                     };
                 }
             }
         }
         MergeCase::Normal
     }
 }
 
 /// A struct responsible for answering "is X ancestors of Y" quickly
 ///
 /// The structure will delegate ancestors call to a callback, and cache the
 /// result.
 #[derive(Debug)]
 struct AncestorOracle<'a, A: Fn(Revision, Revision) -> bool> {
     inner: &'a A,
     pairs: HashMap<(Revision, Revision), bool>,
 }
 
 impl<'a, A: Fn(Revision, Revision) -> bool> AncestorOracle<'a, A> {
     fn new(func: &'a A) -> Self {
         Self {
             inner: func,
             pairs: HashMap::default(),
         }
     }
 
     fn record_overwrite(&mut self, anc: Revision, desc: Revision) {
         self.pairs.insert((anc, desc), true);
     }
 
     /// returns `true` if `anc` is an ancestors of `desc`, `false` otherwise
     fn is_overwrite(&mut self, anc: Revision, desc: Revision) -> bool {
         if anc > desc {
             false
         } else if anc == desc {
             true
         } else {
             if let Some(b) = self.pairs.get(&(anc, desc)) {
                 *b
             } else {
                 let b = (self.inner)(anc, desc);
                 self.pairs.insert((anc, desc), b);
                 b
             }
         }
     }
 }
 
 struct ActionsIterator<'a> {
     changes: &'a ChangedFiles<'a>,
     parent: Parent,
     current: u32,
 }
 
 impl<'a> Iterator for ActionsIterator<'a> {
     type Item = Action<'a>;
 
     fn next(&mut self) -> Option<Action<'a>> {
         let copy_flag = match self.parent {
             Parent::FirstParent => P1_COPY,
             Parent::SecondParent => P2_COPY,
         };
         while self.current < self.changes.nb_items {
             let (flags, file, source) = self.changes.entry(self.current);
             self.current += 1;
             if (flags & ACTION_MASK) == REMOVED {
                 return Some(Action::Removed(file));
             }
             let copy = flags & COPY_MASK;
             if copy == copy_flag {
                 return Some(Action::Copied(file, source));
             }
         }
         return None;
     }
 }
 
 /// A small struct whose purpose is to ensure lifetime of bytes referenced in
 /// ChangedFiles
 ///
 /// It is passed to the RevInfoMaker callback who can assign any necessary
 /// content to the `data` attribute. The copy tracing code is responsible for
 /// keeping the DataHolder alive at least as long as the ChangedFiles object.
 pub struct DataHolder<D> {
     /// RevInfoMaker callback should assign data referenced by the
     /// ChangedFiles struct it return to this attribute. The DataHolder
     /// lifetime will be at least as long as the ChangedFiles one.
     pub data: Option<D>,
 }
 
 pub type RevInfoMaker<'a, D> =
     Box<dyn for<'r> Fn(Revision, &'r mut DataHolder<D>) -> RevInfo<'r> + 'a>;
 
 /// enum used to carry information about the parent → child currently processed
 #[derive(Copy, Clone, Debug)]
 enum Parent {
     /// The `p1(x) → x` edge
     FirstParent,
     /// The `p2(x) → x` edge
     SecondParent,
 }
 
 /// A small "tokenizer" responsible of turning full HgPath into lighter
 /// PathToken
 ///
 /// Dealing with small object, like integer is much faster, so HgPath input are
 /// turned into integer "PathToken" and converted back in the end.
 #[derive(Clone, Debug, Default)]
 struct TwoWayPathMap {
     token: HashMap<HgPathBuf, PathToken>,
     path: Vec<HgPathBuf>,
 }
 
 impl TwoWayPathMap {
     fn tokenize(&mut self, path: &HgPath) -> PathToken {
         match self.token.get(path) {
             Some(a) => *a,
             None => {
                 let a = self.token.len();
                 let buf = path.to_owned();
                 self.path.push(buf.clone());
                 self.token.insert(buf, a);
                 a
             }
         }
     }
 
     fn untokenize(&self, token: PathToken) -> &HgPathBuf {
         assert!(token < self.path.len(), format!("Unknown token: {}", token));
         &self.path[token]
     }
 }
 
 /// Same as mercurial.copies._combine_changeset_copies, but in Rust.
 ///
 /// Arguments are:
 ///
 /// revs: all revisions to be considered
 /// children: a {parent ? [childrens]} mapping
 /// target_rev: the final revision we are combining copies to
 /// rev_info(rev): callback to get revision information:
 ///   * first parent
 ///   * second parent
 ///   * ChangedFiles
 /// isancestors(low_rev, high_rev): callback to check if a revision is an
 ///                                 ancestor of another
 pub fn combine_changeset_copies<A: Fn(Revision, Revision) -> bool, D>(
     revs: Vec<Revision>,
     mut children_count: HashMap<Revision, usize>,
     target_rev: Revision,
     rev_info: RevInfoMaker<D>,
     is_ancestor: &A,
 ) -> PathCopies {
     let mut all_copies = HashMap::new();
     let mut oracle = AncestorOracle::new(is_ancestor);
 
     let mut path_map = TwoWayPathMap::default();
 
     for rev in revs {
         let mut d: DataHolder<D> = DataHolder { data: None };
         let (p1, p2, changes) = rev_info(rev, &mut d);
 
         // We will chain the copies information accumulated for the parent with
         // the individual copies information the curent revision.  Creating a
         // new TimeStampedPath for each `rev` → `children` vertex.
         let mut copies: Option<TimeStampedPathCopies> = None;
         if p1 != NULL_REVISION {
             // Retrieve data computed in a previous iteration
             let parent_copies = get_and_clean_parent_copies(
                 &mut all_copies,
                 &mut children_count,
                 p1,
             );
             if let Some(parent_copies) = parent_copies {
                 // combine it with data for that revision
                 let vertex_copies = add_from_changes(
                     &mut path_map,
                     &mut oracle,
                     &parent_copies,
                     &changes,
                     Parent::FirstParent,
                     rev,
                 );
                 // keep that data around for potential later combination
                 copies = Some(vertex_copies);
             }
         }
         if p2 != NULL_REVISION {
             // Retrieve data computed in a previous iteration
             let parent_copies = get_and_clean_parent_copies(
                 &mut all_copies,
                 &mut children_count,
                 p2,
             );
             if let Some(parent_copies) = parent_copies {
                 // combine it with data for that revision
                 let vertex_copies = add_from_changes(
                     &mut path_map,
                     &mut oracle,
                     &parent_copies,
                     &changes,
                     Parent::SecondParent,
                     rev,
                 );
 
                 copies = match copies {
                     None => Some(vertex_copies),
                     // Merge has two parents needs to combines their copy
                     // information.
                     //
                     // If we got data from both parents, We need to combine
                     // them.
                     Some(copies) => Some(merge_copies_dict(
                         &path_map,
                         rev,
                         vertex_copies,
                         copies,
                         &changes,
                         &mut oracle,
                     )),
                 };
             }
         }
         match copies {
             Some(copies) => {
                 all_copies.insert(rev, copies);
             }
             _ => {}
         }
     }
 
     // Drop internal information (like the timestamp) and return the final
     // mapping.
     let tt_result = all_copies
         .remove(&target_rev)
         .expect("target revision was not processed");
     let mut result = PathCopies::default();
     for (dest, tt_source) in tt_result {
         if let Some(path) = tt_source.path {
             let path_dest = path_map.untokenize(dest).to_owned();
             let path_path = path_map.untokenize(path).to_owned();
             result.insert(path_dest, path_path);
         }
     }
     result
 }
 
 /// fetch previous computed information
 ///
 /// If no other children are expected to need this information, we drop it from
 /// the cache.
 ///
 /// If parent is not part of the set we are expected to walk, return None.
 fn get_and_clean_parent_copies(
     all_copies: &mut HashMap<Revision, TimeStampedPathCopies>,
     children_count: &mut HashMap<Revision, usize>,
     parent_rev: Revision,
 ) -> Option<TimeStampedPathCopies> {
     let count = children_count.get_mut(&parent_rev)?;
     *count -= 1;
     if *count == 0 {
         match all_copies.remove(&parent_rev) {
             Some(c) => Some(c),
             None => Some(TimeStampedPathCopies::default()),
         }
     } else {
         match all_copies.get(&parent_rev) {
             Some(c) => Some(c.clone()),
             None => Some(TimeStampedPathCopies::default()),
         }
     }
 }
 
 /// Combine ChangedFiles with some existing PathCopies information and return
 /// the result
 fn add_from_changes<A: Fn(Revision, Revision) -> bool>(
     path_map: &mut TwoWayPathMap,
     oracle: &mut AncestorOracle<A>,
     base_copies: &TimeStampedPathCopies,
     changes: &ChangedFiles,
     parent: Parent,
     current_rev: Revision,
 ) -> TimeStampedPathCopies {
     let mut copies = base_copies.clone();
     for action in changes.iter_actions(parent) {
         match action {
             Action::Copied(path_dest, path_source) => {
                 let dest = path_map.tokenize(path_dest);
                 let source = path_map.tokenize(path_source);
                 let entry;
                 if let Some(v) = base_copies.get(&source) {
                     entry = match &v.path {
                         Some(path) => Some((*(path)).to_owned()),
                         None => Some(source.to_owned()),
                     }
                 } else {
                     entry = Some(source.to_owned());
                 }
                 // Each new entry is introduced by the children, we
                 // record this information as we will need it to take
                 // the right decision when merging conflicting copy
                 // information. See merge_copies_dict for details.
                 match copies.entry(dest) {
                     Entry::Vacant(slot) => {
                         let ttpc = TimeStampedPathCopy {
                             rev: current_rev,
                             path: entry,
                         };
                         slot.insert(ttpc);
                     }
                     Entry::Occupied(mut slot) => {
                         let mut ttpc = slot.get_mut();
                         oracle.record_overwrite(ttpc.rev, current_rev);
                         ttpc.rev = current_rev;
                         ttpc.path = entry;
                     }
                 }
             }
             Action::Removed(deleted_path) => {
                 // We must drop copy information for removed file.
                 //
                 // We need to explicitly record them as dropped to
                 // propagate this information when merging two
                 // TimeStampedPathCopies object.
                 let deleted = path_map.tokenize(deleted_path);
                 copies.entry(deleted).and_modify(|old| {
                     oracle.record_overwrite(old.rev, current_rev);
                     old.rev = current_rev;
                     old.path = None;
                 });
             }
         }
     }
     copies
 }
 
 /// merge two copies-mapping together, minor and major
 ///
 /// In case of conflict, value from "major" will be picked, unless in some
 /// cases. See inline documentation for details.
 fn merge_copies_dict<A: Fn(Revision, Revision) -> bool>(
     path_map: &TwoWayPathMap,
     current_merge: Revision,
     mut minor: TimeStampedPathCopies,
     mut major: TimeStampedPathCopies,
     changes: &ChangedFiles,
     oracle: &mut AncestorOracle<A>,
 ) -> TimeStampedPathCopies {
     // This closure exist as temporary help while multiple developper are
     // actively working on this code. Feel free to re-inline it once this
     // code is more settled.
-    let mut cmp_value =
-        |dest: &PathToken,
-         src_minor: &TimeStampedPathCopy,
-         src_major: &TimeStampedPathCopy| {
-            compare_value(
-                path_map,
-                current_merge,
-                changes,
-                oracle,
-                dest,
-                src_minor,
-                src_major,
-            )
-        };
+    let cmp_value = |oracle: &mut AncestorOracle<A>,
+                     dest: &PathToken,
+                     src_minor: &TimeStampedPathCopy,
+                     src_major: &TimeStampedPathCopy| {
+        compare_value(
+            path_map,
+            current_merge,
+            changes,
+            oracle,
+            dest,
+            src_minor,
+            src_major,
+        )
+    };
     if minor.is_empty() {
         major
     } else if major.is_empty() {
         minor
     } else if minor.len() * 2 < major.len() {
         // Lets says we are merging two TimeStampedPathCopies instance A and B.
         //
         // If A contains N items, the merge result will never contains more
         // than N values differents than the one in A
         //
         // If B contains M items, with M > N, the merge result will always
         // result in a minimum of M - N value differents than the on in
         // A
         //
         // As a result, if N < (M-N), we know that simply iterating over A will
         // yield less difference than iterating over the difference
         // between A and B.
         //
         // This help performance a lot in case were a tiny
         // TimeStampedPathCopies is merged with a much larger one.
         for (dest, src_minor) in minor {
             let src_major = major.get(&dest);
             match src_major {
-                None => major.insert(dest, src_minor),
+                None => {
+                    major.insert(dest, src_minor);
+                }
                 Some(src_major) => {
-                    match cmp_value(&dest, &src_minor, src_major) {
-                        MergePick::Any | MergePick::Major => None,
-                        MergePick::Minor => major.insert(dest, src_minor),
+                    let (pick, overwrite) =
+                        cmp_value(oracle, &dest, &src_minor, src_major);
+                    if overwrite {
+                        oracle.record_overwrite(src_minor.rev, current_merge);
+                        oracle.record_overwrite(src_major.rev, current_merge);
+                        let path = match pick {
+                            MergePick::Major => src_major.path,
+                            MergePick::Minor => src_minor.path,
+                            MergePick::Any => src_major.path,
+                        };
+                        let src = TimeStampedPathCopy {
+                            rev: current_merge,
+                            path,
+                        };
+                        major.insert(dest, src);
+                    } else {
+                        match pick {
+                            MergePick::Any | MergePick::Major => None,
+                            MergePick::Minor => major.insert(dest, src_minor),
+                        };
                     }
                 }
             };
         }
         major
     } else if major.len() * 2 < minor.len() {
         // This use the same rational than the previous block.
         // (Check previous block documentation for details.)
         for (dest, src_major) in major {
             let src_minor = minor.get(&dest);
             match src_minor {
-                None => minor.insert(dest, src_major),
+                None => {
+                    minor.insert(dest, src_major);
+                }
                 Some(src_minor) => {
-                    match cmp_value(&dest, src_minor, &src_major) {
-                        MergePick::Any | MergePick::Minor => None,
-                        MergePick::Major => minor.insert(dest, src_major),
+                    let (pick, overwrite) =
+                        cmp_value(oracle, &dest, &src_major, src_minor);
+                    if overwrite {
+                        oracle.record_overwrite(src_minor.rev, current_merge);
+                        oracle.record_overwrite(src_major.rev, current_merge);
+                        let path = match pick {
+                            MergePick::Major => src_minor.path,
+                            MergePick::Minor => src_major.path,
+                            MergePick::Any => src_major.path,
+                        };
+                        let src = TimeStampedPathCopy {
+                            rev: current_merge,
+                            path,
+                        };
+                        minor.insert(dest, src);
+                    } else {
+                        match pick {
+                            MergePick::Any | MergePick::Major => None,
+                            MergePick::Minor => minor.insert(dest, src_major),
+                        };
                     }
                 }
             };
         }
         minor
     } else {
         let mut override_minor = Vec::new();
         let mut override_major = Vec::new();
 
         let mut to_major = |k: &PathToken, v: &TimeStampedPathCopy| {
             override_major.push((k.clone(), v.clone()))
         };
         let mut to_minor = |k: &PathToken, v: &TimeStampedPathCopy| {
             override_minor.push((k.clone(), v.clone()))
         };
 
         // The diff function leverage detection of the identical subpart if
         // minor and major has some common ancestors. This make it very
         // fast is most case.
         //
         // In case where the two map are vastly different in size, the current
         // approach is still slowish because the iteration will iterate over
         // all the "exclusive" content of the larger on. This situation can be
         // frequent when the subgraph of revision we are processing has a lot
         // of roots. Each roots adding they own fully new map to the mix (and
         // likely a small map, if the path from the root to the "main path" is
         // small.
         //
         // We could do better by detecting such situation and processing them
         // differently.
         for d in minor.diff(&major) {
             match d {
                 DiffItem::Add(k, v) => to_minor(k, v),
                 DiffItem::Remove(k, v) => to_major(k, v),
                 DiffItem::Update { old, new } => {
                     let (dest, src_major) = new;
                     let (_, src_minor) = old;
-                    match cmp_value(dest, src_minor, src_major) {
-                        MergePick::Major => to_minor(dest, src_major),
-                        MergePick::Minor => to_major(dest, src_minor),
-                        // If the two entry are identical, no need to do
-                        // anything (but diff should not have yield them)
-                        MergePick::Any => unreachable!(),
+                    let (pick, overwrite) =
+                        cmp_value(oracle, dest, src_minor, src_major);
+                    if overwrite {
+                        oracle.record_overwrite(src_minor.rev, current_merge);
+                        oracle.record_overwrite(src_major.rev, current_merge);
+                        let path = match pick {
+                            MergePick::Major => src_major.path,
+                            MergePick::Minor => src_minor.path,
+                            // If the two entry are identical, no need to do
+                            // anything (but diff should not have yield them)
+                            MergePick::Any => src_major.path,
+                        };
+                        let src = TimeStampedPathCopy {
+                            rev: current_merge,
+                            path,
+                        };
+                        to_minor(dest, &src);
+                        to_major(dest, &src);
+                    } else {
+                        match pick {
+                            MergePick::Major => to_minor(dest, src_major),
+                            MergePick::Minor => to_major(dest, src_minor),
+                            // If the two entry are identical, no need to do
+                            // anything (but diff should not have yield them)
+                            MergePick::Any => unreachable!(),
+                        }
                     }
                 }
             };
         }
 
         let updates;
         let mut result;
         if override_major.is_empty() {
             result = major
         } else if override_minor.is_empty() {
             result = minor
         } else {
             if override_minor.len() < override_major.len() {
                 updates = override_minor;
                 result = minor;
             } else {
                 updates = override_major;
                 result = major;
             }
             for (k, v) in updates {
                 result.insert(k, v);
             }
         }
         result
     }
 }
 
 /// represent the side that should prevail when merging two
 /// TimeStampedPathCopies
 enum MergePick {
     /// The "major" (p1) side prevails
     Major,
     /// The "minor" (p2) side prevails
     Minor,
     /// Any side could be used (because they are the same)
     Any,
 }
 
 /// decide which side prevails in case of conflicting values
 #[allow(clippy::if_same_then_else)]
 fn compare_value<A: Fn(Revision, Revision) -> bool>(
     path_map: &TwoWayPathMap,
     current_merge: Revision,
     changes: &ChangedFiles,
     oracle: &mut AncestorOracle<A>,
     dest: &PathToken,
     src_minor: &TimeStampedPathCopy,
     src_major: &TimeStampedPathCopy,
-) -> MergePick {
+) -> (MergePick, bool) {
     if src_major.rev == current_merge {
         if src_minor.rev == current_merge {
             if src_major.path.is_none() {
                 // We cannot get different copy information for both p1 and p2
                 // from the same revision. Unless this was a
                 // deletion
-                MergePick::Any
+                (MergePick::Any, false)
             } else {
                 unreachable!();
             }
         } else {
             // The last value comes the current merge, this value -will- win
             // eventually.
-            oracle.record_overwrite(src_minor.rev, src_major.rev);
-            MergePick::Major
+            (MergePick::Major, true)
         }
     } else if src_minor.rev == current_merge {
         // The last value comes the current merge, this value -will- win
         // eventually.
-        oracle.record_overwrite(src_major.rev, src_minor.rev);
-        MergePick::Minor
+        (MergePick::Minor, true)
     } else if src_major.path == src_minor.path {
         // we have the same value, but from other source;
         if src_major.rev == src_minor.rev {
             // If the two entry are identical, they are both valid
-            MergePick::Any
+            (MergePick::Any, false)
         } else if oracle.is_overwrite(src_major.rev, src_minor.rev) {
-            MergePick::Minor
+            (MergePick::Minor, false)
         } else if oracle.is_overwrite(src_minor.rev, src_major.rev) {
-            MergePick::Major
+            (MergePick::Major, false)
         } else {
-            MergePick::Major
+            (MergePick::Any, true)
         }
     } else if src_major.rev == src_minor.rev {
         // We cannot get copy information for both p1 and p2 in the
         // same rev. So this is the same value.
         unreachable!(
             "conflicting information from p1 and p2 in the same revision"
         );
     } else {
         let dest_path = path_map.untokenize(*dest);
         let action = changes.get_merge_case(dest_path);
         if src_minor.path.is_some()
             && src_major.path.is_none()
             && action == MergeCase::Salvaged
         {
             // If the file is "deleted" in the major side but was
             // salvaged by the merge, we keep the minor side alive
-            MergePick::Minor
+            (MergePick::Minor, true)
         } else if src_major.path.is_some()
             && src_minor.path.is_none()
             && action == MergeCase::Salvaged
         {
             // If the file is "deleted" in the minor side but was
             // salvaged by the merge, unconditionnaly preserve the
             // major side.
-            MergePick::Major
+            (MergePick::Major, true)
         } else if oracle.is_overwrite(src_minor.rev, src_major.rev) {
             // The information from the minor version are strictly older than
             // the major version
             if action == MergeCase::Merged {
                 // If the file was actively merged, its means some non-copy
                 // activity happened on the other branch. It
                 // mean the older copy information are still relevant.
                 //
                 // The major side wins such conflict.
-                MergePick::Major
+                (MergePick::Major, true)
             } else {
                 // No activity on the minor branch, pick the newer one.
-                MergePick::Major
+                (MergePick::Major, false)
             }
         } else if oracle.is_overwrite(src_major.rev, src_minor.rev) {
             if action == MergeCase::Merged {
                 // If the file was actively merged, its means some non-copy
                 // activity happened on the other branch. It
                 // mean the older copy information are still relevant.
                 //
                 // The major side wins such conflict.
-                MergePick::Major
+                (MergePick::Major, true)
             } else {
                 // No activity on the minor branch, pick the newer one.
-                MergePick::Minor
+                (MergePick::Minor, false)
             }
         } else if src_minor.path.is_none() {
             // the minor side has no relevant information, pick the alive one
-            MergePick::Major
+            (MergePick::Major, true)
         } else if src_major.path.is_none() {
             // the major side has no relevant information, pick the alive one
-            MergePick::Minor
+            (MergePick::Minor, true)
         } else {
             // by default the major side wins
-            MergePick::Major
+            (MergePick::Major, true)
         }
     }
 }

tests/test-copies-chain-merge.t

@@ -1,3441 +1,3406 b''
 #testcases filelog compatibility changeset sidedata upgraded
 
 =====================================================
 Test Copy tracing for chain of copies involving merge
 =====================================================
 
 This test files covers copies/rename case for a chains of commit where merges
 are involved. It cheks we do not have unwanted update of behavior and that the
 different options to retrieve copies behave correctly.
 
 
 Setup
 =====
 
 use git diff to see rename
 
   $ cat << EOF >> ./no-linkrev
   > #!$PYTHON
   > # filter out linkrev part of the debugindex command
   > import sys
   > for line in sys.stdin:
   >     if " linkrev " in line:
   >         print(line.rstrip())
   >     else:
   >         l = "%s       *%s" % (line[:6], line[14:].rstrip())
   >         print(l)
   > EOF
   $ chmod +x no-linkrev
 
   $ cat << EOF >> $HGRCPATH
   > [diff]
   > git=yes
   > [command-templates]
   > log={desc}\n
   > EOF
 
 #if compatibility
   $ cat >> $HGRCPATH << EOF
   > [experimental]
   > copies.read-from = compatibility
   > EOF
 #endif
 
 #if changeset
   $ cat >> $HGRCPATH << EOF
   > [experimental]
   > copies.read-from = changeset-only
   > copies.write-to = changeset-only
   > EOF
 #endif
 
 #if sidedata
   $ cat >> $HGRCPATH << EOF
   > [format]
   > exp-use-side-data = yes
   > exp-use-copies-side-data-changeset = yes
   > EOF
 #endif
 
 
   $ cat > same-content.txt << EOF
   > Here is some content that will be the same accros multiple file.
   > 
   > This is done on purpose so that we end up in some merge situation, were the
   > resulting content is the same as in the parent(s), but a new filenodes still
   > need to be created to record some file history information (especially
   > about copies).
   > EOF
 
   $ hg init repo-chain
   $ cd repo-chain
 
 Add some linear rename initialy
 
   $ cp ../same-content.txt a
   $ cp ../same-content.txt b
   $ cp ../same-content.txt h
   $ echo "original content for P" > p
   $ echo "original content for Q" > q
   $ echo "original content for R" > r
   $ hg ci -Am 'i-0 initial commit: a b h'
   adding a
   adding b
   adding h
   adding p
   adding q
   adding r
   $ hg mv a c
   $ hg mv p s
   $ hg ci -Am 'i-1: a -move-> c, p -move-> s'
   $ hg mv c d
   $ hg mv s t
   $ hg ci -Am 'i-2: c -move-> d, s -move-> t'
   $ hg log -G
   @  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 And having another branch with renames on the other side
 
   $ hg mv d e
   $ hg ci -Am 'a-1: d -move-> e'
   $ hg mv e f
   $ hg ci -Am 'a-2: e -move-> f'
   $ hg log -G --rev '::.'
   @  a-2: e -move-> f
   |
   o  a-1: d -move-> e
   |
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Have a branching with nothing on one side
 
   $ hg up 'desc("i-2")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo foo > b
   $ hg ci -m 'b-1: b update'
   created new head
   $ hg log -G --rev '::.'
   @  b-1: b update
   |
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Create a branch that delete a file previous renamed
 
   $ hg up 'desc("i-2")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg rm d
   $ hg ci -m 'c-1 delete d'
   created new head
   $ hg log -G --rev '::.'
   @  c-1 delete d
   |
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Create a branch that delete a file previous renamed and recreate it
 
   $ hg up 'desc("i-2")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg rm d
   $ hg ci -m 'd-1 delete d'
   created new head
   $ echo bar > d
   $ hg add d
   $ hg ci -m 'd-2 re-add d'
   $ hg log -G --rev '::.'
   @  d-2 re-add d
   |
   o  d-1 delete d
   |
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Having another branch renaming a different file to the same filename as another
 
   $ hg up 'desc("i-2")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg mv b g
   $ hg ci -m 'e-1 b -move-> g'
   created new head
   $ hg mv g f
   $ hg ci -m 'e-2 g -move-> f'
   $ hg log -G --rev '::.'
   @  e-2 g -move-> f
   |
   o  e-1 b -move-> g
   |
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
   $ hg up -q null
 
 Having a branch similar to the 'a' one, but moving the 'p' file around.
 
   $ hg up 'desc("i-2")'
   6 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg mv t u
   $ hg ci -Am 'p-1: t -move-> u'
   created new head
   $ hg mv u v
   $ hg ci -Am 'p-2: u -move-> v'
   $ hg log -G --rev '::.'
   @  p-2: u -move-> v
   |
   o  p-1: t -move-> u
   |
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
   $ hg up -q null
 
 Having another branch renaming a different file to the same filename as another
 
   $ hg up 'desc("i-2")'
   6 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg mv r w
   $ hg ci -m 'q-1 r -move-> w'
   created new head
   $ hg mv w v
   $ hg ci -m 'q-2 w -move-> v'
   $ hg log -G --rev '::.'
   @  q-2 w -move-> v
   |
   o  q-1 r -move-> w
   |
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
   $ hg up -q null
 
 Setup all merge
 ===============
 
 This is done beforehand to validate that the upgrade process creates valid copy
 information.
 
 merging with unrelated change does not interfere with the renames
 ---------------------------------------------------------------
 
 - rename on one side
 - unrelated change on the other side
 
   $ case_desc="simple merge - A side: multiple renames, B side: unrelated update"
 
   $ hg up 'desc("b-1")'
   6 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("a-2")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mBAm-0 $case_desc - one way"
   $ hg up 'desc("a-2")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("b-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mABm-0 $case_desc - the other way"
   created new head
   $ hg log -G --rev '::(desc("mABm")+desc("mBAm"))'
   @    mABm-0 simple merge - A side: multiple renames, B side: unrelated update - the other way
   |\
   +---o  mBAm-0 simple merge - A side: multiple renames, B side: unrelated update - one way
   | |/
   | o  b-1: b update
   | |
   o |  a-2: e -move-> f
   | |
   o |  a-1: d -move-> e
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 
 merging with the side having a delete
 -------------------------------------
 
 case summary:
 - one with change to an unrelated file
 - one deleting the change
 and recreate an unrelated file after the merge
 
   $ case_desc="simple merge - C side: delete a file with copies history , B side: unrelated update"
 
   $ hg up 'desc("b-1")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("c-1")'
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mBCm-0 $case_desc - one way"
   $ echo bar > d
   $ hg add d
   $ hg ci -m 'mBCm-1 re-add d'
   $ hg up 'desc("c-1")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("b-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mCBm-0 $case_desc - the other way"
   created new head
   $ echo bar > d
   $ hg add d
   $ hg ci -m 'mCBm-1 re-add d'
   $ hg log -G --rev '::(desc("mCBm")+desc("mBCm"))'
   @  mCBm-1 re-add d
   |
   o    mCBm-0 simple merge - C side: delete a file with copies history , B side: unrelated update - the other way
   |\
   | | o  mBCm-1 re-add d
   | | |
   +---o  mBCm-0 simple merge - C side: delete a file with copies history , B side: unrelated update - one way
   | |/
   | o  c-1 delete d
   | |
   o |  b-1: b update
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Comparing with a merge re-adding the file afterward
 ---------------------------------------------------
 
 Merge:
 - one with change to an unrelated file
 - one deleting and recreating the change
 
   $ case_desc="simple merge - B side: unrelated update, D side: delete and recreate a file (with different content)"
 
   $ hg up 'desc("b-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("d-2")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mBDm-0 $case_desc - one way"
   $ hg up 'desc("d-2")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("b-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mDBm-0 $case_desc - the other way"
   created new head
   $ hg log -G --rev '::(desc("mDBm")+desc("mBDm"))'
   @    mDBm-0 simple merge - B side: unrelated update, D side: delete and recreate a file (with different content) - the other way
   |\
   +---o  mBDm-0 simple merge - B side: unrelated update, D side: delete and recreate a file (with different content) - one way
   | |/
   | o  d-2 re-add d
   | |
   | o  d-1 delete d
   | |
   o |  b-1: b update
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 
 Comparing with a merge with colliding rename
 --------------------------------------------
 
 Subcase: new copy information on both side
 ``````````````````````````````````````````
 
 - the "e-" branch renaming b to f (through 'g')
 - the "a-" branch renaming d to f (through e)
 
   $ case_desc="merge with copies info on both side - A side: rename d to f, E side: b to f, (same content for f)"
 
   $ hg up 'desc("a-2")'
   2 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("e-2")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved (no-changeset !)
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved (changeset !)
   (branch merge, don't forget to commit)
   $ hg ci -m "mAEm-0 $case_desc - one way"
   $ hg up 'desc("e-2")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved (no-changeset !)
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved (changeset !)
   $ hg merge 'desc("a-2")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved (no-changeset !)
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved (changeset !)
   (branch merge, don't forget to commit)
   $ hg ci -m "mEAm-0 $case_desc - the other way"
   created new head
   $ hg log -G --rev '::(desc("mAEm")+desc("mEAm"))'
   @    mEAm-0 merge with copies info on both side - A side: rename d to f, E side: b to f, (same content for f) - the other way
   |\
   +---o  mAEm-0 merge with copies info on both side - A side: rename d to f, E side: b to f, (same content for f) - one way
   | |/
   | o  e-2 g -move-> f
   | |
   | o  e-1 b -move-> g
   | |
   o |  a-2: e -move-> f
   | |
   o |  a-1: d -move-> e
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Subcase: new copy information on both side with an actual merge happening
 `````````````````````````````````````````````````````````````````````````
 
 - the "p-" branch renaming 't' to 'v' (through 'u')
 - the "q-" branch renaming 'r' to 'v' (through 'w')
 
   $ case_desc="merge with copies info on both side - P side: rename t to v, Q side: r to v, (different content)"
 
   $ hg up 'desc("p-2")'
   3 files updated, 0 files merged, 2 files removed, 0 files unresolved
   $ hg merge 'desc("q-2")' --tool ':union'
   merging v
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mPQm-0 $case_desc - one way"
   $ hg up 'desc("q-2")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("p-2")' --tool ':union'
   merging v
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mQPm-0 $case_desc - the other way"
   created new head
   $ hg log -G --rev '::(desc("mAEm")+desc("mEAm"))'
   o    mEAm-0 merge with copies info on both side - A side: rename d to f, E side: b to f, (same content for f) - the other way
   |\
   +---o  mAEm-0 merge with copies info on both side - A side: rename d to f, E side: b to f, (same content for f) - one way
   | |/
   | o  e-2 g -move-> f
   | |
   | o  e-1 b -move-> g
   | |
   o |  a-2: e -move-> f
   | |
   o |  a-1: d -move-> e
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Subcase: existing copy information overwritten on one branch
 ````````````````````````````````````````````````````````````
 
 Merge:
 - one with change to an unrelated file (b)
 - one overwriting a file (d) with a rename (from h to i to d)
 
   $ case_desc="simple merge - B side: unrelated change, F side: overwrite d with a copy (from h->i->d)"
 
   $ hg up 'desc("i-2")'
   2 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg mv h i
   $ hg commit -m "f-1: rename h -> i"
   created new head
   $ hg mv --force i d
   $ hg commit -m "f-2: rename i -> d"
   $ hg debugindex d | ../no-linkrev
      rev linkrev nodeid       p1           p2
        0       * d8252ab2e760 000000000000 000000000000 (no-changeset !)
        0       * ae258f702dfe 000000000000 000000000000 (changeset !)
        1       * b004912a8510 000000000000 000000000000
        2       * 7b79e2fe0c89 000000000000 000000000000 (no-changeset !)
   $ hg up 'desc("b-1")'
   3 files updated, 0 files merged, 0 files removed, 0 files unresolved (no-changeset !)
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved (changeset !)
   $ hg merge 'desc("f-2")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved (no-changeset !)
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved (changeset !)
   (branch merge, don't forget to commit)
   $ hg ci -m "mBFm-0 $case_desc - one way"
   $ hg up 'desc("f-2")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("b-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mFBm-0 $case_desc - the other way"
   created new head
   $ hg up null --quiet
   $ hg log -G --rev '::(desc("mBFm")+desc("mFBm"))'
   o    mFBm-0 simple merge - B side: unrelated change, F side: overwrite d with a copy (from h->i->d) - the other way
   |\
   +---o  mBFm-0 simple merge - B side: unrelated change, F side: overwrite d with a copy (from h->i->d) - one way
   | |/
   | o  f-2: rename i -> d
   | |
   | o  f-1: rename h -> i
   | |
   o |  b-1: b update
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Subcase: existing copy information overwritten on one branch, with different content)
 `````````````````````````````````````````````````````````````````````````````````````
 
 Merge:
 - one with change to an unrelated file (b)
 - one overwriting a file (t) with a rename (from r to x to t), v content is not the same as on the other branch
 
   $ case_desc="simple merge - B side: unrelated change, R side: overwrite d with a copy (from r->x->t) different content"
 
   $ hg up 'desc("i-2")'
   6 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg mv r x
   $ hg commit -m "r-1: rename r -> x"
   created new head
   $ hg mv --force x t
   $ hg commit -m "r-2: rename t -> x"
   $ hg debugindex t | ../no-linkrev
      rev linkrev nodeid       p1           p2
        0       * d74efbf65309 000000000000 000000000000 (no-changeset !)
        1       * 02a930b9d7ad 000000000000 000000000000 (no-changeset !)
        0       * 5aed6a8dbff0 000000000000 000000000000 (changeset !)
        1       * a38b2fa17021 000000000000 000000000000 (changeset !)
   $ hg up 'desc("b-1")'
   3 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("r-2")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mBRm-0 $case_desc - one way"
   $ hg up 'desc("r-2")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("b-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mRBm-0 $case_desc - the other way"
   created new head
   $ hg up null --quiet
   $ hg log -G --rev '::(desc("mBRm")+desc("mRBm"))'
   o    mRBm-0 simple merge - B side: unrelated change, R side: overwrite d with a copy (from r->x->t) different content - the other way
   |\
   +---o  mBRm-0 simple merge - B side: unrelated change, R side: overwrite d with a copy (from r->x->t) different content - one way
   | |/
   | o  r-2: rename t -> x
   | |
   | o  r-1: rename r -> x
   | |
   o |  b-1: b update
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 
 Subcase: reset of the copy history on one side
 ``````````````````````````````````````````````
 
 Merge:
 - one with change to a file
 - one deleting and recreating the file
 
 Unlike in the 'BD/DB' cases, an actual merge happened here. So we should
 consider history and rename on both branch of the merge.
 
   $ case_desc="actual content merge, copies on one side - D side: delete and re-add (different content), G side: update content"
 
   $ hg up 'desc("i-2")'
   6 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo "some update" >> d
   $ hg commit -m "g-1: update d"
   created new head
   $ hg up 'desc("d-2")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("g-1")' --tool :union
   merging d
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mDGm-0 $case_desc - one way"
   $ hg up 'desc("g-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("d-2")' --tool :union
   merging d
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mGDm-0 $case_desc - the other way"
   created new head
   $ hg log -G --rev '::(desc("mDGm")+desc("mGDm"))'
   @    mGDm-0 actual content merge, copies on one side - D side: delete and re-add (different content), G side: update content - the other way
   |\
   +---o  mDGm-0 actual content merge, copies on one side - D side: delete and re-add (different content), G side: update content - one way
   | |/
   | o  g-1: update d
   | |
   o |  d-2 re-add d
   | |
   o |  d-1 delete d
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Subcase: merging a change to a file with a "copy overwrite" to that file from another branch
 ````````````````````````````````````````````````````````````````````````````````````````````
 
 Merge:
 - one with change to a file (d)
 - one overwriting that file with a rename (from h to i, to d)
 
 This case is similar to BF/FB, but an actual merge happens, so both side of the
 history are relevant.
 
 Note:
 | In this case, the merge get conflicting information since on one side we have
 | "a -> c -> d". and one the other one we have "h -> i -> d".
 |
 | The current code arbitrarily pick one side
 
   $ case_desc="merge - G side: content change, F side: copy overwrite, no content change"
 
   $ hg up 'desc("f-2")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("g-1")' --tool :union
   merging d (no-changeset !)
   0 files updated, 1 files merged, 0 files removed, 0 files unresolved (no-changeset !)
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved (changeset !)
   (branch merge, don't forget to commit)
   $ hg ci -m "mFGm-0 $case_desc - one way"
   created new head
   $ hg up 'desc("g-1")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved (no-changeset !)
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved (changeset !)
   $ hg merge 'desc("f-2")' --tool :union
   merging d (no-changeset !)
   0 files updated, 1 files merged, 1 files removed, 0 files unresolved (no-changeset !)
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved (changeset !)
   (branch merge, don't forget to commit)
   $ hg ci -m "mGFm-0 $case_desc - the other way"
   created new head
   $ hg log -G --rev '::(desc("mGFm")+desc("mFGm"))'
   @    mGFm-0 merge - G side: content change, F side: copy overwrite, no content change - the other way
   |\
   +---o  mFGm-0 merge - G side: content change, F side: copy overwrite, no content change - one way
   | |/
   | o  g-1: update d
   | |
   o |  f-2: rename i -> d
   | |
   o |  f-1: rename h -> i
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 
 Comparing with merging with a deletion (and keeping the file)
 -------------------------------------------------------------
 
 Merge:
 - one removing a file (d)
 - one updating that file
 - the merge keep the modified version of the file (canceling the delete)
 
 In this case, the file keep on living after the merge. So we should not drop its
 copy tracing chain.
 
   $ case_desc="merge updated/deleted - revive the file (updated content)"
 
   $ hg up 'desc("c-1")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("g-1")'
   file 'd' was deleted in local [working copy] but was modified in other [merge rev].
   You can use (c)hanged version, leave (d)eleted, or leave (u)nresolved.
   What do you want to do? u
   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]
   $ hg resolve -t :other d
   (no more unresolved files)
   $ hg ci -m "mCGm-0 $case_desc - one way"
   created new head
 
   $ hg up 'desc("g-1")'
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("c-1")'
   file 'd' was deleted in other [merge rev] but was modified in local [working copy].
   You can use (c)hanged version, (d)elete, or leave (u)nresolved.
   What do you want to do? u
   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]
   $ hg resolve -t :local d
   (no more unresolved files)
   $ hg ci -m "mGCm-0 $case_desc - the other way"
   created new head
 
   $ hg log -G --rev '::(desc("mCGm")+desc("mGCm"))'
   @    mGCm-0 merge updated/deleted - revive the file (updated content) - the other way
   |\
   +---o  mCGm-0 merge updated/deleted - revive the file (updated content) - one way
   | |/
   | o  g-1: update d
   | |
   o |  c-1 delete d
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 
 
 Comparing with merge restoring an untouched deleted file
 --------------------------------------------------------
 
 Merge:
 - one removing a file (d)
 - one leaving the file untouched
 - the merge actively restore the file to the same content.
 
 In this case, the file keep on living after the merge. So we should not drop its
 copy tracing chain.
 
   $ case_desc="merge explicitely revive deleted file - B side: unrelated change, C side: delete d (restored by merge)"
 
   $ hg up 'desc("c-1")'
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("b-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg revert --rev 'desc("b-1")' d
   $ hg ci -m "mCB-revert-m-0 $case_desc - one way"
   created new head
 
   $ hg up 'desc("b-1")'
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("c-1")'
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg revert --rev 'desc("b-1")' d
   $ hg ci -m "mBC-revert-m-0 $case_desc - the other way"
   created new head
 
   $ hg log -G --rev '::(desc("mCB-revert-m")+desc("mBC-revert-m"))'
   @    mBC-revert-m-0 merge explicitely revive deleted file - B side: unrelated change, C side: delete d (restored by merge) - the other way
   |\
   +---o  mCB-revert-m-0 merge explicitely revive deleted file - B side: unrelated change, C side: delete d (restored by merge) - one way
   | |/
   | o  c-1 delete d
   | |
   o |  b-1: b update
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 
   $ hg up null --quiet
 
 Merging a branch where a rename was deleted with a branch where the same file was renamed
 ------------------------------------------------------------------------------------------
 
 Create a "conflicting" merge where `d` get removed on one branch before its
 rename information actually conflict with the other branch.
 
 (the copy information from the branch that was not deleted should win).
 
   $ case_desc="simple merge - C side: d is the results of renames then deleted, H side: d is result of another rename (same content as the other branch)"
 
   $ hg up 'desc("i-0")'
   6 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg mv b d
   $ hg ci -m "h-1: b -(move)-> d"
   created new head
 
   $ hg up 'desc("c-1")'
   2 files updated, 0 files merged, 3 files removed, 0 files unresolved
   $ hg merge 'desc("h-1")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mCH-delete-before-conflict-m-0 $case_desc - one way"
 
   $ hg up 'desc("h-1")'
   2 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("c-1")'
   1 files updated, 0 files merged, 2 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mHC-delete-before-conflict-m-0 $case_desc - the other way"
   created new head
   $ hg log -G --rev '::(desc("mCH-delete-before-conflict-m")+desc("mHC-delete-before-conflict-m"))'
   @    mHC-delete-before-conflict-m-0 simple merge - C side: d is the results of renames then deleted, H side: d is result of another rename (same content as the other branch) - the other way
   |\
   +---o  mCH-delete-before-conflict-m-0 simple merge - C side: d is the results of renames then deleted, H side: d is result of another rename (same content as the other branch) - one way
   | |/
   | o  h-1: b -(move)-> d
   | |
   o |  c-1 delete d
   | |
   o |  i-2: c -move-> d, s -move-> t
   | |
   o |  i-1: a -move-> c, p -move-> s
   |/
   o  i-0 initial commit: a b h
   
 
 Variant of previous with extra changes introduced by the merge
 --------------------------------------------------------------
 
 Multiple cases above explicitely test cases where content are the same on both side during merge. In this section we will introduce variants for theses cases where new change are introduced to these file content during the merges.
 
 
 Subcase: merge has same initial content on both side, but merge introduced a change
 ```````````````````````````````````````````````````````````````````````````````````
 
 Same as `mAEm` and `mEAm` but with extra change to the file before commiting
 
 - the "e-" branch renaming b to f (through 'g')
 - the "a-" branch renaming d to f (through e)
 
   $ case_desc="merge with file update and copies info on both side - A side: rename d to f, E side: b to f, (same content for f in parent)"
 
   $ hg up 'desc("a-2")'
   2 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("e-2")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved (no-changeset !)
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved (changeset !)
   (branch merge, don't forget to commit)
   $ echo "content change for mAE-change-m" > f
   $ hg ci -m "mAE-change-m-0 $case_desc - one way"
   created new head
   $ hg up 'desc("e-2")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("a-2")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved (no-changeset !)
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved (changeset !)
   (branch merge, don't forget to commit)
   $ echo "content change for mEA-change-m" > f
   $ hg ci -m "mEA-change-m-0 $case_desc - the other way"
   created new head
   $ hg log -G --rev '::(desc("mAE-change-m")+desc("mEA-change-m"))'
   @    mEA-change-m-0 merge with file update and copies info on both side - A side: rename d to f, E side: b to f, (same content for f in parent) - the other way
   |\
   +---o  mAE-change-m-0 merge with file update and copies info on both side - A side: rename d to f, E side: b to f, (same content for f in parent) - one way
   | |/
   | o  e-2 g -move-> f
   | |
   | o  e-1 b -move-> g
   | |
   o |  a-2: e -move-> f
   | |
   o |  a-1: d -move-> e
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Decision from previous merge are properly chained with later merge
 ------------------------------------------------------------------
 
 Subcase: chaining conflicting rename resolution
 ```````````````````````````````````````````````
 
 The "mAEm" and "mEAm" case create a rename tracking conflict on file 'f'. We
 add more change on the respective branch and merge again. These second merge
 does not involve the file 'f' and the arbitration done within "mAEm" and "mEA"
 about that file should stay unchanged.
 
   $ case_desc="chained merges (conflict -> simple) - same content everywhere"
 
 (extra unrelated changes)
 
   $ hg up 'desc("a-2")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo j > unrelated-j
   $ hg add unrelated-j
   $ hg ci -m 'j-1: unrelated changes (based on the "a" series of changes)'
   created new head
 
   $ hg up 'desc("e-2")'
   2 files updated, 0 files merged, 2 files removed, 0 files unresolved (no-changeset !)
   1 files updated, 0 files merged, 2 files removed, 0 files unresolved (changeset !)
   $ echo k > unrelated-k
   $ hg add unrelated-k
   $ hg ci -m 'k-1: unrelated changes (based on "e" changes)'
   created new head
 
 (merge variant 1)
 
   $ hg up 'desc("mAEm")'
   1 files updated, 0 files merged, 2 files removed, 0 files unresolved (no-changeset !)
   0 files updated, 0 files merged, 2 files removed, 0 files unresolved (changeset !)
   $ hg merge 'desc("k-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mAE,Km: $case_desc"
 
 (merge variant 2)
 
   $ hg up 'desc("k-1")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved (no-changeset !)
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved (changeset !)
 
   $ hg merge 'desc("mAEm")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved (no-changeset !)
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved (changeset !)
   (branch merge, don't forget to commit)
   $ hg ci -m "mK,AEm: $case_desc"
   created new head
 
 (merge variant 3)
 
   $ hg up 'desc("mEAm")'
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("j-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mEA,Jm: $case_desc"
 
 (merge variant 4)
 
   $ hg up 'desc("j-1")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved (no-changeset !)
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved (changeset !)
   $ hg merge 'desc("mEAm")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved (no-changeset !)
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved (changeset !)
   (branch merge, don't forget to commit)
   $ hg ci -m "mJ,EAm: $case_desc"
   created new head
 
 
   $ hg log -G --rev '::(desc("mAE,Km") + desc("mK,AEm") + desc("mEA,Jm") + desc("mJ,EAm"))'
   @    mJ,EAm: chained merges (conflict -> simple) - same content everywhere
   |\
   +---o  mEA,Jm: chained merges (conflict -> simple) - same content everywhere
   | |/
   | | o    mK,AEm: chained merges (conflict -> simple) - same content everywhere
   | | |\
   | | +---o  mAE,Km: chained merges (conflict -> simple) - same content everywhere
   | | | |/
   | | | o  k-1: unrelated changes (based on "e" changes)
   | | | |
   | o | |  j-1: unrelated changes (based on the "a" series of changes)
   | | | |
   o-----+  mEAm-0 merge with copies info on both side - A side: rename d to f, E side: b to f, (same content for f) - the other way
   |/ / /
   | o /  mAEm-0 merge with copies info on both side - A side: rename d to f, E side: b to f, (same content for f) - one way
   |/|/
   | o  e-2 g -move-> f
   | |
   | o  e-1 b -move-> g
   | |
   o |  a-2: e -move-> f
   | |
   o |  a-1: d -move-> e
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Subcase: chaining conflicting rename resolution, with actual merging happening
 ``````````````````````````````````````````````````````````````````````````````
 
 The "mPQm" and "mQPm" case create a rename tracking conflict on file 't'. We
 add more change on the respective branch and merge again. These second merge
 does not involve the file 't' and the arbitration done within "mPQm" and "mQP"
 about that file should stay unchanged.
 
   $ case_desc="chained merges (conflict -> simple) - different content"
 
 (extra unrelated changes)
 
   $ hg up 'desc("p-2")'
   3 files updated, 0 files merged, 3 files removed, 0 files unresolved
   $ echo s > unrelated-s
   $ hg add unrelated-s
   $ hg ci -m 's-1: unrelated changes (based on the "p" series of changes)'
   created new head
 
   $ hg up 'desc("q-2")'
   2 files updated, 0 files merged, 2 files removed, 0 files unresolved
   $ echo t > unrelated-t
   $ hg add unrelated-t
   $ hg ci -m 't-1: unrelated changes (based on "q" changes)'
   created new head
 
 (merge variant 1)
 
   $ hg up 'desc("mPQm")'
   1 files updated, 0 files merged, 2 files removed, 0 files unresolved
   $ hg merge 'desc("t-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mPQ,Tm: $case_desc"
 
 (merge variant 2)
 
   $ hg up 'desc("t-1")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
   $ hg merge 'desc("mPQm")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mT,PQm: $case_desc"
   created new head
 
 (merge variant 3)
 
   $ hg up 'desc("mQPm")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("s-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mQP,Sm: $case_desc"
 
 (merge variant 4)
 
   $ hg up 'desc("s-1")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("mQPm")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mS,QPm: $case_desc"
   created new head
   $ hg up null --quiet
 
 
   $ hg log -G --rev '::(desc("mPQ,Tm") + desc("mT,PQm") + desc("mQP,Sm") + desc("mS,QPm"))'
   o    mS,QPm: chained merges (conflict -> simple) - different content
   |\
   +---o  mQP,Sm: chained merges (conflict -> simple) - different content
   | |/
   | | o    mT,PQm: chained merges (conflict -> simple) - different content
   | | |\
   | | +---o  mPQ,Tm: chained merges (conflict -> simple) - different content
   | | | |/
   | | | o  t-1: unrelated changes (based on "q" changes)
   | | | |
   | o | |  s-1: unrelated changes (based on the "p" series of changes)
   | | | |
   o-----+  mQPm-0 merge with copies info on both side - P side: rename t to v, Q side: r to v, (different content) - the other way
   |/ / /
   | o /  mPQm-0 merge with copies info on both side - P side: rename t to v, Q side: r to v, (different content) - one way
   |/|/
   | o  q-2 w -move-> v
   | |
   | o  q-1 r -move-> w
   | |
   o |  p-2: u -move-> v
   | |
   o |  p-1: t -move-> u
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Subcase: chaining salvage information during a merge
 ````````````````````````````````````````````````````
 
 We add more change on the branch were the file was deleted. merging again
 should preserve the fact eh file was salvaged.
 
   $ case_desc="chained merges (salvaged -> simple) - same content (when the file exists)"
 
 (creating the change)
 
   $ hg up 'desc("c-1")'
   5 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ echo l > unrelated-l
   $ hg add unrelated-l
   $ hg ci -m 'l-1: unrelated changes (based on "c" changes)'
   created new head
 
 (Merge variant 1)
 
   $ hg up 'desc("mBC-revert-m")'
   2 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("l-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mBC+revert,Lm: $case_desc"
 
 (Merge variant 2)
 
   $ hg up 'desc("mCB-revert-m")'
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("l-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mCB+revert,Lm: $case_desc"
 
 (Merge variant 3)
 
   $ hg up 'desc("l-1")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
 
   $ hg merge 'desc("mBC-revert-m")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mL,BC+revertm: $case_desc"
   created new head
 
 (Merge variant 4)
 
   $ hg up 'desc("l-1")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
 
   $ hg merge 'desc("mCB-revert-m")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mL,CB+revertm: $case_desc"
   created new head
 
   $ hg log -G --rev '::(desc("mBC+revert,Lm") + desc("mCB+revert,Lm") + desc("mL,BC+revertm") + desc("mL,CB+revertm"))'
   @    mL,CB+revertm: chained merges (salvaged -> simple) - same content (when the file exists)
   |\
   | | o  mL,BC+revertm: chained merges (salvaged -> simple) - same content (when the file exists)
   | |/|
   +-+---o  mCB+revert,Lm: chained merges (salvaged -> simple) - same content (when the file exists)
   | | |
   | +---o  mBC+revert,Lm: chained merges (salvaged -> simple) - same content (when the file exists)
   | | |/
   | o |  l-1: unrelated changes (based on "c" changes)
   | | |
   | | o  mBC-revert-m-0 merge explicitely revive deleted file - B side: unrelated change, C side: delete d (restored by merge) - the other way
   | |/|
   o---+  mCB-revert-m-0 merge explicitely revive deleted file - B side: unrelated change, C side: delete d (restored by merge) - one way
   |/ /
   o |  c-1 delete d
   | |
   | o  b-1: b update
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 
 Subcase: chaining "merged" information during a merge
 ``````````````````````````````````````````````````````
 
 When a non-rename change are merged with a copy overwrite, the merge pick the copy source from (p1) as the reference. We should preserve this information in subsequent merges.
 
   $ case_desc="chained merges (copy-overwrite -> simple) - same content"
 
 (extra unrelated changes)
 
   $ hg up 'desc("f-2")'
   2 files updated, 0 files merged, 2 files removed, 0 files unresolved (no-changeset !)
   1 files updated, 0 files merged, 2 files removed, 0 files unresolved (changeset !)
   $ echo n > unrelated-n
   $ hg add unrelated-n
   $ hg ci -m 'n-1: unrelated changes (based on the "f" series of changes)'
   created new head
 
   $ hg up 'desc("g-1")'
   2 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo o > unrelated-o
   $ hg add unrelated-o
   $ hg ci -m 'o-1: unrelated changes (based on "g" changes)'
   created new head
 
 (merge variant 1)
 
   $ hg up 'desc("mFGm")'
   1 files updated, 0 files merged, 2 files removed, 0 files unresolved (no-changeset !)
   0 files updated, 0 files merged, 2 files removed, 0 files unresolved (changeset !)
   $ hg merge 'desc("o-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mFG,Om: $case_desc"
 
 (merge variant 2)
 
   $ hg up 'desc("o-1")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved (no-changeset !)
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved (changeset !)
   $ hg merge 'desc("FGm")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved (no-changeset !)
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved (changeset !)
   (branch merge, don't forget to commit)
   $ hg ci -m "mO,FGm: $case_desc"
   created new head
 
 (merge variant 3)
 
   $ hg up 'desc("mGFm")'
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("n-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mGF,Nm: $case_desc"
 
 (merge variant 4)
 
   $ hg up 'desc("n-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("mGFm")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mN,GFm: $case_desc"
   created new head
 
   $ hg log -G --rev '::(desc("mFG,Om") + desc("mO,FGm") + desc("mGF,Nm") + desc("mN,GFm"))'
   @    mN,GFm: chained merges (copy-overwrite -> simple) - same content
   |\
   +---o  mGF,Nm: chained merges (copy-overwrite -> simple) - same content
   | |/
   | | o    mO,FGm: chained merges (copy-overwrite -> simple) - same content
   | | |\
   | | +---o  mFG,Om: chained merges (copy-overwrite -> simple) - same content
   | | | |/
   | | | o  o-1: unrelated changes (based on "g" changes)
   | | | |
   | o | |  n-1: unrelated changes (based on the "f" series of changes)
   | | | |
   o-----+  mGFm-0 merge - G side: content change, F side: copy overwrite, no content change - the other way
   |/ / /
   | o /  mFGm-0 merge - G side: content change, F side: copy overwrite, no content change - one way
   |/|/
   | o  g-1: update d
   | |
   o |  f-2: rename i -> d
   | |
   o |  f-1: rename h -> i
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Subcase: chaining conflicting rename resolution, with extra change during the merge
 ```````````````````````````````````````````````````````````````````````````````````
 
 The "mEA-change-m-0" and "mAE-change-m-0" case create a rename tracking conflict on file 'f'. We
 add more change on the respective branch and merge again. These second merge
 does not involve the file 'f' and the arbitration done within "mAEm" and "mEA"
 about that file should stay unchanged.
 
   $ case_desc="chained merges (conflict+change -> simple) - same content on both branch in the initial merge"
 
 
 (merge variant 1)
 
   $ hg up 'desc("mAE-change-m")'
   2 files updated, 0 files merged, 3 files removed, 0 files unresolved
   $ hg merge 'desc("k-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mAE-change,Km: $case_desc"
 
 (merge variant 2)
 
   $ hg up 'desc("k-1")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
   $ hg merge 'desc("mAE-change-m")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mK,AE-change-m: $case_desc"
   created new head
 
 (merge variant 3)
 
   $ hg up 'desc("mEA-change-m")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg merge 'desc("j-1")'
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mEA-change,Jm: $case_desc"
 
 (merge variant 4)
 
   $ hg up 'desc("j-1")'
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg merge 'desc("mEA-change-m")'
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci -m "mJ,EA-change-m: $case_desc"
   created new head
 
 
   $ hg log -G --rev '::(desc("mAE-change,Km") + desc("mK,AE-change-m") + desc("mEA-change,Jm") + desc("mJ,EA-change-m"))'
   @    mJ,EA-change-m: chained merges (conflict+change -> simple) - same content on both branch in the initial merge
   |\
   +---o  mEA-change,Jm: chained merges (conflict+change -> simple) - same content on both branch in the initial merge
   | |/
   | | o    mK,AE-change-m: chained merges (conflict+change -> simple) - same content on both branch in the initial merge
   | | |\
   | | +---o  mAE-change,Km: chained merges (conflict+change -> simple) - same content on both branch in the initial merge
   | | | |/
   | | | o  k-1: unrelated changes (based on "e" changes)
   | | | |
   | o | |  j-1: unrelated changes (based on the "a" series of changes)
   | | | |
   o-----+  mEA-change-m-0 merge with file update and copies info on both side - A side: rename d to f, E side: b to f, (same content for f in parent) - the other way
   |/ / /
   | o /  mAE-change-m-0 merge with file update and copies info on both side - A side: rename d to f, E side: b to f, (same content for f in parent) - one way
   |/|/
   | o  e-2 g -move-> f
   | |
   | o  e-1 b -move-> g
   | |
   o |  a-2: e -move-> f
   | |
   o |  a-1: d -move-> e
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Summary of all created cases
 ----------------------------
 
   $ hg up --quiet null
 
 (This exists to help keeping a compact list of the various cases we have built)
 
   $ hg log -T '{desc|firstline}\n'| sort
   a-1: d -move-> e
   a-2: e -move-> f
   b-1: b update
   c-1 delete d
   d-1 delete d
   d-2 re-add d
   e-1 b -move-> g
   e-2 g -move-> f
   f-1: rename h -> i
   f-2: rename i -> d
   g-1: update d
   h-1: b -(move)-> d
   i-0 initial commit: a b h
   i-1: a -move-> c, p -move-> s
   i-2: c -move-> d, s -move-> t
   j-1: unrelated changes (based on the "a" series of changes)
   k-1: unrelated changes (based on "e" changes)
   l-1: unrelated changes (based on "c" changes)
   mABm-0 simple merge - A side: multiple renames, B side: unrelated update - the other way
   mAE,Km: chained merges (conflict -> simple) - same content everywhere
   mAE-change,Km: chained merges (conflict+change -> simple) - same content on both branch in the initial merge
   mAE-change-m-0 merge with file update and copies info on both side - A side: rename d to f, E side: b to f, (same content for f in parent) - one way
   mAEm-0 merge with copies info on both side - A side: rename d to f, E side: b to f, (same content for f) - one way
   mBAm-0 simple merge - A side: multiple renames, B side: unrelated update - one way
   mBC+revert,Lm: chained merges (salvaged -> simple) - same content (when the file exists)
   mBC-revert-m-0 merge explicitely revive deleted file - B side: unrelated change, C side: delete d (restored by merge) - the other way
   mBCm-0 simple merge - C side: delete a file with copies history , B side: unrelated update - one way
   mBCm-1 re-add d
   mBDm-0 simple merge - B side: unrelated update, D side: delete and recreate a file (with different content) - one way
   mBFm-0 simple merge - B side: unrelated change, F side: overwrite d with a copy (from h->i->d) - one way
   mBRm-0 simple merge - B side: unrelated change, R side: overwrite d with a copy (from r->x->t) different content - one way
   mCB+revert,Lm: chained merges (salvaged -> simple) - same content (when the file exists)
   mCB-revert-m-0 merge explicitely revive deleted file - B side: unrelated change, C side: delete d (restored by merge) - one way
   mCBm-0 simple merge - C side: delete a file with copies history , B side: unrelated update - the other way
   mCBm-1 re-add d
   mCGm-0 merge updated/deleted - revive the file (updated content) - one way
   mCH-delete-before-conflict-m-0 simple merge - C side: d is the results of renames then deleted, H side: d is result of another rename (same content as the other branch) - one way
   mDBm-0 simple merge - B side: unrelated update, D side: delete and recreate a file (with different content) - the other way
   mDGm-0 actual content merge, copies on one side - D side: delete and re-add (different content), G side: update content - one way
   mEA,Jm: chained merges (conflict -> simple) - same content everywhere
   mEA-change,Jm: chained merges (conflict+change -> simple) - same content on both branch in the initial merge
   mEA-change-m-0 merge with file update and copies info on both side - A side: rename d to f, E side: b to f, (same content for f in parent) - the other way
   mEAm-0 merge with copies info on both side - A side: rename d to f, E side: b to f, (same content for f) - the other way
   mFBm-0 simple merge - B side: unrelated change, F side: overwrite d with a copy (from h->i->d) - the other way
   mFG,Om: chained merges (copy-overwrite -> simple) - same content
   mFGm-0 merge - G side: content change, F side: copy overwrite, no content change - one way
   mGCm-0 merge updated/deleted - revive the file (updated content) - the other way
   mGDm-0 actual content merge, copies on one side - D side: delete and re-add (different content), G side: update content - the other way
   mGF,Nm: chained merges (copy-overwrite -> simple) - same content
   mGFm-0 merge - G side: content change, F side: copy overwrite, no content change - the other way
   mHC-delete-before-conflict-m-0 simple merge - C side: d is the results of renames then deleted, H side: d is result of another rename (same content as the other branch) - the other way
   mJ,EA-change-m: chained merges (conflict+change -> simple) - same content on both branch in the initial merge
   mJ,EAm: chained merges (conflict -> simple) - same content everywhere
   mK,AE-change-m: chained merges (conflict+change -> simple) - same content on both branch in the initial merge
   mK,AEm: chained merges (conflict -> simple) - same content everywhere
   mL,BC+revertm: chained merges (salvaged -> simple) - same content (when the file exists)
   mL,CB+revertm: chained merges (salvaged -> simple) - same content (when the file exists)
   mN,GFm: chained merges (copy-overwrite -> simple) - same content
   mO,FGm: chained merges (copy-overwrite -> simple) - same content
   mPQ,Tm: chained merges (conflict -> simple) - different content
   mPQm-0 merge with copies info on both side - P side: rename t to v, Q side: r to v, (different content) - one way
   mQP,Sm: chained merges (conflict -> simple) - different content
   mQPm-0 merge with copies info on both side - P side: rename t to v, Q side: r to v, (different content) - the other way
   mRBm-0 simple merge - B side: unrelated change, R side: overwrite d with a copy (from r->x->t) different content - the other way
   mS,QPm: chained merges (conflict -> simple) - different content
   mT,PQm: chained merges (conflict -> simple) - different content
   n-1: unrelated changes (based on the "f" series of changes)
   o-1: unrelated changes (based on "g" changes)
   p-1: t -move-> u
   p-2: u -move-> v
   q-1 r -move-> w
   q-2 w -move-> v
   r-1: rename r -> x
   r-2: rename t -> x
   s-1: unrelated changes (based on the "p" series of changes)
   t-1: unrelated changes (based on "q" changes)
 
 
 Test that sidedata computations during upgrades are correct
 ===========================================================
 
 We upgrade a repository that is not using sidedata (the filelog case) and
  check that the same side data have been generated as if they were computed at
  commit time.
 
 
 #if upgraded
   $ cat >> $HGRCPATH << EOF
   > [format]
   > exp-use-side-data = yes
   > exp-use-copies-side-data-changeset = yes
   > EOF
   $ hg debugformat -v
   format-variant     repo config default
   fncache:            yes    yes     yes
   dotencode:          yes    yes     yes
   generaldelta:       yes    yes     yes
   share-safe:          no     no      no
   sparserevlog:       yes    yes     yes
   sidedata:            no    yes      no
   persistent-nodemap:  no     no      no
   copies-sdc:          no    yes      no
   plain-cl-delta:     yes    yes     yes
   compression:        * (glob)
   compression-level:  default default default
   $ hg debugupgraderepo --run --quiet
   upgrade will perform the following actions:
   
   requirements
      preserved: * (glob)
      added: exp-copies-sidedata-changeset, exp-sidedata-flag
   
   processed revlogs:
     - all-filelogs
     - changelog
     - manifest
   
 #endif
 
 
 #if no-compatibility no-filelog no-changeset
 
   $ hg debugchangedfiles --compute 0
   added      : a, ;
   added      : b, ;
   added      : h, ;
   added      : p, ;
   added      : q, ;
   added      : r, ;
 
   $ for rev in `hg log --rev 'all()' -T '{rev}\n'`; do
   >     case_id=`hg log -r $rev -T '{word(0, desc, ":")}\n'`
   >     echo "##### revision \"$case_id\" #####"
   >     hg debugsidedata -c -v -- $rev
   >     hg debugchangedfiles $rev
   > done
   ##### revision "i-0 initial commit" #####
   1 sidedata entries
    entry-0014 size 64
     '\x00\x00\x00\x06\x04\x00\x00\x00\x01\x00\x00\x00\x00\x04\x00\x00\x00\x02\x00\x00\x00\x00\x04\x00\x00\x00\x03\x00\x00\x00\x00\x04\x00\x00\x00\x04\x00\x00\x00\x00\x04\x00\x00\x00\x05\x00\x00\x00\x00\x04\x00\x00\x00\x06\x00\x00\x00\x00abhpqr'
   added      : a, ;
   added      : b, ;
   added      : h, ;
   added      : p, ;
   added      : q, ;
   added      : r, ;
   ##### revision "i-1" #####
   1 sidedata entries
    entry-0014 size 44
     '\x00\x00\x00\x04\x0c\x00\x00\x00\x01\x00\x00\x00\x00\x06\x00\x00\x00\x02\x00\x00\x00\x00\x0c\x00\x00\x00\x03\x00\x00\x00\x00\x06\x00\x00\x00\x04\x00\x00\x00\x02acps'
   removed    : a, ;
   added    p1: c, a;
   removed    : p, ;
   added    p1: s, p;
   ##### revision "i-2" #####
   1 sidedata entries
    entry-0014 size 44
     '\x00\x00\x00\x04\x0c\x00\x00\x00\x01\x00\x00\x00\x00\x06\x00\x00\x00\x02\x00\x00\x00\x00\x0c\x00\x00\x00\x03\x00\x00\x00\x00\x06\x00\x00\x00\x04\x00\x00\x00\x02cdst'
   removed    : c, ;
   added    p1: d, c;
   removed    : s, ;
   added    p1: t, s;
   ##### revision "a-1" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x0c\x00\x00\x00\x01\x00\x00\x00\x00\x06\x00\x00\x00\x02\x00\x00\x00\x00de'
   removed    : d, ;
   added    p1: e, d;
   ##### revision "a-2" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x0c\x00\x00\x00\x01\x00\x00\x00\x00\x06\x00\x00\x00\x02\x00\x00\x00\x00ef'
   removed    : e, ;
   added    p1: f, e;
   ##### revision "b-1" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x14\x00\x00\x00\x01\x00\x00\x00\x00b'
   touched    : b, ;
   ##### revision "c-1 delete d" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x0c\x00\x00\x00\x01\x00\x00\x00\x00d'
   removed    : d, ;
   ##### revision "d-1 delete d" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x0c\x00\x00\x00\x01\x00\x00\x00\x00d'
   removed    : d, ;
   ##### revision "d-2 re-add d" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x04\x00\x00\x00\x01\x00\x00\x00\x00d'
   added      : d, ;
   ##### revision "e-1 b -move-> g" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x0c\x00\x00\x00\x01\x00\x00\x00\x00\x06\x00\x00\x00\x02\x00\x00\x00\x00bg'
   removed    : b, ;
   added    p1: g, b;
   ##### revision "e-2 g -move-> f" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x06\x00\x00\x00\x01\x00\x00\x00\x01\x0c\x00\x00\x00\x02\x00\x00\x00\x00fg'
   added    p1: f, g;
   removed    : g, ;
   ##### revision "p-1" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x0c\x00\x00\x00\x01\x00\x00\x00\x00\x06\x00\x00\x00\x02\x00\x00\x00\x00tu'
   removed    : t, ;
   added    p1: u, t;
   ##### revision "p-2" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x0c\x00\x00\x00\x01\x00\x00\x00\x00\x06\x00\x00\x00\x02\x00\x00\x00\x00uv'
   removed    : u, ;
   added    p1: v, u;
   ##### revision "q-1 r -move-> w" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x0c\x00\x00\x00\x01\x00\x00\x00\x00\x06\x00\x00\x00\x02\x00\x00\x00\x00rw'
   removed    : r, ;
   added    p1: w, r;
   ##### revision "q-2 w -move-> v" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x06\x00\x00\x00\x01\x00\x00\x00\x01\x0c\x00\x00\x00\x02\x00\x00\x00\x00vw'
   added    p1: v, w;
   removed    : w, ;
   ##### revision "mBAm-0 simple merge - A side" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mABm-0 simple merge - A side" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mBCm-0 simple merge - C side" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mBCm-1 re-add d" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x04\x00\x00\x00\x01\x00\x00\x00\x00d'
   added      : d, ;
   ##### revision "mCBm-0 simple merge - C side" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mCBm-1 re-add d" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x04\x00\x00\x00\x01\x00\x00\x00\x00d'
   added      : d, ;
   ##### revision "mBDm-0 simple merge - B side" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mDBm-0 simple merge - B side" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mAEm-0 merge with copies info on both side - A side" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x08\x00\x00\x00\x01\x00\x00\x00\x00f'
   merged     : f, ;
   ##### revision "mEAm-0 merge with copies info on both side - A side" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x08\x00\x00\x00\x01\x00\x00\x00\x00f'
   merged     : f, ;
   ##### revision "mPQm-0 merge with copies info on both side - P side" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x08\x00\x00\x00\x01\x00\x00\x00\x00v'
   merged     : v, ;
   ##### revision "mQPm-0 merge with copies info on both side - P side" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x08\x00\x00\x00\x01\x00\x00\x00\x00v'
   merged     : v, ;
   ##### revision "f-1" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x0c\x00\x00\x00\x01\x00\x00\x00\x00\x06\x00\x00\x00\x02\x00\x00\x00\x00hi'
   removed    : h, ;
   added    p1: i, h;
   ##### revision "f-2" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x16\x00\x00\x00\x01\x00\x00\x00\x01\x0c\x00\x00\x00\x02\x00\x00\x00\x00di'
   touched  p1: d, i;
   removed    : i, ;
   ##### revision "mBFm-0 simple merge - B side" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mFBm-0 simple merge - B side" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "r-1" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x0c\x00\x00\x00\x01\x00\x00\x00\x00\x06\x00\x00\x00\x02\x00\x00\x00\x00rx'
   removed    : r, ;
   added    p1: x, r;
   ##### revision "r-2" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x16\x00\x00\x00\x01\x00\x00\x00\x01\x0c\x00\x00\x00\x02\x00\x00\x00\x00tx'
   touched  p1: t, x;
   removed    : x, ;
   ##### revision "mBRm-0 simple merge - B side" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mRBm-0 simple merge - B side" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "g-1" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x14\x00\x00\x00\x01\x00\x00\x00\x00d'
   touched    : d, ;
   ##### revision "mDGm-0 actual content merge, copies on one side - D side" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x08\x00\x00\x00\x01\x00\x00\x00\x00d'
   merged     : d, ;
   ##### revision "mGDm-0 actual content merge, copies on one side - D side" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x08\x00\x00\x00\x01\x00\x00\x00\x00d'
   merged     : d, ;
   ##### revision "mFGm-0 merge - G side" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x08\x00\x00\x00\x01\x00\x00\x00\x00d'
   merged     : d, ;
   ##### revision "mGFm-0 merge - G side" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x08\x00\x00\x00\x01\x00\x00\x00\x00d'
   merged     : d, ;
   ##### revision "mCGm-0 merge updated/deleted - revive the file (updated content) - one way" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x10\x00\x00\x00\x01\x00\x00\x00\x00d'
   salvaged   : d, ;
   ##### revision "mGCm-0 merge updated/deleted - revive the file (updated content) - the other way" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x10\x00\x00\x00\x01\x00\x00\x00\x00d'
   salvaged   : d, ;
   ##### revision "mCB-revert-m-0 merge explicitely revive deleted file - B side" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x10\x00\x00\x00\x01\x00\x00\x00\x00d'
   salvaged   : d, ;
   ##### revision "mBC-revert-m-0 merge explicitely revive deleted file - B side" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x10\x00\x00\x00\x01\x00\x00\x00\x00d'
   salvaged   : d, ;
   ##### revision "h-1" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x02\x0c\x00\x00\x00\x01\x00\x00\x00\x00\x06\x00\x00\x00\x02\x00\x00\x00\x00bd'
   removed    : b, ;
   added    p1: d, b;
   ##### revision "mCH-delete-before-conflict-m-0 simple merge - C side" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mHC-delete-before-conflict-m-0 simple merge - C side" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mAE-change-m-0 merge with file update and copies info on both side - A side" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x08\x00\x00\x00\x01\x00\x00\x00\x00f'
   merged     : f, ;
   ##### revision "mEA-change-m-0 merge with file update and copies info on both side - A side" #####
   1 sidedata entries
    entry-0014 size 14
     '\x00\x00\x00\x01\x08\x00\x00\x00\x01\x00\x00\x00\x00f'
   merged     : f, ;
   ##### revision "j-1" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x01\x04\x00\x00\x00\x0b\x00\x00\x00\x00unrelated-j'
   added      : unrelated-j, ;
   ##### revision "k-1" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x01\x04\x00\x00\x00\x0b\x00\x00\x00\x00unrelated-k'
   added      : unrelated-k, ;
   ##### revision "mAE,Km" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mK,AEm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mEA,Jm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mJ,EAm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "s-1" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x01\x04\x00\x00\x00\x0b\x00\x00\x00\x00unrelated-s'
   added      : unrelated-s, ;
   ##### revision "t-1" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x01\x04\x00\x00\x00\x0b\x00\x00\x00\x00unrelated-t'
   added      : unrelated-t, ;
   ##### revision "mPQ,Tm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mT,PQm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mQP,Sm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mS,QPm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "l-1" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x01\x04\x00\x00\x00\x0b\x00\x00\x00\x00unrelated-l'
   added      : unrelated-l, ;
   ##### revision "mBC+revert,Lm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mCB+revert,Lm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mL,BC+revertm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mL,CB+revertm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "n-1" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x01\x04\x00\x00\x00\x0b\x00\x00\x00\x00unrelated-n'
   added      : unrelated-n, ;
   ##### revision "o-1" #####
   1 sidedata entries
    entry-0014 size 24
     '\x00\x00\x00\x01\x04\x00\x00\x00\x0b\x00\x00\x00\x00unrelated-o'
   added      : unrelated-o, ;
   ##### revision "mFG,Om" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mO,FGm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mGF,Nm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mN,GFm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mAE-change,Km" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mK,AE-change-m" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mEA-change,Jm" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
   ##### revision "mJ,EA-change-m" #####
   1 sidedata entries
    entry-0014 size 4
     '\x00\x00\x00\x00'
 
 #endif
 
 
 Test copy information chaining
 ==============================
 
 Check that matching only affect the destination and not intermediate path
 -------------------------------------------------------------------------
 
 The two status call should give the same value for f
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("a-2")'
   A f
     a
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("a-2")' f
   A f
     a (no-changeset no-compatibility !)
 
 merging with unrelated change does not interfere with the renames
 ---------------------------------------------------------------
 
 - rename on one side
 - unrelated change on the other side
 
   $ hg log -G --rev '::(desc("mABm")+desc("mBAm"))'
   o    mABm-0 simple merge - A side: multiple renames, B side: unrelated update - the other way
   |\
   +---o  mBAm-0 simple merge - A side: multiple renames, B side: unrelated update - one way
   | |/
   | o  b-1: b update
   | |
   o |  a-2: e -move-> f
   | |
   o |  a-1: d -move-> e
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mABm")'
   A f
     d
   R d
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mBAm")'
   A f
     d
   R d
   $ hg status --copies --rev 'desc("a-2")' --rev 'desc("mABm")'
   M b
   $ hg status --copies --rev 'desc("a-2")' --rev 'desc("mBAm")'
   M b
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mABm")'
   M b
   A f
     d
   R d
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mBAm")'
   M b
   A f
     d
   R d
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mABm")'
   M b
   A f
     a
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mBAm")'
   M b
   A f
     a
   A t
     p
   R a
   R p
 
 merging with the side having a delete
 -------------------------------------
 
 case summary:
 - one with change to an unrelated file
 - one deleting the change
 and recreate an unrelated file after the merge
 
   $ hg log -G --rev '::(desc("mCBm")+desc("mBCm"))'
   o  mCBm-1 re-add d
   |
   o    mCBm-0 simple merge - C side: delete a file with copies history , B side: unrelated update - the other way
   |\
   | | o  mBCm-1 re-add d
   | | |
   +---o  mBCm-0 simple merge - C side: delete a file with copies history , B side: unrelated update - one way
   | |/
   | o  c-1 delete d
   | |
   o |  b-1: b update
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 - comparing from the merge
 
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mBCm-0")'
   R d
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mCBm-0")'
   R d
   $ hg status --copies --rev 'desc("c-1")' --rev 'desc("mBCm-0")'
   M b
   $ hg status --copies --rev 'desc("c-1")' --rev 'desc("mCBm-0")'
   M b
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mBCm-0")'
   M b
   R d
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mCBm-0")'
   M b
   R d
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mBCm-0")'
   M b
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mCBm-0")'
   M b
   A t
     p
   R a
   R p
 
 - comparing with the merge children re-adding the file
 
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mBCm-1")'
   M d
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mCBm-1")'
   M d
   $ hg status --copies --rev 'desc("c-1")' --rev 'desc("mBCm-1")'
   M b
   A d
   $ hg status --copies --rev 'desc("c-1")' --rev 'desc("mCBm-1")'
   M b
   A d
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mBCm-1")'
   M b
   M d
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mCBm-1")'
   M b
   M d
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mBCm-1")'
   M b
   A d
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mCBm-1")'
   M b
   A d
   A t
     p
   R a
   R p
 
 Comparing with a merge re-adding the file afterward
 ---------------------------------------------------
 
 Merge:
 - one with change to an unrelated file
 - one deleting and recreating the change
 
   $ hg log -G --rev '::(desc("mDBm")+desc("mBDm"))'
   o    mDBm-0 simple merge - B side: unrelated update, D side: delete and recreate a file (with different content) - the other way
   |\
   +---o  mBDm-0 simple merge - B side: unrelated update, D side: delete and recreate a file (with different content) - one way
   | |/
   | o  d-2 re-add d
   | |
   | o  d-1 delete d
   | |
   o |  b-1: b update
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mBDm-0")'
   M d
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mDBm-0")'
   M d
   $ hg status --copies --rev 'desc("d-2")' --rev 'desc("mBDm-0")'
   M b
   $ hg status --copies --rev 'desc("d-2")' --rev 'desc("mDBm-0")'
   M b
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mBDm-0")'
   M b
   M d
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mDBm-0")'
   M b
   M d
 
 The bugs makes recorded copy is different depending of where we started the merge from since
 
   $ hg manifest --debug --rev 'desc("mBDm-0")' | grep '644   d'
   b004912a8510032a0350a74daa2803dadfb00e12 644   d
   $ hg manifest --debug --rev 'desc("mDBm-0")' | grep '644   d'
   b004912a8510032a0350a74daa2803dadfb00e12 644   d
 
   $ hg manifest --debug --rev 'desc("d-2")' | grep '644   d'
   b004912a8510032a0350a74daa2803dadfb00e12 644   d
   $ hg manifest --debug --rev 'desc("b-1")' | grep '644   d'
   d8252ab2e760b0d4e5288fd44cbd15a0fa567e16 644   d (no-changeset !)
   ae258f702dfeca05bf9b6a22a97a4b5645570f11 644   d (changeset !)
   $ hg debugindex d | head -n 4 | ../no-linkrev
      rev linkrev nodeid       p1           p2
        0       * d8252ab2e760 000000000000 000000000000 (no-changeset !)
        0       * ae258f702dfe 000000000000 000000000000 (changeset !)
        1       * b004912a8510 000000000000 000000000000
        2       * 7b79e2fe0c89 000000000000 000000000000 (no-changeset !)
        2       * 5cce88bf349f ae258f702dfe 000000000000 (changeset !)
 
 Log output should not include a merge commit as it did not happen
 
   $ hg log -Gfr 'desc("mBDm-0")' d
   o  d-2 re-add d
   |
   ~
 
   $ hg log -Gfr 'desc("mDBm-0")' d
   o  d-2 re-add d
   |
   ~
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mBDm-0")'
   M b
   A d
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mDBm-0")'
   M b
   A d
   A t
     p
   R a
   R p
 
 
 Comparing with a merge with colliding rename
 --------------------------------------------
 
 Subcase: new copy information on both side
 ``````````````````````````````````````````
 
 - the "e-" branch renaming b to f (through 'g')
 - the "a-" branch renaming d to f (through e)
 
   $ hg log -G --rev '::(desc("mAEm")+desc("mEAm"))'
   o    mEAm-0 merge with copies info on both side - A side: rename d to f, E side: b to f, (same content for f) - the other way
   |\
   +---o  mAEm-0 merge with copies info on both side - A side: rename d to f, E side: b to f, (same content for f) - one way
   | |/
   | o  e-2 g -move-> f
   | |
   | o  e-1 b -move-> g
   | |
   o |  a-2: e -move-> f
   | |
   o |  a-1: d -move-> e
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 #if no-changeset
   $ hg manifest --debug --rev 'desc("mAEm-0")' | grep '644   f'
   2ff93c643948464ee1f871867910ae43a45b0bea 644   f
   $ hg manifest --debug --rev 'desc("mEAm-0")' | grep '644   f'
   2ff93c643948464ee1f871867910ae43a45b0bea 644   f
   $ hg manifest --debug --rev 'desc("a-2")' | grep '644   f'
   b76eb76580df486c3d51d63c5c210d4dd43a8ac7 644   f
   $ hg manifest --debug --rev 'desc("e-2")' | grep '644   f'
   e8825b386367b29fec957283a80bb47b47483fe1 644   f
   $ hg debugindex f | ../no-linkrev
      rev linkrev nodeid       p1           p2
        0       * b76eb76580df 000000000000 000000000000
        1       * e8825b386367 000000000000 000000000000
        2       * 2ff93c643948 b76eb76580df e8825b386367
        3       * 2f649fba7eb2 b76eb76580df e8825b386367
        4       * 774e7c1637d5 e8825b386367 b76eb76580df
 #else
   $ hg manifest --debug --rev 'desc("mAEm-0")' | grep '644   f'
   ae258f702dfeca05bf9b6a22a97a4b5645570f11 644   f
   $ hg manifest --debug --rev 'desc("mEAm-0")' | grep '644   f'
   ae258f702dfeca05bf9b6a22a97a4b5645570f11 644   f
   $ hg manifest --debug --rev 'desc("a-2")' | grep '644   f'
   ae258f702dfeca05bf9b6a22a97a4b5645570f11 644   f
   $ hg manifest --debug --rev 'desc("e-2")' | grep '644   f'
   ae258f702dfeca05bf9b6a22a97a4b5645570f11 644   f
   $ hg debugindex f | ../no-linkrev
      rev linkrev nodeid       p1           p2
        0       * ae258f702dfe 000000000000 000000000000
        1       * d3613c1ec831 ae258f702dfe 000000000000
        2       * 05e03c868bbc ae258f702dfe 000000000000
 #endif
 
 # Here the filelog based implementation is not looking at the rename
 # information (because the file exist on both side). However the changelog
 # based on works fine. We have different output.
 
   $ hg status --copies --rev 'desc("a-2")' --rev 'desc("mAEm-0")'
   M f (no-changeset !)
     b (no-filelog no-changeset !)
   R b
   $ hg status --copies --rev 'desc("a-2")' --rev 'desc("mEAm-0")'
   M f (no-changeset !)
     b (no-filelog no-changeset !)
   R b
   $ hg status --copies --rev 'desc("e-2")' --rev 'desc("mAEm-0")'
   M f (no-changeset !)
     d (no-filelog no-changeset !)
   R d
   $ hg status --copies --rev 'desc("e-2")' --rev 'desc("mEAm-0")'
   M f (no-changeset !)
     d (no-filelog no-changeset !)
   R d
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("a-2")'
   A f
     d
   R d
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("e-2")'
   A f
     b
   R b
 
 # From here, we run status against revision where both source file exists.
 #
 # The filelog based implementation picks an arbitrary side based on revision
 # numbers. So the same side "wins" whatever the parents order is. This is
 # sub-optimal because depending on revision numbers means the result can be
 # different from one repository to the next.
 #
 # The changeset based algorithm use the parent order to break tie on conflicting
 # information and will have a different order depending on who is p1 and p2.
 # That order is stable accross repositories. (data from p1 prevails)
 
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mAEm-0")'
   A f
     d
   R b
   R d
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mEAm-0")'
   A f
     d (filelog !)
     b (no-filelog !)
   R b
   R d
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mAEm-0")'
   A f
     a
   A t
     p
   R a
   R b
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mEAm-0")'
   A f
     a (filelog !)
     b (no-filelog !)
   A t
     p
   R a
   R b
   R p
 
 
 Subcase: existing copy information overwritten on one branch
 ````````````````````````````````````````````````````````````
 
 Note:
 | In this case, one of the merge wrongly record a merge while there is none.
 | This lead to bad copy tracing information to be dug up.
 
 
 Merge:
 - one with change to an unrelated file (b)
 - one overwriting a file (d) with a rename (from h to i to d)
 
   $ hg log -G --rev '::(desc("mBFm")+desc("mFBm"))'
   o    mFBm-0 simple merge - B side: unrelated change, F side: overwrite d with a copy (from h->i->d) - the other way
   |\
   +---o  mBFm-0 simple merge - B side: unrelated change, F side: overwrite d with a copy (from h->i->d) - one way
   | |/
   | o  f-2: rename i -> d
   | |
   | o  f-1: rename h -> i
   | |
   o |  b-1: b update
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mBFm-0")'
   M b
   A d
     h
   A t
     p
   R a
   R h
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mFBm-0")'
   M b
   A d
     h
   A t
     p
   R a
   R h
   R p
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mBFm-0")'
   M d (no-changeset !)
     h (no-filelog no-changeset !)
   R h
   $ hg status --copies --rev 'desc("f-2")' --rev 'desc("mBFm-0")'
   M b
   $ hg status --copies --rev 'desc("f-1")' --rev 'desc("mBFm-0")'
   M b
   M d (no-changeset !)
     i (no-filelog no-changeset !)
   R i
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mFBm-0")'
   M d (no-changeset !)
     h (no-filelog no-changeset !)
   R h
   $ hg status --copies --rev 'desc("f-2")' --rev 'desc("mFBm-0")'
   M b
   $ hg status --copies --rev 'desc("f-1")' --rev 'desc("mFBm-0")'
   M b
   M d (no-changeset !)
     i (no-filelog no-changeset !)
   R i
 
 #if no-changeset
   $ hg log -Gfr 'desc("mBFm-0")' d
   o  f-2: rename i -> d
   |
   o  f-1: rename h -> i
   :
   o  i-0 initial commit: a b h
   
 #else
 BROKEN: `hg log --follow <file>` relies on filelog metadata to work
   $ hg log -Gfr 'desc("mBFm-0")' d
   o  i-2: c -move-> d, s -move-> t
   |
   ~
 #endif
 
 #if no-changeset
   $ hg log -Gfr 'desc("mFBm-0")' d
   o  f-2: rename i -> d
   |
   o  f-1: rename h -> i
   :
   o  i-0 initial commit: a b h
   
 #else
 BROKEN: `hg log --follow <file>` relies on filelog metadata to work
   $ hg log -Gfr 'desc("mFBm-0")' d
   o  i-2: c -move-> d, s -move-> t
   |
   ~
 #endif
 
 
 Subcase: existing copy information overwritten on one branch, with different content)
 `````````````````````````````````````````````````````````````````````````````````````
 
 Merge:
 - one with change to an unrelated file (b)
 - one overwriting a file (t) with a rename (from r to x to t), v content is not the same as on the other branch
 
   $ hg log -G --rev '::(desc("mBRm")+desc("mRBm"))'
   o    mRBm-0 simple merge - B side: unrelated change, R side: overwrite d with a copy (from r->x->t) different content - the other way
   |\
   +---o  mBRm-0 simple merge - B side: unrelated change, R side: overwrite d with a copy (from r->x->t) different content - one way
   | |/
   | o  r-2: rename t -> x
   | |
   | o  r-1: rename r -> x
   | |
   o |  b-1: b update
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mBRm-0")'
   M b
   A d
     a
   A t
     r
   R a
   R p
   R r
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mRBm-0")'
   M b
   A d
     a
   A t
     r
   R a
   R p
   R r
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mBRm-0")'
   M t
     r (no-filelog !)
   R r
   $ hg status --copies --rev 'desc("r-2")' --rev 'desc("mBRm-0")'
   M b
   $ hg status --copies --rev 'desc("r-1")' --rev 'desc("mBRm-0")'
   M b
   M t
     x (no-filelog !)
   R x
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mRBm-0")'
   M t
     r (no-filelog !)
   R r
   $ hg status --copies --rev 'desc("r-2")' --rev 'desc("mRBm-0")'
   M b
   $ hg status --copies --rev 'desc("r-1")' --rev 'desc("mRBm-0")'
   M b
   M t
     x (no-filelog !)
   R x
 
 #if no-changeset
   $ hg log -Gfr 'desc("mBRm-0")' d
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 #else
 BROKEN: `hg log --follow <file>` relies on filelog metadata to work
   $ hg log -Gfr 'desc("mBRm-0")' d
   o  i-2: c -move-> d, s -move-> t
   |
   ~
 #endif
 
 #if no-changeset
   $ hg log -Gfr 'desc("mRBm-0")' d
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 #else
 BROKEN: `hg log --follow <file>` relies on filelog metadata to work
   $ hg log -Gfr 'desc("mRBm-0")' d
   o  i-2: c -move-> d, s -move-> t
   |
   ~
 #endif
 
 Subcase: reset of the copy history on one side
 ``````````````````````````````````````````````
 
 Merge:
 - one with change to a file
 - one deleting and recreating the file
 
 Unlike in the 'BD/DB' cases, an actual merge happened here. So we should
 consider history and rename on both branch of the merge.
 
   $ hg log -G --rev '::(desc("mDGm")+desc("mGDm"))'
   o    mGDm-0 actual content merge, copies on one side - D side: delete and re-add (different content), G side: update content - the other way
   |\
   +---o  mDGm-0 actual content merge, copies on one side - D side: delete and re-add (different content), G side: update content - one way
   | |/
   | o  g-1: update d
   | |
   o |  d-2 re-add d
   | |
   o |  d-1 delete d
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 One side of the merge have a long history with rename. The other side of the
 merge point to a new file with a smaller history. Each side is "valid".
 
 (and again the filelog based algorithm only explore one, with a pick based on
 revision numbers)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mDGm-0")'
   A d
     a (filelog !)
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mGDm-0")'
   A d
     a
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("d-2")' --rev 'desc("mDGm-0")'
   M d
   $ hg status --copies --rev 'desc("d-2")' --rev 'desc("mGDm-0")'
   M d
   $ hg status --copies --rev 'desc("g-1")' --rev 'desc("mDGm-0")'
   M d
   $ hg status --copies --rev 'desc("g-1")' --rev 'desc("mGDm-0")'
   M d
 
 #if no-changeset
   $ hg log -Gfr 'desc("mDGm-0")' d
   o    mDGm-0 actual content merge, copies on one side - D side: delete and re-add (different content), G side: update content - one way
   |\
   | o  g-1: update d
   | |
   o |  d-2 re-add d
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 #else
 BROKEN: `hg log --follow <file>` relies on filelog metadata to work
   $ hg log -Gfr 'desc("mDGm-0")' d
   o    mDGm-0 actual content merge, copies on one side - D side: delete and re-add (different content), G side: update content - one way
   |\
   | o  g-1: update d
   | |
   o |  d-2 re-add d
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   ~
 #endif
 
 
 #if no-changeset
   $ hg log -Gfr 'desc("mDGm-0")' d
   o    mDGm-0 actual content merge, copies on one side - D side: delete and re-add (different content), G side: update content - one way
   |\
   | o  g-1: update d
   | |
   o |  d-2 re-add d
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 #else
 BROKEN: `hg log --follow <file>` relies on filelog metadata to work
   $ hg log -Gfr 'desc("mDGm-0")' d
   o    mDGm-0 actual content merge, copies on one side - D side: delete and re-add (different content), G side: update content - one way
   |\
   | o  g-1: update d
   | |
   o |  d-2 re-add d
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   ~
 #endif
 
 Subcase: merging a change to a file with a "copy overwrite" to that file from another branch
 ````````````````````````````````````````````````````````````````````````````````````````````
 
 Merge:
 - one with change to a file (d)
 - one overwriting that file with a rename (from h to i, to d)
 
 This case is similar to BF/FB, but an actual merge happens, so both side of the
 history are relevant.
 
 
   $ hg log -G --rev '::(desc("mGFm")+desc("mFGm"))'
   o    mGFm-0 merge - G side: content change, F side: copy overwrite, no content change - the other way
   |\
   +---o  mFGm-0 merge - G side: content change, F side: copy overwrite, no content change - one way
   | |/
   | o  g-1: update d
   | |
   o |  f-2: rename i -> d
   | |
   o |  f-1: rename h -> i
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 Note:
 | In this case, the merge get conflicting information since on one side we have
 | "a -> c -> d". and one the other one we have "h -> i -> d".
 |
 | The current code arbitrarily pick one side depending the ordering of the merged hash:
 
 In this case, the file hash from "f-2" is lower, so it will be `p1` of the resulting filenode its copy tracing information will win (and trace back to "h"):
 
 Details on this hash ordering pick:
 
   $ hg manifest --debug 'desc("g-1")' | egrep 'd$'
   17ec97e605773eb44a117d1136b3849bcdc1924f 644   d (no-changeset !)
   5cce88bf349f7c742bb440f2c53f81db9c294279 644   d (changeset !)
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("g-1")' d
   A d
     a (no-changeset no-compatibility !)
 
   $ hg manifest --debug 'desc("f-2")' | egrep 'd$'
   7b79e2fe0c8924e0e598a82f048a7b024afa4d96 644   d (no-changeset !)
   ae258f702dfeca05bf9b6a22a97a4b5645570f11 644   d (changeset !)
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("f-2")' d
   A d
     h (no-changeset no-compatibility !)
 
 Copy tracing data on the resulting merge:
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mFGm-0")'
   A d
     h (no-filelog !)
     a (filelog !)
   A t
     p
   R a
   R h
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mGFm-0")'
   A d
     a (no-changeset !)
     h (changeset !)
   A t
     p
   R a
   R h
   R p
   $ hg status --copies --rev 'desc("f-2")' --rev 'desc("mFGm-0")'
   M d
   $ hg status --copies --rev 'desc("f-2")' --rev 'desc("mGFm-0")'
   M d
   $ hg status --copies --rev 'desc("f-1")' --rev 'desc("mFGm-0")'
   M d
     i (no-filelog !)
   R i
   $ hg status --copies --rev 'desc("f-1")' --rev 'desc("mGFm-0")'
   M d
     i (no-filelog !)
   R i
   $ hg status --copies --rev 'desc("g-1")' --rev 'desc("mFGm-0")'
   M d (no-changeset !)
     h (no-filelog no-changeset !)
   R h
   $ hg status --copies --rev 'desc("g-1")' --rev 'desc("mGFm-0")'
   M d (no-changeset !)
     h (no-filelog no-changeset !)
   R h
 
 #if no-changeset
   $ hg log -Gfr 'desc("mFGm-0")' d
   o    mFGm-0 merge - G side: content change, F side: copy overwrite, no content change - one way
   |\
   | o  g-1: update d
   | |
   o |  f-2: rename i -> d
   | |
   o |  f-1: rename h -> i
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 #else
 BROKEN: `hg log --follow <file>` relies on filelog metadata to work
   $ hg log -Gfr 'desc("mFGm-0")' d
   o  g-1: update d
   |
   o  i-2: c -move-> d, s -move-> t
   |
   ~
 #endif
 
 #if no-changeset
   $ hg log -Gfr 'desc("mGFm-0")' d
   o    mGFm-0 merge - G side: content change, F side: copy overwrite, no content change - the other way
   |\
   | o  g-1: update d
   | |
   o |  f-2: rename i -> d
   | |
   o |  f-1: rename h -> i
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 #else
 BROKEN: `hg log --follow <file>` relies on filelog metadata to work
   $ hg log -Gfr 'desc("mGFm-0")' d
   o  g-1: update d
   |
   o  i-2: c -move-> d, s -move-> t
   |
   ~
 #endif
 
 Subcase: new copy information on both side with an actual merge happening
 `````````````````````````````````````````````````````````````````````````
 
 - the "p-" branch renaming 't' to 'v' (through 'u')
 - the "q-" branch renaming 'r' to 'v' (through 'w')
 
 
   $ hg log -G --rev '::(desc("mPQm")+desc("mQPm"))'
   o    mQPm-0 merge with copies info on both side - P side: rename t to v, Q side: r to v, (different content) - the other way
   |\
   +---o  mPQm-0 merge with copies info on both side - P side: rename t to v, Q side: r to v, (different content) - one way
   | |/
   | o  q-2 w -move-> v
   | |
   | o  q-1 r -move-> w
   | |
   o |  p-2: u -move-> v
   | |
   o |  p-1: t -move-> u
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 #if no-changeset
   $ hg manifest --debug --rev 'desc("mPQm-0")' | grep '644   v'
   0946c662ef16e4e67397fd717389eb6693d41749 644   v
   $ hg manifest --debug --rev 'desc("mQPm-0")' | grep '644   v'
   0db3aad7fcc1ec27fab57060e327b9e864ea0cc9 644   v
   $ hg manifest --debug --rev 'desc("p-2")' | grep '644   v'
   3f91841cd75cadc9a1f1b4e7c1aa6d411f76032e 644   v
   $ hg manifest --debug --rev 'desc("q-2")' | grep '644   v'
   c43c088b811fd27983c0a9aadf44f3343cd4cd7e 644   v
   $ hg debugindex v | ../no-linkrev
      rev linkrev nodeid       p1           p2
        0       * 3f91841cd75c 000000000000 000000000000
        1       * c43c088b811f 000000000000 000000000000
        2       * 0946c662ef16 3f91841cd75c c43c088b811f
        3       * 0db3aad7fcc1 c43c088b811f 3f91841cd75c
 #else
   $ hg manifest --debug --rev 'desc("mPQm-0")' | grep '644   v'
   65fde9f6e4d4da23b3f610e07b53673ea9541d75 644   v
   $ hg manifest --debug --rev 'desc("mQPm-0")' | grep '644   v'
   a098dda6413aecf154eefc976afc38b295acb7e5 644   v
   $ hg manifest --debug --rev 'desc("p-2")' | grep '644   v'
   5aed6a8dbff0301328c08360d24354d3d064cf0d 644   v
   $ hg manifest --debug --rev 'desc("q-2")' | grep '644   v'
   a38b2fa170219750dac9bc7d19df831f213ba708 644   v
   $ hg debugindex v | ../no-linkrev
      rev linkrev nodeid       p1           p2
        0       * 5aed6a8dbff0 000000000000 000000000000
        1       * a38b2fa17021 000000000000 000000000000
        2       * 65fde9f6e4d4 5aed6a8dbff0 a38b2fa17021
        3       * a098dda6413a a38b2fa17021 5aed6a8dbff0
 #endif
 
 # Here the filelog based implementation is not looking at the rename
 # information (because the file exist on both side). However the changelog
 # based on works fine. We have different output.
 
   $ hg status --copies --rev 'desc("p-2")' --rev 'desc("mPQm-0")'
   M v
     r (no-filelog !)
   R r
   $ hg status --copies --rev 'desc("p-2")' --rev 'desc("mQPm-0")'
   M v
     r (no-filelog !)
   R r
   $ hg status --copies --rev 'desc("q-2")' --rev 'desc("mPQm-0")'
   M v
     t (no-filelog !)
   R t
   $ hg status --copies --rev 'desc("q-2")' --rev 'desc("mQPm-0")'
   M v
     t (no-filelog !)
   R t
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("p-2")'
   A v
     t
   R t
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("q-2")'
   A v
     r
   R r
 
 # From here, we run status against revision where both source file exists.
 #
 # The filelog based implementation picks an arbitrary side based on revision
 # numbers. So the same side "wins" whatever the parents order is. This is
 # sub-optimal because depending on revision numbers means the result can be
 # different from one repository to the next.
 #
 # The changeset based algorithm use the parent order to break tie on conflicting
 # information and will have a different order depending on who is p1 and p2.
 # That order is stable accross repositories. (data from p1 prevails)
 
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mPQm-0")'
   A v
     t
   R r
   R t
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mQPm-0")'
   A v
     t (filelog !)
     r (no-filelog !)
   R r
   R t
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mPQm-0")'
   A d
     a
   A v
     r (filelog !)
     p (no-filelog !)
   R a
   R p
   R r
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mQPm-0")'
   A d
     a
   A v
     r
   R a
   R p
   R r
 
 
 Comparing with merging with a deletion (and keeping the file)
 -------------------------------------------------------------
 
 Merge:
 - one removing a file (d)
 - one updating that file
 - the merge keep the modified version of the file (canceling the delete)
 
 In this case, the file keep on living after the merge. So we should not drop its
 copy tracing chain.
 
   $ hg log -G --rev '::(desc("mCGm")+desc("mGCm"))'
   o    mGCm-0 merge updated/deleted - revive the file (updated content) - the other way
   |\
   +---o  mCGm-0 merge updated/deleted - revive the file (updated content) - one way
   | |/
   | o  g-1: update d
   | |
   o |  c-1 delete d
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 'a' is the copy source of 'd'
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mCGm-0")'
   A d
     a (no-compatibility no-changeset !)
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mGCm-0")'
   A d
     a (no-compatibility no-changeset !)
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("c-1")' --rev 'desc("mCGm-0")'
   A d
   $ hg status --copies --rev 'desc("c-1")' --rev 'desc("mGCm-0")'
   A d
   $ hg status --copies --rev 'desc("g-1")' --rev 'desc("mCGm-0")'
   $ hg status --copies --rev 'desc("g-1")' --rev 'desc("mGCm-0")'
 
 
 Comparing with merge restoring an untouched deleted file
 --------------------------------------------------------
 
 Merge:
 - one removing a file (d)
 - one leaving the file untouched
 - the merge actively restore the file to the same content.
 
 In this case, the file keep on living after the merge. So we should not drop its
 copy tracing chain.
 
   $ hg log -G --rev '::(desc("mCB-revert-m")+desc("mBC-revert-m"))'
   o    mBC-revert-m-0 merge explicitely revive deleted file - B side: unrelated change, C side: delete d (restored by merge) - the other way
   |\
   +---o  mCB-revert-m-0 merge explicitely revive deleted file - B side: unrelated change, C side: delete d (restored by merge) - one way
   | |/
   | o  c-1 delete d
   | |
   o |  b-1: b update
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 
 'a' is the the copy source of 'd'
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mCB-revert-m-0")'
   M b
   A d
     a (no-compatibility no-changeset !)
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mBC-revert-m-0")'
   M b
   A d
     a (no-compatibility no-changeset !)
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("c-1")' --rev 'desc("mCB-revert-m-0")'
   M b
   A d
   $ hg status --copies --rev 'desc("c-1")' --rev 'desc("mBC-revert-m-0")'
   M b
   A d
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mCB-revert-m-0")'
   $ hg status --copies --rev 'desc("b-1")' --rev 'desc("mBC-revert-m-0")'
 
 
 Merging a branch where a rename was deleted with a branch where the same file was renamed
 ------------------------------------------------------------------------------------------
 
 Create a "conflicting" merge where `d` get removed on one branch before its
 rename information actually conflict with the other branch.
 
 (the copy information from the branch that was not deleted should win).
 
   $ hg log -G --rev '::(desc("mCH-delete-before-conflict-m")+desc("mHC-delete-before-conflict-m"))'
   o    mHC-delete-before-conflict-m-0 simple merge - C side: d is the results of renames then deleted, H side: d is result of another rename (same content as the other branch) - the other way
   |\
   +---o  mCH-delete-before-conflict-m-0 simple merge - C side: d is the results of renames then deleted, H side: d is result of another rename (same content as the other branch) - one way
   | |/
   | o  h-1: b -(move)-> d
   | |
   o |  c-1 delete d
   | |
   o |  i-2: c -move-> d, s -move-> t
   | |
   o |  i-1: a -move-> c, p -move-> s
   |/
   o  i-0 initial commit: a b h
   
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mCH-delete-before-conflict-m")'
   A d
     b (no-compatibility no-changeset !)
   A t
     p
   R a
   R b
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mHC-delete-before-conflict-m")'
   A d
     b
   A t
     p
   R a
   R b
   R p
   $ hg status --copies --rev 'desc("c-1")' --rev 'desc("mCH-delete-before-conflict-m")'
   A d
     b
   R b
   $ hg status --copies --rev 'desc("c-1")' --rev 'desc("mHC-delete-before-conflict-m")'
   A d
     b
   R b
   $ hg status --copies --rev 'desc("h-1")' --rev 'desc("mCH-delete-before-conflict-m")'
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("h-1")' --rev 'desc("mHC-delete-before-conflict-m")'
   A t
     p
   R a
   R p
 
 Variant of previous with extra changes introduced by the merge
 --------------------------------------------------------------
 
 (see case declaration for details)
 
 Subcase: merge has same initial content on both side, but merge introduced a change
 ```````````````````````````````````````````````````````````````````````````````````
 
 - the "e-" branch renaming b to f (through 'g')
 - the "a-" branch renaming d to f (through e)
 - the merge add new change to b
 
   $ hg log -G --rev '::(desc("mAE-change-m")+desc("mEA-change-m"))'
   o    mEA-change-m-0 merge with file update and copies info on both side - A side: rename d to f, E side: b to f, (same content for f in parent) - the other way
   |\
   +---o  mAE-change-m-0 merge with file update and copies info on both side - A side: rename d to f, E side: b to f, (same content for f in parent) - one way
   | |/
   | o  e-2 g -move-> f
   | |
   | o  e-1 b -move-> g
   | |
   o |  a-2: e -move-> f
   | |
   o |  a-1: d -move-> e
   |/
   o  i-2: c -move-> d, s -move-> t
   |
   o  i-1: a -move-> c, p -move-> s
   |
   o  i-0 initial commit: a b h
   
 #if no-changeset
   $ hg manifest --debug --rev 'desc("mAE-change-m-0")' | grep '644   f'
   2f649fba7eb284e720d02b61f0546fcef694c045 644   f
   $ hg manifest --debug --rev 'desc("mEA-change-m-0")' | grep '644   f'
   774e7c1637d536b99e2d8ef16fd731f87a82bd09 644   f
   $ hg manifest --debug --rev 'desc("a-2")' | grep '644   f'
   b76eb76580df486c3d51d63c5c210d4dd43a8ac7 644   f
   $ hg manifest --debug --rev 'desc("e-2")' | grep '644   f'
   e8825b386367b29fec957283a80bb47b47483fe1 644   f
   $ hg debugindex f | ../no-linkrev
      rev linkrev nodeid       p1           p2
        0       * b76eb76580df 000000000000 000000000000
        1       * e8825b386367 000000000000 000000000000
        2       * 2ff93c643948 b76eb76580df e8825b386367
        3       * 2f649fba7eb2 b76eb76580df e8825b386367
        4       * 774e7c1637d5 e8825b386367 b76eb76580df
 #else
   $ hg manifest --debug --rev 'desc("mAE-change-m-0")' | grep '644   f'
   d3613c1ec8310a812ac4268fd853ac576b6caea5 644   f
   $ hg manifest --debug --rev 'desc("mEA-change-m-0")' | grep '644   f'
   05e03c868bbcab4a649cb33a238d7aa07398a469 644   f
   $ hg manifest --debug --rev 'desc("a-2")' | grep '644   f'
   ae258f702dfeca05bf9b6a22a97a4b5645570f11 644   f
   $ hg manifest --debug --rev 'desc("e-2")' | grep '644   f'
   ae258f702dfeca05bf9b6a22a97a4b5645570f11 644   f
   $ hg debugindex f | ../no-linkrev
      rev linkrev nodeid       p1           p2
        0       * ae258f702dfe 000000000000 000000000000
        1       * d3613c1ec831 ae258f702dfe 000000000000
        2       * 05e03c868bbc ae258f702dfe 000000000000
 #endif
 
 # Here the filelog based implementation is not looking at the rename
 # information (because the file exist on both side). However the changelog
 # based on works fine. We have different output.
 
   $ hg status --copies --rev 'desc("a-2")' --rev 'desc("mAE-change-m-0")'
   M f
     b (no-filelog !)
   R b
   $ hg status --copies --rev 'desc("a-2")' --rev 'desc("mEA-change-m-0")'
   M f
     b (no-filelog !)
   R b
   $ hg status --copies --rev 'desc("e-2")' --rev 'desc("mAE-change-m-0")'
   M f
     d (no-filelog !)
   R d
   $ hg status --copies --rev 'desc("e-2")' --rev 'desc("mEA-change-m-0")'
   M f
     d (no-filelog !)
   R d
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("a-2")'
   A f
     d
   R d
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("e-2")'
   A f
     b
   R b
 
 # From here, we run status against revision where both source file exists.
 #
 # The filelog based implementation picks an arbitrary side based on revision
 # numbers. So the same side "wins" whatever the parents order is. This is
 # sub-optimal because depending on revision numbers means the result can be
 # different from one repository to the next.
 #
 # The changeset based algorithm use the parent order to break tie on conflicting
 # information and will have a different order depending on who is p1 and p2.
 # That order is stable accross repositories. (data from p1 prevails)
 
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mAE-change-m-0")'
   A f
     d
   R b
   R d
   $ hg status --copies --rev 'desc("i-2")' --rev 'desc("mEA-change-m-0")'
   A f
     d (filelog !)
     b (no-filelog !)
   R b
   R d
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mAE-change-m-0")'
   A f
     a
   A t
     p
   R a
   R b
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mEA-change-m-0")'
   A f
     a (filelog !)
     b (no-filelog !)
   A t
     p
   R a
   R b
   R p
 
 
 Decision from previous merge are properly chained with later merge
 ------------------------------------------------------------------
 
 
 Subcase: chaining conflicting rename resolution
 ```````````````````````````````````````````````
 
 The "mAEm" and "mEAm" case create a rename tracking conflict on file 'f'. We
 add more change on the respective branch and merge again. These second merge
 does not involve the file 'f' and the arbitration done within "mAEm" and "mEA"
 about that file should stay unchanged.
 
 The result from mAEm is the same for the subsequent merge:
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mAEm")' f
   A f
     a (filelog !)
     a (sidedata !)
     a (upgraded !)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mAE,Km")' f
   A f
     a (filelog !)
     a (sidedata !)
     a (upgraded !)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mK,AEm")' f
   A f
     a (filelog !)
-    a (missing-correct-output sidedata !)
-    a (missing-correct-output upgraded !)
-    b (known-bad-output sidedata !)
-    b (known-bad-output upgraded !)
+    a (sidedata !)
+    a (upgraded !)
 
 
 The result from mEAm is the same for the subsequent merge:
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mEAm")' f
   A f
     a (filelog !)
     b (sidedata !)
     b (upgraded !)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mEA,Jm")' f
   A f
     a (filelog !)
     b (sidedata !)
     b (upgraded !)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mJ,EAm")' f
   A f
     a (filelog !)
-    b (missing-correct-output sidedata !)
-    b (missing-correct-output upgraded !)
-    a (known-bad-output sidedata !)
-    a (known-bad-output upgraded !)
+    b (sidedata !)
+    b (upgraded !)
 
 Subcase: chaining conflicting rename resolution
 ```````````````````````````````````````````````
 
 The "mPQm" and "mQPm" case create a rename tracking conflict on file 'v'. We
 add more change on the respective branch and merge again. These second merge
 does not involve the file 'v' and the arbitration done within "mPQm" and "mQP"
 about that file should stay unchanged.
 
 The result from mPQm is the same for the subsequent merge:
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mPQm")' v
   A v
     r (filelog !)
     p (sidedata !)
     p (upgraded !)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mPQ,Tm")' v
   A v
     r (filelog !)
     p (sidedata !)
     p (upgraded !)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mT,PQm")' v
   A v
     r (filelog !)
-    p (missing-correct-output sidedata !)
-    p (missing-correct-output upgraded !)
-    r (known-bad-output sidedata !)
-    r (known-bad-output upgraded !)
+    p (sidedata !)
+    p (upgraded !)
 
 
 The result from mQPm is the same for the subsequent merge:
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mQPm")' v
   A v
     r (no-changeset no-compatibility !)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mQP,Sm")' v
   A v
     r (no-changeset no-compatibility !)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mS,QPm")' v
   A v
     r (filelog !)
-    r (missing-correct-output sidedata !)
-    r (missing-correct-output upgraded !)
-    p (known-bad-output sidedata !)
-    p (known-bad-output upgraded !)
+    r (sidedata !)
+    r (upgraded !)
 
 
 Subcase: chaining salvage information during a merge
 ````````````````````````````````````````````````````
 
 We add more change on the branch were the file was deleted. merging again
 should preserve the fact eh file was salvaged.
 
 reference output:
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mCB-revert-m-0")'
   M b
   A d
-    a (filelog !)
-    a (sidedata !)
-    a (upgraded !)
+    a (no-changeset no-compatibility !)
   A t
     p
   R a
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mBC-revert-m-0")'
   M b
   A d
-    a (filelog !)
-    a (sidedata !)
-    a (upgraded !)
+    a (no-changeset no-compatibility !)
   A t
     p
   R a
   R p
 
 chained output
-
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mBC+revert,Lm")'
   M b
   A d
-    a (filelog !)
-    a (missing-correct-output sidedata !)
-    a (missing-correct-output upgraded !)
+    a (no-changeset no-compatibility !)
   A t
     p
   A unrelated-l
   R a
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mCB+revert,Lm")'
   M b
   A d
-    a (filelog !)
-    a (missing-correct-output sidedata !)
-    a (missing-correct-output upgraded !)
+    a (no-changeset no-compatibility !)
   A t
     p
   A unrelated-l
   R a
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mL,BC+revertm")'
   M b
   A d
-    a (filelog !)
-    a (missing-correct-output sidedata !)
-    a (missing-correct-output upgraded !)
+    a (no-changeset no-compatibility !)
   A t
     p
   A unrelated-l
   R a
   R p
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mL,CB+revertm")'
   M b
   A d
-    a (filelog !)
-    a (missing-correct-output sidedata !)
-    a (missing-correct-output upgraded !)
+    a (no-changeset no-compatibility !)
   A t
     p
   A unrelated-l
   R a
   R p
 
 Subcase: chaining "merged" information during a merge
 ``````````````````````````````````````````````````````
 
 When a non-rename change are merged with a copy overwrite, the merge pick the copy source from (p1) as the reference. We should preserve this information in subsequent merges.
 
 
 reference output:
 
  (for details about the filelog pick, check the mFGm/mGFm case)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mFGm")' d
   A d
     a (filelog !)
     h (sidedata !)
     h (upgraded !)
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mGFm")' d
   A d
     a (filelog !)
     a (sidedata !)
     a (upgraded !)
 
 Chained output
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mO,FGm")' d
   A d
     a (filelog !)
     h (sidedata !)
     h (upgraded !)
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mFG,Om")' d
   A d
     a (filelog !)
     h (sidedata !)
     h (upgraded !)
 
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mGF,Nm")' d
   A d
-    a (filelog !)
-    a (missing-correct-output sidedata !)
-    a (missing-correct-output upgraded !)
-    h (known-bad-output sidedata !)
-    h (known-bad-output upgraded !)
+    a (no-changeset no-compatibility !)
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mN,GFm")' d
   A d
-    a (filelog !)
-    a (missing-correct-output sidedata !)
-    a (missing-correct-output upgraded !)
-    h (known-bad-output sidedata !)
-    h (known-bad-output upgraded !)
+    a (no-changeset no-compatibility !)
 
 
 Subcase: chaining conflicting rename resolution, with extra change during the merge
 ```````````````````````````````````````````````````````````````````````````````````
 
 The "mAEm" and "mEAm" case create a rename tracking conflict on file 'f'. We
 add more change on the respective branch and merge again. These second merge
 does not involve the file 'f' and the arbitration done within "mAEm" and "mEA"
 about that file should stay unchanged.
 
 The result from mAEm is the same for the subsequent merge:
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mAE-change-m")' f
   A f
     a (filelog !)
     a (sidedata !)
     a (upgraded !)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mAE-change,Km")' f
   A f
     a (filelog !)
     a (sidedata !)
     a (upgraded !)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mK,AE-change-m")' f
   A f
-    a (filelog !)
-    a (missing-correct-output sidedata !)
-    a (missing-correct-output upgraded !)
-    b (known-bad-output sidedata !)
-    b (known-bad-output upgraded !)
+    a (no-changeset no-compatibility !)
 
 
 The result from mEAm is the same for the subsequent merge:
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mEA-change-m")' f
   A f
     a (filelog !)
     b (sidedata !)
     b (upgraded !)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mEA-change,Jm")' f
   A f
     a (filelog !)
     b (sidedata !)
     b (upgraded !)
 
   $ hg status --copies --rev 'desc("i-0")' --rev 'desc("mJ,EA-change-m")' f
   A f
     a (filelog !)
-    b (missing-correct-output sidedata !)
-    b (missing-correct-output upgraded !)
-    a (known-bad-output sidedata !)
-    a (known-bad-output upgraded !)
+    b (sidedata !)
+    b (upgraded !)