view hgext/notify.py @ 46155:fce2f20a54ce

copies-rust: start recording overwrite as they happens If a revision has information overwriting data from another revision, the overwriting revision is a descendant of the overwritten one. So we could warm the Oracle cache with such information to avoid potential future `is_ancestors` call. This provide us with a large speedup in the most expensive cases: Repo Case Source-Rev Dest-Rev # of revisions old time new time Difference Factor time per rev --------------------------------------------------------------------------------------------------------------------------------------------------------------- mozilla-try x00000_revs_x00000_added_x0000_copies 1b661134e2ca 1ae03d022d6d : 228985 revs, 41.113063 s, 36.001255 s, -5.111808 s, × 0.8757, 157 µs/rev mozilla-try x00000_revs_x00000_added_x000_copies 9b2a99adc05e 8e29777b48e6 : 382065 revs, 27.891612 s, 14.340641 s, -13.550971 s, × 0.5142, 37 µs/rev Full comparison below: Repo Case Source-Rev Dest-Rev # of revisions old time new time Difference Factor time per rev --------------------------------------------------------------------------------------------------------------------------------------------------------------- mercurial x_revs_x_added_0_copies ad6b123de1c7 39cfcef4f463 : 1 revs, 0.000042 s, 0.000042 s, +0.000000 s, × 1.0000, 42 µs/rev mercurial x_revs_x_added_x_copies 2b1c78674230 0c1d10351869 : 6 revs, 0.000114 s, 0.000109 s, -0.000005 s, × 0.9561, 18 µs/rev mercurial x000_revs_x000_added_x_copies 81f8ff2a9bf2 dd3267698d84 : 1032 revs, 0.004934 s, 0.004953 s, +0.000019 s, × 1.0039, 4 µs/rev pypy x_revs_x_added_0_copies aed021ee8ae8 099ed31b181b : 9 revs, 0.000195 s, 0.000237 s, +0.000042 s, × 1.2154, 26 µs/rev pypy x_revs_x000_added_0_copies 4aa4e1f8e19a 359343b9ac0e : 1 revs, 0.000050 s, 0.000050 s, +0.000000 s, × 1.0000, 50 µs/rev pypy x_revs_x_added_x_copies ac52eb7bbbb0 72e022663155 : 7 revs, 0.000113 s, 0.000113 s, +0.000000 s, × 1.0000, 16 µs/rev pypy x_revs_x00_added_x_copies c3b14617fbd7 ace7255d9a26 : 1 revs, 0.6f1f4a s, 0.6f1f4a s, +0.000000 s, × 1.0000, 322 µs/rev pypy x_revs_x000_added_x000_copies df6f7a526b60 a83dc6a2d56f : 6 revs, 0.010788 s, 0.010702 s, -0.000086 s, × 0.9920, 1783 µs/rev pypy x000_revs_xx00_added_0_copies 89a76aede314 2f22446ff07e : 4785 revs, 0.050880 s, 0.050504 s, -0.000376 s, × 0.9926, 10 µs/rev pypy x000_revs_x000_added_x_copies 8a3b5bfd266e 2c68e87c3efe : 6780 revs, 0.081760 s, 0.080159 s, -0.001601 s, × 0.9804, 11 µs/rev pypy x000_revs_x000_added_x000_copies 89a76aede314 7b3dda341c84 : 5441 revs, 0.061382 s, 0.060058 s, -0.001324 s, × 0.9784, 11 µs/rev pypy x0000_revs_x_added_0_copies d1defd0dc478 c9cb1334cc78 : 43645 revs, 0.585802 s, 0.536950 s, -0.048852 s, × 0.9166, 12 µs/rev pypy x0000_revs_xx000_added_0_copies bf2c629d0071 4ffed77c095c : 2 revs, 0.012803 s, 0.012868 s, +0.000065 s, × 1.0051, 6434 µs/rev pypy x0000_revs_xx000_added_x000_copies 08ea3258278e d9fa043f30c0 : 11316 revs, 0.113558 s, 0.112806 s, -0.000752 s, × 0.9934, 9 µs/rev netbeans x_revs_x_added_0_copies fb0955ffcbcd a01e9239f9e7 : 2 revs, 0.000085 s, 0.000084 s, -0.000001 s, × 0.9882, 42 µs/rev netbeans x_revs_x000_added_0_copies 6f360122949f 20eb231cc7d0 : 2 revs, 0.000106 s, 0.000106 s, +0.000000 s, × 1.0000, 53 µs/rev netbeans x_revs_x_added_x_copies 1ada3faf6fb6 5a39d12eecf4 : 3 revs, 0.000175 s, 0.000174 s, -0.000001 s, × 0.9943, 58 µs/rev netbeans x_revs_x00_added_x_copies 35be93ba1e2c 9eec5e90c05f : 9 revs, 0.000721 s, 0.000726 s, +0.000005 s, × 1.0069, 80 µs/rev netbeans x000_revs_xx00_added_0_copies eac3045b4fdd 51d4ae7f1290 : 1421 revs, 0.010127 s, 0.010105 s, -0.000022 s, × 0.9978, 7 µs/rev netbeans x000_revs_x000_added_x_copies e2063d266acd 6081d72689dc : 1533 revs, 0.015616 s, 0.015748 s, +0.000132 s, × 1.0085, 10 µs/rev netbeans x000_revs_x000_added_x000_copies ff453e9fee32 411350406ec2 : 5750 revs, 0.061341 s, 0.060357 s, -0.000984 s, × 0.9840, 10 µs/rev netbeans x0000_revs_xx000_added_x000_copies 588c2d1ced70 1aad62e59ddd : 66949 revs, 0.542214 s, 0.499356 s, -0.042858 s, × 0.9210, 7 µs/rev mozilla-central x_revs_x_added_0_copies 3697f962bb7b 7015fcdd43a2 : 2 revs, 0.000089 s, 0.000092 s, +0.000003 s, × 1.0337, 46 µs/rev mozilla-central x_revs_x000_added_0_copies dd390860c6c9 40d0c5bed75d : 8 revs, 0.000279 s, 0.000279 s, +0.000000 s, × 1.0000, 34 µs/rev mozilla-central x_revs_x_added_x_copies 8d198483ae3b 14207ffc2b2f : 9 revs, 0.000184 s, 0.000186 s, +0.000002 s, × 1.0109, 20 µs/rev mozilla-central x_revs_x00_added_x_copies 98cbc58cc6bc 446a150332c3 : 7 revs, 0.000661 s, 0.000660 s, -0.000001 s, × 0.9985, 94 µs/rev mozilla-central x_revs_x000_added_x000_copies 3c684b4b8f68 0a5e72d1b479 : 3 revs, 0.003377 s, 0.003372 s, -0.000005 s, × 0.9985, 1124 µs/rev mozilla-central x_revs_x0000_added_x0000_copies effb563bb7e5 c07a39dc4e80 : 6 revs, 0.070508 s, 0.070294 s, -0.000214 s, × 0.9970, 11715 µs/rev mozilla-central x000_revs_xx00_added_0_copies 6100d773079a 04a55431795e : 1593 revs, 0.006576 s, 0.006545 s, -0.000031 s, × 0.9953, 4 µs/rev mozilla-central x000_revs_x000_added_x_copies 9f17a6fc04f9 2d37b966abed : 41 revs, 0.004809 s, 0.004998 s, +0.000189 s, × 1.0393, 121 µs/rev mozilla-central x000_revs_x000_added_x000_copies 7c97034feb78 4407bd0c6330 : 7839 revs, 0.064872 s, 0.063348 s, -0.001524 s, × 0.9765, 8 µs/rev mozilla-central x0000_revs_xx000_added_0_copies 9eec5917337d 67118cc6dcad : 615 revs, 0.026142 s, 0.026154 s, +0.000012 s, × 1.0005, 42 µs/rev mozilla-central x0000_revs_xx000_added_x000_copies f78c615a656c 96a38b690156 : 30263 revs, 0.203956 s, 0.199063 s, -0.004893 s, × 0.9760, 6 µs/rev mozilla-central x00000_revs_x0000_added_x0000_copies 6832ae71433c 4c222a1d9a00 : 153721 revs, 1.763853 s, 1.277320 s, -0.486533 s, × 0.7242, 8 µs/rev mozilla-central x00000_revs_x00000_added_x000_copies 76caed42cf7c 1daa622bbe42 : 204976 revs, 2.609761 s, 1.698794 s, -0.910967 s, × 0.6509, 8 µs/rev mozilla-try x_revs_x_added_0_copies aaf6dde0deb8 9790f499805a : 2 revs, 0.000847 s, 0.000842 s, -0.000005 s, × 0.9941, 421 µs/rev mozilla-try x_revs_x000_added_0_copies d8d0222927b4 5bb8ce8c7450 : 2 revs, 0.000867 s, 0.000865 s, -0.000002 s, × 0.9977, 432 µs/rev mozilla-try x_revs_x_added_x_copies 092fcca11bdb 936255a0384a : 4 revs, 0.000161 s, 0.000160 s, -0.000001 s, × 0.9938, 40 µs/rev mozilla-try x_revs_x00_added_x_copies b53d2fadbdb5 017afae788ec : 2 revs, 0.001131 s, 0.001122 s, -0.000009 s, × 0.9920, 561 µs/rev mozilla-try x_revs_x000_added_x000_copies 20408ad61ce5 6f0ee96e21ad : 1 revs, 0.033114 s, 0.032743 s, -0.000371 s, × 0.9888, 32743 µs/rev mozilla-try x_revs_x0000_added_x0000_copies effb563bb7e5 c07a39dc4e80 : 6 revs, 0.071092 s, 0.071529 s, +0.000437 s, × 1.0061, 11921 µs/rev mozilla-try x000_revs_xx00_added_0_copies 6100d773079a 04a55431795e : 1593 revs, 0.006554 s, 0.006593 s, +0.000039 s, × 1.0060, 4 µs/rev mozilla-try x000_revs_x000_added_x_copies 9f17a6fc04f9 2d37b966abed : 41 revs, 0.005160 s, 0.005311 s, +0.000151 s, × 1.0293, 129 µs/rev mozilla-try x000_revs_x000_added_x000_copies 1346fd0130e4 4c65cbdabc1f : 6657 revs, 0.065063 s, 0.063063 s, -0.002000 s, × 0.9693, 9 µs/rev mozilla-try x0000_revs_x_added_0_copies 63519bfd42ee a36a2a865d92 : 40314 revs, 0.297118 s, 0.312363 s, +0.015245 s, × 1.0513, 7 µs/rev mozilla-try x0000_revs_x_added_x_copies 9fe69ff0762d bcabf2a78927 : 38690 revs, 0.284002 s, 0.283106 s, -0.000896 s, × 0.9968, 7 µs/rev mozilla-try x0000_revs_xx000_added_x_copies 156f6e2674f2 4d0f2c178e66 : 8598 revs, 0.086311 s, 0.083817 s, -0.002494 s, × 0.9711, 9 µs/rev mozilla-try x0000_revs_xx000_added_0_copies 9eec5917337d 67118cc6dcad : 615 revs, 0.026738 s, 0.026516 s, -0.000222 s, × 0.9917, 43 µs/rev mozilla-try x0000_revs_xx000_added_x000_copies 89294cd501d9 7ccb2fc7ccb5 : 97052 revs, 1.514270 s, 1.304865 s, -0.209405 s, × 0.8617, 13 µs/rev mozilla-try x0000_revs_x0000_added_x0000_copies e928c65095ed e951f4ad123a : 52031 revs, 0.735875 s, 0.681088 s, -0.054787 s, × 0.9255, 13 µs/rev mozilla-try x00000_revs_x_added_0_copies 6a320851d377 1ebb79acd503 : 363753 revs, 4.843329 s, 4.454320 s, -0.389009 s, × 0.9197, 12 µs/rev mozilla-try x00000_revs_x00000_added_0_copies dc8a3ca7010e d16fde900c9c : 34414 revs, 0.591752 s, 0.567913 s, -0.023839 s, × 0.9597, 16 µs/rev mozilla-try x00000_revs_x_added_x_copies 5173c4b6f97c 95d83ee7242d : 362229 revs, 4.760563 s, 4.547043 s, -0.213520 s, × 0.9551, 12 µs/rev mozilla-try x00000_revs_x000_added_x_copies 9126823d0e9c ca82787bb23c : 359344 revs, 4.751942 s, 4.378579 s, -0.373363 s, × 0.9214, 12 µs/rev mozilla-try x00000_revs_x0000_added_x0000_copies 8d3fafa80d4b eb884023b810 : 192665 revs, 2.605014 s, 1.703622 s, -0.901392 s, × 0.6540, 8 µs/rev mozilla-try x00000_revs_x00000_added_x0000_copies 1b661134e2ca 1ae03d022d6d : 228985 revs, 41.113063 s, 36.001255 s, -5.111808 s, × 0.8757, 157 µs/rev mozilla-try x00000_revs_x00000_added_x000_copies 9b2a99adc05e 8e29777b48e6 : 382065 revs, 27.891612 s, 14.340641 s, -13.550971 s, × 0.5142, 37 µs/rev Differential Revision: https://phab.mercurial-scm.org/D9497
author Pierre-Yves David <pierre-yves.david@octobus.net>
date Sat, 21 Nov 2020 17:00:32 +0100
parents 89a2afe31e82
children ae27a0684e75
line wrap: on
line source

# notify.py - email notifications for mercurial
#
# Copyright 2006 Vadim Gelfer <vadim.gelfer@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''hooks for sending email push notifications

This extension implements hooks to send email notifications when
changesets are sent from or received by the local repository.

First, enable the extension as explained in :hg:`help extensions`, and
register the hook you want to run. ``incoming`` and ``changegroup`` hooks
are run when changesets are received, while ``outgoing`` hooks are for
changesets sent to another repository::

  [hooks]
  # one email for each incoming changeset
  incoming.notify = python:hgext.notify.hook
  # one email for all incoming changesets
  changegroup.notify = python:hgext.notify.hook

  # one email for all outgoing changesets
  outgoing.notify = python:hgext.notify.hook

This registers the hooks. To enable notification, subscribers must
be assigned to repositories. The ``[usersubs]`` section maps multiple
repositories to a given recipient. The ``[reposubs]`` section maps
multiple recipients to a single repository::

  [usersubs]
  # key is subscriber email, value is a comma-separated list of repo patterns
  user@host = pattern

  [reposubs]
  # key is repo pattern, value is a comma-separated list of subscriber emails
  pattern = user@host

A ``pattern`` is a ``glob`` matching the absolute path to a repository,
optionally combined with a revset expression. A revset expression, if
present, is separated from the glob by a hash. Example::

  [reposubs]
  */widgets#branch(release) = qa-team@example.com

This sends to ``qa-team@example.com`` whenever a changeset on the ``release``
branch triggers a notification in any repository ending in ``widgets``.

In order to place them under direct user management, ``[usersubs]`` and
``[reposubs]`` sections may be placed in a separate ``hgrc`` file and
incorporated by reference::

  [notify]
  config = /path/to/subscriptionsfile

Notifications will not be sent until the ``notify.test`` value is set
to ``False``; see below.

Notifications content can be tweaked with the following configuration entries:

notify.test
  If ``True``, print messages to stdout instead of sending them. Default: True.

notify.sources
  Space-separated list of change sources. Notifications are activated only
  when a changeset's source is in this list. Sources may be:

  :``serve``: changesets received via http or ssh
  :``pull``: changesets received via ``hg pull``
  :``unbundle``: changesets received via ``hg unbundle``
  :``push``: changesets sent or received via ``hg push``
  :``bundle``: changesets sent via ``hg unbundle``

  Default: serve.

notify.strip
  Number of leading slashes to strip from url paths. By default, notifications
  reference repositories with their absolute path. ``notify.strip`` lets you
  turn them into relative paths. For example, ``notify.strip=3`` will change
  ``/long/path/repository`` into ``repository``. Default: 0.

notify.domain
  Default email domain for sender or recipients with no explicit domain.
  It is also used for the domain part of the ``Message-Id`` when using
  ``notify.messageidseed``.

notify.messageidseed
  Create deterministic ``Message-Id`` headers for the mails based on the seed
  and the revision identifier of the first commit in the changeset.

notify.style
  Style file to use when formatting emails.

notify.template
  Template to use when formatting emails.

notify.incoming
  Template to use when run as an incoming hook, overriding ``notify.template``.

notify.outgoing
  Template to use when run as an outgoing hook, overriding ``notify.template``.

notify.changegroup
  Template to use when running as a changegroup hook, overriding
  ``notify.template``.

notify.maxdiff
  Maximum number of diff lines to include in notification email. Set to 0
  to disable the diff, or -1 to include all of it. Default: 300.

notify.maxdiffstat
  Maximum number of diffstat lines to include in notification email. Set to -1
  to include all of it. Default: -1.

notify.maxsubject
  Maximum number of characters in email's subject line. Default: 67.

notify.diffstat
  Set to True to include a diffstat before diff content. Default: True.

notify.showfunc
  If set, override ``diff.showfunc`` for the diff content. Default: None.

notify.merge
  If True, send notifications for merge changesets. Default: True.

notify.mbox
  If set, append mails to this mbox file instead of sending. Default: None.

notify.fromauthor
  If set, use the committer of the first changeset in a changegroup for
  the "From" field of the notification mail. If not set, take the user
  from the pushing repo.  Default: False.

notify.reply-to-predecessor (EXPERIMENTAL)
  If set and the changeset has a predecessor in the repository, try to thread
  the notification mail with the predecessor. This adds the "In-Reply-To" header
  to the notification mail with a reference to the predecessor with the smallest
  revision number. Mail threads can still be torn, especially when changesets
  are folded.

  This option must  be used in combination with ``notify.messageidseed``.

If set, the following entries will also be used to customize the
notifications:

email.from
  Email ``From`` address to use if none can be found in the generated
  email content.

web.baseurl
  Root repository URL to combine with repository paths when making
  references. See also ``notify.strip``.

'''
from __future__ import absolute_import

import email.errors as emailerrors
import email.utils as emailutils
import fnmatch
import hashlib
import socket
import time

from mercurial.i18n import _
from mercurial import (
    encoding,
    error,
    logcmdutil,
    mail,
    obsutil,
    patch,
    pycompat,
    registrar,
    util,
)
from mercurial.utils import (
    dateutil,
    stringutil,
)

# 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 = b'ships-with-hg-core'

configtable = {}
configitem = registrar.configitem(configtable)

configitem(
    b'notify',
    b'changegroup',
    default=None,
)
configitem(
    b'notify',
    b'config',
    default=None,
)
configitem(
    b'notify',
    b'diffstat',
    default=True,
)
configitem(
    b'notify',
    b'domain',
    default=None,
)
configitem(
    b'notify',
    b'messageidseed',
    default=None,
)
configitem(
    b'notify',
    b'fromauthor',
    default=None,
)
configitem(
    b'notify',
    b'incoming',
    default=None,
)
configitem(
    b'notify',
    b'maxdiff',
    default=300,
)
configitem(
    b'notify',
    b'maxdiffstat',
    default=-1,
)
configitem(
    b'notify',
    b'maxsubject',
    default=67,
)
configitem(
    b'notify',
    b'mbox',
    default=None,
)
configitem(
    b'notify',
    b'merge',
    default=True,
)
configitem(
    b'notify',
    b'outgoing',
    default=None,
)
configitem(
    b'notify',
    b'reply-to-predecessor',
    default=False,
)
configitem(
    b'notify',
    b'sources',
    default=b'serve',
)
configitem(
    b'notify',
    b'showfunc',
    default=None,
)
configitem(
    b'notify',
    b'strip',
    default=0,
)
configitem(
    b'notify',
    b'style',
    default=None,
)
configitem(
    b'notify',
    b'template',
    default=None,
)
configitem(
    b'notify',
    b'test',
    default=True,
)

# template for single changeset can include email headers.
single_template = b'''
Subject: changeset in {webroot}: {desc|firstline|strip}
From: {author}

changeset {node|short} in {root}
details: {baseurl}{webroot}?cmd=changeset;node={node|short}
description:
\t{desc|tabindent|strip}
'''.lstrip()

# template for multiple changesets should not contain email headers,
# because only first set of headers will be used and result will look
# strange.
multiple_template = b'''
changeset {node|short} in {root}
details: {baseurl}{webroot}?cmd=changeset;node={node|short}
summary: {desc|firstline}
'''

deftemplates = {
    b'changegroup': multiple_template,
}


class notifier(object):
    '''email notification class.'''

    def __init__(self, ui, repo, hooktype):
        self.ui = ui
        cfg = self.ui.config(b'notify', b'config')
        if cfg:
            self.ui.readconfig(cfg, sections=[b'usersubs', b'reposubs'])
        self.repo = repo
        self.stripcount = int(self.ui.config(b'notify', b'strip'))
        self.root = self.strip(self.repo.root)
        self.domain = self.ui.config(b'notify', b'domain')
        self.mbox = self.ui.config(b'notify', b'mbox')
        self.test = self.ui.configbool(b'notify', b'test')
        self.charsets = mail._charsets(self.ui)
        self.subs = self.subscribers()
        self.merge = self.ui.configbool(b'notify', b'merge')
        self.showfunc = self.ui.configbool(b'notify', b'showfunc')
        self.messageidseed = self.ui.config(b'notify', b'messageidseed')
        self.reply = self.ui.configbool(b'notify', b'reply-to-predecessor')

        if self.reply and not self.messageidseed:
            raise error.Abort(
                _(
                    b'notify.reply-to-predecessor used without '
                    b'notify.messageidseed'
                )
            )

        if self.showfunc is None:
            self.showfunc = self.ui.configbool(b'diff', b'showfunc')

        mapfile = None
        template = self.ui.config(b'notify', hooktype) or self.ui.config(
            b'notify', b'template'
        )
        if not template:
            mapfile = self.ui.config(b'notify', b'style')
        if not mapfile and not template:
            template = deftemplates.get(hooktype) or single_template
        spec = logcmdutil.templatespec(template, mapfile)
        self.t = logcmdutil.changesettemplater(self.ui, self.repo, spec)

    def strip(self, path):
        '''strip leading slashes from local path, turn into web-safe path.'''

        path = util.pconvert(path)
        count = self.stripcount
        while count > 0:
            c = path.find(b'/')
            if c == -1:
                break
            path = path[c + 1 :]
            count -= 1
        return path

    def fixmail(self, addr):
        '''try to clean up email addresses.'''

        addr = stringutil.email(addr.strip())
        if self.domain:
            a = addr.find(b'@localhost')
            if a != -1:
                addr = addr[:a]
            if b'@' not in addr:
                return addr + b'@' + self.domain
        return addr

    def subscribers(self):
        '''return list of email addresses of subscribers to this repo.'''
        subs = set()
        for user, pats in self.ui.configitems(b'usersubs'):
            for pat in pats.split(b','):
                if b'#' in pat:
                    pat, revs = pat.split(b'#', 1)
                else:
                    revs = None
                if fnmatch.fnmatch(self.repo.root, pat.strip()):
                    subs.add((self.fixmail(user), revs))
        for pat, users in self.ui.configitems(b'reposubs'):
            if b'#' in pat:
                pat, revs = pat.split(b'#', 1)
            else:
                revs = None
            if fnmatch.fnmatch(self.repo.root, pat):
                for user in users.split(b','):
                    subs.add((self.fixmail(user), revs))
        return [
            (mail.addressencode(self.ui, s, self.charsets, self.test), r)
            for s, r in sorted(subs)
        ]

    def node(self, ctx, **props):
        '''format one changeset, unless it is a suppressed merge.'''
        if not self.merge and len(ctx.parents()) > 1:
            return False
        self.t.show(
            ctx,
            changes=ctx.changeset(),
            baseurl=self.ui.config(b'web', b'baseurl'),
            root=self.repo.root,
            webroot=self.root,
            **props
        )
        return True

    def skipsource(self, source):
        '''true if incoming changes from this source should be skipped.'''
        ok_sources = self.ui.config(b'notify', b'sources').split()
        return source not in ok_sources

    def send(self, ctx, count, data):
        '''send message.'''

        # Select subscribers by revset
        subs = set()
        for sub, spec in self.subs:
            if spec is None:
                subs.add(sub)
                continue
            revs = self.repo.revs(b'%r and %d:', spec, ctx.rev())
            if len(revs):
                subs.add(sub)
                continue
        if len(subs) == 0:
            self.ui.debug(
                b'notify: no subscribers to selected repo and revset\n'
            )
            return

        try:
            msg = mail.parsebytes(data)
        except emailerrors.MessageParseError as inst:
            raise error.Abort(inst)

        # store sender and subject
        sender = msg['From']
        subject = msg['Subject']
        if sender is not None:
            sender = mail.headdecode(sender)
        if subject is not None:
            subject = mail.headdecode(subject)
        del msg['From'], msg['Subject']

        if not msg.is_multipart():
            # create fresh mime message from scratch
            # (multipart templates must take care of this themselves)
            headers = msg.items()
            payload = msg.get_payload(decode=pycompat.ispy3)
            # for notification prefer readability over data precision
            msg = mail.mimeencode(self.ui, payload, self.charsets, self.test)
            # reinstate custom headers
            for k, v in headers:
                msg[k] = v

        msg['Date'] = encoding.strfromlocal(
            dateutil.datestr(format=b"%a, %d %b %Y %H:%M:%S %1%2")
        )

        # try to make subject line exist and be useful
        if not subject:
            if count > 1:
                subject = _(b'%s: %d new changesets') % (self.root, count)
            else:
                s = ctx.description().lstrip().split(b'\n', 1)[0].rstrip()
                subject = b'%s: %s' % (self.root, s)
        maxsubject = int(self.ui.config(b'notify', b'maxsubject'))
        if maxsubject:
            subject = stringutil.ellipsis(subject, maxsubject)
        msg['Subject'] = mail.headencode(
            self.ui, subject, self.charsets, self.test
        )

        # try to make message have proper sender
        if not sender:
            sender = self.ui.config(b'email', b'from') or self.ui.username()
        if b'@' not in sender or b'@localhost' in sender:
            sender = self.fixmail(sender)
        msg['From'] = mail.addressencode(
            self.ui, sender, self.charsets, self.test
        )

        msg['X-Hg-Notification'] = 'changeset %s' % ctx
        if not msg['Message-Id']:
            msg['Message-Id'] = messageid(ctx, self.domain, self.messageidseed)
        if self.reply:
            unfi = self.repo.unfiltered()
            has_node = unfi.changelog.index.has_node
            predecessors = [
                unfi[ctx2]
                for ctx2 in obsutil.allpredecessors(unfi.obsstore, [ctx.node()])
                if ctx2 != ctx.node() and has_node(ctx2)
            ]
            if predecessors:
                # There is at least one predecessor, so which to pick?
                # Ideally, there is a unique root because changesets have
                # been evolved/rebased one step at a time. In this case,
                # just picking the oldest known changeset provides a stable
                # base. It doesn't help when changesets are folded. Any
                # better solution would require storing more information
                # in the repository.
                pred = min(predecessors, key=lambda ctx: ctx.rev())
                msg['In-Reply-To'] = messageid(
                    pred, self.domain, self.messageidseed
                )
        msg['To'] = ', '.join(sorted(subs))

        msgtext = msg.as_bytes() if pycompat.ispy3 else msg.as_string()
        if self.test:
            self.ui.write(msgtext)
            if not msgtext.endswith(b'\n'):
                self.ui.write(b'\n')
        else:
            self.ui.status(
                _(b'notify: sending %d subscribers %d changes\n')
                % (len(subs), count)
            )
            mail.sendmail(
                self.ui,
                emailutils.parseaddr(msg['From'])[1],
                subs,
                msgtext,
                mbox=self.mbox,
            )

    def diff(self, ctx, ref=None):

        maxdiff = int(self.ui.config(b'notify', b'maxdiff'))
        prev = ctx.p1().node()
        if ref:
            ref = ref.node()
        else:
            ref = ctx.node()
        diffopts = patch.diffallopts(self.ui)
        diffopts.showfunc = self.showfunc
        chunks = patch.diff(self.repo, prev, ref, opts=diffopts)
        difflines = b''.join(chunks).splitlines()

        if self.ui.configbool(b'notify', b'diffstat'):
            maxdiffstat = int(self.ui.config(b'notify', b'maxdiffstat'))
            s = patch.diffstat(difflines)
            # s may be nil, don't include the header if it is
            if s:
                if maxdiffstat >= 0 and s.count(b"\n") > maxdiffstat + 1:
                    s = s.split(b"\n")
                    msg = _(b'\ndiffstat (truncated from %d to %d lines):\n\n')
                    self.ui.write(msg % (len(s) - 2, maxdiffstat))
                    self.ui.write(b"\n".join(s[:maxdiffstat] + s[-2:]))
                else:
                    self.ui.write(_(b'\ndiffstat:\n\n%s') % s)

        if maxdiff == 0:
            return
        elif maxdiff > 0 and len(difflines) > maxdiff:
            msg = _(b'\ndiffs (truncated from %d to %d lines):\n\n')
            self.ui.write(msg % (len(difflines), maxdiff))
            difflines = difflines[:maxdiff]
        elif difflines:
            self.ui.write(_(b'\ndiffs (%d lines):\n\n') % len(difflines))

        self.ui.write(b"\n".join(difflines))


def hook(ui, repo, hooktype, node=None, source=None, **kwargs):
    """send email notifications to interested subscribers.

    if used as changegroup hook, send one email for all changesets in
    changegroup. else send one email per changeset."""

    n = notifier(ui, repo, hooktype)
    ctx = repo.unfiltered()[node]

    if not n.subs:
        ui.debug(b'notify: no subscribers to repository %s\n' % n.root)
        return
    if n.skipsource(source):
        ui.debug(b'notify: changes have source "%s" - skipping\n' % source)
        return

    ui.pushbuffer()
    data = b''
    count = 0
    author = b''
    if hooktype == b'changegroup' or hooktype == b'outgoing':
        for rev in repo.changelog.revs(start=ctx.rev()):
            if n.node(repo[rev]):
                count += 1
                if not author:
                    author = repo[rev].user()
            else:
                data += ui.popbuffer()
                ui.note(
                    _(b'notify: suppressing notification for merge %d:%s\n')
                    % (rev, repo[rev].hex()[:12])
                )
                ui.pushbuffer()
        if count:
            n.diff(ctx, repo[b'tip'])
    elif ctx.rev() in repo:
        if not n.node(ctx):
            ui.popbuffer()
            ui.note(
                _(b'notify: suppressing notification for merge %d:%s\n')
                % (ctx.rev(), ctx.hex()[:12])
            )
            return
        count += 1
        n.diff(ctx)
        if not author:
            author = ctx.user()

    data += ui.popbuffer()
    fromauthor = ui.config(b'notify', b'fromauthor')
    if author and fromauthor:
        data = b'\n'.join([b'From: %s' % author, data])

    if count:
        n.send(ctx, count, data)


def messageid(ctx, domain, messageidseed):
    if domain and messageidseed:
        host = domain
    else:
        host = encoding.strtolocal(socket.getfqdn())
    if messageidseed:
        messagehash = hashlib.sha512(ctx.hex() + messageidseed)
        messageid = b'<hg.%s@%s>' % (
            pycompat.sysbytes(messagehash.hexdigest()[:64]),
            host,
        )
    else:
        messageid = b'<hg.%s.%d.%d@%s>' % (
            ctx,
            int(time.time()),
            hash(ctx.repo().root),
            host,
        )
    return encoding.strfromlocal(messageid)