mercurial/mail.py

rebase: exclude descendants of obsoletes w/o a successor in dest (issue5300)

.. feature::

   Let 'hg rebase' avoid content-divergence by skipping obsolete
   changesets (and their descendants) when they are present in the rebase
   set along with one of their successors but none of their successors is
   in destination.

In the following example, when trying to rebase 3:: onto 2, the rebase
will abort with "this rebase will cause divergence from: 4":

    o  7 f
    |
    | o  6 e
    | |
    | o  5 d'
    | |
    x |  4 d (rewritten as 5)
    |/
    o  3 c
    |
    | o  2 x
    | |
    o |  1 b
    |/
    o  0 a

By excluding obsolete changesets without a successor in destination (4
in the example above) and their descendants, we make rebase work in this
case, thus giving:

    o  11 e
    |
    o  10 d'
    |
    o  9 c
    |
    o  8 b
    |
    | o  7 f
    | |
    | | x  6 e (rewritten using rebase as 11)
    | | |
    | | x  5 d' (rewritten using rebase as 10)
    | | |
    | x |  4 d
    | |/
    | x  3 c (rewritten using rebase as 9)
    | |
    o |  2 x
    | |
    | x  1 b (rewritten using rebase as 8)
    |/
    o  0 a

where branch 4:: is left behind while branch 5:: is rebased as expected.

The rationale is that users may not be interested in rebasing orphan
changesets when specifying a rebase set that include them but would
still want "stable" ones to be rebased. Currently, the user is suggested
to allow divergence (but probably does not want it) or they must specify
a rebase set excluding problematic changesets (which might be a bit
cumbersome). The approach proposed here corresponds to "Option 2" in
https://www.mercurial-scm.org/wiki/CEDRebase.


We extend _computeobsoletenotrebased() so that it also return a set of
obsolete changesets in rebase set without a successor in destination but
with at least one successor in rebase set. This
'obsoletewithoutsuccessorindestination' is then stored as an attribute
of rebaseruntime and used in _performrebasesubset() to:

* filter out descendants of these changesets from the revisions to
  rebase;
* issue a message about these revisions being skipped.

This only occurs if 'evolution.allowdivergence' option is off and
'rebaseskipobsolete' is on.

# mail.py - mail sending bits for mercurial
#
# Copyright 2006 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import email
import email.charset
import email.header
import email.message
import os
import smtplib
import socket
import time

from .i18n import _
from . import (
    encoding,
    error,
    sslutil,
    util,
)

class STARTTLS(smtplib.SMTP):
    '''Derived class to verify the peer certificate for STARTTLS.

    This class allows to pass any keyword arguments to SSL socket creation.
    '''
    def __init__(self, ui, host=None, **kwargs):
        smtplib.SMTP.__init__(self, **kwargs)
        self._ui = ui
        self._host = host

    def starttls(self, keyfile=None, certfile=None):
        if not self.has_extn("starttls"):
            msg = "STARTTLS extension not supported by server"
            raise smtplib.SMTPException(msg)
        (resp, reply) = self.docmd("STARTTLS")
        if resp == 220:
            self.sock = sslutil.wrapsocket(self.sock, keyfile, certfile,
                                           ui=self._ui,
                                           serverhostname=self._host)
            self.file = smtplib.SSLFakeFile(self.sock)
            self.helo_resp = None
            self.ehlo_resp = None
            self.esmtp_features = {}
            self.does_esmtp = 0
        return (resp, reply)

class SMTPS(smtplib.SMTP):
    '''Derived class to verify the peer certificate for SMTPS.

    This class allows to pass any keyword arguments to SSL socket creation.
    '''
    def __init__(self, ui, keyfile=None, certfile=None, host=None,
                 **kwargs):
        self.keyfile = keyfile
        self.certfile = certfile
        smtplib.SMTP.__init__(self, **kwargs)
        self._host = host
        self.default_port = smtplib.SMTP_SSL_PORT
        self._ui = ui

    def _get_socket(self, host, port, timeout):
        if self.debuglevel > 0:
            self._ui.debug('connect: %r\n' % (host, port))
        new_socket = socket.create_connection((host, port), timeout)
        new_socket = sslutil.wrapsocket(new_socket,
                                        self.keyfile, self.certfile,
                                        ui=self._ui,
                                        serverhostname=self._host)
        self.file = smtplib.SSLFakeFile(new_socket)
        return new_socket

def _smtp(ui):
    '''build an smtp connection and return a function to send mail'''
    local_hostname = ui.config('smtp', 'local_hostname')
    tls = ui.config('smtp', 'tls')
    # backward compatible: when tls = true, we use starttls.
    starttls = tls == 'starttls' or util.parsebool(tls)
    smtps = tls == 'smtps'
    if (starttls or smtps) and not util.safehasattr(socket, 'ssl'):
        raise error.Abort(_("can't use TLS: Python SSL support not installed"))
    mailhost = ui.config('smtp', 'host')
    if not mailhost:
        raise error.Abort(_('smtp.host not configured - cannot send mail'))
    if smtps:
        ui.note(_('(using smtps)\n'))
        s = SMTPS(ui, local_hostname=local_hostname, host=mailhost)
    elif starttls:
        s = STARTTLS(ui, local_hostname=local_hostname, host=mailhost)
    else:
        s = smtplib.SMTP(local_hostname=local_hostname)
    if smtps:
        defaultport = 465
    else:
        defaultport = 25
    mailport = util.getport(ui.config('smtp', 'port', defaultport))
    ui.note(_('sending mail: smtp host %s, port %d\n') %
            (mailhost, mailport))
    s.connect(host=mailhost, port=mailport)
    if starttls:
        ui.note(_('(using starttls)\n'))
        s.ehlo()
        s.starttls()
        s.ehlo()
    if starttls or smtps:
        ui.note(_('(verifying remote certificate)\n'))
        sslutil.validatesocket(s.sock)
    username = ui.config('smtp', 'username')
    password = ui.config('smtp', 'password')
    if username and not password:
        password = ui.getpass()
    if username and password:
        ui.note(_('(authenticating to mail server as %s)\n') %
                  (username))
        try:
            s.login(username, password)
        except smtplib.SMTPException as inst:
            raise error.Abort(inst)

    def send(sender, recipients, msg):
        try:
            return s.sendmail(sender, recipients, msg)
        except smtplib.SMTPRecipientsRefused as inst:
            recipients = [r[1] for r in inst.recipients.values()]
            raise error.Abort('\n' + '\n'.join(recipients))
        except smtplib.SMTPException as inst:
            raise error.Abort(inst)

    return send

def _sendmail(ui, sender, recipients, msg):
    '''send mail using sendmail.'''
    program = ui.config('email', 'method')
    cmdline = '%s -f %s %s' % (program, util.email(sender),
                               ' '.join(map(util.email, recipients)))
    ui.note(_('sending mail: %s\n') % cmdline)
    fp = util.popen(cmdline, 'w')
    fp.write(msg)
    ret = fp.close()
    if ret:
        raise error.Abort('%s %s' % (
            os.path.basename(program.split(None, 1)[0]),
            util.explainexit(ret)[0]))

def _mbox(mbox, sender, recipients, msg):
    '''write mails to mbox'''
    fp = open(mbox, 'ab+')
    # Should be time.asctime(), but Windows prints 2-characters day
    # of month instead of one. Make them print the same thing.
    date = time.strftime('%a %b %d %H:%M:%S %Y', time.localtime())
    fp.write('From %s %s\n' % (sender, date))
    fp.write(msg)
    fp.write('\n\n')
    fp.close()

def connect(ui, mbox=None):
    '''make a mail connection. return a function to send mail.
    call as sendmail(sender, list-of-recipients, msg).'''
    if mbox:
        open(mbox, 'wb').close()
        return lambda s, r, m: _mbox(mbox, s, r, m)
    if ui.config('email', 'method') == 'smtp':
        return _smtp(ui)
    return lambda s, r, m: _sendmail(ui, s, r, m)

def sendmail(ui, sender, recipients, msg, mbox=None):
    send = connect(ui, mbox=mbox)
    return send(sender, recipients, msg)

def validateconfig(ui):
    '''determine if we have enough config data to try sending email.'''
    method = ui.config('email', 'method')
    if method == 'smtp':
        if not ui.config('smtp', 'host'):
            raise error.Abort(_('smtp specified as email transport, '
                               'but no smtp host configured'))
    else:
        if not util.findexe(method):
            raise error.Abort(_('%r specified as email transport, '
                               'but not in PATH') % method)

def codec2iana(cs):
    ''''''
    cs = email.charset.Charset(cs).input_charset.lower()

    # "latin1" normalizes to "iso8859-1", standard calls for "iso-8859-1"
    if cs.startswith("iso") and not cs.startswith("iso-"):
        return "iso-" + cs[3:]
    return cs

def mimetextpatch(s, subtype='plain', display=False):
    '''Return MIME message suitable for a patch.
    Charset will be detected by first trying to decode as us-ascii, then utf-8,
    and finally the global encodings. If all those fail, fall back to
    ISO-8859-1, an encoding with that allows all byte sequences.
    Transfer encodings will be used if necessary.'''

    cs = ['us-ascii', 'utf-8', encoding.encoding, encoding.fallbackencoding]
    if display:
        return mimetextqp(s, subtype, 'us-ascii')
    for charset in cs:
        try:
            s.decode(charset)
            return mimetextqp(s, subtype, codec2iana(charset))
        except UnicodeDecodeError:
            pass

    return mimetextqp(s, subtype, "iso-8859-1")

def mimetextqp(body, subtype, charset):
    '''Return MIME message.
    Quoted-printable transfer encoding will be used if necessary.
    '''
    cs = email.charset.Charset(charset)
    msg = email.message.Message()
    msg.set_type('text/' + subtype)

    for line in body.splitlines():
        if len(line) > 950:
            cs.body_encoding = email.charset.QP
            break

    msg.set_payload(body, cs)

    return msg

def _charsets(ui):
    '''Obtains charsets to send mail parts not containing patches.'''
    charsets = [cs.lower() for cs in ui.configlist('email', 'charsets')]
    fallbacks = [encoding.fallbackencoding.lower(),
                 encoding.encoding.lower(), 'utf-8']
    for cs in fallbacks: # find unique charsets while keeping order
        if cs not in charsets:
            charsets.append(cs)
    return [cs for cs in charsets if not cs.endswith('ascii')]

def _encode(ui, s, charsets):
    '''Returns (converted) string, charset tuple.
    Finds out best charset by cycling through sendcharsets in descending
    order. Tries both encoding and fallbackencoding for input. Only as
    last resort send as is in fake ascii.
    Caveat: Do not use for mail parts containing patches!'''
    try:
        s.decode('ascii')
    except UnicodeDecodeError:
        sendcharsets = charsets or _charsets(ui)
        for ics in (encoding.encoding, encoding.fallbackencoding):
            try:
                u = s.decode(ics)
            except UnicodeDecodeError:
                continue
            for ocs in sendcharsets:
                try:
                    return u.encode(ocs), ocs
                except UnicodeEncodeError:
                    pass
                except LookupError:
                    ui.warn(_('ignoring invalid sendcharset: %s\n') % ocs)
    # if ascii, or all conversion attempts fail, send (broken) ascii
    return s, 'us-ascii'

def headencode(ui, s, charsets=None, display=False):
    '''Returns RFC-2047 compliant header from given string.'''
    if not display:
        # split into words?
        s, cs = _encode(ui, s, charsets)
        return str(email.header.Header(s, cs))
    return s

def _addressencode(ui, name, addr, charsets=None):
    name = headencode(ui, name, charsets)
    try:
        acc, dom = addr.split('@')
        acc = acc.encode('ascii')
        dom = dom.decode(encoding.encoding).encode('idna')
        addr = '%s@%s' % (acc, dom)
    except UnicodeDecodeError:
        raise error.Abort(_('invalid email address: %s') % addr)
    except ValueError:
        try:
            # too strict?
            addr = addr.encode('ascii')
        except UnicodeDecodeError:
            raise error.Abort(_('invalid local address: %s') % addr)
    return email.Utils.formataddr((name, addr))

def addressencode(ui, address, charsets=None, display=False):
    '''Turns address into RFC-2047 compliant header.'''
    if display or not address:
        return address or ''
    name, addr = email.Utils.parseaddr(address)
    return _addressencode(ui, name, addr, charsets)

def addrlistencode(ui, addrs, charsets=None, display=False):
    '''Turns a list of addresses into a list of RFC-2047 compliant headers.
    A single element of input list may contain multiple addresses, but output
    always has one address per item'''
    if display:
        return [a.strip() for a in addrs if a.strip()]

    result = []
    for name, addr in email.Utils.getaddresses(addrs):
        if name or addr:
            result.append(_addressencode(ui, name, addr, charsets))
    return result

def mimeencode(ui, s, charsets=None, display=False):
    '''creates mime text object, encodes it if needed, and sets
    charset and transfer-encoding accordingly.'''
    cs = 'us-ascii'
    if not display:
        s, cs = _encode(ui, s, charsets)
    return mimetextqp(s, 'plain', cs)

def headdecode(s):
    '''Decodes RFC-2047 header'''
    uparts = []
    for part, charset in email.header.decode_header(s):
        if charset is not None:
            try:
                uparts.append(part.decode(charset))
                continue
            except UnicodeDecodeError:
                pass
        try:
            uparts.append(part.decode('UTF-8'))
            continue
        except UnicodeDecodeError:
            pass
        uparts.append(part.decode('ISO-8859-1'))
    return encoding.unitolocal(u' '.join(uparts))