view mercurial/hgweb/__init__.py @ 43913:4b7d5d10c45d

exchange: ensure all outgoing subrepo references are present before pushing

We've run into occasional problems with people committing a repo, and then
amending or rebasing in the subrepo.  That makes it so that the revision in the
parent can't be checked out, and the problem gets propagated on push.  Mercurial
already tries to defend against this sort of dangling reference by pushing *all*
subrepo revisions first.  This reuses the checks that trigger warnings in
`hg verify` to bail on the push unless using `--force`.

I thought about putting this on the server side, but at that point, all of the
data has been transferred, only to bail out.  Additionally, SCM Manager hosts
subrepos in a location that isn't nested in the parent, so normal subrepo code
would complain that the subrepo is missing when run on the server.

Because the push command pushes subrepos before calling this exchange code, a
subrepo will be pushed before the parent is verified.  Not great, but no
dangling references are exchanged, so it solves the problem.  This code isn't in
the loop that pushes the subrepos because:

  1) the list of outgoing revisions is needed to limit the scope of the check
  2) the loop only accesses the current revision, and therefore can miss
     subrepos that were dropped in previous commits
  3) this code is called when pushing a subrepo, so the protection is recursive

I'm not sure if there's a cheap check for the list of files in the outgoing
bundle.  If there is, that would provide a fast path to bypass this check for
people not using subrepos (or if no subrepo changes were made).  There's
probably also room for verifying other references like tags.  But since that
doesn't break checkouts, it's much less of a problem.

Differential Revision: https://phab.mercurial-scm.org/D7616

# hgweb/__init__.py - web interface to a mercurial repository
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <[e-mail]>
# Copyright 2005 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 os

from ..i18n import _

from .. import (
    error,
    pycompat,
)

from ..utils import procutil

from . import (
    hgweb_mod,
    hgwebdir_mod,
    server,
)


def hgweb(config, name=None, baseui=None):
    '''create an hgweb wsgi object

    config can be one of:
    - repo object (single repo view)
    - path to repo (single repo view)
    - path to config file (multi-repo view)
    - dict of virtual:real pairs (multi-repo view)
    - list of virtual:real tuples (multi-repo view)
    '''

    if isinstance(config, pycompat.unicode):
        raise error.ProgrammingError(
            b'Mercurial only supports encoded strings: %r' % config
        )
    if (
        (isinstance(config, bytes) and not os.path.isdir(config))
        or isinstance(config, dict)
        or isinstance(config, list)
    ):
        # create a multi-dir interface
        return hgwebdir_mod.hgwebdir(config, baseui=baseui)
    return hgweb_mod.hgweb(config, name=name, baseui=baseui)


def hgwebdir(config, baseui=None):
    return hgwebdir_mod.hgwebdir(config, baseui=baseui)


class httpservice(object):
    def __init__(self, ui, app, opts):
        self.ui = ui
        self.app = app
        self.opts = opts

    def init(self):
        procutil.setsignalhandler()
        self.httpd = server.create_server(self.ui, self.app)

        if (
            self.opts[b'port']
            and not self.ui.verbose
            and not self.opts[b'print_url']
        ):
            return

        if self.httpd.prefix:
            prefix = self.httpd.prefix.strip(b'/') + b'/'
        else:
            prefix = b''

        port = ':%d' % self.httpd.port
        if port == ':80':
            port = ''

        bindaddr = self.httpd.addr
        if bindaddr == '0.0.0.0':
            bindaddr = '*'
        elif ':' in bindaddr:  # IPv6
            bindaddr = '[%s]' % bindaddr

        fqaddr = self.httpd.fqaddr
        if ':' in fqaddr:
            fqaddr = '[%s]' % fqaddr

        url = b'http://%s%s/%s' % (
            pycompat.sysbytes(fqaddr),
            pycompat.sysbytes(port),
            prefix,
        )
        if self.opts[b'print_url']:
            self.ui.write(b'%s\n' % url)
        else:
            if self.opts[b'port']:
                write = self.ui.status
            else:
                write = self.ui.write
            write(
                _(b'listening at %s (bound to %s:%d)\n')
                % (url, pycompat.sysbytes(bindaddr), self.httpd.port)
            )
        self.ui.flush()  # avoid buffering of status message

    def run(self):
        self.httpd.serve_forever()


def createapp(baseui, repo, webconf):
    if webconf:
        return hgwebdir_mod.hgwebdir(webconf, baseui=baseui)
    else:
        if not repo:
            raise error.RepoError(
                _(b"there is no Mercurial repository here (.hg not found)")
            )
        return hgweb_mod.hgweb(repo, baseui=baseui)