git-commit-vandalism/git-merge-fredrik.py
Junio C Hamano 720d150c48 Add a new merge strategy by Fredrik Kuivinen.
I really wanted to try this out, instead of asking for an adjustment
to the 'git merge' driver and waiting.  For now the new strategy is
called 'fredrik' and not in the list of default strategies to be tried.

The script wants Python 2.4 so this commit also adjusts Debian and RPM
build procecure files.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-09-10 19:46:53 -07:00

427 lines
14 KiB
Python
Executable File

#!/usr/bin/python
import sys, math, random, os, re, signal, tempfile, stat, errno
from heapq import heappush, heappop
from sets import Set
sys.path.append('@@GIT_PYTHON_PATH@@')
from gitMergeCommon import *
alwaysWriteTree = False
# The actual merge code
# ---------------------
def merge(h1, h2, branch1Name, branch2Name, graph, callDepth=0):
'''Merge the commits h1 and h2, return the resulting virtual
commit object and a flag indicating the cleaness of the merge.'''
assert(isinstance(h1, Commit) and isinstance(h2, Commit))
assert(isinstance(graph, Graph))
def infoMsg(*args):
sys.stdout.write(' '*callDepth)
printList(args)
infoMsg('Merging:')
infoMsg(h1)
infoMsg(h2)
sys.stdout.flush()
ca = getCommonAncestors(graph, h1, h2)
infoMsg('found', len(ca), 'common ancestor(s):')
for x in ca:
infoMsg(x)
sys.stdout.flush()
Ms = ca[0]
for h in ca[1:]:
[Ms, ignore] = merge(Ms, h,
'Temporary shared merge branch 1',
'Temporary shared merge branch 2',
graph, callDepth+1)
assert(isinstance(Ms, Commit))
if callDepth == 0:
if len(ca) > 1:
runProgram(['git-read-tree', h1.tree()])
runProgram(['git-update-cache', '-q', '--refresh'])
# Use the original index if we only have one common ancestor
updateWd = True
if alwaysWriteTree:
cleanCache = True
else:
cleanCache = False
else:
runProgram(['git-read-tree', h1.tree()])
updateWd = False
cleanCache = True
[shaRes, clean] = mergeTrees(h1.tree(), h2.tree(), Ms.tree(),
branch1Name, branch2Name,
cleanCache, updateWd)
if clean or alwaysWriteTree:
res = Commit(None, [h1, h2], tree=shaRes)
graph.addNode(res)
else:
res = None
return [res, clean]
getFilesRE = re.compile('([0-9]+) ([a-z0-9]+) ([0-9a-f]{40})\t(.*)')
def getFilesAndDirs(tree):
files = Set()
dirs = Set()
out = runProgram(['git-ls-tree', '-r', '-z', 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]
class CacheEntry:
def __init__(self, path):
class Stage:
def __init__(self):
self.sha1 = None
self.mode = None
self.stages = [Stage(), Stage(), Stage()]
self.path = path
unmergedRE = re.compile('^([0-9]+) ([0-9a-f]{40}) ([1-3])\t(.*)$')
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 = {}
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)) - 1
path = m.group(4)
if res.has_key(path):
e = res[path]
else:
e = CacheEntry(path)
res[path] = e
e.stages[stage].mode = mode
e.stages[stage].sha1 = sha1
else:
print 'Error: Merge program failed: Unexpected output from', \
'git-ls-files:', l
sys.exit(2)
return res
def mergeTrees(head, merge, common, branch1Name, branch2Name,
cleanCache, updateWd):
'''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:
print 'Already uptodate!'
return [head, True]
if updateWd:
updateArg = '-u'
else:
updateArg = '-i'
runProgram(['git-read-tree', updateArg, '-m', common, head, merge])
cleanMerge = True
[tree, code] = runProgram('git-write-tree', returnCode=True)
tree = tree.rstrip()
if code != 0:
[files, dirs] = getFilesAndDirs(head)
[filesM, dirsM] = getFilesAndDirs(merge)
files.union_update(filesM)
dirs.union_update(dirsM)
cleanMerge = True
entries = unmergedCacheEntries()
for name in entries:
if not processEntry(entries[name], branch1Name, branch2Name,
files, dirs, cleanCache, updateWd):
cleanMerge = False
if cleanMerge or cleanCache:
tree = runProgram('git-write-tree').rstrip()
else:
tree = None
else:
cleanMerge = True
return [tree, cleanMerge]
def processEntry(entry, branch1Name, branch2Name, files, dirs,
cleanCache, updateWd):
'''Merge one cache entry. 'files' is a Set with the files in both of
the heads that we are going to merge. 'dirs' contains the
corresponding data for directories. If 'cleanCache' is True no
non-zero stages will be left in the cache for the path
corresponding to the entry 'entry'.'''
# cleanCache == True => Don't leave any non-stage 0 entries in the cache.
# False => Leave unmerged entries
# updateWd == True => Update the working directory to correspond to the cache
# False => Leave the working directory unchanged
# clean == True => non-conflict case
# False => conflict case
# If cleanCache == False then the cache shouldn't be updated if clean == False
def updateFile(clean, sha, mode, path):
if cleanCache or (not cleanCache and clean):
runProgram(['git-update-cache', '--add', '--cacheinfo',
'0%o' % mode, sha, path])
if updateWd:
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)
runProgram(['git-update-cache', '--', path])
def removeFile(clean, path):
if cleanCache or (not cleanCache and clean):
runProgram(['git-update-cache', '--force-remove', '--', path])
if updateWd:
try:
os.unlink(path)
except OSError, e:
if e.errno != errno.ENOENT and e.errno != errno.EISDIR:
raise
def uniquePath(path, branch):
newPath = path + '_' + branch
suffix = 0
while newPath in files or newPath in dirs:
suffix += 1
newPath = path + '_' + branch + '_' + str(suffix)
files.add(newPath)
return newPath
debug('processing', entry.path, 'clean cache:', cleanCache,
'wd:', updateWd)
cleanMerge = True
path = entry.path
oSha = entry.stages[0].sha1
oMode = entry.stages[0].mode
aSha = entry.stages[1].sha1
aMode = entry.stages[1].mode
bSha = entry.stages[2].sha1
bMode = entry.stages[2].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:
print 'Removing ' + path
removeFile(True, path)
else:
# Deleted in one and changed in the other
cleanMerge = False
if not aSha:
print 'CONFLICT (del/mod): "' + path + '" deleted in', \
branch1Name, 'and modified in', branch2Name, \
'. Version', branch2Name, ' of "' + path + \
'" left in tree'
mode = bMode
sha = bSha
else:
print 'CONFLICT (mod/del): "' + 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/dir'
else:
addBranch = branch2Name
otherBranch = branch1Name
mode = bMode
sha = bSha
conf = 'dir/file'
if path in dirs:
cleanMerge = False
newPath = uniquePath(path, addBranch)
print 'CONFLICT (' + conf + \
'): There is a directory with name "' + path + '" in', \
otherBranch + '. Adding "' + path + '" as "' + newPath + '"'
removeFile(False, path)
path = newPath
else:
print '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
print 'CONFLICT: File "' + path + \
'" added identically in both branches,'
print 'CONFLICT: but permissions conflict', '0%o' % aMode, \
'->', '0%o' % bMode
print '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)
print 'CONFLICT (add/add): File "' + path + \
'" added non-identically in both branches.', \
'Adding "' + 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.
#
print 'Auto-merging', path
orig = runProgram(['git-unpack-file', oSha]).rstrip()
src1 = runProgram(['git-unpack-file', aSha]).rstrip()
src2 = runProgram(['git-unpack-file', bSha]).rstrip()
[out, ret] = runProgram(['merge',
'-L', branch1Name + '/' + path,
'-L', 'orig/' + path,
'-L', branch2Name + '/' + path,
src1, orig, src2], returnCode=True)
if aMode == oMode:
mode = bMode
else:
mode = aMode
sha = runProgram(['git-hash-object', '-t', 'blob', '-w',
src1]).rstrip()
if ret != 0:
cleanMerge = False
print 'CONFLICT (content): Merge conflict in "' + path + '".'
updateFile(False, sha, mode, path)
else:
updateFile(True, sha, mode, path)
os.unlink(orig)
os.unlink(src1)
os.unlink(src2)
else:
print 'ERROR: Fatal merge failure.'
print "ERROR: Shouldn't happen"
sys.exit(2)
return cleanMerge
def usage():
print 'Usage:', sys.argv[0], ' <base>... -- <head> <remote>..'
sys.exit(2)
# main entry point as merge strategy module
# The first parameters up to -- are merge bases, and the rest are heads.
# This strategy module figures out merge bases itself, so we only
# get heads.
for nextArg in xrange(1, len(sys.argv)):
if sys.argv[nextArg] == '--':
if len(sys.argv) != nextArg + 3:
print 'Not handling anything other than two heads merge.'
sys.exit(2)
try:
h1 = firstBranch = sys.argv[nextArg + 1]
h2 = secondBranch = sys.argv[nextArg + 2]
except IndexError:
usage()
break
print 'Merging', h1, 'with', h2
h1 = runProgram(['git-rev-parse', '--verify', h1 + '^0']).rstrip()
h2 = runProgram(['git-rev-parse', '--verify', h2 + '^0']).rstrip()
graph = buildGraph([h1, h2])
[res, clean] = merge(graph.shaMap[h1], graph.shaMap[h2],
firstBranch, secondBranch, graph)
print ''
if clean:
sys.exit(0)
else:
print 'Automatic merge failed, fix up by hand'
sys.exit(1)