amend: fix amending rename commit with diverged topologies (issue4405)

This addresses the bug described in issue4405: when obsolescence markers are
enabled, amending a commit with a file move can lead to the copy information
being lost.

However, the bug is more general and can be reproduced without obsmarkers as
well, as demonstracted by Pierre-Yves and put into the updated test.
Specifically, graph topology divergences between the filelogs and the changelog
can cause copy information to be lost during amends.

mercurial/copies.py

@@ -1,441 +1,469 b''
 # 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.
 
 import util
 import heapq
 
 def _nonoverlap(d1, d2, d3):
     "Return list of elements in d1 not in d2 or d3"
     return sorted([d for d in d1 if d not in d3 and d not in d2])
 
 def _dirname(f):
     s = f.rfind("/")
     if s == -1:
         return ""
     return f[:s]
 
 def _findlimit(repo, a, b):
-    """Find the earliest revision that's an ancestor of a or b but not both,
+    """
+    Find the last revision that needs to be checked to ensure that a full
+    transitive closure for file copies can be properly calculated.
+    Generally, this means finding the earliest revision number that's an
+    ancestor of a or b but not both, except when a or b is a direct descendent
+    of the other, in which case we can return the minimum revnum of a and b.
     None if no such revision exists.
     """
+
     # basic idea:
     # - mark a and b with different sides
     # - if a parent's children are all on the same side, the parent is
     #   on that side, otherwise it is on no side
     # - walk the graph in topological order with the help of a heap;
     #   - add unseen parents to side map
     #   - clear side of any parent that has children on different sides
     #   - track number of interesting revs that might still be on a side
     #   - track the lowest interesting rev seen
     #   - quit when interesting revs is zero
 
     cl = repo.changelog
     working = len(cl) # pseudo rev for the working directory
     if a is None:
         a = working
     if b is None:
         b = working
 
     side = {a: -1, b: 1}
     visit = [-a, -b]
     heapq.heapify(visit)
     interesting = len(visit)
     hascommonancestor = False
     limit = working
 
     while interesting:
         r = -heapq.heappop(visit)
         if r == working:
             parents = [cl.rev(p) for p in repo.dirstate.parents()]
         else:
             parents = cl.parentrevs(r)
         for p in parents:
             if p < 0:
                 continue
             if p not in side:
                 # first time we see p; add it to visit
                 side[p] = side[r]
                 if side[p]:
                     interesting += 1
                 heapq.heappush(visit, -p)
             elif side[p] and side[p] != side[r]:
                 # p was interesting but now we know better
                 side[p] = 0
                 interesting -= 1
                 hascommonancestor = True
         if side[r]:
             limit = r # lowest rev visited
             interesting -= 1
 
     if not hascommonancestor:
         return None
-    return limit
+
+    # Consider the following flow (see test-commit-amend.t under issue4405):
+    # 1/ File 'a0' committed
+    # 2/ File renamed from 'a0' to 'a1' in a new commit (call it 'a1')
+    # 3/ Move back to first commit
+    # 4/ Create a new commit via revert to contents of 'a1' (call it 'a1-amend')
+    # 5/ Rename file from 'a1' to 'a2' and commit --amend 'a1-msg'
+    #
+    # During the amend in step five, we will be in this state:
+    #
+    # @  3 temporary amend commit for a1-amend
+    # |
+    # o  2 a1-amend
+    # |
+    # | o  1 a1
+    # |/
+    # o  0 a0
+    #
+    # When findlimit is called, a and b are revs 3 and 0, so limit will be 2,
+    # yet the filelog has the copy information in rev 1 and we will not look
+    # back far enough unless we also look at the a and b as candidates.
+    # This only occurs when a is a descendent of b or visa-versa.
+    return min(limit, a, b)
 
 def _chain(src, dst, a, b):
     '''chain two sets of copies a->b'''
     t = a.copy()
     for k, v in b.iteritems():
         if v in t:
             # found a chain
             if t[v] != k:
                 # file wasn't renamed back to itself
                 t[k] = t[v]
             if v not in dst:
                 # chain was a rename, not a copy
                 del t[v]
         if v in src:
             # file is a copy of an existing file
             t[k] = v
 
     # remove criss-crossed copies
     for k, v in t.items():
         if k in src and v in dst:
             del t[k]
 
     return t
 
 def _tracefile(fctx, am, limit=-1):
     '''return file context that is the ancestor of fctx present in ancestor
     manifest am, stopping after the first ancestor lower than limit'''
 
     for f in fctx.ancestors():
         if am.get(f.path(), None) == f.filenode():
             return f
         if f.rev() < limit:
             return None
 
 def _dirstatecopies(d):
     ds = d._repo.dirstate
     c = ds.copies().copy()
     for k in c.keys():
         if ds[k] not in 'anm':
             del c[k]
     return c
 
 def _forwardcopies(a, b):
     '''find {dst@b: src@a} copy mapping where a is an ancestor of b'''
 
     # check for working copy
     w = None
     if b.rev() is None:
         w = b
         b = w.p1()
         if a == b:
             # short-circuit to avoid issues with merge states
             return _dirstatecopies(w)
 
     # files might have to be traced back to the fctx parent of the last
     # one-side-only changeset, but not further back than that
     limit = _findlimit(a._repo, a.rev(), b.rev())
     if limit is None:
         limit = -1
     am = a.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 = {}
     missing = set(b.manifest().iterkeys())
     missing.difference_update(a.manifest().iterkeys())
 
     for f in missing:
         ofctx = _tracefile(b[f], am, limit)
         if ofctx:
             cm[f] = ofctx.path()
 
     # combine copies from dirstate if necessary
     if w is not None:
         cm = _chain(a, w, cm, _dirstatecopies(w))
 
     return cm
 
 def _backwardrenames(a, b):
     # 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.
     f = _forwardcopies(b, a)
     r = {}
     for k, v in sorted(f.iteritems()):
         # remove copies
         if v in a:
             continue
         r[v] = k
     return r
 
 def pathcopies(x, y):
     '''find {dst@y: src@x} copy mapping for directed compare'''
     if x == y or not x or not y:
         return {}
     a = y.ancestor(x)
     if a == x:
         return _forwardcopies(x, y)
     if a == y:
         return _backwardrenames(x, y)
     return _chain(x, y, _backwardrenames(x, a), _forwardcopies(a, y))
 
 def mergecopies(repo, c1, c2, ca):
     """
     Find moves and copies between context c1 and c2 that are relevant
     for merging.
 
     Returns four dicts: "copy", "movewithdir", "diverge", and
     "renamedelete".
 
     "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.
 
     "diverge" is a mapping of source name -> list of destination names
     for divergent renames.
 
     "renamedelete" is a mapping of source name -> list of destination
     names for files deleted in c1 that were renamed in c2 or vice-versa.
     """
     # avoid silly behavior for update from empty dir
     if not c1 or not c2 or c1 == c2:
         return {}, {}, {}, {}
 
     # avoid silly behavior for parent -> working dir
     if c2.node() is None and c1.node() == repo.dirstate.p1():
         return repo.dirstate.copies(), {}, {}, {}
 
     limit = _findlimit(repo, c1.rev(), c2.rev())
     if limit is None:
         # no common ancestor, no copies
         return {}, {}, {}, {}
     m1 = c1.manifest()
     m2 = c2.manifest()
     ma = ca.manifest()
 
     def makectx(f, n):
         if len(n) != 20: # in a working context?
             if c1.rev() is None:
                 return c1.filectx(f)
             return c2.filectx(f)
         return repo.filectx(f, fileid=n)
 
     ctx = util.lrucachefunc(makectx)
     copy = {}
     movewithdir = {}
     fullcopy = {}
     diverge = {}
 
     repo.ui.debug("  searching for copies back to rev %d\n" % limit)
 
     u1 = _nonoverlap(m1, m2, ma)
     u2 = _nonoverlap(m2, m1, ma)
 
     if u1:
         repo.ui.debug("  unmatched files in local:\n   %s\n"
                       % "\n   ".join(u1))
     if u2:
         repo.ui.debug("  unmatched files in other:\n   %s\n"
                       % "\n   ".join(u2))
 
     for f in u1:
         checkcopies(ctx, f, m1, m2, ca, limit, diverge, copy, fullcopy)
 
     for f in u2:
         checkcopies(ctx, f, m2, m1, ca, limit, diverge, copy, fullcopy)
 
     renamedelete = {}
     renamedelete2 = set()
     diverge2 = set()
     for of, fl in diverge.items():
         if len(fl) == 1 or of in c1 or of in c2:
             del diverge[of] # not actually divergent, or not a rename
             if of not in c1 and of not in c2:
                 # renamed on one side, deleted on the other side, but filter
                 # out files that have been renamed and then deleted
                 renamedelete[of] = [f for f in fl if f in c1 or f in c2]
                 renamedelete2.update(fl) # reverse map for below
         else:
             diverge2.update(fl) # reverse map for below
 
     bothnew = sorted([d for d in m1 if d in m2 and d not in ma])
     if bothnew:
         repo.ui.debug("  unmatched files new in both:\n   %s\n"
                       % "\n   ".join(bothnew))
     bothdiverge, _copy, _fullcopy = {}, {}, {}
     for f in bothnew:
         checkcopies(ctx, f, m1, m2, ca, limit, bothdiverge, _copy, _fullcopy)
         checkcopies(ctx, f, m2, m1, ca, limit, bothdiverge, _copy, _fullcopy)
     for of, fl in bothdiverge.items():
         if len(fl) == 2 and fl[0] == fl[1]:
             copy[fl[0]] = of # not actually divergent, just matching renames
 
     if fullcopy and repo.ui.debugflag:
         repo.ui.debug("  all copies found (* = to merge, ! = divergent, "
                       "% = renamed and deleted):\n")
         for f in sorted(fullcopy):
             note = ""
             if f in copy:
                 note += "*"
             if f in diverge2:
                 note += "!"
             if f in renamedelete2:
                 note += "%"
             repo.ui.debug("   src: '%s' -> dst: '%s' %s\n" % (fullcopy[f], f,
                                                               note))
     del diverge2
 
     if not fullcopy:
         return copy, movewithdir, diverge, renamedelete
 
     repo.ui.debug("  checking for directory renames\n")
 
     # generate a directory move map
     d1, d2 = c1.dirs(), c2.dirs()
     d1.addpath('/')
     d2.addpath('/')
     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 fullcopy.iteritems():
         dsrc, ddst = _dirname(src), _dirname(dst)
         if dsrc in invalid:
             # already seen to be uninteresting
             continue
         elif dsrc in d1 and ddst in d1:
             # directory wasn't entirely moved locally
             invalid.add(dsrc)
         elif dsrc in d2 and ddst in d2:
             # directory wasn't entirely moved remotely
             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 d1, d2, invalid
 
     if not dirmove:
         return copy, movewithdir, diverge, renamedelete
 
     for d in dirmove:
         repo.ui.debug("   discovered dir src: '%s' -> dst: '%s'\n" %
                       (d, dirmove[d]))
 
     # check unaccounted nonoverlapping files against directory moves
     for f in u1 + u2:
         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(("   pending file src: '%s' -> "
                                        "dst: '%s'\n") % (f, df))
                     break
 
     return copy, movewithdir, diverge, renamedelete
 
 def checkcopies(ctx, f, m1, m2, ca, limit, diverge, copy, fullcopy):
     """
     check possible copies of f from m1 to m2
 
     ctx = function accepting (filename, node) that returns a filectx.
     f = the filename to check
     m1 = the source manifest
     m2 = the destination manifest
     ca = the changectx of the common ancestor
     limit = the rev number to not search beyond
     diverge = record all diverges in this dict
     copy = record all non-divergent copies in this dict
     fullcopy = record all copies in this dict
     """
 
     ma = ca.manifest()
 
     def _related(f1, f2, limit):
         # 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 f1 # a match
 
         g1, g2 = f1.ancestors(), f2.ancestors()
         try:
             f1r, f2r = f1.rev(), f2.rev()
 
             if f1r is None:
                 f1 = g1.next()
             if f2r is None:
                 f2 = g2.next()
 
             while True:
                 f1r, f2r = f1.rev(), f2.rev()
                 if f1r > f2r:
                     f1 = g1.next()
                 elif f2r > f1r:
                     f2 = g2.next()
                 elif f1 == f2:
                     return f1 # a match
                 elif f1r == f2r or f1r < limit or f2r < limit:
                     return False # copy no longer relevant
         except StopIteration:
             return False
 
     of = None
     seen = set([f])
     for oc in ctx(f, m1[f]).ancestors():
         ocr = oc.rev()
         of = oc.path()
         if of in seen:
             # check limit late - grab last rename before
             if ocr < limit:
                 break
             continue
         seen.add(of)
 
         fullcopy[f] = of # remember for dir rename detection
         if of not in m2:
             continue # no match, keep looking
         if m2[of] == ma.get(of):
             break # no merge needed, quit early
         c2 = ctx(of, m2[of])
         cr = _related(oc, c2, ca.rev())
         if cr and (of == f or of == c2.path()): # non-divergent
             copy[f] = of
             of = None
             break
 
     if of in ma:
         diverge.setdefault(of, []).append(f)
 
 def duplicatecopies(repo, rev, fromrev, skiprev=None):
     '''reproduce copies from fromrev to rev in the dirstate
 
     If skiprev is specified, it's a revision that should be used to
     filter copy records. Any copies that occur between fromrev and
     skiprev will not be duplicated, even if they appear in the set of
     copies between fromrev and rev.
     '''
     exclude = {}
     if skiprev is not None:
         exclude = pathcopies(repo[fromrev], repo[skiprev])
     for dst, src in pathcopies(repo[fromrev], repo[rev]).iteritems():
         # copies.pathcopies returns backward renames, so dst might not
         # actually be in the dirstate
         if dst in exclude:
             continue
         if repo.dirstate[dst] in "nma":
             repo.dirstate.copy(src, dst)

tests/test-commit-amend.t

@@ -1,856 +1,914 b''
   $ hg init
 
 Setup:
 
   $ echo a >> a
   $ hg ci -Am 'base'
   adding a
 
 Refuse to amend public csets:
 
   $ hg phase -r . -p
   $ hg ci --amend
   abort: cannot amend public changesets
   [255]
   $ hg phase -r . -f -d
 
   $ echo a >> a
   $ hg ci -Am 'base1'
 
 Nothing to amend:
 
   $ hg ci --amend
   nothing changed
   [1]
 
   $ cat >> $HGRCPATH <<EOF
   > [hooks]
   > pretxncommit.foo = sh -c "echo \\"pretxncommit \$HG_NODE\\"; hg id -r \$HG_NODE"
   > EOF
 
 Amending changeset with changes in working dir:
 (and check that --message does not trigger an editor)
 
   $ echo a >> a
   $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg commit --amend -m 'amend base1'
   pretxncommit 43f1ba15f28a50abf0aae529cf8a16bfced7b149
   43f1ba15f28a tip
   saved backup bundle to $TESTTMP/.hg/strip-backup/489edb5b847d-amend-backup.hg (glob)
   $ echo 'pretxncommit.foo = ' >> $HGRCPATH
   $ hg diff -c .
   diff -r ad120869acf0 -r 43f1ba15f28a a
   --- a/a	Thu Jan 01 00:00:00 1970 +0000
   +++ b/a	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,1 +1,3 @@
    a
   +a
   +a
   $ hg log
   changeset:   1:43f1ba15f28a
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     amend base1
   
   changeset:   0:ad120869acf0
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     base
   
 
 Check proper abort for empty message
 
   $ cat > editor.sh << '__EOF__'
   > #!/bin/sh
   > echo "" > "$1"
   > __EOF__
   $ echo b > b
   $ hg add b
   $ hg summary
   parent: 1:43f1ba15f28a tip
    amend base1
   branch: default
   commit: 1 added, 1 unknown
   update: (current)
   $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg commit --amend
   transaction abort!
   rollback completed
   abort: empty commit message
   [255]
   $ hg summary
   parent: 1:43f1ba15f28a tip
    amend base1
   branch: default
   commit: 1 added, 1 unknown
   update: (current)
 
 Add new file:
   $ hg ci --amend -m 'amend base1 new file'
   saved backup bundle to $TESTTMP/.hg/strip-backup/43f1ba15f28a-amend-backup.hg (glob)
 
 Remove file that was added in amended commit:
 (and test logfile option)
 (and test that logfile option do not trigger an editor)
 
   $ hg rm b
   $ echo 'amend base1 remove new file' > ../logfile
   $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg ci --amend --logfile ../logfile
   saved backup bundle to $TESTTMP/.hg/strip-backup/b8e3cb2b3882-amend-backup.hg (glob)
 
   $ hg cat b
   b: no such file in rev 74609c7f506e
   [1]
 
 No changes, just a different message:
 
   $ hg ci -v --amend -m 'no changes, new message'
   amending changeset 74609c7f506e
   copying changeset 74609c7f506e to ad120869acf0
   a
   stripping amended changeset 74609c7f506e
   1 changesets found
   saved backup bundle to $TESTTMP/.hg/strip-backup/74609c7f506e-amend-backup.hg (glob)
   1 changesets found
   adding branch
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   committed changeset 1:1cd866679df8
   $ hg diff -c .
   diff -r ad120869acf0 -r 1cd866679df8 a
   --- a/a	Thu Jan 01 00:00:00 1970 +0000
   +++ b/a	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,1 +1,3 @@
    a
   +a
   +a
   $ hg log
   changeset:   1:1cd866679df8
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     no changes, new message
   
   changeset:   0:ad120869acf0
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     base
   
 
 Disable default date on commit so when -d isn't given, the old date is preserved:
 
   $ echo '[defaults]' >> $HGRCPATH
   $ echo 'commit=' >> $HGRCPATH
 
 Test -u/-d:
 
   $ cat > .hg/checkeditform.sh <<EOF
   > env | grep HGEDITFORM
   > true
   > EOF
   $ HGEDITOR="sh .hg/checkeditform.sh" hg ci --amend -u foo -d '1 0'
   HGEDITFORM=commit.amend.normal
   saved backup bundle to $TESTTMP/.hg/strip-backup/1cd866679df8-amend-backup.hg (glob)
   $ echo a >> a
   $ hg ci --amend -u foo -d '1 0'
   saved backup bundle to $TESTTMP/.hg/strip-backup/780e6f23e03d-amend-backup.hg (glob)
   $ hg log -r .
   changeset:   1:5f357c7560ab
   tag:         tip
   user:        foo
   date:        Thu Jan 01 00:00:01 1970 +0000
   summary:     no changes, new message
   
 
 Open editor with old commit message if a message isn't given otherwise:
 
   $ cat > editor.sh << '__EOF__'
   > #!/bin/sh
   > cat $1
   > echo "another precious commit message" > "$1"
   > __EOF__
 
 at first, test saving last-message.txt
 
   $ cat > .hg/hgrc << '__EOF__'
   > [hooks]
   > pretxncommit.test-saving-last-message = false
   > __EOF__
 
   $ rm -f .hg/last-message.txt
   $ hg commit --amend -v -m "message given from command line"
   amending changeset 5f357c7560ab
   copying changeset 5f357c7560ab to ad120869acf0
   a
   running hook pretxncommit.test-saving-last-message: false
   transaction abort!
   rollback completed
   abort: pretxncommit.test-saving-last-message hook exited with status 1
   [255]
   $ cat .hg/last-message.txt
   message given from command line (no-eol)
 
   $ rm -f .hg/last-message.txt
   $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg commit --amend -v
   amending changeset 5f357c7560ab
   copying changeset 5f357c7560ab to ad120869acf0
   no changes, new message
   
   
   HG: Enter commit message.  Lines beginning with 'HG:' are removed.
   HG: Leave message empty to abort commit.
   HG: --
   HG: user: foo
   HG: branch 'default'
   HG: changed a
   a
   running hook pretxncommit.test-saving-last-message: false
   transaction abort!
   rollback completed
   abort: pretxncommit.test-saving-last-message hook exited with status 1
   [255]
 
   $ cat .hg/last-message.txt
   another precious commit message
 
   $ cat > .hg/hgrc << '__EOF__'
   > [hooks]
   > pretxncommit.test-saving-last-message =
   > __EOF__
 
 then, test editing custom commit message
 
   $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg commit --amend -v
   amending changeset 5f357c7560ab
   copying changeset 5f357c7560ab to ad120869acf0
   no changes, new message
   
   
   HG: Enter commit message.  Lines beginning with 'HG:' are removed.
   HG: Leave message empty to abort commit.
   HG: --
   HG: user: foo
   HG: branch 'default'
   HG: changed a
   a
   stripping amended changeset 5f357c7560ab
   1 changesets found
   saved backup bundle to $TESTTMP/.hg/strip-backup/5f357c7560ab-amend-backup.hg (glob)
   1 changesets found
   adding branch
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   committed changeset 1:7ab3bf440b54
 
 Same, but with changes in working dir (different code path):
 
   $ echo a >> a
   $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg commit --amend -v
   amending changeset 7ab3bf440b54
   a
   copying changeset a0ea9b1a4c8c to ad120869acf0
   another precious commit message
   
   
   HG: Enter commit message.  Lines beginning with 'HG:' are removed.
   HG: Leave message empty to abort commit.
   HG: --
   HG: user: foo
   HG: branch 'default'
   HG: changed a
   a
   stripping intermediate changeset a0ea9b1a4c8c
   stripping amended changeset 7ab3bf440b54
   2 changesets found
   saved backup bundle to $TESTTMP/.hg/strip-backup/7ab3bf440b54-amend-backup.hg (glob)
   1 changesets found
   adding branch
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
   committed changeset 1:ea22a388757c
 
   $ rm editor.sh
   $ hg log -r .
   changeset:   1:ea22a388757c
   tag:         tip
   user:        foo
   date:        Thu Jan 01 00:00:01 1970 +0000
   summary:     another precious commit message
   
 
 Moving bookmarks, preserve active bookmark:
 
   $ hg book book1
   $ hg book book2
   $ hg ci --amend -m 'move bookmarks'
   saved backup bundle to $TESTTMP/.hg/strip-backup/ea22a388757c-amend-backup.hg (glob)
   $ hg book
      book1                     1:6cec5aa930e2
    * book2                     1:6cec5aa930e2
   $ echo a >> a
   $ hg ci --amend -m 'move bookmarks'
   saved backup bundle to $TESTTMP/.hg/strip-backup/6cec5aa930e2-amend-backup.hg (glob)
   $ hg book
      book1                     1:48bb6e53a15f
    * book2                     1:48bb6e53a15f
 
 abort does not loose bookmarks
 
   $ cat > editor.sh << '__EOF__'
   > #!/bin/sh
   > echo "" > "$1"
   > __EOF__
   $ echo a >> a
   $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg commit --amend
   transaction abort!
   rollback completed
   abort: empty commit message
   [255]
   $ hg book
      book1                     1:48bb6e53a15f
    * book2                     1:48bb6e53a15f
   $ hg revert -Caq
   $ rm editor.sh
 
   $ echo '[defaults]' >> $HGRCPATH
   $ echo "commit=-d '0 0'" >> $HGRCPATH
 
 Moving branches:
 
   $ hg branch foo
   marked working directory as branch foo
   (branches are permanent and global, did you want a bookmark?)
   $ echo a >> a
   $ hg ci -m 'branch foo'
   $ hg branch default -f
   marked working directory as branch default
   (branches are permanent and global, did you want a bookmark?)
   $ hg ci --amend -m 'back to default'
   saved backup bundle to $TESTTMP/.hg/strip-backup/8ac881fbf49d-amend-backup.hg (glob)
   $ hg branches
   default                        2:ce12b0b57d46
 
 Close branch:
 
   $ hg up -q 0
   $ echo b >> b
   $ hg branch foo
   marked working directory as branch foo
   (branches are permanent and global, did you want a bookmark?)
   $ hg ci -Am 'fork'
   adding b
   $ echo b >> b
   $ hg ci -mb
   $ hg ci --amend --close-branch -m 'closing branch foo'
   saved backup bundle to $TESTTMP/.hg/strip-backup/c962248fa264-amend-backup.hg (glob)
 
 Same thing, different code path:
 
   $ echo b >> b
   $ hg ci -m 'reopen branch'
   reopening closed branch head 4
   $ echo b >> b
   $ hg ci --amend --close-branch
   saved backup bundle to $TESTTMP/.hg/strip-backup/027371728205-amend-backup.hg (glob)
   $ hg branches
   default                        2:ce12b0b57d46
 
 Refuse to amend during a merge:
 
   $ hg up -q default
   $ hg merge foo
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   (branch merge, don't forget to commit)
   $ hg ci --amend
   abort: cannot amend while merging
   [255]
   $ hg ci -m 'merge'
 
 Follow copies/renames:
 
   $ hg mv b c
   $ hg ci -m 'b -> c'
   $ hg mv c d
   $ hg ci --amend -m 'b -> d'
   saved backup bundle to $TESTTMP/.hg/strip-backup/b8c6eac7f12e-amend-backup.hg (glob)
   $ hg st --rev '.^' --copies d
   A d
     b
   $ hg cp d e
   $ hg ci -m 'e = d'
   $ hg cp e f
   $ hg ci --amend -m 'f = d'
   saved backup bundle to $TESTTMP/.hg/strip-backup/7f9761d65613-amend-backup.hg (glob)
   $ hg st --rev '.^' --copies f
   A f
     d
 
   $ mv f f.orig
   $ hg rm -A f
   $ hg ci -m removef
   $ hg cp a f
   $ mv f.orig f
   $ hg ci --amend -m replacef
   saved backup bundle to $TESTTMP/.hg/strip-backup/9e8c5f7e3d95-amend-backup.hg (glob)
   $ hg st --change . --copies
   $ hg log -r . --template "{file_copies}\n"
   
 
 Move added file (issue3410):
 
   $ echo g >> g
   $ hg ci -Am g
   adding g
   $ hg mv g h
   $ hg ci --amend
   saved backup bundle to $TESTTMP/.hg/strip-backup/24aa8eacce2b-amend-backup.hg (glob)
   $ hg st --change . --copies h
   A h
   $ hg log -r . --template "{file_copies}\n"
   
 
 Can't rollback an amend:
 
   $ hg rollback
   no rollback information available
   [1]
 
 Preserve extra dict (issue3430):
 
   $ hg branch a
   marked working directory as branch a
   (branches are permanent and global, did you want a bookmark?)
   $ echo a >> a
   $ hg ci -ma
   $ hg ci --amend -m "a'"
   saved backup bundle to $TESTTMP/.hg/strip-backup/3837aa2a2fdb-amend-backup.hg (glob)
   $ hg log -r . --template "{branch}\n"
   a
   $ hg ci --amend -m "a''"
   saved backup bundle to $TESTTMP/.hg/strip-backup/c05c06be7514-amend-backup.hg (glob)
   $ hg log -r . --template "{branch}\n"
   a
 
 Also preserve other entries in the dict that are in the old commit,
 first graft something so there's an additional entry:
 
   $ hg up 0 -q
   $ echo z > z
   $ hg ci -Am 'fork'
   adding z
   created new head
   $ hg up 11
   5 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg graft 12
   grafting revision 12
   $ hg ci --amend -m 'graft amend'
   saved backup bundle to $TESTTMP/.hg/strip-backup/bd010aea3f39-amend-backup.hg (glob)
   $ hg log -r . --debug | grep extra
   extra:       amend_source=bd010aea3f39f3fb2a2f884b9ccb0471cd77398e
   extra:       branch=a
   extra:       source=2647734878ef0236dda712fae9c1651cf694ea8a
 
 Preserve phase
 
   $ hg phase '.^::.'
   11: draft
   13: draft
   $ hg phase --secret --force .
   $ hg phase '.^::.'
   11: draft
   13: secret
   $ hg commit --amend -m 'amend for phase' -q
   $ hg phase '.^::.'
   11: draft
   13: secret
 
 Test amend with obsolete
 ---------------------------
 
 Enable obsolete
 
   $ cat >> $HGRCPATH << EOF
   > [experimental]
   > evolution=createmarkers,allowunstable
   > EOF
 
 Amend with no files changes
 
   $ hg id -n
   13
   $ hg ci --amend -m 'babar'
   $ hg id -n
   14
   $ hg log -Gl 3 --style=compact
   @  14[tip]:11   b650e6ee8614   1970-01-01 00:00 +0000   test
   |    babar
   |
   | o  12:0   2647734878ef   1970-01-01 00:00 +0000   test
   | |    fork
   | |
   o |  11   3334b7925910   1970-01-01 00:00 +0000   test
   | |    a''
   | |
   $ hg log -Gl 4 --hidden --style=compact
   @  14[tip]:11   b650e6ee8614   1970-01-01 00:00 +0000   test
   |    babar
   |
   | x  13:11   68ff8ff97044   1970-01-01 00:00 +0000   test
   |/     amend for phase
   |
   | o  12:0   2647734878ef   1970-01-01 00:00 +0000   test
   | |    fork
   | |
   o |  11   3334b7925910   1970-01-01 00:00 +0000   test
   | |    a''
   | |
 
 Amend with files changes
 
 (note: the extra commit over 15 is a temporary junk I would be happy to get
 ride of)
 
   $ echo 'babar' >> a
   $ hg commit --amend
   $ hg log -Gl 6 --hidden --style=compact
   @  16[tip]:11   9f9e9bccf56c   1970-01-01 00:00 +0000   test
   |    babar
   |
   | x  15   90fef497c56f   1970-01-01 00:00 +0000   test
   | |    temporary amend commit for b650e6ee8614
   | |
   | x  14:11   b650e6ee8614   1970-01-01 00:00 +0000   test
   |/     babar
   |
   | x  13:11   68ff8ff97044   1970-01-01 00:00 +0000   test
   |/     amend for phase
   |
   | o  12:0   2647734878ef   1970-01-01 00:00 +0000   test
   | |    fork
   | |
   o |  11   3334b7925910   1970-01-01 00:00 +0000   test
   | |    a''
   | |
 
 
 Test that amend does not make it easy to create obsolescence cycle
 ---------------------------------------------------------------------
 
   $ hg id -r 14 --hidden
   b650e6ee8614 (a)
   $ hg revert -ar 14 --hidden
   reverting a
   $ hg commit --amend
   $ hg id
   b99e5df575f7 (a) tip
 
 Test that rewriting leaving instability behind is allowed
 ---------------------------------------------------------------------
 
   $ hg up '.^'
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ echo 'b' >> a
   $ hg log --style compact -r 'children(.)'
   18[tip]:11   b99e5df575f7   1970-01-01 00:00 +0000   test
     babar
   
   $ hg commit --amend
   $ hg log -r 'unstable()'
   changeset:   18:b99e5df575f7
   branch:      a
   parent:      11:3334b7925910
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     babar
   
 
 Amend a merge changeset (with renames and conflicts from the second parent):
 
   $ hg up -q default
   $ hg branch -q bar
   $ hg cp a aa
   $ hg mv z zz
   $ echo cc > cc
   $ hg add cc
   $ hg ci -m aazzcc
   $ hg up -q default
   $ echo a >> a
   $ echo dd > cc
   $ hg add cc
   $ hg ci -m aa
   $ hg merge -q bar
   warning: conflicts during merge.
   merging cc incomplete! (edit conflicts, then use 'hg resolve --mark')
   [1]
   $ hg resolve -m cc
   (no more unresolved files)
   $ hg ci -m 'merge bar'
   $ hg log --config diff.git=1 -pr .
   changeset:   23:93cd4445f720
   tag:         tip
   parent:      22:30d96aeaf27b
   parent:      21:1aa437659d19
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     merge bar
   
   diff --git a/a b/aa
   copy from a
   copy to aa
   diff --git a/cc b/cc
   --- a/cc
   +++ b/cc
   @@ -1,1 +1,5 @@
   +<<<<<<< local: 30d96aeaf27b - test: aa
    dd
   +=======
   +cc
   +>>>>>>> other: 1aa437659d19  bar - test: aazzcc
   diff --git a/z b/zz
   rename from z
   rename to zz
   
   $ hg debugrename aa
   aa renamed from a:a80d06849b333b8a3d5c445f8ba3142010dcdc9e
   $ hg debugrename zz
   zz renamed from z:69a1b67522704ec122181c0890bd16e9d3e7516a
   $ hg debugrename cc
   cc not renamed
   $ HGEDITOR="sh .hg/checkeditform.sh" hg ci --amend -m 'merge bar (amend message)' --edit
   HGEDITFORM=commit.amend.merge
   $ hg log --config diff.git=1 -pr .
   changeset:   24:832b50f2c271
   tag:         tip
   parent:      22:30d96aeaf27b
   parent:      21:1aa437659d19
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     merge bar (amend message)
   
   diff --git a/a b/aa
   copy from a
   copy to aa
   diff --git a/cc b/cc
   --- a/cc
   +++ b/cc
   @@ -1,1 +1,5 @@
   +<<<<<<< local: 30d96aeaf27b - test: aa
    dd
   +=======
   +cc
   +>>>>>>> other: 1aa437659d19  bar - test: aazzcc
   diff --git a/z b/zz
   rename from z
   rename to zz
   
   $ hg debugrename aa
   aa renamed from a:a80d06849b333b8a3d5c445f8ba3142010dcdc9e
   $ hg debugrename zz
   zz renamed from z:69a1b67522704ec122181c0890bd16e9d3e7516a
   $ hg debugrename cc
   cc not renamed
   $ hg mv zz z
   $ hg ci --amend -m 'merge bar (undo rename)'
   $ hg log --config diff.git=1 -pr .
   changeset:   26:bdafc5c72f74
   tag:         tip
   parent:      22:30d96aeaf27b
   parent:      21:1aa437659d19
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     merge bar (undo rename)
   
   diff --git a/a b/aa
   copy from a
   copy to aa
   diff --git a/cc b/cc
   --- a/cc
   +++ b/cc
   @@ -1,1 +1,5 @@
   +<<<<<<< local: 30d96aeaf27b - test: aa
    dd
   +=======
   +cc
   +>>>>>>> other: 1aa437659d19  bar - test: aazzcc
   
   $ hg debugrename z
   z not renamed
 
 Amend a merge changeset (with renames during the merge):
 
   $ hg up -q bar
   $ echo x > x
   $ hg add x
   $ hg ci -m x
   $ hg up -q default
   $ hg merge -q bar
   $ hg mv aa aaa
   $ echo aa >> aaa
   $ hg ci -m 'merge bar again'
   $ hg log --config diff.git=1 -pr .
   changeset:   28:32f19415b634
   tag:         tip
   parent:      26:bdafc5c72f74
   parent:      27:4c94d5bc65f5
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     merge bar again
   
   diff --git a/aa b/aa
   deleted file mode 100644
   --- a/aa
   +++ /dev/null
   @@ -1,2 +0,0 @@
   -a
   -a
   diff --git a/aaa b/aaa
   new file mode 100644
   --- /dev/null
   +++ b/aaa
   @@ -0,0 +1,3 @@
   +a
   +a
   +aa
   diff --git a/x b/x
   new file mode 100644
   --- /dev/null
   +++ b/x
   @@ -0,0 +1,1 @@
   +x
   
   $ hg debugrename aaa
   aaa renamed from aa:37d9b5d994eab34eda9c16b195ace52c7b129980
   $ hg mv aaa aa
   $ hg ci --amend -m 'merge bar again (undo rename)'
   $ hg log --config diff.git=1 -pr .
   changeset:   30:1e2a06b3d312
   tag:         tip
   parent:      26:bdafc5c72f74
   parent:      27:4c94d5bc65f5
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     merge bar again (undo rename)
   
   diff --git a/aa b/aa
   --- a/aa
   +++ b/aa
   @@ -1,2 +1,3 @@
    a
    a
   +aa
   diff --git a/x b/x
   new file mode 100644
   --- /dev/null
   +++ b/x
   @@ -0,0 +1,1 @@
   +x
   
   $ hg debugrename aa
   aa not renamed
   $ hg debugrename -r '.^' aa
   aa renamed from a:a80d06849b333b8a3d5c445f8ba3142010dcdc9e
 
 Amend a merge changeset (with manifest-level conflicts):
 
   $ hg up -q bar
   $ hg rm aa
   $ hg ci -m 'rm aa'
   $ hg up -q default
   $ echo aa >> aa
   $ hg ci -m aa
   $ hg merge -q bar
   local changed aa which remote deleted
   use (c)hanged version or (d)elete? c
   $ hg ci -m 'merge bar (with conflicts)'
   $ hg log --config diff.git=1 -pr .
   changeset:   33:97a298b0c59f
   tag:         tip
   parent:      32:3d78ce4226b8
   parent:      31:67db8847a540
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     merge bar (with conflicts)
   
   
   $ hg rm aa
   $ hg ci --amend -m 'merge bar (with conflicts, amended)'
   $ hg log --config diff.git=1 -pr .
   changeset:   35:6de0c1bde1c8
   tag:         tip
   parent:      32:3d78ce4226b8
   parent:      31:67db8847a540
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     merge bar (with conflicts, amended)
   
   diff --git a/aa b/aa
   deleted file mode 100644
   --- a/aa
   +++ /dev/null
   @@ -1,4 +0,0 @@
   -a
   -a
   -aa
   -aa
   
 Issue 3445: amending with --close-branch a commit that created a new head should fail
 This shouldn't be possible:
 
   $ hg up -q default
   $ hg branch closewithamend
   marked working directory as branch closewithamend
   (branches are permanent and global, did you want a bookmark?)
   $ touch foo
   $ hg add foo
   $ hg ci -m..
   $ hg ci --amend --close-branch -m 'closing'
   abort: can only close branch heads
   [255]
 
 This silliness fails:
 
   $ hg branch silliness
   marked working directory as branch silliness
   (branches are permanent and global, did you want a bookmark?)
   $ echo b >> b
   $ hg ci --close-branch -m'open and close'
   abort: can only close branch heads
   [255]
 
 Test that amend with --secret creates new secret changeset forcibly
 ---------------------------------------------------------------------
 
   $ hg phase '.^::.'
   35: draft
   36: draft
   $ hg commit --amend --secret -m 'amend as secret' -q
   $ hg phase '.^::.'
   35: draft
   38: secret
 
 Test that amend with --edit invokes editor forcibly
 ---------------------------------------------------
 
   $ hg parents --template "{desc}\n"
   amend as secret
   $ HGEDITOR=cat hg commit --amend -m "editor should be suppressed"
   $ hg parents --template "{desc}\n"
   editor should be suppressed
 
   $ HGEDITOR=cat hg commit --amend -m "editor should be invoked" --edit
   editor should be invoked
   
   
   HG: Enter commit message.  Lines beginning with 'HG:' are removed.
   HG: Leave message empty to abort commit.
   HG: --
   HG: user: test
   HG: branch 'silliness'
   HG: changed foo
   $ hg parents --template "{desc}\n"
   editor should be invoked
+
+Check for issue4405
+-------------------
+
+Setup the repo with a file that gets moved in a second commit.
+  $ hg init repo
+  $ cd repo
+  $ touch a0
+  $ hg add a0
+  $ hg commit -m a0
+  $ hg mv a0 a1
+  $ hg commit -m a1
+  $ hg up -q 0
+  $ hg log -G --template '{rev} {desc}'
+  o  1 a1
+  |
+  @  0 a0
+  
+
+Now we branch the repro, but re-use the file contents, so we have a divergence
+in the file revlog topology and the changelog topology.
+  $ hg revert --rev 1 --all
+  removing a0
+  adding a1
+  $ hg ci -qm 'a1-amend'
+  $ hg log -G --template '{rev} {desc}'
+  @  2 a1-amend
+  |
+  | o  1 a1
+  |/
+  o  0 a0
+  
+
+The way mercurial does amends is to create a temporary commit (rev 3) and then
+fold the new and old commits together into another commit (rev 4). During this
+process, findlimit is called to check how far back to look for the transitive
+closure of file copy information, but due to the divergence of the filelog
+and changelog graph topologies, before findlimit was fixed, it returned a rev
+which was not far enough back in this case.
+  $ hg mv a1 a2
+  $ hg status --copies --rev 0
+  A a2
+    a0
+  R a0
+  $ hg ci --amend -q
+  $ hg log -G --template '{rev} {desc}'
+  @  4 a1-amend
+  |
+  | o  1 a1
+  |/
+  o  0 a0
+  
+
+Before the fix, the copy information was lost.
+  $ hg status --copies --rev 0
+  A a2
+    a0
+  R a0