view mercurial/treediscovery.py @ 52053:af54626bf358

dirstate-map: add a missing debug wait point when accessing the v2 docket

fc8e37c380d3 added synchronization points to the dirstate to allow for race
condition testing without actually requiring a time-based race condition
to happen.

This changes adds the `pre-read-file` wait point before we read the docket,
since callers might ask for the parents before anything else is
read, leading to the first read being done before the wait point.

This removes some differences in test output which were presumed to be
speed related, but weren't.

# discovery.py - protocol changeset discovery functions
#
# Copyright 2010 Olivia 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 annotations

import collections

from .i18n import _
from .node import short
from . import (
    error,
)


def findcommonincoming(repo, remote, heads=None, force=False, audit=None):
    """Return a tuple (common, fetch, heads) used to identify the common
    subset of nodes between repo and remote.

    "common" is a list of (at least) the heads of the common subset.
    "fetch" is a list of roots of the nodes that would be incoming, to be
      supplied to changegroupsubset.
    "heads" is either the supplied heads, or else the remote's heads.
    """

    knownnode = repo.changelog.hasnode
    search = []
    fetch = set()
    seen = set()
    seenbranch = set()
    base = set()

    if not heads:
        with remote.commandexecutor() as e:
            heads = e.callcommand(b'heads', {}).result()

    if audit is not None:
        audit[b'total-roundtrips'] = 1
        audit[b'total-roundtrips-heads'] = 1
        audit[b'total-roundtrips-branches'] = 0
        audit[b'total-roundtrips-between'] = 0
        audit[b'total-queries'] = 0
        audit[b'total-queries-branches'] = 0
        audit[b'total-queries-between'] = 0

    if repo.changelog.tip() == repo.nullid:
        base.add(repo.nullid)
        if heads != [repo.nullid]:
            return [repo.nullid], [repo.nullid], list(heads)
        return [repo.nullid], [], heads

    # assume we're closer to the tip than the root
    # and start by examining the heads
    repo.ui.status(_(b"searching for changes\n"))

    unknown = []
    for h in heads:
        if not knownnode(h):
            unknown.append(h)
        else:
            base.add(h)

    if not unknown:
        return list(base), [], list(heads)

    req = set(unknown)
    reqcnt = 0
    progress = repo.ui.makeprogress(_(b'searching'), unit=_(b'queries'))

    # search through remote branches
    # a 'branch' here is a linear segment of history, with four parts:
    # head, root, first parent, second parent
    # (a branch always has two parents (or none) by definition)
    with remote.commandexecutor() as e:
        if audit is not None:
            audit[b'total-queries'] += len(unknown)
            audit[b'total-queries-branches'] += len(unknown)
            audit[b'total-roundtrips'] += 1
            audit[b'total-roundtrips-branches'] += 1
        branches = e.callcommand(b'branches', {b'nodes': unknown}).result()

    unknown = collections.deque(branches)
    while unknown:
        r = []
        while unknown:
            n = unknown.popleft()
            if n[0] in seen:
                continue

            repo.ui.debug(b"examining %s:%s\n" % (short(n[0]), short(n[1])))
            if n[0] == repo.nullid:  # found the end of the branch
                pass
            elif n in seenbranch:
                repo.ui.debug(b"branch already found\n")
                continue
            elif n[1] and knownnode(n[1]):  # do we know the base?
                repo.ui.debug(
                    b"found incomplete branch %s:%s\n"
                    % (short(n[0]), short(n[1]))
                )
                search.append(n[0:2])  # schedule branch range for scanning
                seenbranch.add(n)
            else:
                if n[1] not in seen and n[1] not in fetch:
                    if knownnode(n[2]) and knownnode(n[3]):
                        repo.ui.debug(b"found new changeset %s\n" % short(n[1]))
                        fetch.add(n[1])  # earliest unknown
                    for p in n[2:4]:
                        if knownnode(p):
                            base.add(p)  # latest known

                for p in n[2:4]:
                    if p not in req and not knownnode(p):
                        r.append(p)
                        req.add(p)
            seen.add(n[0])

        if r:
            for p in range(0, len(r), 10):
                reqcnt += 1
                progress.increment()
                if repo.ui.debugflag:
                    msg = b"request %d: %s\n"
                    msg %= (reqcnt, b" ".join(map(short, r)))
                    repo.ui.debug(msg)
                with remote.commandexecutor() as e:
                    subset = r[p : p + 10]
                    if audit is not None:
                        audit[b'total-queries'] += len(subset)
                        audit[b'total-queries-branches'] += len(subset)
                        audit[b'total-roundtrips'] += 1
                        audit[b'total-roundtrips-branches'] += 1
                    branches = e.callcommand(
                        b'branches',
                        {
                            b'nodes': subset,
                        },
                    ).result()

                for b in branches:
                    repo.ui.debug(
                        b"received %s:%s\n" % (short(b[0]), short(b[1]))
                    )
                    unknown.append(b)

    # do binary search on the branches we found
    while search:
        newsearch = []
        reqcnt += 1
        progress.increment()

        with remote.commandexecutor() as e:
            if audit is not None:
                audit[b'total-queries'] += len(search)
                audit[b'total-queries-between'] += len(search)
                audit[b'total-roundtrips'] += 1
                audit[b'total-roundtrips-between'] += 1
            between = e.callcommand(b'between', {b'pairs': search}).result()

        for n, l in zip(search, between):
            l.append(n[1])
            p = n[0]
            f = 1
            for i in l:
                repo.ui.debug(b"narrowing %d:%d %s\n" % (f, len(l), short(i)))
                if knownnode(i):
                    if f <= 2:
                        repo.ui.debug(
                            b"found new branch changeset %s\n" % short(p)
                        )
                        fetch.add(p)
                        base.add(i)
                    else:
                        repo.ui.debug(
                            b"narrowed branch search to %s:%s\n"
                            % (short(p), short(i))
                        )
                        newsearch.append((p, i))
                    break
                p, f = i, f * 2
            search = newsearch

    # sanity check our fetch list
    for f in fetch:
        if knownnode(f):
            raise error.RepoError(_(b"already have changeset ") + short(f[:4]))

    base = list(base)
    if base == [repo.nullid]:
        if force:
            repo.ui.warn(_(b"warning: repository is unrelated\n"))
        else:
            raise error.Abort(_(b"repository is unrelated"))

    repo.ui.debug(
        b"found new changesets starting at "
        + b" ".join([short(f) for f in fetch])
        + b"\n"
    )

    progress.complete()
    repo.ui.debug(b"%d total queries\n" % reqcnt)

    return base, list(fetch), heads