Fix long-standing excessive file merges

Since switching to the multihead approach, we've been creating
excessive file-level merges where files are marked as merged with
their ancestors.

This explicitly checks at commit time whether the two parent versions
are linearly related, and if so, reduces the file check-in to a
non-merge. Then the file is compared against the remaining parent,
and, if equal, skips check-in of that file (as it's not changed).

Since we're not checking in all files that were different between
versions, we no longer need to mark so many files for merge. This
removes most of the 'm' state marking as well.

Finally, it is possible to do a tree-level merge with no file-level
changes. This will happen if one user changes file A and another
changes file B. Thus, if we have have two parents, we allow commit to
proceed even if there are no file-level changes.

tests/test-filebranch

@@ -0,0 +1,73 b''
+#!/bin/sh
+
+# This test makes sure that we don't mark a file as merged with its ancestor
+# when we do a merge.
+
+cat <<'EOF' > merge
+#!/bin/sh
+echo merging for `basename $1`
+EOF
+chmod +x merge
+
+echo creating base
+hg init a
+cd a
+echo 1 > foo
+echo 1 > bar
+echo 1 > baz
+echo 1 > quux
+hg add foo bar baz quux
+hg commit -m "base" -d "0 0"
+
+cd ..
+hg clone a b
+
+echo creating branch a
+cd a
+echo 2a > foo
+echo 2a > bar
+hg commit -m "branch a" -d "0 0"
+
+echo creating branch b
+
+cd ..
+cd b
+echo 2b > foo
+echo 2b > baz
+hg commit -m "branch b" -d "0 0"
+
+echo "we shouldn't have anything but n state here"
+hg debugstate | cut -b 1-16,35-
+
+echo merging
+hg pull ../a
+env HGMERGE=../merge hg update -vm --debug
+
+echo 2m > foo
+echo 2b > baz
+echo new > quux
+
+echo "we shouldn't have anything but foo in merge state here"
+hg debugstate | cut -b 1-16,35- | grep "^m"
+
+hg ci -m "merge" -d "0 0"
+
+echo "main: we should have a merge here"
+hg debugindex .hg/00changelog.i
+
+echo "foo: we should have a merge here"
+hg debugindex .hg/data/foo.i
+
+echo "bar: we shouldn't have a merge here"
+hg debugindex .hg/data/bar.i
+
+echo "baz: we shouldn't have a merge here"
+hg debugindex .hg/data/baz.i
+
+echo "quux: we shouldn't have a merge here"
+hg debugindex .hg/data/quux.i
+
+echo "everything should be clean now"
+hg status
+
+hg verify

tests/test-filebranch.out

@@ -0,0 +1,58 b''
+creating base
+creating branch a
+creating branch b
+we shouldn't have anything but n state here
+n 644          2 bar
+n 644          3 baz
+n 644          3 foo
+n 644          2 quux
+merging
+pulling from ../a
+searching for changes
+adding changesets
+adding manifests
+adding file changes
+added 1 changesets with 2 changes to 2 files
+(run 'hg update' to get a working copy)
+merging for foo
+resolving manifests
+ force None allow 1 moddirstate True linear False
+ ancestor a0486579db29 local ef1b4dbe2193 remote 336d8406d617
+ remote bar is newer, get
+ foo versions differ, resolve
+getting bar
+merging foo
+resolving foo
+file foo: other 33d1fb69067a ancestor b8e02f643373
+we shouldn't have anything but foo in merge state here
+m 644          3 foo
+main: we should have a merge here
+   rev    offset  length   base linkrev nodeid       p1           p2
+     0         0      73      0       0 cdca01651b96 000000000000 000000000000
+     1        73      68      1       1 f6718a9cb7f3 cdca01651b96 000000000000
+     2       141      68      2       2 bdd988058d16 cdca01651b96 000000000000
+     3       209      66      3       3 9da9fbd62226 f6718a9cb7f3 bdd988058d16
+foo: we should have a merge here
+   rev    offset  length   base linkrev nodeid       p1           p2
+     0         0       3      0       0 b8e02f643373 000000000000 000000000000
+     1         3       4      1       1 2ffeddde1b65 b8e02f643373 000000000000
+     2         7       4      2       2 33d1fb69067a b8e02f643373 000000000000
+     3        11       4      3       3 aa27919ee430 2ffeddde1b65 33d1fb69067a
+bar: we shouldn't have a merge here
+   rev    offset  length   base linkrev nodeid       p1           p2
+     0         0       3      0       0 b8e02f643373 000000000000 000000000000
+     1         3       4      1       2 33d1fb69067a b8e02f643373 000000000000
+baz: we shouldn't have a merge here
+   rev    offset  length   base linkrev nodeid       p1           p2
+     0         0       3      0       0 b8e02f643373 000000000000 000000000000
+     1         3       4      1       1 2ffeddde1b65 b8e02f643373 000000000000
+quux: we shouldn't have a merge here
+   rev    offset  length   base linkrev nodeid       p1           p2
+     0         0       3      0       0 b8e02f643373 000000000000 000000000000
+     1         3       5      1       3 6128c0f33108 b8e02f643373 000000000000
+everything should be clean now
+checking changesets
+checking manifests
+crosschecking files in changesets and manifests
+checking files
+4 files, 4 changesets, 10 total revisions

mercurial/hg.py

@@ -1,2230 +1,2268 b''
 # hg.py - repository classes for mercurial
 #
 # Copyright 2005 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms
 # of the GNU General Public License, incorporated herein by reference.
 
 import sys, struct, os
 import util
 from revlog import *
 from demandload import *
 demandload(globals(), "re lock urllib urllib2 transaction time socket")
 demandload(globals(), "tempfile httprangereader bdiff urlparse")
 demandload(globals(), "bisect errno select stat")
 
 class filelog(revlog):
     def __init__(self, opener, path):
         revlog.__init__(self, opener,
                         os.path.join("data", self.encodedir(path + ".i")),
                         os.path.join("data", self.encodedir(path + ".d")))
 
     # This avoids a collision between a file named foo and a dir named
     # foo.i or foo.d
     def encodedir(self, path):
         return (path
                 .replace(".hg/", ".hg.hg/")
                 .replace(".i/", ".i.hg/")
                 .replace(".d/", ".d.hg/"))
 
     def decodedir(self, path):
         return (path
                 .replace(".d.hg/", ".d/")
                 .replace(".i.hg/", ".i/")
                 .replace(".hg.hg/", ".hg/"))
 
     def read(self, node):
         t = self.revision(node)
         if not t.startswith('\1\n'):
             return t
         s = t.find('\1\n', 2)
         return t[s+2:]
 
     def readmeta(self, node):
         t = self.revision(node)
         if not t.startswith('\1\n'):
             return t
         s = t.find('\1\n', 2)
         mt = t[2:s]
         for l in mt.splitlines():
             k, v = l.split(": ", 1)
             m[k] = v
         return m
 
     def add(self, text, meta, transaction, link, p1=None, p2=None):
         if meta or text.startswith('\1\n'):
             mt = ""
             if meta:
                 mt = [ "%s: %s\n" % (k, v) for k,v in meta.items() ]
             text = "\1\n" + "".join(mt) + "\1\n" + text
         return self.addrevision(text, transaction, link, p1, p2)
 
     def annotate(self, node):
 
         def decorate(text, rev):
             return ([rev] * len(text.splitlines()), text)
 
         def pair(parent, child):
             for a1, a2, b1, b2 in bdiff.blocks(parent[1], child[1]):
                 child[0][b1:b2] = parent[0][a1:a2]
             return child
 
         # find all ancestors
         needed = {node:1}
         visit = [node]
         while visit:
             n = visit.pop(0)
             for p in self.parents(n):
                 if p not in needed:
                     needed[p] = 1
                     visit.append(p)
                 else:
                     # count how many times we'll use this
                     needed[p] += 1
 
         # sort by revision which is a topological order
         visit = [ (self.rev(n), n) for n in needed.keys() ]
         visit.sort()
         hist = {}
 
         for r,n in visit:
             curr = decorate(self.read(n), self.linkrev(n))
             for p in self.parents(n):
                 if p != nullid:
                     curr = pair(hist[p], curr)
                     # trim the history of unneeded revs
                     needed[p] -= 1
                     if not needed[p]:
                         del hist[p]
             hist[n] = curr
 
         return zip(hist[n][0], hist[n][1].splitlines(1))
 
 class manifest(revlog):
     def __init__(self, opener):
         self.mapcache = None
         self.listcache = None
         self.addlist = None
         revlog.__init__(self, opener, "00manifest.i", "00manifest.d")
 
     def read(self, node):
         if node == nullid: return {} # don't upset local cache
         if self.mapcache and self.mapcache[0] == node:
             return self.mapcache[1]
         text = self.revision(node)
         map = {}
         flag = {}
         self.listcache = (text, text.splitlines(1))
         for l in self.listcache[1]:
             (f, n) = l.split('\0')
             map[f] = bin(n[:40])
             flag[f] = (n[40:-1] == "x")
         self.mapcache = (node, map, flag)
         return map
 
     def readflags(self, node):
         if node == nullid: return {} # don't upset local cache
         if not self.mapcache or self.mapcache[0] != node:
             self.read(node)
         return self.mapcache[2]
 
     def diff(self, a, b):
         # this is sneaky, as we're not actually using a and b
         if self.listcache and self.addlist and self.listcache[0] == a:
             d = mdiff.diff(self.listcache[1], self.addlist, 1)
             if mdiff.patch(a, d) != b:
                 sys.stderr.write("*** sortdiff failed, falling back ***\n")
                 return mdiff.textdiff(a, b)
             return d
         else:
             return mdiff.textdiff(a, b)
 
     def add(self, map, flags, transaction, link, p1=None, p2=None,
             changed=None):
         # directly generate the mdiff delta from the data collected during
         # the bisect loop below
         def gendelta(delta):
             i = 0
             result = []
             while i < len(delta):
                 start = delta[i][2]
                 end = delta[i][3]
                 l = delta[i][4]
                 if l == None:
                     l = ""
                 while i < len(delta) - 1 and start <= delta[i+1][2] \
                           and end >= delta[i+1][2]:
                     if delta[i+1][3] > end:
                         end = delta[i+1][3]
                     if delta[i+1][4]:
                         l += delta[i+1][4]
                     i += 1
                 result.append(struct.pack(">lll", start, end, len(l)) +  l)
                 i += 1
             return result
 
         # apply the changes collected during the bisect loop to our addlist
         def addlistdelta(addlist, delta):
             # apply the deltas to the addlist.  start from the bottom up
             # so changes to the offsets don't mess things up.
             i = len(delta)
             while i > 0:
                 i -= 1
                 start = delta[i][0]
                 end = delta[i][1]
                 if delta[i][4]:
                     addlist[start:end] = [delta[i][4]]
                 else:
                     del addlist[start:end]
             return addlist
 
         # calculate the byte offset of the start of each line in the
         # manifest
         def calcoffsets(addlist):
             offsets = [0] * (len(addlist) + 1)
             offset = 0
             i = 0
             while i < len(addlist):
                 offsets[i] = offset
                 offset += len(addlist[i])
                 i += 1
             offsets[i] = offset
             return offsets
 
         # if we're using the listcache, make sure it is valid and
         # parented by the same node we're diffing against
         if not changed or not self.listcache or not p1 or \
                self.mapcache[0] != p1:
             files = map.keys()
             files.sort()
 
             self.addlist = ["%s\000%s%s\n" %
                             (f, hex(map[f]), flags[f] and "x" or '')
                             for f in files]
             cachedelta = None
         else:
             addlist = self.listcache[1]
 
             # find the starting offset for each line in the add list
             offsets = calcoffsets(addlist)
 
             # combine the changed lists into one list for sorting
             work = [[x, 0] for x in changed[0]]
             work[len(work):] = [[x, 1] for x in changed[1]]
             work.sort()
 
             delta = []
             bs = 0
 
             for w in work:
                 f = w[0]
                 # bs will either be the index of the item or the insert point
                 bs = bisect.bisect(addlist, f, bs)
                 if bs < len(addlist):
                     fn = addlist[bs][:addlist[bs].index('\0')]
                 else:
                     fn = None
                 if w[1] == 0:
                     l = "%s\000%s%s\n" % (f, hex(map[f]),
                                           flags[f] and "x" or '')
                 else:
                     l = None
                 start = bs
                 if fn != f:
                     # item not found, insert a new one
                     end = bs
                     if w[1] == 1:
                         sys.stderr.write("failed to remove %s from manifest\n"
                                          % f)
                         sys.exit(1)
                 else:
                     # item is found, replace/delete the existing line
                     end = bs + 1
                 delta.append([start, end, offsets[start], offsets[end], l])
 
             self.addlist = addlistdelta(addlist, delta)
             if self.mapcache[0] == self.tip():
                 cachedelta = "".join(gendelta(delta))
             else:
                 cachedelta = None
 
         text = "".join(self.addlist)
         if cachedelta and mdiff.patch(self.listcache[0], cachedelta) != text:
             sys.stderr.write("manifest delta failure\n")
             sys.exit(1)
         n = self.addrevision(text, transaction, link, p1, p2, cachedelta)
         self.mapcache = (n, map, flags)
         self.listcache = (text, self.addlist)
         self.addlist = None
 
         return n
 
 class changelog(revlog):
     def __init__(self, opener):
         revlog.__init__(self, opener, "00changelog.i", "00changelog.d")
 
     def extract(self, text):
         if not text:
             return (nullid, "", "0", [], "")
         last = text.index("\n\n")
         desc = text[last + 2:]
         l = text[:last].splitlines()
         manifest = bin(l[0])
         user = l[1]
         date = l[2]
         files = l[3:]
         return (manifest, user, date, files, desc)
 
     def read(self, node):
         return self.extract(self.revision(node))
 
     def add(self, manifest, list, desc, transaction, p1=None, p2=None,
                   user=None, date=None):
         if not date:
             if time.daylight: offset = time.altzone
             else: offset = time.timezone
             date = "%d %d" % (time.time(), offset)
         list.sort()
         l = [hex(manifest), user, date] + list + ["", desc]
         text = "\n".join(l)
         return self.addrevision(text, transaction, self.count(), p1, p2)
 
 class dirstate:
     def __init__(self, opener, ui, root):
         self.opener = opener
         self.root = root
         self.dirty = 0
         self.ui = ui
         self.map = None
         self.pl = None
         self.copies = {}
         self.ignorefunc = None
 
     def wjoin(self, f):
         return os.path.join(self.root, f)
 
     def getcwd(self):
         cwd = os.getcwd()
         if cwd == self.root: return ''
         return cwd[len(self.root) + 1:]
 
     def ignore(self, f):
         if not self.ignorefunc:
             bigpat = []
             try:
                 l = file(self.wjoin(".hgignore"))
                 for pat in l:
                     p = pat.rstrip()
                     if p:
                         try:
                             re.compile(p)
                         except:
                             self.ui.warn("ignoring invalid ignore"
                                          + " regular expression '%s'\n" % p)
                         else:
                             bigpat.append(p)
             except IOError: pass
 
             if bigpat:
                 s = "(?:%s)" % (")|(?:".join(bigpat))
                 r = re.compile(s)
                 self.ignorefunc = r.search
             else:
                 self.ignorefunc = util.never
 
         return self.ignorefunc(f)
 
     def __del__(self):
         if self.dirty:
             self.write()
 
     def __getitem__(self, key):
         try:
             return self.map[key]
         except TypeError:
             self.read()
             return self[key]
 
     def __contains__(self, key):
         if not self.map: self.read()
         return key in self.map
 
     def parents(self):
         if not self.pl:
             self.read()
         return self.pl
 
     def markdirty(self):
         if not self.dirty:
             self.dirty = 1
 
     def setparents(self, p1, p2 = nullid):
         self.markdirty()
         self.pl = p1, p2
 
     def state(self, key):
         try:
             return self[key][0]
         except KeyError:
             return "?"
 
     def read(self):
         if self.map is not None: return self.map
 
         self.map = {}
         self.pl = [nullid, nullid]
         try:
             st = self.opener("dirstate").read()
             if not st: return
         except: return
 
         self.pl = [st[:20], st[20: 40]]
 
         pos = 40
         while pos < len(st):
             e = struct.unpack(">cllll", st[pos:pos+17])
             l = e[4]
             pos += 17
             f = st[pos:pos + l]
             if '\0' in f:
                 f, c = f.split('\0')
                 self.copies[f] = c
             self.map[f] = e[:4]
             pos += l
 
     def copy(self, source, dest):
         self.read()
         self.markdirty()
         self.copies[dest] = source
 
     def copied(self, file):
         return self.copies.get(file, None)
 
     def update(self, files, state, **kw):
         ''' current states:
         n  normal
         m  needs merging
         r  marked for removal
         a  marked for addition'''
 
         if not files: return
         self.read()
         self.markdirty()
         for f in files:
             if state == "r":
                 self.map[f] = ('r', 0, 0, 0)
             else:
                 s = os.stat(os.path.join(self.root, f))
                 st_size = kw.get('st_size', s.st_size)
                 st_mtime = kw.get('st_mtime', s.st_mtime)
                 self.map[f] = (state, s.st_mode, st_size, st_mtime)
 
     def forget(self, files):
         if not files: return
         self.read()
         self.markdirty()
         for f in files:
             try:
                 del self.map[f]
             except KeyError:
                 self.ui.warn("not in dirstate: %s!\n" % f)
                 pass
 
     def clear(self):
         self.map = {}
         self.markdirty()
 
     def write(self):
         st = self.opener("dirstate", "w")
         st.write("".join(self.pl))
         for f, e in self.map.items():
             c = self.copied(f)
             if c:
                 f = f + "\0" + c
             e = struct.pack(">cllll", e[0], e[1], e[2], e[3], len(f))
             st.write(e + f)
         self.dirty = 0
 
     def filterfiles(self, files):
         ret = {}
         unknown = []
 
         for x in files:
             if x is '.':
                 return self.map.copy()
             if x not in self.map:
                 unknown.append(x)
             else:
                 ret[x] = self.map[x]
 
         if not unknown:
             return ret
 
         b = self.map.keys()
         b.sort()
         blen = len(b)
 
         for x in unknown:
             bs = bisect.bisect(b, x)
             if bs != 0 and  b[bs-1] == x:
                 ret[x] = self.map[x]
                 continue
             while bs < blen:
                 s = b[bs]
                 if len(s) > len(x) and s.startswith(x) and s[len(x)] == '/':
                     ret[s] = self.map[s]
                 else:
                     break
                 bs += 1
         return ret
 
     def walk(self, files = None, match = util.always, dc=None):
         self.read()
 
         # walk all files by default
         if not files:
             files = [self.root]
             if not dc:
                 dc = self.map.copy()
         elif not dc:
             dc = self.filterfiles(files)
 
         known = {'.hg': 1}
         def seen(fn):
             if fn in known: return True
             known[fn] = 1
         def traverse():
             for ff in util.unique(files):
                 f = os.path.join(self.root, ff)
                 try:
                     st = os.stat(f)
                 except OSError, inst:
                     if ff not in dc: self.ui.warn('%s: %s\n' % (
                         util.pathto(self.getcwd(), ff),
                         inst.strerror))
                     continue
                 if stat.S_ISDIR(st.st_mode):
                     for dir, subdirs, fl in os.walk(f):
                         d = dir[len(self.root) + 1:]
                         nd = util.normpath(d)
                         if nd == '.': nd = ''
                         if seen(nd):
                             subdirs[:] = []
                             continue
                         for sd in subdirs:
                             ds = os.path.join(nd, sd +'/')
                             if self.ignore(ds) or not match(ds):
                                 subdirs.remove(sd)
                         subdirs.sort()
                         fl.sort()
                         for fn in fl:
                             fn = util.pconvert(os.path.join(d, fn))
                             yield 'f', fn
                 elif stat.S_ISREG(st.st_mode):
                     yield 'f', ff
                 else:
                     kind = 'unknown'
                     if stat.S_ISCHR(st.st_mode): kind = 'character device'
                     elif stat.S_ISBLK(st.st_mode): kind = 'block device'
                     elif stat.S_ISFIFO(st.st_mode): kind = 'fifo'
                     elif stat.S_ISLNK(st.st_mode): kind = 'symbolic link'
                     elif stat.S_ISSOCK(st.st_mode): kind = 'socket'
                     self.ui.warn('%s: unsupported file type (type is %s)\n' % (
                         util.pathto(self.getcwd(), ff),
                         kind))
 
             ks = dc.keys()
             ks.sort()
             for k in ks:
                 yield 'm', k
 
         # yield only files that match: all in dirstate, others only if
         # not in .hgignore
 
         for src, fn in util.unique(traverse()):
             fn = util.normpath(fn)
             if seen(fn): continue
             if fn not in dc and self.ignore(fn):
                 continue
             if match(fn):
                 yield src, fn
 
     def changes(self, files=None, match=util.always):
         self.read()
         if not files:
             dc = self.map.copy()
         else:
             dc = self.filterfiles(files)
         lookup, modified, added, unknown = [], [], [], []
         removed, deleted = [], []
 
         for src, fn in self.walk(files, match, dc=dc):
             try:
                 s = os.stat(os.path.join(self.root, fn))
             except OSError:
                 continue
             if not stat.S_ISREG(s.st_mode):
                 continue
             c = dc.get(fn)
             if c:
                 del dc[fn]
                 if c[0] == 'm':
                     modified.append(fn)
                 elif c[0] == 'a':
                     added.append(fn)
                 elif c[0] == 'r':
                     unknown.append(fn)
                 elif c[2] != s.st_size or (c[1] ^ s.st_mode) & 0100:
                     modified.append(fn)
                 elif c[3] != s.st_mtime:
                     lookup.append(fn)
             else:
                 unknown.append(fn)
 
         for fn, c in [(fn, c) for fn, c in dc.items() if match(fn)]:
             if c[0] == 'r':
                 removed.append(fn)
             else:
                 deleted.append(fn)
         return (lookup, modified, added, removed + deleted, unknown)
 
 # used to avoid circular references so destructors work
 def opener(base):
     p = base
     def o(path, mode="r"):
         if p.startswith("http://"):
             f = os.path.join(p, urllib.quote(path))
             return httprangereader.httprangereader(f)
 
         f = os.path.join(p, path)
 
         mode += "b" # for that other OS
 
         if mode[0] != "r":
             try:
                 s = os.stat(f)
             except OSError:
                 d = os.path.dirname(f)
                 if not os.path.isdir(d):
                     os.makedirs(d)
             else:
                 if s.st_nlink > 1:
                     file(f + ".tmp", "wb").write(file(f, "rb").read())
                     util.rename(f+".tmp", f)
 
         return file(f, mode)
 
     return o
 
 class RepoError(Exception): pass
 
 class localrepository:
     def __init__(self, ui, path=None, create=0):
         self.remote = 0
         if path and path.startswith("http://"):
             self.remote = 1
             self.path = path
         else:
             if not path:
                 p = os.getcwd()
                 while not os.path.isdir(os.path.join(p, ".hg")):
                     oldp = p
                     p = os.path.dirname(p)
                     if p == oldp: raise RepoError("no repo found")
                 path = p
             self.path = os.path.join(path, ".hg")
 
             if not create and not os.path.isdir(self.path):
                 raise RepoError("repository %s not found" % self.path)
 
         self.root = os.path.abspath(path)
         self.ui = ui
 
         if create:
             os.mkdir(self.path)
             os.mkdir(self.join("data"))
 
         self.opener = opener(self.path)
         self.wopener = opener(self.root)
         self.manifest = manifest(self.opener)
         self.changelog = changelog(self.opener)
         self.tagscache = None
         self.nodetagscache = None
 
         if not self.remote:
             self.dirstate = dirstate(self.opener, ui, self.root)
             try:
                 self.ui.readconfig(self.opener("hgrc"))
             except IOError: pass
 
     def hook(self, name, **args):
         s = self.ui.config("hooks", name)
         if s:
             self.ui.note("running hook %s: %s\n" % (name, s))
             old = {}
             for k, v in args.items():
                 k = k.upper()
                 old[k] = os.environ.get(k, None)
                 os.environ[k] = v
 
             r = os.system(s)
 
             for k, v in old.items():
                 if v != None:
                     os.environ[k] = v
                 else:
                     del os.environ[k]
 
             if r:
                 self.ui.warn("abort: %s hook failed with status %d!\n" %
                              (name, r))
                 return False
         return True
 
     def tags(self):
         '''return a mapping of tag to node'''
         if not self.tagscache:
             self.tagscache = {}
             def addtag(self, k, n):
                 try:
                     bin_n = bin(n)
                 except TypeError:
                     bin_n = ''
                 self.tagscache[k.strip()] = bin_n
 
             try:
                 # read each head of the tags file, ending with the tip
                 # and add each tag found to the map, with "newer" ones
                 # taking precedence
                 fl = self.file(".hgtags")
                 h = fl.heads()
                 h.reverse()
                 for r in h:
                     for l in fl.revision(r).splitlines():
                         if l:
                             n, k = l.split(" ", 1)
                             addtag(self, k, n)
             except KeyError:
                 pass
 
             try:
                 f = self.opener("localtags")
                 for l in f:
                     n, k = l.split(" ", 1)
                     addtag(self, k, n)
             except IOError:
                 pass
 
             self.tagscache['tip'] = self.changelog.tip()
 
         return self.tagscache
 
     def tagslist(self):
         '''return a list of tags ordered by revision'''
         l = []
         for t, n in self.tags().items():
             try:
                 r = self.changelog.rev(n)
             except:
                 r = -2 # sort to the beginning of the list if unknown
             l.append((r,t,n))
         l.sort()
         return [(t,n) for r,t,n in l]
 
     def nodetags(self, node):
         '''return the tags associated with a node'''
         if not self.nodetagscache:
             self.nodetagscache = {}
             for t,n in self.tags().items():
                 self.nodetagscache.setdefault(n,[]).append(t)
         return self.nodetagscache.get(node, [])
 
     def lookup(self, key):
         try:
             return self.tags()[key]
         except KeyError:
             try:
                 return self.changelog.lookup(key)
             except:
                 raise RepoError("unknown revision '%s'" % key)
 
     def dev(self):
         if self.remote: return -1
         return os.stat(self.path).st_dev
 
     def local(self):
         return not self.remote
 
     def join(self, f):
         return os.path.join(self.path, f)
 
     def wjoin(self, f):
         return os.path.join(self.root, f)
 
     def file(self, f):
         if f[0] == '/': f = f[1:]
         return filelog(self.opener, f)
 
     def getcwd(self):
         return self.dirstate.getcwd()
 
     def wfile(self, f, mode='r'):
         return self.wopener(f, mode)
 
     def transaction(self):
         # save dirstate for undo
         try:
             ds = self.opener("dirstate").read()
         except IOError:
             ds = ""
         self.opener("journal.dirstate", "w").write(ds)
 
         def after():
             util.rename(self.join("journal"), self.join("undo"))
             util.rename(self.join("journal.dirstate"),
                         self.join("undo.dirstate"))
 
         return transaction.transaction(self.ui.warn, self.opener,
                                        self.join("journal"), after)
 
     def recover(self):
         lock = self.lock()
         if os.path.exists(self.join("journal")):
             self.ui.status("rolling back interrupted transaction\n")
             return transaction.rollback(self.opener, self.join("journal"))
         else:
             self.ui.warn("no interrupted transaction available\n")
 
     def undo(self):
         lock = self.lock()
         if os.path.exists(self.join("undo")):
             self.ui.status("rolling back last transaction\n")
             transaction.rollback(self.opener, self.join("undo"))
             self.dirstate = None
             util.rename(self.join("undo.dirstate"), self.join("dirstate"))
             self.dirstate = dirstate(self.opener, self.ui, self.root)
         else:
             self.ui.warn("no undo information available\n")
 
     def lock(self, wait = 1):
         try:
             return lock.lock(self.join("lock"), 0)
         except lock.LockHeld, inst:
             if wait:
                 self.ui.warn("waiting for lock held by %s\n" % inst.args[0])
                 return lock.lock(self.join("lock"), wait)
             raise inst
 
     def rawcommit(self, files, text, user, date, p1=None, p2=None):
         orig_parent = self.dirstate.parents()[0] or nullid
         p1 = p1 or self.dirstate.parents()[0] or nullid
         p2 = p2 or self.dirstate.parents()[1] or nullid
         c1 = self.changelog.read(p1)
         c2 = self.changelog.read(p2)
         m1 = self.manifest.read(c1[0])
         mf1 = self.manifest.readflags(c1[0])
         m2 = self.manifest.read(c2[0])
 
         if orig_parent == p1:
             update_dirstate = 1
         else:
             update_dirstate = 0
 
         tr = self.transaction()
         mm = m1.copy()
         mfm = mf1.copy()
         linkrev = self.changelog.count()
         for f in files:
             try:
                 t = self.wfile(f).read()
                 tm = util.is_exec(self.wjoin(f), mfm.get(f, False))
                 r = self.file(f)
                 mfm[f] = tm
-                mm[f] = r.add(t, {}, tr, linkrev,
-                              m1.get(f, nullid), m2.get(f, nullid))
+
+                fp1 = m1.get(f, nullid)
+                fp2 = m2.get(f, nullid)
+
+                # is the same revision on two branches of a merge?
+                if fp2 == fp1:
+                    fp2 = nullid
+
+                if fp2 != nullid:
+                    # is one parent an ancestor of the other?
+                    fpa = r.ancestor(fp1, fp2)
+                    if fpa == fp1:
+                        fp1, fp2 = fp2, nullid
+                    elif fpa == fp2:
+                        fp2 = nullid
+
+                    # is the file unmodified from the parent?
+                    if t == r.read(fp1):
+                        # record the proper existing parent in manifest
+                        # no need to add a revision
+                        mm[f] = fp1
+                        continue
+
+                mm[f] = r.add(t, {}, tr, linkrev, fp1, fp2)
                 if update_dirstate:
                     self.dirstate.update([f], "n")
             except IOError:
                 try:
                     del mm[f]
                     del mfm[f]
                     if update_dirstate:
                         self.dirstate.forget([f])
                 except:
                     # deleted from p2?
                     pass
 
         mnode = self.manifest.add(mm, mfm, tr, linkrev, c1[0], c2[0])
         user = user or self.ui.username()
         n = self.changelog.add(mnode, files, text, tr, p1, p2, user, date)
         tr.close()
         if update_dirstate:
             self.dirstate.setparents(n, nullid)
 
     def commit(self, files = None, text = "", user = None, date = None,
                match = util.always, force=False):
         commit = []
         remove = []
         if files:
             for f in files:
                 s = self.dirstate.state(f)
                 if s in 'nmai':
                     commit.append(f)
                 elif s == 'r':
                     remove.append(f)
                 else:
                     self.ui.warn("%s not tracked!\n" % f)
         else:
             (c, a, d, u) = self.changes(match = match)
             commit = c + a
             remove = d
 
-        if not commit and not remove and not force:
+        p1, p2 = self.dirstate.parents()
+        c1 = self.changelog.read(p1)
+        c2 = self.changelog.read(p2)
+        m1 = self.manifest.read(c1[0])
+        mf1 = self.manifest.readflags(c1[0])
+        m2 = self.manifest.read(c2[0])
+
+        if not commit and not remove and not force and p2 == nullid:
             self.ui.status("nothing changed\n")
             return None
 
         if not self.hook("precommit"):
             return None
 
-        p1, p2 = self.dirstate.parents()
-        c1 = self.changelog.read(p1)
-        c2 = self.changelog.read(p2)
-        m1 = self.manifest.read(c1[0])
-        mf1 = self.manifest.readflags(c1[0])
-        m2 = self.manifest.read(c2[0])
         lock = self.lock()
         tr = self.transaction()
 
         # check in files
         new = {}
         linkrev = self.changelog.count()
         commit.sort()
         for f in commit:
             self.ui.note(f + "\n")
             try:
                 mf1[f] = util.is_exec(self.wjoin(f), mf1.get(f, False))
                 t = self.wfile(f).read()
             except IOError:
                 self.ui.warn("trouble committing %s!\n" % f)
                 raise
 
             meta = {}
             cp = self.dirstate.copied(f)
             if cp:
                 meta["copy"] = cp
                 meta["copyrev"] = hex(m1.get(cp, m2.get(cp, nullid)))
                 self.ui.debug(" %s: copy %s:%s\n" % (f, cp, meta["copyrev"]))
 
             r = self.file(f)
             fp1 = m1.get(f, nullid)
             fp2 = m2.get(f, nullid)
+
+            # is the same revision on two branches of a merge?
+            if fp2 == fp1:
+                fp2 = nullid
+
+            if fp2 != nullid:
+                # is one parent an ancestor of the other?
+                fpa = r.ancestor(fp1, fp2)
+                if fpa == fp1:
+                    fp1, fp2 = fp2, nullid
+                elif fpa == fp2:
+                    fp2 = nullid
+
+                # is the file unmodified from the parent?
+                if not meta and t == r.read(fp1):
+                    # record the proper existing parent in manifest
+                    # no need to add a revision
+                    new[f] = fp1
+                    continue
+
             new[f] = r.add(t, meta, tr, linkrev, fp1, fp2)
 
         # update manifest
         m1.update(new)
         for f in remove:
             if f in m1:
                 del m1[f]
         mn = self.manifest.add(m1, mf1, tr, linkrev, c1[0], c2[0],
                                (new, remove))
 
         # add changeset
         new = new.keys()
         new.sort()
 
         if not text:
             edittext = "\n" + "HG: manifest hash %s\n" % hex(mn)
             edittext += "".join(["HG: changed %s\n" % f for f in new])
             edittext += "".join(["HG: removed %s\n" % f for f in remove])
             edittext = self.ui.edit(edittext)
             if not edittext.rstrip():
                 return None
             text = edittext
 
         user = user or self.ui.username()
         n = self.changelog.add(mn, new, text, tr, p1, p2, user, date)
         tr.close()
 
         self.dirstate.setparents(n)
         self.dirstate.update(new, "n")
         self.dirstate.forget(remove)
 
         if not self.hook("commit", node=hex(n)):
             return None
         return n
 
     def walk(self, node = None, files = [], match = util.always):
         if node:
             for fn in self.manifest.read(self.changelog.read(node)[0]):
                 if match(fn): yield 'm', fn
         else:
             for src, fn in self.dirstate.walk(files, match):
                 yield src, fn
 
     def changes(self, node1 = None, node2 = None, files = [],
                 match = util.always):
         mf2, u = None, []
 
         def fcmp(fn, mf):
             t1 = self.wfile(fn).read()
             t2 = self.file(fn).revision(mf[fn])
             return cmp(t1, t2)
 
         def mfmatches(node):
             mf = dict(self.manifest.read(node))
             for fn in mf.keys():
                 if not match(fn):
                     del mf[fn]
             return mf
 
         # are we comparing the working directory?
         if not node2:
             l, c, a, d, u = self.dirstate.changes(files, match)
 
             # are we comparing working dir against its parent?
             if not node1:
                 if l:
                     # do a full compare of any files that might have changed
                     change = self.changelog.read(self.dirstate.parents()[0])
                     mf2 = mfmatches(change[0])
                     for f in l:
                         if fcmp(f, mf2):
                             c.append(f)
 
                 for l in c, a, d, u:
                     l.sort()
 
                 return (c, a, d, u)
 
         # are we comparing working dir against non-tip?
         # generate a pseudo-manifest for the working dir
         if not node2:
             if not mf2:
                 change = self.changelog.read(self.dirstate.parents()[0])
                 mf2 = mfmatches(change[0])
             for f in a + c + l:
                 mf2[f] = ""
             for f in d:
                 if f in mf2: del mf2[f]
         else:
             change = self.changelog.read(node2)
             mf2 = mfmatches(change[0])
 
         # flush lists from dirstate before comparing manifests
         c, a = [], []
 
         change = self.changelog.read(node1)
         mf1 = mfmatches(change[0])
 
         for fn in mf2:
             if mf1.has_key(fn):
                 if mf1[fn] != mf2[fn]:
                     if mf2[fn] != "" or fcmp(fn, mf1):
                         c.append(fn)
                 del mf1[fn]
             else:
                 a.append(fn)
 
         d = mf1.keys()
 
         for l in c, a, d, u:
             l.sort()
 
         return (c, a, d, u)
 
     def add(self, list):
         for f in list:
             p = self.wjoin(f)
             if not os.path.exists(p):
                 self.ui.warn("%s does not exist!\n" % f)
             elif not os.path.isfile(p):
                 self.ui.warn("%s not added: only files supported currently\n" % f)
             elif self.dirstate.state(f) in 'an':
                 self.ui.warn("%s already tracked!\n" % f)
             else:
                 self.dirstate.update([f], "a")
 
     def forget(self, list):
         for f in list:
             if self.dirstate.state(f) not in 'ai':
                 self.ui.warn("%s not added!\n" % f)
             else:
                 self.dirstate.forget([f])
 
     def remove(self, list):
         for f in list:
             p = self.wjoin(f)
             if os.path.exists(p):
                 self.ui.warn("%s still exists!\n" % f)
             elif self.dirstate.state(f) == 'a':
                 self.ui.warn("%s never committed!\n" % f)
                 self.dirstate.forget([f])
             elif f not in self.dirstate:
                 self.ui.warn("%s not tracked!\n" % f)
             else:
                 self.dirstate.update([f], "r")
 
     def copy(self, source, dest):
         p = self.wjoin(dest)
         if not os.path.exists(p):
             self.ui.warn("%s does not exist!\n" % dest)
         elif not os.path.isfile(p):
             self.ui.warn("copy failed: %s is not a file\n" % dest)
         else:
             if self.dirstate.state(dest) == '?':
                 self.dirstate.update([dest], "a")
             self.dirstate.copy(source, dest)
 
     def heads(self):
         return self.changelog.heads()
 
     # branchlookup returns a dict giving a list of branches for
     # each head.  A branch is defined as the tag of a node or
     # the branch of the node's parents.  If a node has multiple
     # branch tags, tags are eliminated if they are visible from other
     # branch tags.
     #
     # So, for this graph:  a->b->c->d->e
     #                       \         /
     #                        aa -----/
     # a has tag 2.6.12
     # d has tag 2.6.13
     # e would have branch tags for 2.6.12 and 2.6.13.  Because the node
     # for 2.6.12 can be reached from the node 2.6.13, that is eliminated
     # from the list.
     #
     # It is possible that more than one head will have the same branch tag.
     # callers need to check the result for multiple heads under the same
     # branch tag if that is a problem for them (ie checkout of a specific
     # branch).
     #
     # passing in a specific branch will limit the depth of the search
     # through the parents.  It won't limit the branches returned in the
     # result though.
     def branchlookup(self, heads=None, branch=None):
         if not heads:
             heads = self.heads()
         headt = [ h for h in heads ]
         chlog = self.changelog
         branches = {}
         merges = []
         seenmerge = {}
 
         # traverse the tree once for each head, recording in the branches
         # dict which tags are visible from this head.  The branches
         # dict also records which tags are visible from each tag
         # while we traverse.
         while headt or merges:
             if merges:
                 n, found = merges.pop()
                 visit = [n]
             else:
                 h = headt.pop()
                 visit = [h]
                 found = [h]
                 seen = {}
             while visit:
                 n = visit.pop()
                 if n in seen:
                     continue
                 pp = chlog.parents(n)
                 tags = self.nodetags(n)
                 if tags:
                     for x in tags:
                         if x == 'tip':
                             continue
                         for f in found:
                             branches.setdefault(f, {})[n] = 1
                         branches.setdefault(n, {})[n] = 1
                         break
                     if n not in found:
                         found.append(n)
                     if branch in tags:
                         continue
                 seen[n] = 1
                 if pp[1] != nullid and n not in seenmerge:
                     merges.append((pp[1], [x for x in found]))
                     seenmerge[n] = 1
                 if pp[0] != nullid:
                     visit.append(pp[0])
         # traverse the branches dict, eliminating branch tags from each
         # head that are visible from another branch tag for that head.
         out = {}
         viscache = {}
         for h in heads:
             def visible(node):
                 if node in viscache:
                     return viscache[node]
                 ret = {}
                 visit = [node]
                 while visit:
                     x = visit.pop()
                     if x in viscache:
                         ret.update(viscache[x])
                     elif x not in ret:
                         ret[x] = 1
                         if x in branches:
                             visit[len(visit):] = branches[x].keys()
                 viscache[node] = ret
                 return ret
             if h not in branches:
                 continue
             # O(n^2), but somewhat limited.  This only searches the
             # tags visible from a specific head, not all the tags in the
             # whole repo.
             for b in branches[h]:
                 vis = False
                 for bb in branches[h].keys():
                     if b != bb:
                         if b in visible(bb):
                             vis = True
                             break
                 if not vis:
                     l = out.setdefault(h, [])
                     l[len(l):] = self.nodetags(b)
         return out
 
     def branches(self, nodes):
         if not nodes: nodes = [self.changelog.tip()]
         b = []
         for n in nodes:
             t = n
             while n:
                 p = self.changelog.parents(n)
                 if p[1] != nullid or p[0] == nullid:
                     b.append((t, n, p[0], p[1]))
                     break
                 n = p[0]
         return b
 
     def between(self, pairs):
         r = []
 
         for top, bottom in pairs:
             n, l, i = top, [], 0
             f = 1
 
             while n != bottom:
                 p = self.changelog.parents(n)[0]
                 if i == f:
                     l.append(n)
                     f = f * 2
                 n = p
                 i += 1
 
             r.append(l)
 
         return r
 
     def newer(self, nodes):
         m = {}
         nl = []
         pm = {}
         cl = self.changelog
         t = l = cl.count()
 
         # find the lowest numbered node
         for n in nodes:
             l = min(l, cl.rev(n))
             m[n] = 1
 
         for i in xrange(l, t):
             n = cl.node(i)
             if n in m: # explicitly listed
                 pm[n] = 1
                 nl.append(n)
                 continue
             for p in cl.parents(n):
                 if p in pm: # parent listed
                     pm[n] = 1
                     nl.append(n)
                     break
 
         return nl
 
     def findincoming(self, remote, base=None, heads=None):
         m = self.changelog.nodemap
         search = []
         fetch = []
         seen = {}
         seenbranch = {}
         if base == None:
             base = {}
 
         # assume we're closer to the tip than the root
         # and start by examining the heads
         self.ui.status("searching for changes\n")
 
         if not heads:
             heads = remote.heads()
 
         unknown = []
         for h in heads:
             if h not in m:
                 unknown.append(h)
             else:
                 base[h] = 1
 
         if not unknown:
             return None
 
         rep = {}
         reqcnt = 0
 
         # search through remote branches
         # a 'branch' here is a linear segment of history, with four parts:
         # head, root, first parent, second parent
         # (a branch always has two parents (or none) by definition)
         unknown = remote.branches(unknown)
         while unknown:
             r = []
             while unknown:
                 n = unknown.pop(0)
                 if n[0] in seen:
                     continue
 
                 self.ui.debug("examining %s:%s\n" % (short(n[0]), short(n[1])))
                 if n[0] == nullid:
                     break
                 if n in seenbranch:
                     self.ui.debug("branch already found\n")
                     continue
                 if n[1] and n[1] in m: # do we know the base?
                     self.ui.debug("found incomplete branch %s:%s\n"
                                   % (short(n[0]), short(n[1])))
                     search.append(n) # schedule branch range for scanning
                     seenbranch[n] = 1
                 else:
                     if n[1] not in seen and n[1] not in fetch:
                         if n[2] in m and n[3] in m:
                             self.ui.debug("found new changeset %s\n" %
                                           short(n[1]))
                             fetch.append(n[1]) # earliest unknown
                             base[n[2]] = 1 # latest known
                             continue
 
                     for a in n[2:4]:
                         if a not in rep:
                             r.append(a)
                             rep[a] = 1
 
                 seen[n[0]] = 1
 
             if r:
                 reqcnt += 1
                 self.ui.debug("request %d: %s\n" %
                             (reqcnt, " ".join(map(short, r))))
                 for p in range(0, len(r), 10):
                     for b in remote.branches(r[p:p+10]):
                         self.ui.debug("received %s:%s\n" %
                                       (short(b[0]), short(b[1])))
                         if b[0] not in m and b[0] not in seen:
                             unknown.append(b)
 
         # do binary search on the branches we found
         while search:
             n = search.pop(0)
             reqcnt += 1
             l = remote.between([(n[0], n[1])])[0]
             l.append(n[1])
             p = n[0]
             f = 1
             for i in l:
                 self.ui.debug("narrowing %d:%d %s\n" % (f, len(l), short(i)))
                 if i in m:
                     if f <= 2:
                         self.ui.debug("found new branch changeset %s\n" %
                                           short(p))
                         fetch.append(p)
                         base[i] = 1
                     else:
                         self.ui.debug("narrowed branch search to %s:%s\n"
                                       % (short(p), short(i)))
                         search.append((p, i))
                     break
                 p, f = i, f * 2
 
         # sanity check our fetch list
         for f in fetch:
             if f in m:
                 raise RepoError("already have changeset " + short(f[:4]))
 
         if base.keys() == [nullid]:
             self.ui.warn("warning: pulling from an unrelated repository!\n")
 
         self.ui.note("adding new changesets starting at " +
                      " ".join([short(f) for f in fetch]) + "\n")
 
         self.ui.debug("%d total queries\n" % reqcnt)
 
         return fetch
 
     def findoutgoing(self, remote, base=None, heads=None):
         if base == None:
             base = {}
             self.findincoming(remote, base, heads)
 
         remain = dict.fromkeys(self.changelog.nodemap)
 
         # prune everything remote has from the tree
         del remain[nullid]
         remove = base.keys()
         while remove:
             n = remove.pop(0)
             if n in remain:
                 del remain[n]
                 for p in self.changelog.parents(n):
                     remove.append(p)
 
         # find every node whose parents have been pruned
         subset = []
         for n in remain:
             p1, p2 = self.changelog.parents(n)
             if p1 not in remain and p2 not in remain:
                 subset.append(n)
 
         # this is the set of all roots we have to push
         return subset
 
     def pull(self, remote):
         lock = self.lock()
 
         # if we have an empty repo, fetch everything
         if self.changelog.tip() == nullid:
             self.ui.status("requesting all changes\n")
             fetch = [nullid]
         else:
             fetch = self.findincoming(remote)
 
         if not fetch:
             self.ui.status("no changes found\n")
             return 1
 
         cg = remote.changegroup(fetch)
         return self.addchangegroup(cg)
 
     def push(self, remote, force=False):
         lock = remote.lock()
 
         base = {}
         heads = remote.heads()
         inc = self.findincoming(remote, base, heads)
         if not force and inc:
             self.ui.warn("abort: unsynced remote changes!\n")
             self.ui.status("(did you forget to sync? use push -f to force)\n")
             return 1
 
         update = self.findoutgoing(remote, base)
         if not update:
             self.ui.status("no changes found\n")
             return 1
         elif not force:
             if len(heads) < len(self.changelog.heads()):
                 self.ui.warn("abort: push creates new remote branches!\n")
                 self.ui.status("(did you forget to merge?" +
                                " use push -f to force)\n")
                 return 1
 
         cg = self.changegroup(update)
         return remote.addchangegroup(cg)
 
     def changegroup(self, basenodes):
         class genread:
             def __init__(self, generator):
                 self.g = generator
                 self.buf = ""
             def fillbuf(self):
                 self.buf += "".join(self.g)
 
             def read(self, l):
                 while l > len(self.buf):
                     try:
                         self.buf += self.g.next()
                     except StopIteration:
                         break
                 d, self.buf = self.buf[:l], self.buf[l:]
                 return d
 
         def gengroup():
             nodes = self.newer(basenodes)
 
             # construct the link map
             linkmap = {}
             for n in nodes:
                 linkmap[self.changelog.rev(n)] = n
 
             # construct a list of all changed files
             changed = {}
             for n in nodes:
                 c = self.changelog.read(n)
                 for f in c[3]:
                     changed[f] = 1
             changed = changed.keys()
             changed.sort()
 
             # the changegroup is changesets + manifests + all file revs
             revs = [ self.changelog.rev(n) for n in nodes ]
 
             for y in self.changelog.group(linkmap): yield y
             for y in self.manifest.group(linkmap): yield y
             for f in changed:
                 yield struct.pack(">l", len(f) + 4) + f
                 g = self.file(f).group(linkmap)
                 for y in g:
                     yield y
 
             yield struct.pack(">l", 0)
 
         return genread(gengroup())
 
     def addchangegroup(self, source):
 
         def getchunk():
             d = source.read(4)
             if not d: return ""
             l = struct.unpack(">l", d)[0]
             if l <= 4: return ""
             return source.read(l - 4)
 
         def getgroup():
             while 1:
                 c = getchunk()
                 if not c: break
                 yield c
 
         def csmap(x):
             self.ui.debug("add changeset %s\n" % short(x))
             return self.changelog.count()
 
         def revmap(x):
             return self.changelog.rev(x)
 
         if not source: return
         changesets = files = revisions = 0
 
         tr = self.transaction()
 
         # pull off the changeset group
         self.ui.status("adding changesets\n")
         co = self.changelog.tip()
         cn = self.changelog.addgroup(getgroup(), csmap, tr, 1) # unique
         changesets = self.changelog.rev(cn) - self.changelog.rev(co)
 
         # pull off the manifest group
         self.ui.status("adding manifests\n")
         mm = self.manifest.tip()
         mo = self.manifest.addgroup(getgroup(), revmap, tr)
 
         # process the files
         self.ui.status("adding file changes\n")
         while 1:
             f = getchunk()
             if not f: break
             self.ui.debug("adding %s revisions\n" % f)
             fl = self.file(f)
             o = fl.count()
             n = fl.addgroup(getgroup(), revmap, tr)
             revisions += fl.count() - o
             files += 1
 
         self.ui.status(("added %d changesets" +
                         " with %d changes to %d files\n")
                        % (changesets, revisions, files))
 
         tr.close()
 
         if not self.hook("changegroup"):
             return 1
 
         return
 
     def update(self, node, allow=False, force=False, choose=None,
                moddirstate=True):
         pl = self.dirstate.parents()
         if not force and pl[1] != nullid:
             self.ui.warn("aborting: outstanding uncommitted merges\n")
             return 1
 
         p1, p2 = pl[0], node
         pa = self.changelog.ancestor(p1, p2)
         m1n = self.changelog.read(p1)[0]
         m2n = self.changelog.read(p2)[0]
         man = self.manifest.ancestor(m1n, m2n)
         m1 = self.manifest.read(m1n)
         mf1 = self.manifest.readflags(m1n)
         m2 = self.manifest.read(m2n)
         mf2 = self.manifest.readflags(m2n)
         ma = self.manifest.read(man)
         mfa = self.manifest.readflags(man)
 
         (c, a, d, u) = self.changes()
 
         # is this a jump, or a merge?  i.e. is there a linear path
         # from p1 to p2?
         linear_path = (pa == p1 or pa == p2)
 
         # resolve the manifest to determine which files
         # we care about merging
         self.ui.note("resolving manifests\n")
         self.ui.debug(" force %s allow %s moddirstate %s linear %s\n" %
                       (force, allow, moddirstate, linear_path))
         self.ui.debug(" ancestor %s local %s remote %s\n" %
                       (short(man), short(m1n), short(m2n)))
 
         merge = {}
         get = {}
         remove = []
         mark = {}
 
         # construct a working dir manifest
         mw = m1.copy()
         mfw = mf1.copy()
         umap = dict.fromkeys(u)
 
         for f in a + c + u:
             mw[f] = ""
             mfw[f] = util.is_exec(self.wjoin(f), mfw.get(f, False))
 
         for f in d:
             if f in mw: del mw[f]
 
             # If we're jumping between revisions (as opposed to merging),
             # and if neither the working directory nor the target rev has
             # the file, then we need to remove it from the dirstate, to
             # prevent the dirstate from listing the file when it is no
             # longer in the manifest.
             if moddirstate and linear_path and f not in m2:
                 self.dirstate.forget((f,))
 
         # Compare manifests
         for f, n in mw.iteritems():
             if choose and not choose(f): continue
             if f in m2:
                 s = 0
 
                 # is the wfile new since m1, and match m2?
                 if f not in m1:
                     t1 = self.wfile(f).read()
                     t2 = self.file(f).revision(m2[f])
                     if cmp(t1, t2) == 0:
                         mark[f] = 1
                         n = m2[f]
                     del t1, t2
 
                 # are files different?
                 if n != m2[f]:
                     a = ma.get(f, nullid)
                     # are both different from the ancestor?
                     if n != a and m2[f] != a:
                         self.ui.debug(" %s versions differ, resolve\n" % f)
                         # merge executable bits
                         # "if we changed or they changed, change in merge"
                         a, b, c = mfa.get(f, 0), mfw[f], mf2[f]
                         mode = ((a^b) | (a^c)) ^ a
                         merge[f] = (m1.get(f, nullid), m2[f], mode)
                         s = 1
                     # are we clobbering?
                     # is remote's version newer?
                     # or are we going back in time?
                     elif force or m2[f] != a or (p2 == pa and mw[f] == m1[f]):
                         self.ui.debug(" remote %s is newer, get\n" % f)
                         get[f] = m2[f]
                         s = 1
                     else:
                         mark[f] = 1
                 elif f in umap:
                     # this unknown file is the same as the checkout
                     get[f] = m2[f]
 
                 if not s and mfw[f] != mf2[f]:
                     if force:
                         self.ui.debug(" updating permissions for %s\n" % f)
                         util.set_exec(self.wjoin(f), mf2[f])
                     else:
                         a, b, c = mfa.get(f, 0), mfw[f], mf2[f]
                         mode = ((a^b) | (a^c)) ^ a
                         if mode != b:
                             self.ui.debug(" updating permissions for %s\n" % f)
                             util.set_exec(self.wjoin(f), mode)
                             mark[f] = 1
                 del m2[f]
             elif f in ma:
                 if n != ma[f]:
                     r = "d"
                     if not force and (linear_path or allow):
                         r = self.ui.prompt(
                             (" local changed %s which remote deleted\n" % f) +
                             "(k)eep or (d)elete?", "[kd]", "k")
                     if r == "d":
                         remove.append(f)
                 else:
                     self.ui.debug("other deleted %s\n" % f)
                     remove.append(f) # other deleted it
             else:
                 if n == m1.get(f, nullid): # same as parent
                     if p2 == pa: # going backwards?
                         self.ui.debug("remote deleted %s\n" % f)
                         remove.append(f)
                     else:
                         self.ui.debug("local created %s, keeping\n" % f)
                 else:
                     self.ui.debug("working dir created %s, keeping\n" % f)
 
         for f, n in m2.iteritems():
             if choose and not choose(f): continue
             if f[0] == "/": continue
             if f in ma and n != ma[f]:
                 r = "k"
                 if not force and (linear_path or allow):
                     r = self.ui.prompt(
                         ("remote changed %s which local deleted\n" % f) +
                         "(k)eep or (d)elete?", "[kd]", "k")
                 if r == "k": get[f] = n
             elif f not in ma:
                 self.ui.debug("remote created %s\n" % f)
                 get[f] = n
             else:
                 if force or p2 == pa: # going backwards?
                     self.ui.debug("local deleted %s, recreating\n" % f)
                     get[f] = n
                 else:
                     self.ui.debug("local deleted %s\n" % f)
 
         del mw, m1, m2, ma
 
         if force:
             for f in merge:
                 get[f] = merge[f][1]
             merge = {}
 
         if linear_path or force:
             # we don't need to do any magic, just jump to the new rev
             mode = 'n'
             p1, p2 = p2, nullid
         else:
             if not allow:
                 self.ui.status("this update spans a branch" +
                                " affecting the following files:\n")
                 fl = merge.keys() + get.keys()
                 fl.sort()
                 for f in fl:
                     cf = ""
                     if f in merge: cf = " (resolve)"
                     self.ui.status(" %s%s\n" % (f, cf))
                 self.ui.warn("aborting update spanning branches!\n")
                 self.ui.status("(use update -m to merge across branches" +
                                " or -C to lose changes)\n")
                 return 1
-            # we have to remember what files we needed to get/change
-            # because any file that's different from either one of its
-            # parents must be in the changeset
             mode = 'm'
-            if moddirstate:
-                self.dirstate.update(mark.keys(), "m")
 
         if moddirstate:
             self.dirstate.setparents(p1, p2)
 
         # get the files we don't need to change
         files = get.keys()
         files.sort()
         for f in files:
             if f[0] == "/": continue
             self.ui.note("getting %s\n" % f)
             t = self.file(f).read(get[f])
             try:
                 self.wfile(f, "w").write(t)
             except IOError:
                 os.makedirs(os.path.dirname(self.wjoin(f)))
                 self.wfile(f, "w").write(t)
             util.set_exec(self.wjoin(f), mf2[f])
             if moddirstate:
-                self.dirstate.update([f], mode)
+                self.dirstate.update([f], 'n')
 
         # merge the tricky bits
         files = merge.keys()
         files.sort()
         for f in files:
             self.ui.status("merging %s\n" % f)
             m, o, flag = merge[f]
             self.merge3(f, m, o)
             util.set_exec(self.wjoin(f), flag)
             if moddirstate:
                 if mode == 'm':
                     # only update dirstate on branch merge, otherwise we
                     # could mark files with changes as unchanged
                     self.dirstate.update([f], mode)
                 elif p2 == nullid:
                     # update dirstate from parent1's manifest
                     m1n = self.changelog.read(p1)[0]
                     m1 = self.manifest.read(m1n)
                     f_len = len(self.file(f).read(m1[f]))
                     self.dirstate.update([f], mode, st_size=f_len, st_mtime=0)
                 else:
                     self.ui.warn("Second parent without branch merge!?\n"
                                  "Dirstate for file %s may be wrong.\n" % f)
 
         remove.sort()
         for f in remove:
             self.ui.note("removing %s\n" % f)
             try:
                 os.unlink(self.wjoin(f))
             except OSError, inst:
                 self.ui.warn("update failed to remove %s: %s!\n" % (f, inst))
             # try removing directories that might now be empty
             try: os.removedirs(os.path.dirname(self.wjoin(f)))
             except: pass
         if moddirstate:
             if mode == 'n':
                 self.dirstate.forget(remove)
             else:
                 self.dirstate.update(remove, 'r')
 
     def merge3(self, fn, my, other):
         """perform a 3-way merge in the working directory"""
 
         def temp(prefix, node):
             pre = "%s~%s." % (os.path.basename(fn), prefix)
             (fd, name) = tempfile.mkstemp("", pre)
             f = os.fdopen(fd, "wb")
             f.write(fl.revision(node))
             f.close()
             return name
 
         fl = self.file(fn)
         base = fl.ancestor(my, other)
         a = self.wjoin(fn)
         b = temp("base", base)
         c = temp("other", other)
 
         self.ui.note("resolving %s\n" % fn)
         self.ui.debug("file %s: other %s ancestor %s\n" %
                               (fn, short(other), short(base)))
 
         cmd = (os.environ.get("HGMERGE") or self.ui.config("ui", "merge")
                or "hgmerge")
         r = os.system("%s %s %s %s" % (cmd, a, b, c))
         if r:
             self.ui.warn("merging %s failed!\n" % fn)
 
         os.unlink(b)
         os.unlink(c)
 
     def verify(self):
         filelinkrevs = {}
         filenodes = {}
         changesets = revisions = files = 0
         errors = 0
 
         seen = {}
         self.ui.status("checking changesets\n")
         for i in range(self.changelog.count()):
             changesets += 1
             n = self.changelog.node(i)
             if n in seen:
                 self.ui.warn("duplicate changeset at revision %d\n" % i)
                 errors += 1
             seen[n] = 1
 
             for p in self.changelog.parents(n):
                 if p not in self.changelog.nodemap:
                     self.ui.warn("changeset %s has unknown parent %s\n" %
                                  (short(n), short(p)))
                     errors += 1
             try:
                 changes = self.changelog.read(n)
             except Exception, inst:
                 self.ui.warn("unpacking changeset %s: %s\n" % (short(n), inst))
                 errors += 1
 
             for f in changes[3]:
                 filelinkrevs.setdefault(f, []).append(i)
 
         seen = {}
         self.ui.status("checking manifests\n")
         for i in range(self.manifest.count()):
             n = self.manifest.node(i)
             if n in seen:
                 self.ui.warn("duplicate manifest at revision %d\n" % i)
                 errors += 1
             seen[n] = 1
 
             for p in self.manifest.parents(n):
                 if p not in self.manifest.nodemap:
                     self.ui.warn("manifest %s has unknown parent %s\n" %
                             (short(n), short(p)))
                     errors += 1
 
             try:
                 delta = mdiff.patchtext(self.manifest.delta(n))
             except KeyboardInterrupt:
                 self.ui.warn("aborted")
                 sys.exit(0)
             except Exception, inst:
                 self.ui.warn("unpacking manifest %s: %s\n"
                              % (short(n), inst))
                 errors += 1
 
             ff = [ l.split('\0') for l in delta.splitlines() ]
             for f, fn in ff:
                 filenodes.setdefault(f, {})[bin(fn[:40])] = 1
 
         self.ui.status("crosschecking files in changesets and manifests\n")
         for f in filenodes:
             if f not in filelinkrevs:
                 self.ui.warn("file %s in manifest but not in changesets\n" % f)
                 errors += 1
 
         for f in filelinkrevs:
             if f not in filenodes:
                 self.ui.warn("file %s in changeset but not in manifest\n" % f)
                 errors += 1
 
         self.ui.status("checking files\n")
         ff = filenodes.keys()
         ff.sort()
         for f in ff:
             if f == "/dev/null": continue
             files += 1
             fl = self.file(f)
             nodes = { nullid: 1 }
             seen = {}
             for i in range(fl.count()):
                 revisions += 1
                 n = fl.node(i)
 
                 if n in seen:
                     self.ui.warn("%s: duplicate revision %d\n" % (f, i))
                     errors += 1
 
                 if n not in filenodes[f]:
                     self.ui.warn("%s: %d:%s not in manifests\n"
                                  % (f, i, short(n)))
                     errors += 1
                 else:
                     del filenodes[f][n]
 
                 flr = fl.linkrev(n)
                 if flr not in filelinkrevs[f]:
                     self.ui.warn("%s:%s points to unexpected changeset %d\n"
                             % (f, short(n), fl.linkrev(n)))
                     errors += 1
                 else:
                     filelinkrevs[f].remove(flr)
 
                 # verify contents
                 try:
                     t = fl.read(n)
                 except Exception, inst:
                     self.ui.warn("unpacking file %s %s: %s\n"
                                  % (f, short(n), inst))
                     errors += 1
 
                 # verify parents
                 (p1, p2) = fl.parents(n)
                 if p1 not in nodes:
                     self.ui.warn("file %s:%s unknown parent 1 %s" %
                             (f, short(n), short(p1)))
                     errors += 1
                 if p2 not in nodes:
                     self.ui.warn("file %s:%s unknown parent 2 %s" %
                             (f, short(n), short(p1)))
                     errors += 1
                 nodes[n] = 1
 
             # cross-check
             for node in filenodes[f]:
                 self.ui.warn("node %s in manifests not in %s\n"
                              % (hex(node), f))
                 errors += 1
 
         self.ui.status("%d files, %d changesets, %d total revisions\n" %
                        (files, changesets, revisions))
 
         if errors:
             self.ui.warn("%d integrity errors encountered!\n" % errors)
             return 1
 
 class remoterepository:
     def local(self):
         return False
 
 class httprepository(remoterepository):
     def __init__(self, ui, path):
         # fix missing / after hostname
         s = urlparse.urlsplit(path)
         partial = s[2]
         if not partial: partial = "/"
         self.url = urlparse.urlunsplit((s[0], s[1], partial, '', ''))
         self.ui = ui
         no_list = [ "localhost", "127.0.0.1" ]
         host = ui.config("http_proxy", "host")
         if host is None:
             host = os.environ.get("http_proxy")
         if host and host.startswith('http://'):
             host = host[7:]
         user = ui.config("http_proxy", "user")
         passwd = ui.config("http_proxy", "passwd")
         no = ui.config("http_proxy", "no")
         if no is None:
             no = os.environ.get("no_proxy")
         if no:
             no_list = no_list + no.split(",")
 
         no_proxy = 0
         for h in no_list:
             if (path.startswith("http://" + h + "/") or
                 path.startswith("http://" + h + ":") or
                 path == "http://" + h):
                 no_proxy = 1
 
         # Note: urllib2 takes proxy values from the environment and those will
         # take precedence
         for env in ["HTTP_PROXY", "http_proxy", "no_proxy"]:
             try:
                 if os.environ.has_key(env):
                     del os.environ[env]
             except OSError:
                 pass
 
         proxy_handler = urllib2.BaseHandler()
         if host and not no_proxy:
             proxy_handler = urllib2.ProxyHandler({"http" : "http://" + host})
 
         authinfo = None
         if user and passwd:
             passmgr = urllib2.HTTPPasswordMgrWithDefaultRealm()
             passmgr.add_password(None, host, user, passwd)
             authinfo = urllib2.ProxyBasicAuthHandler(passmgr)
 
         opener = urllib2.build_opener(proxy_handler, authinfo)
         urllib2.install_opener(opener)
 
     def dev(self):
         return -1
 
     def do_cmd(self, cmd, **args):
         self.ui.debug("sending %s command\n" % cmd)
         q = {"cmd": cmd}
         q.update(args)
         qs = urllib.urlencode(q)
         cu = "%s?%s" % (self.url, qs)
         resp = urllib2.urlopen(cu)
         proto = resp.headers['content-type']
 
         # accept old "text/plain" and "application/hg-changegroup" for now
         if not proto.startswith('application/mercurial') and \
                not proto.startswith('text/plain') and \
                not proto.startswith('application/hg-changegroup'):
             raise RepoError("'%s' does not appear to be an hg repository"
                             % self.url)
 
         if proto.startswith('application/mercurial'):
             version = proto[22:]
             if float(version) > 0.1:
                 raise RepoError("'%s' uses newer protocol %s" %
                                 (self.url, version))
 
         return resp
 
     def heads(self):
         d = self.do_cmd("heads").read()
         try:
             return map(bin, d[:-1].split(" "))
         except:
             self.ui.warn("unexpected response:\n" + d[:400] + "\n...\n")
             raise
 
     def branches(self, nodes):
         n = " ".join(map(hex, nodes))
         d = self.do_cmd("branches", nodes=n).read()
         try:
             br = [ tuple(map(bin, b.split(" "))) for b in d.splitlines() ]
             return br
         except:
             self.ui.warn("unexpected response:\n" + d[:400] + "\n...\n")
             raise
 
     def between(self, pairs):
         n = "\n".join(["-".join(map(hex, p)) for p in pairs])
         d = self.do_cmd("between", pairs=n).read()
         try:
             p = [ l and map(bin, l.split(" ")) or [] for l in d.splitlines() ]
             return p
         except:
             self.ui.warn("unexpected response:\n" + d[:400] + "\n...\n")
             raise
 
     def changegroup(self, nodes):
         n = " ".join(map(hex, nodes))
         f = self.do_cmd("changegroup", roots=n)
         bytes = 0
 
         class zread:
             def __init__(self, f):
                 self.zd = zlib.decompressobj()
                 self.f = f
                 self.buf = ""
             def read(self, l):
                 while l > len(self.buf):
                     r = self.f.read(4096)
                     if r:
                         self.buf += self.zd.decompress(r)
                     else:
                         self.buf += self.zd.flush()
                         break
                 d, self.buf = self.buf[:l], self.buf[l:]
                 return d
 
         return zread(f)
 
 class remotelock:
     def __init__(self, repo):
         self.repo = repo
     def release(self):
         self.repo.unlock()
         self.repo = None
     def __del__(self):
         if self.repo:
             self.release()
 
 class sshrepository(remoterepository):
     def __init__(self, ui, path):
         self.url = path
         self.ui = ui
 
         m = re.match(r'ssh://(([^@]+)@)?([^:/]+)(:(\d+))?(/(.*))', path)
         if not m:
             raise RepoError("couldn't parse destination %s" % path)
 
         self.user = m.group(2)
         self.host = m.group(3)
         self.port = m.group(5)
         self.path = m.group(7)
 
         args = self.user and ("%s@%s" % (self.user, self.host)) or self.host
         args = self.port and ("%s -p %s") % (args, self.port) or args
         path = self.path or ""
 
         if not path:
             raise RepoError("no remote repository path specified")
 
         sshcmd = self.ui.config("ui", "ssh", "ssh")
         remotecmd = self.ui.config("ui", "remotecmd", "hg")
         cmd = "%s %s '%s -R %s serve --stdio'"
         cmd = cmd % (sshcmd, args, remotecmd, path)
 
         self.pipeo, self.pipei, self.pipee = os.popen3(cmd)
 
     def readerr(self):
         while 1:
             r,w,x = select.select([self.pipee], [], [], 0)
             if not r: break
             l = self.pipee.readline()
             if not l: break
             self.ui.status("remote: ", l)
 
     def __del__(self):
         try:
             self.pipeo.close()
             self.pipei.close()
             for l in self.pipee:
                 self.ui.status("remote: ", l)
             self.pipee.close()
         except:
             pass
 
     def dev(self):
         return -1
 
     def do_cmd(self, cmd, **args):
         self.ui.debug("sending %s command\n" % cmd)
         self.pipeo.write("%s\n" % cmd)
         for k, v in args.items():
             self.pipeo.write("%s %d\n" % (k, len(v)))
             self.pipeo.write(v)
         self.pipeo.flush()
 
         return self.pipei
 
     def call(self, cmd, **args):
         r = self.do_cmd(cmd, **args)
         l = r.readline()
         self.readerr()
         try:
             l = int(l)
         except:
             raise RepoError("unexpected response '%s'" % l)
         return r.read(l)
 
     def lock(self):
         self.call("lock")
         return remotelock(self)
 
     def unlock(self):
         self.call("unlock")
 
     def heads(self):
         d = self.call("heads")
         try:
             return map(bin, d[:-1].split(" "))
         except:
             raise RepoError("unexpected response '%s'" % (d[:400] + "..."))
 
     def branches(self, nodes):
         n = " ".join(map(hex, nodes))
         d = self.call("branches", nodes=n)
         try:
             br = [ tuple(map(bin, b.split(" "))) for b in d.splitlines() ]
             return br
         except:
             raise RepoError("unexpected response '%s'" % (d[:400] + "..."))
 
     def between(self, pairs):
         n = "\n".join(["-".join(map(hex, p)) for p in pairs])
         d = self.call("between", pairs=n)
         try:
             p = [ l and map(bin, l.split(" ")) or [] for l in d.splitlines() ]
             return p
         except:
             raise RepoError("unexpected response '%s'" % (d[:400] + "..."))
 
     def changegroup(self, nodes):
         n = " ".join(map(hex, nodes))
         f = self.do_cmd("changegroup", roots=n)
         return self.pipei
 
     def addchangegroup(self, cg):
         d = self.call("addchangegroup")
         if d:
             raise RepoError("push refused: %s", d)
 
         while 1:
             d = cg.read(4096)
             if not d: break
             self.pipeo.write(d)
             self.readerr()
 
         self.pipeo.flush()
 
         self.readerr()
         l = int(self.pipei.readline())
         return self.pipei.read(l) != ""
 
 class httpsrepository(httprepository):
     pass
 
 def repository(ui, path=None, create=0):
     if path:
         if path.startswith("http://"):
             return httprepository(ui, path)
         if path.startswith("https://"):
             return httpsrepository(ui, path)
         if path.startswith("hg://"):
             return httprepository(ui, path.replace("hg://", "http://"))
         if path.startswith("old-http://"):
             return localrepository(ui, path.replace("old-http://", "http://"))
         if path.startswith("ssh://"):
             return sshrepository(ui, path)
 
     return localrepository(ui, path, create)

tests/test-merge6.out

@@ -1,18 +1,18 b''
 pulling from ../B1
 searching for changes
 adding changesets
 adding manifests
 adding file changes
 added 1 changesets with 1 changes to 1 files
 (run 'hg update' to get a working copy)
 bar should remain deleted.
-6b70e9e451a5a33faad7bbebe627e46b937b7364 644 foo
+f405ac83a5611071d6b54dd5eb26943b1fdc4460 644 foo
 pulling from ../A2
 searching for changes
 adding changesets
 adding manifests
 adding file changes
 added 1 changesets with 0 changes to 0 files
 (run 'hg update' to get a working copy)
 bar should remain deleted.
-6b70e9e451a5a33faad7bbebe627e46b937b7364 644 foo
+f9b0e817f6a48de3564c6b2957687c5e7297c5a0 644 foo

tests/test-push-warn.out

@@ -1,21 +1,21 b''
 pushing to ../a
 searching for changes
 abort: unsynced remote changes!
 (did you forget to sync? use push -f to force)
 pulling from ../a
 searching for changes
 adding changesets
 adding manifests
 adding file changes
 added 1 changesets with 1 changes to 1 files
 (run 'hg update' to get a working copy)
 pushing to ../a
 searching for changes
 abort: push creates new remote branches!
 (did you forget to merge? use push -f to force)
 pushing to ../a
 searching for changes
 adding changesets
 adding manifests
 adding file changes
-added 2 changesets with 2 changes to 2 files
+added 2 changesets with 1 changes to 1 files

tests/test-tags.out

@@ -1,15 +1,13 b''
 unknown
 acb14030fe0a tip
 acb14030fe0a21b60322c440ad2d20cf7685a376 first
 tip                                1:b9154636be938d3d431e75a7c906504a079bfe07
 first                              0:acb14030fe0a21b60322c440ad2d20cf7685a376
 b9154636be93 tip
 M a
 b9154636be93+ tip
 acb14030fe0a+ first
 acb14030fe0a21b60322c440ad2d20cf7685a376+ first
 M a
 c8edf04160c7 tip
-c8edf04160c7+b9154636be93+ tip
-M .hgtags
-M a
+c8edf04160c7+b9154636be93 tip