mercurial/upgrade.py

branchmap: skip obsolete revisions while computing heads

It's time to make this part of core Mercurial obsolescence-aware.

Not considering obsolete revisions when computing heads is clearly what
Mercurial should do. But there are a couple of small issues:

- Let's say tip of the repo is obsolete. There are two ways of finding tiprev
  for branchcache (both are in use): looking at input data for update() and
  looking at computed heads after update(). Previously, repo tip would be
  tiprev of the branchcache. With this patch, an obsolete revision can no
  longer be tiprev. And depending on what way we use for finding tiprev (input
  data vs computed heads) we'll get a different result. This is relevant when
  recomputing cache key from cache contents, and may lead to updating cache for
  obsolete revisions multiple times (not from scratch, because it still would
  be considered valid for a subset of revisions in the repo).

- If all commits on a branch are obsolete, the branchcache will include that
  branch, but the list of heads will be empty (that's why there's now `if not
  heads` when recomputing tiprev/tipnode from cache contents). Having an entry
  for every branch is currently required for notify extension (and
  test-notify.t to pass), because notify doesn't handle revsets in its
  subscription config very well and will throw an error if e.g. a branch
  doesn't exist.

- Cloning static HTTP repos may try to stat() a non-existent obsstore file. The
  issue is that we now care about obsolescence during clone, but statichttpvfs
  doesn't implement a stat method, so a regular vfs.stat() is used, and it
  assumes that file is local and calls os.stat().  During a clone, we're trying
  to stat() .hg/store/obsstore, but in static HTTP case we provide a literal
  URL to the obsstore file on the remote as if it were a local file path. On
  windows it actually results in a failure in test-static-http.t.

The first issue is going to be addressed in a series dedicated to making sure
branchcache is properly and timely written on disk (it wasn't perfect even
before this patch, but there aren't enough tests to demonstrate that). The
second issue will be addressed in a future patch for notify extension that will
make it not raise an exception if a branch doesn't exist. And the third one was
partially addressed in the previous patch in this series and will be properly
fixed in a future patch when this series is accepted.

filteredhash() grows a keyword argument to make sure that branchcache is also
invalidated when there are new obsolete revisions in its repo view. This way
the on-disk cache format is unchanged and compatible between versions (although
it will obviously be recomputed when switching versions before/after this patch
and the repo has obsolete revisions).

There's one test that uses plain `hg up` without arguments while updated to a
pruned commit. To make this test pass, simply return current working directory
parent. Later in this series this code will be replaced by what prune command
does: updating to the closest non-obsolete ancestor.

Test changes:

test-branch-change.t: update branch head and cache update message. The head of
default listed in hg heads is changed because revision 2 was rewritten as 7,
and 1 is the closest ancestor on the same branch, so it's the head of default
now.

The cache invalidation message appears now because of the cache hash change,
since we're now accounting for obsolete revisions. Here's some context:

"served.hidden" repo filter means everything is visible (no filtered
revisions), so before this series branch2-served.hidden file would not contain
any cache hash, only revnum and node. Now it also has a hash when there are
obsolete changesets in the repo. The command that the message appears for is
changing branch of 5 and 6, which are now obsolete, so the cache hash changes.

In general, when cache is simply out-of-date, it can be updated using the old
version as a base. But if cache hash differs, then the cache for that
particular repo filter is recomputed (at least with the current
implementation). This is what happens here.

test-obsmarker-template.t: the pull reports 2 heads changed, but after that the
repo correctly sees only 1. The new message could be better, but it's still an
improvement over the previous one where hg pull suggested merging with an
obsolete revision.

test-obsolete.t: we can see these revisions in hg log --hidden, but they
shouldn't be considered heads even with --hidden.

test-rebase-obsolete{,2}.t: there were new heads created previously after
making new orphan changesets, but they weren't detected. Now we are properly
detecting and reporting them.

test-rebase-obsolete4.t: there's only one head now because the other head is
pruned and was falsely reported before.

test-static-http.t: add obsstore to the list of requested files. This file
doesn't exist on the remotes, but clients want it anyway (they get 404). This
is fine, because there are other nonexistent files that clients request, like
.hg/bookmarks or .hg/cache/tags2-served.

Differential Revision: https://phab.mercurial-scm.org/D12097

# upgrade.py - functions for in place upgrade of Mercurial repository
#
# Copyright (c) 2016-present, Gregory Szorc
#
# 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

from .i18n import _
from . import (
    error,
    hg,
    localrepo,
    lock as lockmod,
    pycompat,
    requirements as requirementsmod,
    scmutil,
)

from .upgrade_utils import (
    actions as upgrade_actions,
    engine as upgrade_engine,
)

from .utils import (
    stringutil,
)

allformatvariant = upgrade_actions.allformatvariant


def upgraderepo(
    ui,
    repo,
    run=False,
    optimize=None,
    backup=True,
    manifest=None,
    changelog=None,
    filelogs=None,
):
    """Upgrade a repository in place."""
    if optimize is None:
        optimize = set()
    repo = repo.unfiltered()

    specified_revlogs = {}
    if changelog is not None:
        specified_revlogs[upgrade_engine.UPGRADE_CHANGELOG] = changelog
    if manifest is not None:
        specified_revlogs[upgrade_engine.UPGRADE_MANIFEST] = manifest
    if filelogs is not None:
        specified_revlogs[upgrade_engine.UPGRADE_FILELOGS] = filelogs

    # Ensure the repository can be upgraded.
    upgrade_actions.check_source_requirements(repo)

    default_options = localrepo.defaultcreateopts(repo.ui)
    newreqs = localrepo.newreporequirements(repo.ui, default_options)
    newreqs.update(upgrade_actions.preservedrequirements(repo))

    upgrade_actions.check_requirements_changes(repo, newreqs)

    # Find and validate all improvements that can be made.
    alloptimizations = upgrade_actions.findoptimizations(repo)

    # Apply and Validate arguments.
    optimizations = []
    for o in alloptimizations:
        if o.name in optimize:
            optimizations.append(o)
            optimize.discard(o.name)

    if optimize:  # anything left is unknown
        raise error.Abort(
            _(b'unknown optimization action requested: %s')
            % b', '.join(sorted(optimize)),
            hint=_(b'run without arguments to see valid optimizations'),
        )

    format_upgrades = upgrade_actions.find_format_upgrades(repo)
    up_actions = upgrade_actions.determine_upgrade_actions(
        repo, format_upgrades, optimizations, repo.requirements, newreqs
    )
    removed_actions = upgrade_actions.find_format_downgrades(repo)

    # check if we need to touch revlog and if so, which ones

    touched_revlogs = set()
    overwrite_msg = _(b'warning: ignoring %14s, as upgrade is changing: %s\n')
    select_msg = _(b'note:    selecting %s for processing to change: %s\n')
    msg_issued = 0

    FL = upgrade_engine.UPGRADE_FILELOGS
    MN = upgrade_engine.UPGRADE_MANIFEST
    CL = upgrade_engine.UPGRADE_CHANGELOG

    if optimizations:
        if any(specified_revlogs.values()):
            # we have some limitation on revlogs to be recloned
            for rl, enabled in specified_revlogs.items():
                if enabled:
                    touched_revlogs.add(rl)
        else:
            touched_revlogs = set(upgrade_engine.UPGRADE_ALL_REVLOGS)
            for rl, enabled in specified_revlogs.items():
                if not enabled:
                    touched_revlogs.discard(rl)

    for action in sorted(up_actions + removed_actions, key=lambda a: a.name):
        # optimisation does not "requires anything, they just needs it.
        if action.type != upgrade_actions.FORMAT_VARIANT:
            continue

        if action.touches_filelogs and FL not in touched_revlogs:
            if FL in specified_revlogs:
                if not specified_revlogs[FL]:
                    msg = overwrite_msg % (b'--no-filelogs', action.name)
                    ui.warn(msg)
                    msg_issued = 2
            else:
                msg = select_msg % (b'all-filelogs', action.name)
                ui.status(msg)
                if not ui.quiet:
                    msg_issued = 1
            touched_revlogs.add(FL)

        if action.touches_manifests and MN not in touched_revlogs:
            if MN in specified_revlogs:
                if not specified_revlogs[MN]:
                    msg = overwrite_msg % (b'--no-manifest', action.name)
                    ui.warn(msg)
                    msg_issued = 2
            else:
                msg = select_msg % (b'all-manifestlogs', action.name)
                ui.status(msg)
                if not ui.quiet:
                    msg_issued = 1
            touched_revlogs.add(MN)

        if action.touches_changelog and CL not in touched_revlogs:
            if CL in specified_revlogs:
                if not specified_revlogs[CL]:
                    msg = overwrite_msg % (b'--no-changelog', action.name)
                    ui.warn(msg)
                    msg_issued = True
            else:
                msg = select_msg % (b'changelog', action.name)
                ui.status(msg)
                if not ui.quiet:
                    msg_issued = 1
            touched_revlogs.add(CL)
    if msg_issued >= 2:
        ui.warn((b"\n"))
    elif msg_issued >= 1:
        ui.status((b"\n"))

    upgrade_op = upgrade_actions.UpgradeOperation(
        ui,
        newreqs,
        repo.requirements,
        up_actions,
        removed_actions,
        touched_revlogs,
        backup,
    )

    if not run:
        fromconfig = []
        onlydefault = []

        for d in format_upgrades:
            if d.fromconfig(repo):
                fromconfig.append(d)
            elif d.default:
                onlydefault.append(d)

        if fromconfig or onlydefault:

            if fromconfig:
                ui.status(
                    _(
                        b'repository lacks features recommended by '
                        b'current config options:\n\n'
                    )
                )
                for i in fromconfig:
                    ui.status(b'%s\n   %s\n\n' % (i.name, i.description))

            if onlydefault:
                ui.status(
                    _(
                        b'repository lacks features used by the default '
                        b'config options:\n\n'
                    )
                )
                for i in onlydefault:
                    ui.status(b'%s\n   %s\n\n' % (i.name, i.description))

            ui.status(b'\n')
        else:
            ui.status(_(b'(no format upgrades found in existing repository)\n'))

        ui.status(
            _(
                b'performing an upgrade with "--run" will make the following '
                b'changes:\n\n'
            )
        )

        upgrade_op.print_requirements()
        upgrade_op.print_optimisations()
        upgrade_op.print_upgrade_actions()
        upgrade_op.print_affected_revlogs()

        if upgrade_op.unused_optimizations:
            ui.status(
                _(
                    b'additional optimizations are available by specifying '
                    b'"--optimize <name>":\n\n'
                )
            )
            upgrade_op.print_unused_optimizations()
        return

    if not (upgrade_op.upgrade_actions or upgrade_op.removed_actions):
        ui.status(_(b'nothing to do\n'))
        return
    # Else we're in the run=true case.
    ui.write(_(b'upgrade will perform the following actions:\n\n'))
    upgrade_op.print_requirements()
    upgrade_op.print_optimisations()
    upgrade_op.print_upgrade_actions()
    upgrade_op.print_affected_revlogs()

    ui.status(_(b'beginning upgrade...\n'))
    with repo.wlock(), repo.lock():
        ui.status(_(b'repository locked and read-only\n'))
        # Our strategy for upgrading the repository is to create a new,
        # temporary repository, write data to it, then do a swap of the
        # data. There are less heavyweight ways to do this, but it is easier
        # to create a new repo object than to instantiate all the components
        # (like the store) separately.
        tmppath = pycompat.mkdtemp(prefix=b'upgrade.', dir=repo.path)
        backuppath = None
        try:
            ui.status(
                _(
                    b'creating temporary repository to stage upgraded '
                    b'data: %s\n'
                )
                % tmppath
            )

            # clone ui without using ui.copy because repo.ui is protected
            repoui = repo.ui.__class__(repo.ui)
            dstrepo = hg.repository(repoui, path=tmppath, create=True)

            with dstrepo.wlock(), dstrepo.lock():
                backuppath = upgrade_engine.upgrade(
                    ui, repo, dstrepo, upgrade_op
                )

        finally:
            ui.status(_(b'removing temporary repository %s\n') % tmppath)
            repo.vfs.rmtree(tmppath, forcibly=True)

            if backuppath and not ui.quiet:
                ui.warn(
                    _(b'copy of old repository backed up at %s\n') % backuppath
                )
                ui.warn(
                    _(
                        b'the old repository will not be deleted; remove '
                        b'it to free up disk space once the upgraded '
                        b'repository is verified\n'
                    )
                )

            upgrade_op.print_post_op_messages()


def upgrade_share_to_safe(
    ui,
    hgvfs,
    storevfs,
    current_requirements,
    mismatch_config,
    mismatch_warn,
):
    """Upgrades a share to use share-safe mechanism"""
    wlock = None
    store_requirements = localrepo._readrequires(storevfs, False)
    original_crequirements = current_requirements.copy()
    # after upgrade, store requires will be shared, so lets find
    # the requirements which are not present in store and
    # write them to share's .hg/requires
    diffrequires = current_requirements - store_requirements
    # add share-safe requirement as it will mark the share as share-safe
    diffrequires.add(requirementsmod.SHARESAFE_REQUIREMENT)
    current_requirements.add(requirementsmod.SHARESAFE_REQUIREMENT)
    # in `allow` case, we don't try to upgrade, we just respect the source
    # state, update requirements and continue
    if mismatch_config == b'allow':
        return
    try:
        wlock = lockmod.trylock(ui, hgvfs, b'wlock', 0, 0)
        # some process might change the requirement in between, re-read
        # and update current_requirements
        locked_requirements = localrepo._readrequires(hgvfs, True)
        if locked_requirements != original_crequirements:
            removed = current_requirements - locked_requirements
            # update current_requirements in place because it's passed
            # as reference
            current_requirements -= removed
            current_requirements |= locked_requirements
            diffrequires = current_requirements - store_requirements
            # add share-safe requirement as it will mark the share as share-safe
            diffrequires.add(requirementsmod.SHARESAFE_REQUIREMENT)
            current_requirements.add(requirementsmod.SHARESAFE_REQUIREMENT)
        scmutil.writerequires(hgvfs, diffrequires)
        ui.warn(_(b'repository upgraded to use share-safe mode\n'))
    except error.LockError as e:
        hint = _(
            b"see `hg help config.format.use-share-safe` for more information"
        )
        if mismatch_config == b'upgrade-abort':
            raise error.Abort(
                _(b'failed to upgrade share, got error: %s')
                % stringutil.forcebytestr(e.strerror),
                hint=hint,
            )
        elif mismatch_warn:
            ui.warn(
                _(b'failed to upgrade share, got error: %s\n')
                % stringutil.forcebytestr(e.strerror),
                hint=hint,
            )
    finally:
        if wlock:
            wlock.release()


def downgrade_share_to_non_safe(
    ui,
    hgvfs,
    sharedvfs,
    current_requirements,
    mismatch_config,
    mismatch_warn,
):
    """Downgrades a share which use share-safe to not use it"""
    wlock = None
    source_requirements = localrepo._readrequires(sharedvfs, True)
    original_crequirements = current_requirements.copy()
    # we cannot be 100% sure on which requirements were present in store when
    # the source supported share-safe. However, we do know that working
    # directory requirements were not there. Hence we remove them
    source_requirements -= requirementsmod.WORKING_DIR_REQUIREMENTS
    current_requirements |= source_requirements
    current_requirements.remove(requirementsmod.SHARESAFE_REQUIREMENT)
    if mismatch_config == b'allow':
        return

    try:
        wlock = lockmod.trylock(ui, hgvfs, b'wlock', 0, 0)
        # some process might change the requirement in between, re-read
        # and update current_requirements
        locked_requirements = localrepo._readrequires(hgvfs, True)
        if locked_requirements != original_crequirements:
            removed = current_requirements - locked_requirements
            # update current_requirements in place because it's passed
            # as reference
            current_requirements -= removed
            current_requirements |= locked_requirements
            current_requirements |= source_requirements
            current_requirements -= set(requirementsmod.SHARESAFE_REQUIREMENT)
        scmutil.writerequires(hgvfs, current_requirements)
        ui.warn(_(b'repository downgraded to not use share-safe mode\n'))
    except error.LockError as e:
        hint = _(
            b"see `hg help config.format.use-share-safe` for more information"
        )
        # If upgrade-abort is set, abort when upgrade fails, else let the
        # process continue as `upgrade-allow` is set
        if mismatch_config == b'downgrade-abort':
            raise error.Abort(
                _(b'failed to downgrade share, got error: %s')
                % stringutil.forcebytestr(e.strerror),
                hint=hint,
            )
        elif mismatch_warn:
            ui.warn(
                _(b'failed to downgrade share, got error: %s\n')
                % stringutil.forcebytestr(e.strerror),
                hint=hint,
            )
    finally:
        if wlock:
            wlock.release()