Deprecate merge-recursive.py

This renames merge-recursive written in Python to merge-recursive-old,
and makes merge-recur as a synonym to merge-recursive.  We do not remove
merge-recur yet, but we will remove merge-recur and merge-recursive-old
in a few releases down the road.

Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 944 insertions, 0 deletions

diff --git a/git-merge-recursive-old.py b/git-merge-recursive-old.py
new file mode 100755
index 000000000..4039435ce
--- /dev/null
+++ b/git-merge-recursive-old.py
@@ -0,0 +1,944 @@
+#!/usr/bin/python
+#
+# Copyright (C) 2005 Fredrik Kuivinen
+#
+
+import sys
+sys.path.append('''@@GIT_PYTHON_PATH@@''')
+
+import math, random, os, re, signal, tempfile, stat, errno, traceback
+from heapq import heappush, heappop
+from sets import Set
+
+from gitMergeCommon import *
+
+outputIndent = 0
+def output(*args):
+    sys.stdout.write('  '*outputIndent)
+    printList(args)
+
+originalIndexFile = os.environ.get('GIT_INDEX_FILE',
+                                   os.environ.get('GIT_DIR', '.git') + '/index')
+temporaryIndexFile = os.environ.get('GIT_DIR', '.git') + \
+                     '/merge-recursive-tmp-index'
+def setupIndex(temporary):
+    try:
+        os.unlink(temporaryIndexFile)
+    except OSError:
+        pass
+    if temporary:
+        newIndex = temporaryIndexFile
+    else:
+        newIndex = originalIndexFile
+    os.environ['GIT_INDEX_FILE'] = newIndex
+
+# This is a global variable which is used in a number of places but
+# only written to in the 'merge' function.
+
+# cacheOnly == True  => Don't leave any non-stage 0 entries in the cache and
+#                       don't update the working directory.
+#              False => Leave unmerged entries in the cache and update
+#                       the working directory.
+
+cacheOnly = False
+
+# The entry point to the merge code
+# ---------------------------------
+
+def merge(h1, h2, branch1Name, branch2Name, graph, callDepth=0, ancestor=None):
+    '''Merge the commits h1 and h2, return the resulting virtual
+    commit object and a flag indicating the cleanness of the merge.'''
+    assert(isinstance(h1, Commit) and isinstance(h2, Commit))
+
+    global outputIndent
+
+    output('Merging:')
+    output(h1)
+    output(h2)
+    sys.stdout.flush()
+
+    if ancestor:
+        ca = [ancestor]
+    else:
+        assert(isinstance(graph, Graph))
+        ca = getCommonAncestors(graph, h1, h2)
+    output('found', len(ca), 'common ancestor(s):')
+    for x in ca:
+        output(x)
+    sys.stdout.flush()
+
+    mergedCA = ca[0]
+    for h in ca[1:]:
+        outputIndent = callDepth+1
+        [mergedCA, dummy] = merge(mergedCA, h,
+                                  'Temporary merge branch 1',
+                                  'Temporary merge branch 2',
+                                  graph, callDepth+1)
+        outputIndent = callDepth
+        assert(isinstance(mergedCA, Commit))
+
+    global cacheOnly
+    if callDepth == 0:
+        setupIndex(False)
+        cacheOnly = False
+    else:
+        setupIndex(True)
+        runProgram(['git-read-tree', h1.tree()])
+        cacheOnly = True
+
+    [shaRes, clean] = mergeTrees(h1.tree(), h2.tree(), mergedCA.tree(),
+                                 branch1Name, branch2Name)
+
+    if graph and (clean or cacheOnly):
+        res = Commit(None, [h1, h2], tree=shaRes)
+        graph.addNode(res)
+    else:
+        res = None
+
+    return [res, clean]
+
+getFilesRE = re.compile(r'^([0-7]+) (\S+) ([0-9a-f]{40})\t(.*)$', re.S)
+def getFilesAndDirs(tree):
+    files = Set()
+    dirs = Set()
+    out = runProgram(['git-ls-tree', '-r', '-z', '-t', tree])
+    for l in out.split('\0'):
+        m = getFilesRE.match(l)
+        if m:
+            if m.group(2) == 'tree':
+                dirs.add(m.group(4))
+            elif m.group(2) == 'blob':
+                files.add(m.group(4))
+
+    return [files, dirs]
+
+# Those two global variables are used in a number of places but only
+# written to in 'mergeTrees' and 'uniquePath'. They keep track of
+# every file and directory in the two branches that are about to be
+# merged.
+currentFileSet = None
+currentDirectorySet = None
+
+def mergeTrees(head, merge, common, branch1Name, branch2Name):
+    '''Merge the trees 'head' and 'merge' with the common ancestor
+    'common'. The name of the head branch is 'branch1Name' and the name of
+    the merge branch is 'branch2Name'. Return a tuple (tree, cleanMerge)
+    where tree is the resulting tree and cleanMerge is True iff the
+    merge was clean.'''
+    
+    assert(isSha(head) and isSha(merge) and isSha(common))
+
+    if common == merge:
+        output('Already uptodate!')
+        return [head, True]
+
+    if cacheOnly:
+        updateArg = '-i'
+    else:
+        updateArg = '-u'
+
+    [out, code] = runProgram(['git-read-tree', updateArg, '-m',
+                                common, head, merge], returnCode = True)
+    if code != 0:
+        die('git-read-tree:', out)
+
+    [tree, code] = runProgram('git-write-tree', returnCode=True)
+    tree = tree.rstrip()
+    if code != 0:
+        global currentFileSet, currentDirectorySet
+        [currentFileSet, currentDirectorySet] = getFilesAndDirs(head)
+        [filesM, dirsM] = getFilesAndDirs(merge)
+        currentFileSet.union_update(filesM)
+        currentDirectorySet.union_update(dirsM)
+
+        entries = unmergedCacheEntries()
+        renamesHead =  getRenames(head, common, head, merge, entries)
+        renamesMerge = getRenames(merge, common, head, merge, entries)
+
+        cleanMerge = processRenames(renamesHead, renamesMerge,
+                                    branch1Name, branch2Name)
+        for entry in entries:
+            if entry.processed:
+                continue
+            if not processEntry(entry, branch1Name, branch2Name):
+                cleanMerge = False
+                
+        if cleanMerge or cacheOnly:
+            tree = runProgram('git-write-tree').rstrip()
+        else:
+            tree = None
+    else:
+        cleanMerge = True
+
+    return [tree, cleanMerge]
+
+# Low level file merging, update and removal
+# ------------------------------------------
+
+def mergeFile(oPath, oSha, oMode, aPath, aSha, aMode, bPath, bSha, bMode,
+              branch1Name, branch2Name):
+
+    merge = False
+    clean = True
+
+    if stat.S_IFMT(aMode) != stat.S_IFMT(bMode):
+        clean = False
+        if stat.S_ISREG(aMode):
+            mode = aMode
+            sha = aSha
+        else:
+            mode = bMode
+            sha = bSha
+    else:
+        if aSha != oSha and bSha != oSha:
+            merge = True
+
+        if aMode == oMode:
+            mode = bMode
+        else:
+            mode = aMode
+
+        if aSha == oSha:
+            sha = bSha
+        elif bSha == oSha:
+            sha = aSha
+        elif stat.S_ISREG(aMode):
+            assert(stat.S_ISREG(bMode))
+
+            orig = runProgram(['git-unpack-file', oSha]).rstrip()
+            src1 = runProgram(['git-unpack-file', aSha]).rstrip()
+            src2 = runProgram(['git-unpack-file', bSha]).rstrip()
+            try:
+                [out, code] = runProgram(['merge',
+                                          '-L', branch1Name + '/' + aPath,
+                                          '-L', 'orig/' + oPath,
+                                          '-L', branch2Name + '/' + bPath,
+                                          src1, orig, src2], returnCode=True)
+            except ProgramError, e:
+                print >>sys.stderr, e
+                die("Failed to execute 'merge'. merge(1) is used as the "
+                    "file-level merge tool. Is 'merge' in your path?")
+
+            sha = runProgram(['git-hash-object', '-t', 'blob', '-w',
+                              src1]).rstrip()
+
+            os.unlink(orig)
+            os.unlink(src1)
+            os.unlink(src2)
+
+            clean = (code == 0)
+        else:
+            assert(stat.S_ISLNK(aMode) and stat.S_ISLNK(bMode))
+            sha = aSha
+
+            if aSha != bSha:
+                clean = False
+
+    return [sha, mode, clean, merge]
+
+def updateFile(clean, sha, mode, path):
+    updateCache = cacheOnly or clean
+    updateWd = not cacheOnly
+
+    return updateFileExt(sha, mode, path, updateCache, updateWd)
+
+def updateFileExt(sha, mode, path, updateCache, updateWd):
+    if cacheOnly:
+        updateWd = False
+
+    if updateWd:
+        pathComponents = path.split('/')
+        for x in xrange(1, len(pathComponents)):
+            p = '/'.join(pathComponents[0:x])
+
+            try:
+                createDir = not stat.S_ISDIR(os.lstat(p).st_mode)
+            except OSError:
+                createDir = True
+            
+            if createDir:
+                try:
+                    os.mkdir(p)
+                except OSError, e:
+                    die("Couldn't create directory", p, e.strerror)
+
+        prog = ['git-cat-file', 'blob', sha]
+        if stat.S_ISREG(mode):
+            try:
+                os.unlink(path)
+            except OSError:
+                pass
+            if mode & 0100:
+                mode = 0777
+            else:
+                mode = 0666
+            fd = os.open(path, os.O_WRONLY | os.O_TRUNC | os.O_CREAT, mode)
+            proc = subprocess.Popen(prog, stdout=fd)
+            proc.wait()
+            os.close(fd)
+        elif stat.S_ISLNK(mode):
+            linkTarget = runProgram(prog)
+            os.symlink(linkTarget, path)
+        else:
+            assert(False)
+
+    if updateWd and updateCache:
+        runProgram(['git-update-index', '--add', '--', path])
+    elif updateCache:
+        runProgram(['git-update-index', '--add', '--cacheinfo',
+                    '0%o' % mode, sha, path])
+
+def setIndexStages(path,
+                   oSHA1, oMode,
+                   aSHA1, aMode,
+                   bSHA1, bMode,
+                   clear=True):
+    istring = []
+    if clear:
+        istring.append("0 " + ("0" * 40) + "\t" + path + "\0")
+    if oMode:
+        istring.append("%o %s %d\t%s\0" % (oMode, oSHA1, 1, path))
+    if aMode:
+        istring.append("%o %s %d\t%s\0" % (aMode, aSHA1, 2, path))
+    if bMode:
+        istring.append("%o %s %d\t%s\0" % (bMode, bSHA1, 3, path))
+
+    runProgram(['git-update-index', '-z', '--index-info'],
+               input="".join(istring))
+
+def removeFile(clean, path):
+    updateCache = cacheOnly or clean
+    updateWd = not cacheOnly
+
+    if updateCache:
+        runProgram(['git-update-index', '--force-remove', '--', path])
+
+    if updateWd:
+        try:
+            os.unlink(path)
+        except OSError, e:
+            if e.errno != errno.ENOENT and e.errno != errno.EISDIR:
+                raise
+        try:
+            os.removedirs(os.path.dirname(path))
+        except OSError:
+            pass
+
+def uniquePath(path, branch):
+    def fileExists(path):
+        try:
+            os.lstat(path)
+            return True
+        except OSError, e:
+            if e.errno == errno.ENOENT:
+                return False
+            else:
+                raise
+
+    branch = branch.replace('/', '_')
+    newPath = path + '~' + branch
+    suffix = 0
+    while newPath in currentFileSet or \
+          newPath in currentDirectorySet  or \
+          fileExists(newPath):
+        suffix += 1
+        newPath = path + '~' + branch + '_' + str(suffix)
+    currentFileSet.add(newPath)
+    return newPath
+
+# Cache entry management
+# ----------------------
+
+class CacheEntry:
+    def __init__(self, path):
+        class Stage:
+            def __init__(self):
+                self.sha1 = None
+                self.mode = None
+
+            # Used for debugging only
+            def __str__(self):
+                if self.mode != None:
+                    m = '0%o' % self.mode
+                else:
+                    m = 'None'
+
+                if self.sha1:
+                    sha1 = self.sha1
+                else:
+                    sha1 = 'None'
+                return 'sha1: ' + sha1 + ' mode: ' + m
+        
+        self.stages = [Stage(), Stage(), Stage(), Stage()]
+        self.path = path
+        self.processed = False
+
+    def __str__(self):
+        return 'path: ' + self.path + ' stages: ' + repr([str(x) for x in self.stages])
+
+class CacheEntryContainer:
+    def __init__(self):
+        self.entries = {}
+
+    def add(self, entry):
+        self.entries[entry.path] = entry
+
+    def get(self, path):
+        return self.entries.get(path)
+
+    def __iter__(self):
+        return self.entries.itervalues()
+    
+unmergedRE = re.compile(r'^([0-7]+) ([0-9a-f]{40}) ([1-3])\t(.*)$', re.S)
+def unmergedCacheEntries():
+    '''Create a dictionary mapping file names to CacheEntry
+    objects. The dictionary contains one entry for every path with a
+    non-zero stage entry.'''
+
+    lines = runProgram(['git-ls-files', '-z', '--unmerged']).split('\0')
+    lines.pop()
+
+    res = CacheEntryContainer()
+    for l in lines:
+        m = unmergedRE.match(l)
+        if m:
+            mode = int(m.group(1), 8)
+            sha1 = m.group(2)
+            stage = int(m.group(3))
+            path = m.group(4)
+
+            e = res.get(path)
+            if not e:
+                e = CacheEntry(path)
+                res.add(e)
+
+            e.stages[stage].mode = mode
+            e.stages[stage].sha1 = sha1
+        else:
+            die('Error: Merge program failed: Unexpected output from',
+                'git-ls-files:', l)
+    return res
+
+lsTreeRE = re.compile(r'^([0-7]+) (\S+) ([0-9a-f]{40})\t(.*)\n$', re.S)
+def getCacheEntry(path, origTree, aTree, bTree):
+    '''Returns a CacheEntry object which doesn't have to correspond to
+    a real cache entry in Git's index.'''
+    
+    def parse(out):
+        if out == '':
+            return [None, None]
+        else:
+            m = lsTreeRE.match(out)
+            if not m:
+                die('Unexpected output from git-ls-tree:', out)
+            elif m.group(2) == 'blob':
+                return [m.group(3), int(m.group(1), 8)]
+            else:
+                return [None, None]
+
+    res = CacheEntry(path)
+
+    [oSha, oMode] = parse(runProgram(['git-ls-tree', origTree, '--', path]))
+    [aSha, aMode] = parse(runProgram(['git-ls-tree', aTree, '--', path]))
+    [bSha, bMode] = parse(runProgram(['git-ls-tree', bTree, '--', path]))
+
+    res.stages[1].sha1 = oSha
+    res.stages[1].mode = oMode
+    res.stages[2].sha1 = aSha
+    res.stages[2].mode = aMode
+    res.stages[3].sha1 = bSha
+    res.stages[3].mode = bMode
+
+    return res
+
+# Rename detection and handling
+# -----------------------------
+
+class RenameEntry:
+    def __init__(self,
+                 src, srcSha, srcMode, srcCacheEntry,
+                 dst, dstSha, dstMode, dstCacheEntry,
+                 score):
+        self.srcName = src
+        self.srcSha = srcSha
+        self.srcMode = srcMode
+        self.srcCacheEntry = srcCacheEntry
+        self.dstName = dst
+        self.dstSha = dstSha
+        self.dstMode = dstMode
+        self.dstCacheEntry = dstCacheEntry
+        self.score = score
+
+        self.processed = False
+
+class RenameEntryContainer:
+    def __init__(self):
+        self.entriesSrc = {}
+        self.entriesDst = {}
+
+    def add(self, entry):
+        self.entriesSrc[entry.srcName] = entry
+        self.entriesDst[entry.dstName] = entry
+
+    def getSrc(self, path):
+        return self.entriesSrc.get(path)
+
+    def getDst(self, path):
+        return self.entriesDst.get(path)
+
+    def __iter__(self):
+        return self.entriesSrc.itervalues()
+
+parseDiffRenamesRE = re.compile('^:([0-7]+) ([0-7]+) ([0-9a-f]{40}) ([0-9a-f]{40}) R([0-9]*)$')
+def getRenames(tree, oTree, aTree, bTree, cacheEntries):
+    '''Get information of all renames which occured between 'oTree' and
+    'tree'. We need the three trees in the merge ('oTree', 'aTree' and
+    'bTree') to be able to associate the correct cache entries with
+    the rename information. 'tree' is always equal to either aTree or bTree.'''
+
+    assert(tree == aTree or tree == bTree)
+    inp = runProgram(['git-diff-tree', '-M', '--diff-filter=R', '-r',
+                      '-z', oTree, tree])
+
+    ret = RenameEntryContainer()
+    try:
+        recs = inp.split("\0")
+        recs.pop() # remove last entry (which is '')
+        it = recs.__iter__()
+        while True:
+            rec = it.next()
+            m = parseDiffRenamesRE.match(rec)
+
+            if not m:
+                die('Unexpected output from git-diff-tree:', rec)
+
+            srcMode = int(m.group(1), 8)
+            dstMode = int(m.group(2), 8)
+            srcSha = m.group(3)
+            dstSha = m.group(4)
+            score = m.group(5)
+            src = it.next()
+            dst = it.next()
+
+            srcCacheEntry = cacheEntries.get(src)
+            if not srcCacheEntry:
+                srcCacheEntry = getCacheEntry(src, oTree, aTree, bTree)
+                cacheEntries.add(srcCacheEntry)
+
+            dstCacheEntry = cacheEntries.get(dst)
+            if not dstCacheEntry:
+                dstCacheEntry = getCacheEntry(dst, oTree, aTree, bTree)
+                cacheEntries.add(dstCacheEntry)
+
+            ret.add(RenameEntry(src, srcSha, srcMode, srcCacheEntry,
+                                dst, dstSha, dstMode, dstCacheEntry,
+                                score))
+    except StopIteration:
+        pass
+    return ret
+
+def fmtRename(src, dst):
+    srcPath = src.split('/')
+    dstPath = dst.split('/')
+    path = []
+    endIndex = min(len(srcPath), len(dstPath)) - 1
+    for x in range(0, endIndex):
+        if srcPath[x] == dstPath[x]:
+            path.append(srcPath[x])
+        else:
+            endIndex = x
+            break
+
+    if len(path) > 0:
+        return '/'.join(path) + \
+               '/{' + '/'.join(srcPath[endIndex:]) + ' => ' + \
+               '/'.join(dstPath[endIndex:]) + '}'
+    else:
+        return src + ' => ' + dst
+
+def processRenames(renamesA, renamesB, branchNameA, branchNameB):
+    srcNames = Set()
+    for x in renamesA:
+        srcNames.add(x.srcName)
+    for x in renamesB:
+        srcNames.add(x.srcName)
+
+    cleanMerge = True
+    for path in srcNames:
+        if renamesA.getSrc(path):
+            renames1 = renamesA
+            renames2 = renamesB
+            branchName1 = branchNameA
+            branchName2 = branchNameB
+        else:
+            renames1 = renamesB
+            renames2 = renamesA
+            branchName1 = branchNameB
+            branchName2 = branchNameA
+        
+        ren1 = renames1.getSrc(path)
+        ren2 = renames2.getSrc(path)
+
+        ren1.dstCacheEntry.processed = True
+        ren1.srcCacheEntry.processed = True
+
+        if ren1.processed:
+            continue
+
+        ren1.processed = True
+
+        if ren2:
+            # Renamed in 1 and renamed in 2
+            assert(ren1.srcName == ren2.srcName)
+            ren2.dstCacheEntry.processed = True
+            ren2.processed = True
+
+            if ren1.dstName != ren2.dstName:
+                output('CONFLICT (rename/rename): Rename',
+                       fmtRename(path, ren1.dstName), 'in branch', branchName1,
+                       'rename', fmtRename(path, ren2.dstName), 'in',
+                       branchName2)
+                cleanMerge = False
+
+                if ren1.dstName in currentDirectorySet:
+                    dstName1 = uniquePath(ren1.dstName, branchName1)
+                    output(ren1.dstName, 'is a directory in', branchName2,
+                           'adding as', dstName1, 'instead.')
+                    removeFile(False, ren1.dstName)
+                else:
+                    dstName1 = ren1.dstName
+
+                if ren2.dstName in currentDirectorySet:
+                    dstName2 = uniquePath(ren2.dstName, branchName2)
+                    output(ren2.dstName, 'is a directory in', branchName1,
+                           'adding as', dstName2, 'instead.')
+                    removeFile(False, ren2.dstName)
+                else:
+                    dstName2 = ren2.dstName
+                setIndexStages(dstName1,
+                               None, None,
+                               ren1.dstSha, ren1.dstMode,
+			       None, None)
+                setIndexStages(dstName2,
+                               None, None,
+                               None, None,
+                               ren2.dstSha, ren2.dstMode)
+
+            else:
+                removeFile(True, ren1.srcName)
+
+                [resSha, resMode, clean, merge] = \
+                         mergeFile(ren1.srcName, ren1.srcSha, ren1.srcMode,
+                                   ren1.dstName, ren1.dstSha, ren1.dstMode,
+                                   ren2.dstName, ren2.dstSha, ren2.dstMode,
+                                   branchName1, branchName2)
+
+                if merge or not clean:
+                    output('Renaming', fmtRename(path, ren1.dstName))
+
+                if merge:
+                    output('Auto-merging', ren1.dstName)
+
+                if not clean:
+                    output('CONFLICT (content): merge conflict in',
+                           ren1.dstName)
+                    cleanMerge = False
+
+                    if not cacheOnly:
+                        setIndexStages(ren1.dstName,
+                                       ren1.srcSha, ren1.srcMode,
+                                       ren1.dstSha, ren1.dstMode,
+                                       ren2.dstSha, ren2.dstMode)
+
+                updateFile(clean, resSha, resMode, ren1.dstName)
+        else:
+            removeFile(True, ren1.srcName)
+
+            # Renamed in 1, maybe changed in 2
+            if renamesA == renames1:
+                stage = 3
+            else:
+                stage = 2
+                
+            srcShaOtherBranch  = ren1.srcCacheEntry.stages[stage].sha1
+            srcModeOtherBranch = ren1.srcCacheEntry.stages[stage].mode
+
+            dstShaOtherBranch  = ren1.dstCacheEntry.stages[stage].sha1
+            dstModeOtherBranch = ren1.dstCacheEntry.stages[stage].mode
+
+            tryMerge = False
+            
+            if ren1.dstName in currentDirectorySet:
+                newPath = uniquePath(ren1.dstName, branchName1)
+                output('CONFLICT (rename/directory): Rename',
+                       fmtRename(ren1.srcName, ren1.dstName), 'in', branchName1,
+                       'directory', ren1.dstName, 'added in', branchName2)
+                output('Renaming', ren1.srcName, 'to', newPath, 'instead')
+                cleanMerge = False
+                removeFile(False, ren1.dstName)
+                updateFile(False, ren1.dstSha, ren1.dstMode, newPath)
+            elif srcShaOtherBranch == None:
+                output('CONFLICT (rename/delete): Rename',
+                       fmtRename(ren1.srcName, ren1.dstName), 'in',
+                       branchName1, 'and deleted in', branchName2)
+                cleanMerge = False
+                updateFile(False, ren1.dstSha, ren1.dstMode, ren1.dstName)
+            elif dstShaOtherBranch:
+                newPath = uniquePath(ren1.dstName, branchName2)
+                output('CONFLICT (rename/add): Rename',
+                       fmtRename(ren1.srcName, ren1.dstName), 'in',
+                       branchName1 + '.', ren1.dstName, 'added in', branchName2)
+                output('Adding as', newPath, 'instead')
+                updateFile(False, dstShaOtherBranch, dstModeOtherBranch, newPath)
+                cleanMerge = False
+                tryMerge = True
+            elif renames2.getDst(ren1.dstName):
+                dst2 = renames2.getDst(ren1.dstName)
+                newPath1 = uniquePath(ren1.dstName, branchName1)
+                newPath2 = uniquePath(dst2.dstName, branchName2)
+                output('CONFLICT (rename/rename): Rename',
+                       fmtRename(ren1.srcName, ren1.dstName), 'in',
+                       branchName1+'. Rename',
+                       fmtRename(dst2.srcName, dst2.dstName), 'in', branchName2)
+                output('Renaming', ren1.srcName, 'to', newPath1, 'and',
+                       dst2.srcName, 'to', newPath2, 'instead')
+                removeFile(False, ren1.dstName)
+                updateFile(False, ren1.dstSha, ren1.dstMode, newPath1)
+                updateFile(False, dst2.dstSha, dst2.dstMode, newPath2)
+                dst2.processed = True
+                cleanMerge = False
+            else:
+                tryMerge = True
+
+            if tryMerge:
+
+                oName, oSHA1, oMode = ren1.srcName, ren1.srcSha, ren1.srcMode
+                aName, bName = ren1.dstName, ren1.srcName
+                aSHA1, bSHA1 = ren1.dstSha, srcShaOtherBranch
+                aMode, bMode = ren1.dstMode, srcModeOtherBranch
+                aBranch, bBranch = branchName1, branchName2
+
+                if renamesA != renames1:
+                    aName, bName = bName, aName
+                    aSHA1, bSHA1 = bSHA1, aSHA1
+                    aMode, bMode = bMode, aMode
+                    aBranch, bBranch = bBranch, aBranch
+
+                [resSha, resMode, clean, merge] = \
+                         mergeFile(oName, oSHA1, oMode,
+                                   aName, aSHA1, aMode,
+                                   bName, bSHA1, bMode,
+                                   aBranch, bBranch);
+
+                if merge or not clean:
+                    output('Renaming', fmtRename(ren1.srcName, ren1.dstName))
+
+                if merge:
+                    output('Auto-merging', ren1.dstName)
+
+                if not clean:
+                    output('CONFLICT (rename/modify): Merge conflict in',
+                           ren1.dstName)
+                    cleanMerge = False
+
+                    if not cacheOnly:
+                        setIndexStages(ren1.dstName,
+                                       oSHA1, oMode,
+                                       aSHA1, aMode,
+                                       bSHA1, bMode)
+
+                updateFile(clean, resSha, resMode, ren1.dstName)
+
+    return cleanMerge
+
+# Per entry merge function
+# ------------------------
+
+def processEntry(entry, branch1Name, branch2Name):
+    '''Merge one cache entry.'''
+
+    debug('processing', entry.path, 'clean cache:', cacheOnly)
+
+    cleanMerge = True
+
+    path = entry.path
+    oSha = entry.stages[1].sha1
+    oMode = entry.stages[1].mode
+    aSha = entry.stages[2].sha1
+    aMode = entry.stages[2].mode
+    bSha = entry.stages[3].sha1
+    bMode = entry.stages[3].mode
+
+    assert(oSha == None or isSha(oSha))
+    assert(aSha == None or isSha(aSha))
+    assert(bSha == None or isSha(bSha))
+
+    assert(oMode == None or type(oMode) is int)
+    assert(aMode == None or type(aMode) is int)
+    assert(bMode == None or type(bMode) is int)
+
+    if (oSha and (not aSha or not bSha)):
+    #
+    # Case A: Deleted in one
+    #
+        if (not aSha     and not bSha) or \
+           (aSha == oSha and not bSha) or \
+           (not aSha     and bSha == oSha):
+    # Deleted in both or deleted in one and unchanged in the other
+            if aSha:
+                output('Removing', path)
+            removeFile(True, path)
+        else:
+    # Deleted in one and changed in the other
+            cleanMerge = False
+            if not aSha:
+                output('CONFLICT (delete/modify):', path, 'deleted in',
+                       branch1Name, 'and modified in', branch2Name + '.',
+                       'Version', branch2Name, 'of', path, 'left in tree.')
+                mode = bMode
+                sha = bSha
+            else:
+                output('CONFLICT (modify/delete):', path, 'deleted in',
+                       branch2Name, 'and modified in', branch1Name + '.',
+                       'Version', branch1Name, 'of', path, 'left in tree.')
+                mode = aMode
+                sha = aSha
+
+            updateFile(False, sha, mode, path)
+
+    elif (not oSha and aSha     and not bSha) or \
+         (not oSha and not aSha and bSha):
+    #
+    # Case B: Added in one.
+    #
+        if aSha:
+            addBranch = branch1Name
+            otherBranch = branch2Name
+            mode = aMode
+            sha = aSha
+            conf = 'file/directory'
+        else:
+            addBranch = branch2Name
+            otherBranch = branch1Name
+            mode = bMode
+            sha = bSha
+            conf = 'directory/file'
+    
+        if path in currentDirectorySet:
+            cleanMerge = False
+            newPath = uniquePath(path, addBranch)
+            output('CONFLICT (' + conf + '):',
+                   'There is a directory with name', path, 'in',
+                   otherBranch + '. Adding', path, 'as', newPath)
+
+            removeFile(False, path)
+            updateFile(False, sha, mode, newPath)
+        else:
+            output('Adding', path)
+            updateFile(True, sha, mode, path)
+    
+    elif not oSha and aSha and bSha:
+    #
+    # Case C: Added in both (check for same permissions).
+    #
+        if aSha == bSha:
+            if aMode != bMode:
+                cleanMerge = False
+                output('CONFLICT: File', path,
+                       'added identically in both branches, but permissions',
+                       'conflict', '0%o' % aMode, '->', '0%o' % bMode)
+                output('CONFLICT: adding with permission:', '0%o' % aMode)
+
+                updateFile(False, aSha, aMode, path)
+            else:
+                # This case is handled by git-read-tree
+                assert(False)
+        else:
+            cleanMerge = False
+            newPath1 = uniquePath(path, branch1Name)
+            newPath2 = uniquePath(path, branch2Name)
+            output('CONFLICT (add/add): File', path,
+                   'added non-identically in both branches. Adding as',
+                   newPath1, 'and', newPath2, 'instead.')
+            removeFile(False, path)
+            updateFile(False, aSha, aMode, newPath1)
+            updateFile(False, bSha, bMode, newPath2)
+
+    elif oSha and aSha and bSha:
+    #
+    # case D: Modified in both, but differently.
+    #
+        output('Auto-merging', path)
+        [sha, mode, clean, dummy] = \
+              mergeFile(path, oSha, oMode,
+                        path, aSha, aMode,
+                        path, bSha, bMode,
+                        branch1Name, branch2Name)
+        if clean:
+            updateFile(True, sha, mode, path)
+        else:
+            cleanMerge = False
+            output('CONFLICT (content): Merge conflict in', path)
+
+            if cacheOnly:
+                updateFile(False, sha, mode, path)
+            else:
+                updateFileExt(sha, mode, path, updateCache=False, updateWd=True)
+    else:
+        die("ERROR: Fatal merge failure, shouldn't happen.")
+
+    return cleanMerge
+
+def usage():
+    die('Usage:', sys.argv[0], ' <base>... -- <head> <remote>..')
+
+# main entry point as merge strategy module
+# The first parameters up to -- are merge bases, and the rest are heads.
+
+if len(sys.argv) < 4:
+    usage()
+
+bases = []
+for nextArg in xrange(1, len(sys.argv)):
+    if sys.argv[nextArg] == '--':
+        if len(sys.argv) != nextArg + 3:
+            die('Not handling anything other than two heads merge.')
+        try:
+            h1 = firstBranch = sys.argv[nextArg + 1]
+            h2 = secondBranch = sys.argv[nextArg + 2]
+        except IndexError:
+            usage()
+        break
+    else:
+        bases.append(sys.argv[nextArg])
+
+print 'Merging', h1, 'with', h2
+
+try:
+    h1 = runProgram(['git-rev-parse', '--verify', h1 + '^0']).rstrip()
+    h2 = runProgram(['git-rev-parse', '--verify', h2 + '^0']).rstrip()
+
+    if len(bases) == 1:
+        base = runProgram(['git-rev-parse', '--verify',
+                           bases[0] + '^0']).rstrip()
+        ancestor = Commit(base, None)
+        [dummy, clean] = merge(Commit(h1, None), Commit(h2, None),
+                               firstBranch, secondBranch, None, 0,
+                               ancestor)
+    else:
+        graph = buildGraph([h1, h2])
+        [dummy, clean] = merge(graph.shaMap[h1], graph.shaMap[h2],
+                               firstBranch, secondBranch, graph)
+
+    print ''
+except:
+    if isinstance(sys.exc_info()[1], SystemExit):
+        raise
+    else:
+        traceback.print_exc(None, sys.stderr)
+        sys.exit(2)
+
+if clean:
+    sys.exit(0)
+else:
+    sys.exit(1)