annotate contrib/synthrepo.py @ 34815:68e0bcb90357

subrepo: share instead of clone if the parent repo is shared (issue5675) (BC)

Previously, only the top level repo was shared, and then any subrepos were
cloned on demand.  This is problematic because commits to the parent repo would
write an updated .hgsubstate to the share source, but the corresponding subrepo
commit would be stuck in the local subrepo.  That would prevent an update in the
source repo.  We already go to great lengths to avoid having inconsistent repos
(e.g., `hg push -r rev` will push _everything_ in a subrepo, even if it isn't
referenced in one of the parent's outgoing commits).  Therefore, this seems like
a bug fix, and there's no option to get the old behavior.  I can't imagine the
previous behavior was useful to anybody.

There shouldn't be an issue with svn, since it is centralized.  Maybe --git-dir
can be used for git subrepos, but I'll leave that to someone more familiar with
git.

An integer was previously being implicitly returned from commands.share(), which
caused dispatch() to start crashing when changing over to returning the shared
repo.  All error paths appear to raise, so this can be hardcoded to success.
The clone command checks for 'is None' in a similar pattern, but since
hg.clone() always returns a tuple, that seems wrong?

.. fix:: Issue 5675

   Creating a share of a repository with a Mercurial subrepository will now
   share the subrepository.

and

.. bc::

   Mercurial subrepositories are now shared instead of cloned when the parent
   repository is shared.  This prevents dangling subrepository references in the
   share source.  Previously shared repositories with cloned subrepositories
   will continue to function unchanged.

# 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),
                            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