# synthrepo.py - repo synthesis
#
# Copyright 2012 Facebook
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
'''synthesize structurally interesting change history
This extension is useful for creating a repository with properties
that are statistically similar to an existing repository. During
analysis, a simple probability table is constructed from the history
of an existing repository. During synthesis, these properties are
reconstructed.
Properties that are analyzed and synthesized include the following:
- Lines added or removed when an existing file is modified
- Number and sizes of files added
- Number of files removed
- Line lengths
- Topological distance to parent changeset(s)
- Probability of a commit being a merge
- Probability of a newly added file being added to a new directory
- Interarrival time, and time zone, of commits
- Number of files in each directory
A few obvious properties that are not currently handled realistically:
- Merges are treated as regular commits with two parents, which is not
realistic
- Modifications are not treated as operations on hunks of lines, but
as insertions and deletions of randomly chosen single lines
- Committer ID (always random)
- Executability of files
- Symlinks and binary files are ignored
'''
from __future__ import absolute_import
import bisect
import collections
import itertools
import json
import os
import random
import sys
import time
from mercurial.i18n import _
from mercurial.node import (
nullid,
nullrev,
short,
)
from mercurial import (
context,
error,
hg,
patch,
registrar,
scmutil,
util,
)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'
cmdtable = {}
command = registrar.command(cmdtable)
newfile = {'new fi', 'rename', 'copy f', 'copy t'}
def zerodict():
return collections.defaultdict(lambda: 0)
def roundto(x, k):
if x > k * 2:
return int(round(x / float(k)) * k)
return int(round(x))
def parsegitdiff(lines):
filename, mar, lineadd, lineremove = None, None, zerodict(), 0
binary = False
for line in lines:
start = line[:6]
if start == 'diff -':
if filename:
yield filename, mar, lineadd, lineremove, binary
mar, lineadd, lineremove, binary = 'm', zerodict(), 0, False
filename = patch.gitre.match(line).group(1)
elif start in newfile:
mar = 'a'
elif start == 'GIT bi':
binary = True
elif start == 'delete':
mar = 'r'
elif start:
s = start[0]
if s == '-' and not line.startswith('--- '):
lineremove += 1
elif s == '+' and not line.startswith('+++ '):
lineadd[roundto(len(line) - 1, 5)] += 1
if filename:
yield filename, mar, lineadd, lineremove, binary
@command('analyze',
[('o', 'output', '', _('write output to given file'), _('FILE')),
('r', 'rev', [], _('analyze specified revisions'), _('REV'))],
_('hg analyze'), optionalrepo=True)
def analyze(ui, repo, *revs, **opts):
'''create a simple model of a repository to use for later synthesis
This command examines every changeset in the given range (or all
of history if none are specified) and creates a simple statistical
model of the history of the repository. It also measures the directory
structure of the repository as checked out.
The model is written out to a JSON file, and can be used by
:hg:`synthesize` to create or augment a repository with synthetic
commits that have a structure that is statistically similar to the
analyzed repository.
'''
root = repo.root
if not root.endswith(os.path.sep):
root += os.path.sep
revs = list(revs)
revs.extend(opts['rev'])
if not revs:
revs = [':']
output = opts['output']
if not output:
output = os.path.basename(root) + '.json'
if output == '-':
fp = sys.stdout
else:
fp = open(output, 'w')
# Always obtain file counts of each directory in the given root directory.
def onerror(e):
ui.warn(_('error walking directory structure: %s\n') % e)
dirs = {}
rootprefixlen = len(root)
for dirpath, dirnames, filenames in os.walk(root, onerror=onerror):
dirpathfromroot = dirpath[rootprefixlen:]
dirs[dirpathfromroot] = len(filenames)
if '.hg' in dirnames:
dirnames.remove('.hg')
lineschanged = zerodict()
children = zerodict()
p1distance = zerodict()
p2distance = zerodict()
linesinfilesadded = zerodict()
fileschanged = zerodict()
filesadded = zerodict()
filesremoved = zerodict()
linelengths = zerodict()
interarrival = zerodict()
parents = zerodict()
dirsadded = zerodict()
tzoffset = zerodict()
# If a mercurial repo is available, also model the commit history.
if repo:
revs = scmutil.revrange(repo, revs)
revs.sort()
progress = ui.progress
_analyzing = _('analyzing')
_changesets = _('changesets')
_total = len(revs)
for i, rev in enumerate(revs):
progress(_analyzing, i, unit=_changesets, total=_total)
ctx = repo[rev]
pl = ctx.parents()
pctx = pl[0]
prev = pctx.rev()
children[prev] += 1
p1distance[rev - prev] += 1
parents[len(pl)] += 1
tzoffset[ctx.date()[1]] += 1
if len(pl) > 1:
p2distance[rev - pl[1].rev()] += 1
if prev == rev - 1:
lastctx = pctx
else:
lastctx = repo[rev - 1]
if lastctx.rev() != nullrev:
timedelta = ctx.date()[0] - lastctx.date()[0]
interarrival[roundto(timedelta, 300)] += 1
diff = sum((d.splitlines() for d in ctx.diff(pctx, git=True)), [])
fileadds, diradds, fileremoves, filechanges = 0, 0, 0, 0
for filename, mar, lineadd, lineremove, isbin in parsegitdiff(diff):
if isbin:
continue
added = sum(lineadd.itervalues(), 0)
if mar == 'm':
if added and lineremove:
lineschanged[roundto(added, 5),
roundto(lineremove, 5)] += 1
filechanges += 1
elif mar == 'a':
fileadds += 1
if '/' in filename:
filedir = filename.rsplit('/', 1)[0]
if filedir not in pctx.dirs():
diradds += 1
linesinfilesadded[roundto(added, 5)] += 1
elif mar == 'r':
fileremoves += 1
for length, count in lineadd.iteritems():
linelengths[length] += count
fileschanged[filechanges] += 1
filesadded[fileadds] += 1
dirsadded[diradds] += 1
filesremoved[fileremoves] += 1
invchildren = zerodict()
for rev, count in children.iteritems():
invchildren[count] += 1
if output != '-':
ui.status(_('writing output to %s\n') % output)
def pronk(d):
return sorted(d.iteritems(), key=lambda x: x[1], reverse=True)
json.dump({'revs': len(revs),
'initdirs': pronk(dirs),
'lineschanged': pronk(lineschanged),
'children': pronk(invchildren),
'fileschanged': pronk(fileschanged),
'filesadded': pronk(filesadded),
'linesinfilesadded': pronk(linesinfilesadded),
'dirsadded': pronk(dirsadded),
'filesremoved': pronk(filesremoved),
'linelengths': pronk(linelengths),
'parents': pronk(parents),
'p1distance': pronk(p1distance),
'p2distance': pronk(p2distance),
'interarrival': pronk(interarrival),
'tzoffset': pronk(tzoffset),
},
fp)
fp.close()
@command('synthesize',
[('c', 'count', 0, _('create given number of commits'), _('COUNT')),
('', 'dict', '', _('path to a dictionary of words'), _('FILE')),
('', 'initfiles', 0, _('initial file count to create'), _('COUNT'))],
_('hg synthesize [OPTION].. DESCFILE'))
def synthesize(ui, repo, descpath, **opts):
'''synthesize commits based on a model of an existing repository
The model must have been generated by :hg:`analyze`. Commits will
be generated randomly according to the probabilities described in
the model. If --initfiles is set, the repository will be seeded with
the given number files following the modeled repository's directory
structure.
When synthesizing new content, commit descriptions, and user
names, words will be chosen randomly from a dictionary that is
presumed to contain one word per line. Use --dict to specify the
path to an alternate dictionary to use.
'''
try:
fp = hg.openpath(ui, descpath)
except Exception as err:
raise error.Abort('%s: %s' % (descpath, err[0].strerror))
desc = json.load(fp)
fp.close()
def cdf(l):
if not l:
return [], []
vals, probs = zip(*sorted(l, key=lambda x: x[1], reverse=True))
t = float(sum(probs, 0))
s, cdfs = 0, []
for v in probs:
s += v
cdfs.append(s / t)
return vals, cdfs
lineschanged = cdf(desc['lineschanged'])
fileschanged = cdf(desc['fileschanged'])
filesadded = cdf(desc['filesadded'])
dirsadded = cdf(desc['dirsadded'])
filesremoved = cdf(desc['filesremoved'])
linelengths = cdf(desc['linelengths'])
parents = cdf(desc['parents'])
p1distance = cdf(desc['p1distance'])
p2distance = cdf(desc['p2distance'])
interarrival = cdf(desc['interarrival'])
linesinfilesadded = cdf(desc['linesinfilesadded'])
tzoffset = cdf(desc['tzoffset'])
dictfile = opts.get('dict') or '/usr/share/dict/words'
try:
fp = open(dictfile, 'rU')
except IOError as err:
raise error.Abort('%s: %s' % (dictfile, err.strerror))
words = fp.read().splitlines()
fp.close()
initdirs = {}
if desc['initdirs']:
for k, v in desc['initdirs']:
initdirs[k.encode('utf-8').replace('.hg', '_hg')] = v
initdirs = renamedirs(initdirs, words)
initdirscdf = cdf(initdirs)
def pick(cdf):
return cdf[0][bisect.bisect_left(cdf[1], random.random())]
def pickpath():
return os.path.join(pick(initdirscdf), random.choice(words))
def makeline(minimum=0):
total = max(minimum, pick(linelengths))
c, l = 0, []
while c < total:
w = random.choice(words)
c += len(w) + 1
l.append(w)
return ' '.join(l)
wlock = repo.wlock()
lock = repo.lock()
nevertouch = {'.hgsub', '.hgignore', '.hgtags'}
progress = ui.progress
_synthesizing = _('synthesizing')
_files = _('initial files')
_changesets = _('changesets')
# Synthesize a single initial revision adding files to the repo according
# to the modeled directory structure.
initcount = int(opts['initfiles'])
if initcount and initdirs:
pctx = repo[None].parents()[0]
dirs = set(pctx.dirs())
files = {}
def validpath(path):
# Don't pick filenames which are already directory names.
if path in dirs:
return False
# Don't pick directories which were used as file names.
while path:
if path in files:
return False
path = os.path.dirname(path)
return True
for i in xrange(0, initcount):
ui.progress(_synthesizing, i, unit=_files, total=initcount)
path = pickpath()
while not validpath(path):
path = pickpath()
data = '%s contents\n' % path
files[path] = context.memfilectx(repo, path, data)
dir = os.path.dirname(path)
while dir and dir not in dirs:
dirs.add(dir)
dir = os.path.dirname(dir)
def filectxfn(repo, memctx, path):
return files[path]
ui.progress(_synthesizing, None)
message = 'synthesized wide repo with %d files' % (len(files),)
mc = context.memctx(repo, [pctx.node(), nullid], message,
files.iterkeys(), filectxfn, ui.username(),
'%d %d' % util.makedate())
initnode = mc.commit()
if ui.debugflag:
hexfn = hex
else:
hexfn = short
ui.status(_('added commit %s with %d files\n')
% (hexfn(initnode), len(files)))
# Synthesize incremental revisions to the repository, adding repo depth.
count = int(opts['count'])
heads = set(map(repo.changelog.rev, repo.heads()))
for i in xrange(count):
progress(_synthesizing, i, unit=_changesets, total=count)
node = repo.changelog.node
revs = len(repo)
def pickhead(heads, distance):
if heads:
lheads = sorted(heads)
rev = revs - min(pick(distance), revs)
if rev < lheads[-1]:
rev = lheads[bisect.bisect_left(lheads, rev)]
else:
rev = lheads[-1]
return rev, node(rev)
return nullrev, nullid
r1 = revs - min(pick(p1distance), revs)
p1 = node(r1)
# the number of heads will grow without bound if we use a pure
# model, so artificially constrain their proliferation
toomanyheads = len(heads) > random.randint(1, 20)
if p2distance[0] and (pick(parents) == 2 or toomanyheads):
r2, p2 = pickhead(heads.difference([r1]), p2distance)
else:
r2, p2 = nullrev, nullid
pl = [p1, p2]
pctx = repo[r1]
mf = pctx.manifest()
mfk = mf.keys()
changes = {}
if mfk:
for __ in xrange(pick(fileschanged)):
for __ in xrange(10):
fctx = pctx.filectx(random.choice(mfk))
path = fctx.path()
if not (path in nevertouch or fctx.isbinary() or
'l' in fctx.flags()):
break
lines = fctx.data().splitlines()
add, remove = pick(lineschanged)
for __ in xrange(remove):
if not lines:
break
del lines[random.randrange(0, len(lines))]
for __ in xrange(add):
lines.insert(random.randint(0, len(lines)), makeline())
path = fctx.path()
changes[path] = context.memfilectx(repo, path,
'\n'.join(lines) + '\n')
for __ in xrange(pick(filesremoved)):
path = random.choice(mfk)
for __ in xrange(10):
path = random.choice(mfk)
if path not in changes:
changes[path] = None
break
if filesadded:
dirs = list(pctx.dirs())
dirs.insert(0, '')
for __ in xrange(pick(filesadded)):
pathstr = ''
while pathstr in dirs:
path = [random.choice(dirs)]
if pick(dirsadded):
path.append(random.choice(words))
path.append(random.choice(words))
pathstr = '/'.join(filter(None, path))
data = '\n'.join(makeline()
for __ in xrange(pick(linesinfilesadded))) + '\n'
changes[pathstr] = context.memfilectx(repo, pathstr, data)
def filectxfn(repo, memctx, path):
return changes[path]
if not changes:
continue
if revs:
date = repo['tip'].date()[0] + pick(interarrival)
else:
date = time.time() - (86400 * count)
# dates in mercurial must be positive, fit in 32-bit signed integers.
date = min(0x7fffffff, max(0, date))
user = random.choice(words) + '@' + random.choice(words)
mc = context.memctx(repo, pl, makeline(minimum=2),
sorted(changes.iterkeys()),
filectxfn, user, '%d %d' % (date, pick(tzoffset)))
newnode = mc.commit()
heads.add(repo.changelog.rev(newnode))
heads.discard(r1)
heads.discard(r2)
lock.release()
wlock.release()
def renamedirs(dirs, words):
'''Randomly rename the directory names in the per-dir file count dict.'''
wordgen = itertools.cycle(words)
replacements = {'': ''}
def rename(dirpath):
'''Recursively rename the directory and all path prefixes.
The mapping from path to renamed path is stored for all path prefixes
as in dynamic programming, ensuring linear runtime and consistent
renaming regardless of iteration order through the model.
'''
if dirpath in replacements:
return replacements[dirpath]
head, _ = os.path.split(dirpath)
if head:
head = rename(head)
else:
head = ''
renamed = os.path.join(head, next(wordgen))
replacements[dirpath] = renamed
return renamed
result = []
for dirpath, count in dirs.iteritems():
result.append([rename(dirpath.lstrip(os.sep)), count])
return result