view hgext/patchbomb.py @ 26623:5a95fe44121d

clonebundles: support for seeding clones from pre-generated bundles

Cloning can be an expensive operation for servers because the server
generates a bundle from existing repository data at request time. For
a large repository like mozilla-central, this consumes 4+ minutes
of CPU time on the server. It also results in significant network
utilization. Multiplied by hundreds or even thousands of clients and
the ensuing load can result in difficulties scaling the Mercurial server.

Despite generation of bundles being deterministic until the next
changeset is added, the generation of bundles to service a clone request
is not cached. Each clone thus performs redundant work. This is
wasteful.

This patch introduces the "clonebundles" extension and related
client-side functionality to help alleviate this deficiency. The
client-side feature is behind an experimental flag and is not enabled by
default.

It works as follows:

1) Server operator generates a bundle and makes it available on a
   server (likely HTTP).
2) Server operator defines the URL of a bundle file in a
   .hg/clonebundles.manifest file.
3) Client `hg clone`ing sees the server is advertising bundle URLs.
4) Client fetches and applies the advertised bundle.
5) Client performs equivalent of `hg pull` to fetch changes made since
   the bundle was created.

Essentially, the server performs the expensive work of generating a
bundle once and all subsequent clones fetch a static file from
somewhere. Scaling static file serving is a much more manageable
problem than scaling a Python application like Mercurial. Assuming your
repository grows less than 1% per day, the end result is 99+% of CPU
and network load from clones is eliminated, allowing Mercurial servers
to scale more easily. Serving static files also means data can be
transferred to clients as fast as they can consume it, rather than as
fast as servers can generate it. This makes clones faster.

Mozilla has implemented similar functionality of this patch on
hg.mozilla.org using a custom extension. We are hosting bundle files in
Amazon S3 and CloudFront (a CDN) and have successfully offloaded
>1 TB/day in data transfer from hg.mozilla.org, freeing up significant
bandwidth and CPU resources. The positive impact has been stellar and
I believe it has proved its value to be included in Mercurial core. I
feel it is important for the client-side support to be enabled in core
by default because it means that clients will get faster, more reliable
clones and will enable server operators to reduce load without
requiring any client-side configuration changes (assuming clients are
up to date, of course).

The scope of this feature is narrowly and specifically tailored to
cloning, despite "serve pulls from pre-generated bundles" being a valid
and useful feature. I would eventually like for Mercurial servers to
support transferring *all* repository data via statically hosted files.
You could imagine a server that siphons all pushed data to bundle files
and instructs clients to apply a stream of bundles to reconstruct all
repository data. This feature, while useful and powerful, is
significantly more work to implement because it requires the server
component have awareness of discovery and a mapping of which changesets
are in which files. Full, clone bundles, by contrast, are much simpler.

The wire protocol command is named "clonebundles" instead of something
more generic like "staticbundles" to leave the door open for a new, more
powerful and more generic server-side component with minimal backwards
compatibility implications. The name "bundleclone" is used by Mozilla's
extension and would cause problems since there are subtle differences
in Mozilla's extension.

Mozilla's experience with this idea has taught us that some form of
"content negotiation" is required. Not all clients will support all
bundle formats or even URLs (advanced TLS requirements, etc). To ensure
the highest uptake possible, a server needs to advertise multiple
versions of bundles and clients need to be able to choose the most
appropriate from that list one. The "attributes" in each
server-advertised entry facilitate this filtering and sorting. Their
use will become apparent in subsequent patches.

Initial inspiration and credit for the idea of cloning from static files
belongs to Augie Fackler and his "lookaside clone" extension proof of
concept.

# patchbomb.py - sending Mercurial changesets as patch emails
#
#  Copyright 2005-2009 Matt Mackall <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''command to send changesets as (a series of) patch emails

The series is started off with a "[PATCH 0 of N]" introduction, which
describes the series as a whole.

Each patch email has a Subject line of "[PATCH M of N] ...", using the
first line of the changeset description as the subject text. The
message contains two or three body parts:

- The changeset description.
- [Optional] The result of running diffstat on the patch.
- The patch itself, as generated by :hg:`export`.

Each message refers to the first in the series using the In-Reply-To
and References headers, so they will show up as a sequence in threaded
mail and news readers, and in mail archives.

To configure other defaults, add a section like this to your
configuration file::

  [email]
  from = My Name <my@email>
  to = recipient1, recipient2, ...
  cc = cc1, cc2, ...
  bcc = bcc1, bcc2, ...
  reply-to = address1, address2, ...

Use ``[patchbomb]`` as configuration section name if you need to
override global ``[email]`` address settings.

Then you can use the :hg:`email` command to mail a series of
changesets as a patchbomb.

You can also either configure the method option in the email section
to be a sendmail compatible mailer or fill out the [smtp] section so
that the patchbomb extension can automatically send patchbombs
directly from the commandline. See the [email] and [smtp] sections in
hgrc(5) for details.

You can control the default inclusion of an introduction message with the
``patchbomb.intro`` configuration option. The configuration is always
overwritten by command line flags like --intro and --desc::

  [patchbomb]
  intro=auto   # include introduction message if more than 1 patch (default)
  intro=never  # never include an introduction message
  intro=always # always include an introduction message

You can set patchbomb to always ask for confirmation by setting
``patchbomb.confirm`` to true.
'''

import os, errno, socket, tempfile, cStringIO
import email

from mercurial import cmdutil, commands, hg, mail, patch, util, error
from mercurial import scmutil
from mercurial.i18n import _
from mercurial.node import bin

cmdtable = {}
command = cmdutil.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'internal' 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 = 'internal'

def _addpullheader(seq, ctx):
    """Add a header pointing to a public URL where the changeset is available
    """
    repo = ctx.repo()
    # experimental config: patchbomb.publicurl
    # waiting for some logic that check that the changeset are available on the
    # destination before patchbombing anything.
    pullurl = repo.ui.config('patchbomb', 'publicurl')
    if pullurl is not None:
        return ('Available At %s\n'
                '#              hg pull %s -r %s' % (pullurl, pullurl, ctx))
    return None

def uisetup(ui):
    cmdutil.extraexport.append('pullurl')
    cmdutil.extraexportmap['pullurl'] = _addpullheader


def prompt(ui, prompt, default=None, rest=':'):
    if default:
        prompt += ' [%s]' % default
    return ui.prompt(prompt + rest, default)

def introwanted(ui, opts, number):
    '''is an introductory message apparently wanted?'''
    introconfig = ui.config('patchbomb', 'intro', 'auto')
    if opts.get('intro') or opts.get('desc'):
        intro = True
    elif introconfig == 'always':
        intro = True
    elif introconfig == 'never':
        intro = False
    elif introconfig == 'auto':
        intro = 1 < number
    else:
        ui.write_err(_('warning: invalid patchbomb.intro value "%s"\n')
                     % introconfig)
        ui.write_err(_('(should be one of always, never, auto)\n'))
        intro = 1 < number
    return intro

def makepatch(ui, repo, patchlines, opts, _charsets, idx, total, numbered,
              patchname=None):

    desc = []
    node = None
    body = ''

    for line in patchlines:
        if line.startswith('#'):
            if line.startswith('# Node ID'):
                node = line.split()[-1]
            continue
        if line.startswith('diff -r') or line.startswith('diff --git'):
            break
        desc.append(line)

    if not patchname and not node:
        raise ValueError

    if opts.get('attach') and not opts.get('body'):
        body = ('\n'.join(desc[1:]).strip() or
                'Patch subject is complete summary.')
        body += '\n\n\n'

    if opts.get('plain'):
        while patchlines and patchlines[0].startswith('# '):
            patchlines.pop(0)
        if patchlines:
            patchlines.pop(0)
        while patchlines and not patchlines[0].strip():
            patchlines.pop(0)

    ds = patch.diffstat(patchlines, git=opts.get('git'))
    if opts.get('diffstat'):
        body += ds + '\n\n'

    addattachment = opts.get('attach') or opts.get('inline')
    if not addattachment or opts.get('body'):
        body += '\n'.join(patchlines)

    if addattachment:
        msg = email.MIMEMultipart.MIMEMultipart()
        if body:
            msg.attach(mail.mimeencode(ui, body, _charsets, opts.get('test')))
        p = mail.mimetextpatch('\n'.join(patchlines), 'x-patch',
                               opts.get('test'))
        binnode = bin(node)
        # if node is mq patch, it will have the patch file's name as a tag
        if not patchname:
            patchtags = [t for t in repo.nodetags(binnode)
                         if t.endswith('.patch') or t.endswith('.diff')]
            if patchtags:
                patchname = patchtags[0]
            elif total > 1:
                patchname = cmdutil.makefilename(repo, '%b-%n.patch',
                                                 binnode, seqno=idx,
                                                 total=total)
            else:
                patchname = cmdutil.makefilename(repo, '%b.patch', binnode)
        disposition = 'inline'
        if opts.get('attach'):
            disposition = 'attachment'
        p['Content-Disposition'] = disposition + '; filename=' + patchname
        msg.attach(p)
    else:
        msg = mail.mimetextpatch(body, display=opts.get('test'))

    flag = ' '.join(opts.get('flag'))
    if flag:
        flag = ' ' + flag

    subj = desc[0].strip().rstrip('. ')
    if not numbered:
        subj = '[PATCH%s] %s' % (flag, opts.get('subject') or subj)
    else:
        tlen = len(str(total))
        subj = '[PATCH %0*d of %d%s] %s' % (tlen, idx, total, flag, subj)
    msg['Subject'] = mail.headencode(ui, subj, _charsets, opts.get('test'))
    msg['X-Mercurial-Node'] = node
    msg['X-Mercurial-Series-Index'] = '%i' % idx
    msg['X-Mercurial-Series-Total'] = '%i' % total
    return msg, subj, ds

def _getpatches(repo, revs, **opts):
    """return a list of patches for a list of revisions

    Each patch in the list is itself a list of lines.
    """
    ui = repo.ui
    prev = repo['.'].rev()
    for r in revs:
        if r == prev and (repo[None].files() or repo[None].deleted()):
            ui.warn(_('warning: working directory has '
                      'uncommitted changes\n'))
        output = cStringIO.StringIO()
        cmdutil.export(repo, [r], fp=output,
                     opts=patch.difffeatureopts(ui, opts, git=True))
        yield output.getvalue().split('\n')
def _getbundle(repo, dest, **opts):
    """return a bundle containing changesets missing in "dest"

    The `opts` keyword-arguments are the same as the one accepted by the
    `bundle` command.

    The bundle is a returned as a single in-memory binary blob.
    """
    ui = repo.ui
    tmpdir = tempfile.mkdtemp(prefix='hg-email-bundle-')
    tmpfn = os.path.join(tmpdir, 'bundle')
    btype = ui.config('patchbomb', 'bundletype')
    if btype:
        opts['type'] = btype
    try:
        commands.bundle(ui, repo, tmpfn, dest, **opts)
        fp = open(tmpfn, 'rb')
        data = fp.read()
        fp.close()
        return data
    finally:
        try:
            os.unlink(tmpfn)
        except OSError:
            pass
        os.rmdir(tmpdir)

def _getdescription(repo, defaultbody, sender, **opts):
    """obtain the body of the introduction message and return it

    This is also used for the body of email with an attached bundle.

    The body can be obtained either from the command line option or entered by
    the user through the editor.
    """
    ui = repo.ui
    if opts.get('desc'):
        body = open(opts.get('desc')).read()
    else:
        ui.write(_('\nWrite the introductory message for the '
                   'patch series.\n\n'))
        body = ui.edit(defaultbody, sender)
        # Save series description in case sendmail fails
        msgfile = repo.vfs('last-email.txt', 'wb')
        msgfile.write(body)
        msgfile.close()
    return body

def _getbundlemsgs(repo, sender, bundle, **opts):
    """Get the full email for sending a given bundle

    This function returns a list of "email" tuples (subject, content, None).
    The list is always one message long in that case.
    """
    ui = repo.ui
    _charsets = mail._charsets(ui)
    subj = (opts.get('subject')
            or prompt(ui, 'Subject:', 'A bundle for your repository'))

    body = _getdescription(repo, '', sender, **opts)
    msg = email.MIMEMultipart.MIMEMultipart()
    if body:
        msg.attach(mail.mimeencode(ui, body, _charsets, opts.get('test')))
    datapart = email.MIMEBase.MIMEBase('application', 'x-mercurial-bundle')
    datapart.set_payload(bundle)
    bundlename = '%s.hg' % opts.get('bundlename', 'bundle')
    datapart.add_header('Content-Disposition', 'attachment',
                        filename=bundlename)
    email.Encoders.encode_base64(datapart)
    msg.attach(datapart)
    msg['Subject'] = mail.headencode(ui, subj, _charsets, opts.get('test'))
    return [(msg, subj, None)]

def _makeintro(repo, sender, patches, **opts):
    """make an introduction email, asking the user for content if needed

    email is returned as (subject, body, cumulative-diffstat)"""
    ui = repo.ui
    _charsets = mail._charsets(ui)
    tlen = len(str(len(patches)))

    flag = opts.get('flag') or ''
    if flag:
        flag = ' ' + ' '.join(flag)
    prefix = '[PATCH %0*d of %d%s]' % (tlen, 0, len(patches), flag)

    subj = (opts.get('subject') or
            prompt(ui, '(optional) Subject: ', rest=prefix, default=''))
    if not subj:
        return None         # skip intro if the user doesn't bother

    subj = prefix + ' ' + subj

    body = ''
    if opts.get('diffstat'):
        # generate a cumulative diffstat of the whole patch series
        diffstat = patch.diffstat(sum(patches, []))
        body = '\n' + diffstat
    else:
        diffstat = None

    body = _getdescription(repo, body, sender, **opts)
    msg = mail.mimeencode(ui, body, _charsets, opts.get('test'))
    msg['Subject'] = mail.headencode(ui, subj, _charsets,
                                     opts.get('test'))
    return (msg, subj, diffstat)

def _getpatchmsgs(repo, sender, patches, patchnames=None, **opts):
    """return a list of emails from a list of patches

    This involves introduction message creation if necessary.

    This function returns a list of "email" tuples (subject, content, None).
    """
    ui = repo.ui
    _charsets = mail._charsets(ui)
    msgs = []

    ui.write(_('this patch series consists of %d patches.\n\n')
             % len(patches))

    # build the intro message, or skip it if the user declines
    if introwanted(ui, opts, len(patches)):
        msg = _makeintro(repo, sender, patches, **opts)
        if msg:
            msgs.append(msg)

    # are we going to send more than one message?
    numbered = len(msgs) + len(patches) > 1

    # now generate the actual patch messages
    name = None
    for i, p in enumerate(patches):
        if patchnames:
            name = patchnames[i]
        msg = makepatch(ui, repo, p, opts, _charsets, i + 1,
                        len(patches), numbered, name)
        msgs.append(msg)

    return msgs

def _getoutgoing(repo, dest, revs):
    '''Return the revisions present locally but not in dest'''
    ui = repo.ui
    url = ui.expandpath(dest or 'default-push', dest or 'default')
    url = hg.parseurl(url)[0]
    ui.status(_('comparing with %s\n') % util.hidepassword(url))

    revs = [r for r in revs if r >= 0]
    if not revs:
        revs = [len(repo) - 1]
    revs = repo.revs('outgoing(%s) and ::%ld', dest or '', revs)
    if not revs:
        ui.status(_("no changes found\n"))
    return revs

emailopts = [
    ('', 'body', None, _('send patches as inline message text (default)')),
    ('a', 'attach', None, _('send patches as attachments')),
    ('i', 'inline', None, _('send patches as inline attachments')),
    ('', 'bcc', [], _('email addresses of blind carbon copy recipients')),
    ('c', 'cc', [], _('email addresses of copy recipients')),
    ('', 'confirm', None, _('ask for confirmation before sending')),
    ('d', 'diffstat', None, _('add diffstat output to messages')),
    ('', 'date', '', _('use the given date as the sending date')),
    ('', 'desc', '', _('use the given file as the series description')),
    ('f', 'from', '', _('email address of sender')),
    ('n', 'test', None, _('print messages that would be sent')),
    ('m', 'mbox', '', _('write messages to mbox file instead of sending them')),
    ('', 'reply-to', [], _('email addresses replies should be sent to')),
    ('s', 'subject', '', _('subject of first message (intro or single patch)')),
    ('', 'in-reply-to', '', _('message identifier to reply to')),
    ('', 'flag', [], _('flags to add in subject prefixes')),
    ('t', 'to', [], _('email addresses of recipients'))]

@command('email',
    [('g', 'git', None, _('use git extended diff format')),
    ('', 'plain', None, _('omit hg patch header')),
    ('o', 'outgoing', None,
     _('send changes not found in the target repository')),
    ('b', 'bundle', None, _('send changes not in target as a binary bundle')),
    ('', 'bundlename', 'bundle',
     _('name of the bundle attachment file'), _('NAME')),
    ('r', 'rev', [], _('a revision to send'), _('REV')),
    ('', 'force', None, _('run even when remote repository is unrelated '
       '(with -b/--bundle)')),
    ('', 'base', [], _('a base changeset to specify instead of a destination '
       '(with -b/--bundle)'), _('REV')),
    ('', 'intro', None, _('send an introduction email for a single patch')),
    ] + emailopts + commands.remoteopts,
    _('hg email [OPTION]... [DEST]...'))
def patchbomb(ui, repo, *revs, **opts):
    '''send changesets by email

    By default, diffs are sent in the format generated by
    :hg:`export`, one per message. The series starts with a "[PATCH 0
    of N]" introduction, which describes the series as a whole.

    Each patch email has a Subject line of "[PATCH M of N] ...", using
    the first line of the changeset description as the subject text.
    The message contains two or three parts. First, the changeset
    description.

    With the -d/--diffstat option, if the diffstat program is
    installed, the result of running diffstat on the patch is inserted.

    Finally, the patch itself, as generated by :hg:`export`.

    With the -d/--diffstat or --confirm options, you will be presented
    with a final summary of all messages and asked for confirmation before
    the messages are sent.

    By default the patch is included as text in the email body for
    easy reviewing. Using the -a/--attach option will instead create
    an attachment for the patch. With -i/--inline an inline attachment
    will be created. You can include a patch both as text in the email
    body and as a regular or an inline attachment by combining the
    -a/--attach or -i/--inline with the --body option.

    With -o/--outgoing, emails will be generated for patches not found
    in the destination repository (or only those which are ancestors
    of the specified revisions if any are provided)

    With -b/--bundle, changesets are selected as for --outgoing, but a
    single email containing a binary Mercurial bundle as an attachment
    will be sent. Use the ``patchbomb.bundletype`` config option to
    control the bundle type as with :hg:`bundle --type`.

    With -m/--mbox, instead of previewing each patchbomb message in a
    pager or sending the messages directly, it will create a UNIX
    mailbox file with the patch emails. This mailbox file can be
    previewed with any mail user agent which supports UNIX mbox
    files.

    With -n/--test, all steps will run, but mail will not be sent.
    You will be prompted for an email recipient address, a subject and
    an introductory message describing the patches of your patchbomb.
    Then when all is done, patchbomb messages are displayed. If the
    PAGER environment variable is set, your pager will be fired up once
    for each patchbomb message, so you can verify everything is alright.

    In case email sending fails, you will find a backup of your series
    introductory message in ``.hg/last-email.txt``.

    The default behavior of this command can be customized through
    configuration. (See :hg:`help patchbomb` for details)

    Examples::

      hg email -r 3000          # send patch 3000 only
      hg email -r 3000 -r 3001  # send patches 3000 and 3001
      hg email -r 3000:3005     # send patches 3000 through 3005
      hg email 3000             # send patch 3000 (deprecated)

      hg email -o               # send all patches not in default
      hg email -o DEST          # send all patches not in DEST
      hg email -o -r 3000       # send all ancestors of 3000 not in default
      hg email -o -r 3000 DEST  # send all ancestors of 3000 not in DEST

      hg email -b               # send bundle of all patches not in default
      hg email -b DEST          # send bundle of all patches not in DEST
      hg email -b -r 3000       # bundle of all ancestors of 3000 not in default
      hg email -b -r 3000 DEST  # bundle of all ancestors of 3000 not in DEST

      hg email -o -m mbox &&    # generate an mbox file...
        mutt -R -f mbox         # ... and view it with mutt
      hg email -o -m mbox &&    # generate an mbox file ...
        formail -s sendmail \\   # ... and use formail to send from the mbox
          -bm -t < mbox         # ... using sendmail

    Before using this command, you will need to enable email in your
    hgrc. See the [email] section in hgrc(5) for details.
    '''

    _charsets = mail._charsets(ui)

    bundle = opts.get('bundle')
    date = opts.get('date')
    mbox = opts.get('mbox')
    outgoing = opts.get('outgoing')
    rev = opts.get('rev')
    # internal option used by pbranches
    patches = opts.get('patches')

    if not (opts.get('test') or mbox):
        # really sending
        mail.validateconfig(ui)

    if not (revs or rev or outgoing or bundle or patches):
        raise error.Abort(_('specify at least one changeset with -r or -o'))

    if outgoing and bundle:
        raise error.Abort(_("--outgoing mode always on with --bundle;"
                           " do not re-specify --outgoing"))

    if outgoing or bundle:
        if len(revs) > 1:
            raise error.Abort(_("too many destinations"))
        if revs:
            dest = revs[0]
        else:
            dest = None
        revs = []

    if rev:
        if revs:
            raise error.Abort(_('use only one form to specify the revision'))
        revs = rev

    revs = scmutil.revrange(repo, revs)
    if outgoing:
        revs = _getoutgoing(repo, dest, revs)
    if bundle:
        opts['revs'] = [str(r) for r in revs]

    # start
    if date:
        start_time = util.parsedate(date)
    else:
        start_time = util.makedate()

    def genmsgid(id):
        return '<%s.%s@%s>' % (id[:20], int(start_time[0]), socket.getfqdn())

    # deprecated config: patchbomb.from
    sender = (opts.get('from') or ui.config('email', 'from') or
              ui.config('patchbomb', 'from') or
              prompt(ui, 'From', ui.username()))

    if patches:
        msgs = _getpatchmsgs(repo, sender, patches, opts.get('patchnames'),
                             **opts)
    elif bundle:
        bundledata = _getbundle(repo, dest, **opts)
        bundleopts = opts.copy()
        bundleopts.pop('bundle', None)  # already processed
        msgs = _getbundlemsgs(repo, sender, bundledata, **bundleopts)
    else:
        _patches = list(_getpatches(repo, revs, **opts))
        msgs = _getpatchmsgs(repo, sender, _patches, **opts)

    showaddrs = []

    def getaddrs(header, ask=False, default=None):
        configkey = header.lower()
        opt = header.replace('-', '_').lower()
        addrs = opts.get(opt)
        if addrs:
            showaddrs.append('%s: %s' % (header, ', '.join(addrs)))
            return mail.addrlistencode(ui, addrs, _charsets, opts.get('test'))

        # not on the command line: fallback to config and then maybe ask
        addr = (ui.config('email', configkey) or
                ui.config('patchbomb', configkey) or
                '')
        if not addr and ask:
            addr = prompt(ui, header, default=default)
        if addr:
            showaddrs.append('%s: %s' % (header, addr))
            return mail.addrlistencode(ui, [addr], _charsets, opts.get('test'))
        else:
            return default

    to = getaddrs('To', ask=True)
    if not to:
        # we can get here in non-interactive mode
        raise error.Abort(_('no recipient addresses provided'))
    cc = getaddrs('Cc', ask=True, default='') or []
    bcc = getaddrs('Bcc') or []
    replyto = getaddrs('Reply-To')

    confirm = ui.configbool('patchbomb', 'confirm')
    confirm |= bool(opts.get('diffstat') or opts.get('confirm'))

    if confirm:
        ui.write(_('\nFinal summary:\n\n'), label='patchbomb.finalsummary')
        ui.write(('From: %s\n' % sender), label='patchbomb.from')
        for addr in showaddrs:
            ui.write('%s\n' % addr, label='patchbomb.to')
        for m, subj, ds in msgs:
            ui.write(('Subject: %s\n' % subj), label='patchbomb.subject')
            if ds:
                ui.write(ds, label='patchbomb.diffstats')
        ui.write('\n')
        if ui.promptchoice(_('are you sure you want to send (yn)?'
                             '$$ &Yes $$ &No')):
            raise error.Abort(_('patchbomb canceled'))

    ui.write('\n')

    parent = opts.get('in_reply_to') or None
    # angle brackets may be omitted, they're not semantically part of the msg-id
    if parent is not None:
        if not parent.startswith('<'):
            parent = '<' + parent
        if not parent.endswith('>'):
            parent += '>'

    sender_addr = email.Utils.parseaddr(sender)[1]
    sender = mail.addressencode(ui, sender, _charsets, opts.get('test'))
    sendmail = None
    firstpatch = None
    for i, (m, subj, ds) in enumerate(msgs):
        try:
            m['Message-Id'] = genmsgid(m['X-Mercurial-Node'])
            if not firstpatch:
                firstpatch = m['Message-Id']
            m['X-Mercurial-Series-Id'] = firstpatch
        except TypeError:
            m['Message-Id'] = genmsgid('patchbomb')
        if parent:
            m['In-Reply-To'] = parent
            m['References'] = parent
        if not parent or 'X-Mercurial-Node' not in m:
            parent = m['Message-Id']

        m['User-Agent'] = 'Mercurial-patchbomb/%s' % util.version()
        m['Date'] = email.Utils.formatdate(start_time[0], localtime=True)

        start_time = (start_time[0] + 1, start_time[1])
        m['From'] = sender
        m['To'] = ', '.join(to)
        if cc:
            m['Cc']  = ', '.join(cc)
        if bcc:
            m['Bcc'] = ', '.join(bcc)
        if replyto:
            m['Reply-To'] = ', '.join(replyto)
        if opts.get('test'):
            ui.status(_('displaying '), subj, ' ...\n')
            ui.flush()
            if 'PAGER' in os.environ and not ui.plain():
                fp = util.popen(os.environ['PAGER'], 'w')
            else:
                fp = ui
            generator = email.Generator.Generator(fp, mangle_from_=False)
            try:
                generator.flatten(m, 0)
                fp.write('\n')
            except IOError as inst:
                if inst.errno != errno.EPIPE:
                    raise
            if fp is not ui:
                fp.close()
        else:
            if not sendmail:
                verifycert = ui.config('smtp', 'verifycert', 'strict')
                if opts.get('insecure'):
                    ui.setconfig('smtp', 'verifycert', 'loose', 'patchbomb')
                try:
                    sendmail = mail.connect(ui, mbox=mbox)
                finally:
                    ui.setconfig('smtp', 'verifycert', verifycert, 'patchbomb')
            ui.status(_('sending '), subj, ' ...\n')
            ui.progress(_('sending'), i, item=subj, total=len(msgs))
            if not mbox:
                # Exim does not remove the Bcc field
                del m['Bcc']
            fp = cStringIO.StringIO()
            generator = email.Generator.Generator(fp, mangle_from_=False)
            generator.flatten(m, 0)
            sendmail(sender_addr, to + bcc + cc, fp.getvalue())

    ui.progress(_('writing'), None)
    ui.progress(_('sending'), None)