Patchwork D9477: upgrade: split definition and management of the actions from the main code

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Submitter phabricator
Date Dec. 1, 2020, 2:28 p.m.
Message ID <differential-rev-PHID-DREV-e472l752rpxmcxx5q5qa-req@mercurial-scm.org>
Download mbox | patch
Permalink /patch/47759/
State Superseded
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phabricator - Dec. 1, 2020, 2:28 p.m.
marmoute created this revision.
Herald added a reviewer: hg-reviewers.
Herald added a subscriber: mercurial-patches.

REVISION SUMMARY
  This is a second step to clarify and clean up this code. The code responsible
  for definition which action exist, are possible and their compatibility if moved
  into a sub module.
  
  This clarify the main code and prepare further cleanup.

REPOSITORY
  rHG Mercurial

BRANCH
  default

REVISION DETAIL
  https://phab.mercurial-scm.org/D9477

AFFECTED FILES
  hgext/largefiles/overrides.py
  hgext/lfs/wrapper.py
  mercurial/upgrade.py
  mercurial/upgrade_utils/actions.py

CHANGE DETAILS




To: marmoute, #hg-reviewers
Cc: mercurial-patches, mercurial-devel

Patch

diff --git a/mercurial/upgrade.py b/mercurial/upgrade_utils/actions.py
copy from mercurial/upgrade.py
copy to mercurial/upgrade_utils/actions.py
--- a/mercurial/upgrade.py
+++ b/mercurial/upgrade_utils/actions.py
@@ -7,21 +7,14 @@ 
 
 from __future__ import absolute_import
 
-from .i18n import _
-from . import (
-    error,
-    hg,
+from ..i18n import _
+from .. import (
     localrepo,
-    pycompat,
     requirements,
     util,
 )
 
-from .upgrade_utils import (
-    engine as upgrade_engine,
-)
-
-from .utils import compression
+from ..utils import compression
 
 # list of requirements that request a clone of all revlog if added/removed
 RECLONES_REQUIREMENTS = {
@@ -522,19 +515,6 @@ 
     return deficiencies
 
 
-# search without '-' to support older form on newer client.
-#
-# We don't enforce backward compatibility for debug command so this
-# might eventually be dropped. However, having to use two different
-# forms in script when comparing result is anoying enough to add
-# backward compatibility for a while.
-legacy_opts_map = {
-    b'redeltaparent': b're-delta-parent',
-    b'redeltamultibase': b're-delta-multibase',
-    b'redeltaall': b're-delta-all',
-    b'redeltafulladd': b're-delta-fulladd',
-}
-
 ALL_OPTIMISATIONS = []
 
 
@@ -662,311 +642,3 @@ 
     # e.g. adding generaldelta could schedule parent redeltas.
 
     return newactions
-
-
-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 = []
-    optimize = {legacy_opts_map.get(o, o) for o in optimize}
-    repo = repo.unfiltered()
-
-    revlogs = set(upgrade_engine.UPGRADE_ALL_REVLOGS)
-    specentries = (
-        (upgrade_engine.UPGRADE_CHANGELOG, changelog),
-        (upgrade_engine.UPGRADE_MANIFEST, manifest),
-        (upgrade_engine.UPGRADE_FILELOGS, filelogs),
-    )
-    specified = [(y, x) for (y, x) in specentries if x is not None]
-    if specified:
-        # we have some limitation on revlogs to be recloned
-        if any(x for y, x in specified):
-            revlogs = set()
-            for upgrade, enabled in specified:
-                if enabled:
-                    revlogs.add(upgrade)
-        else:
-            # none are enabled
-            for upgrade, __ in specified:
-                revlogs.discard(upgrade)
-
-    # Ensure the repository can be upgraded.
-    missingreqs = requiredsourcerequirements(repo) - repo.requirements
-    if missingreqs:
-        raise error.Abort(
-            _(b'cannot upgrade repository; requirement missing: %s')
-            % _(b', ').join(sorted(missingreqs))
-        )
-
-    blockedreqs = blocksourcerequirements(repo) & repo.requirements
-    if blockedreqs:
-        raise error.Abort(
-            _(
-                b'cannot upgrade repository; unsupported source '
-                b'requirement: %s'
-            )
-            % _(b', ').join(sorted(blockedreqs))
-        )
-
-    # FUTURE there is potentially a need to control the wanted requirements via
-    # command arguments or via an extension hook point.
-    newreqs = localrepo.newreporequirements(
-        repo.ui, localrepo.defaultcreateopts(repo.ui)
-    )
-    newreqs.update(preservedrequirements(repo))
-
-    noremovereqs = (
-        repo.requirements - newreqs - supportremovedrequirements(repo)
-    )
-    if noremovereqs:
-        raise error.Abort(
-            _(
-                b'cannot upgrade repository; requirement would be '
-                b'removed: %s'
-            )
-            % _(b', ').join(sorted(noremovereqs))
-        )
-
-    noaddreqs = newreqs - repo.requirements - allowednewrequirements(repo)
-    if noaddreqs:
-        raise error.Abort(
-            _(
-                b'cannot upgrade repository; do not support adding '
-                b'requirement: %s'
-            )
-            % _(b', ').join(sorted(noaddreqs))
-        )
-
-    unsupportedreqs = newreqs - supporteddestrequirements(repo)
-    if unsupportedreqs:
-        raise error.Abort(
-            _(
-                b'cannot upgrade repository; do not support '
-                b'destination requirement: %s'
-            )
-            % _(b', ').join(sorted(unsupportedreqs))
-        )
-
-    # Find and validate all improvements that can be made.
-    alloptimizations = 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'),
-        )
-
-    deficiencies = finddeficiencies(repo)
-    actions = determineactions(repo, deficiencies, repo.requirements, newreqs)
-    actions.extend(
-        o
-        for o in sorted(optimizations)
-        # determineactions could have added optimisation
-        if o not in actions
-    )
-
-    removedreqs = repo.requirements - newreqs
-    addedreqs = newreqs - repo.requirements
-
-    if revlogs != upgrade_engine.UPGRADE_ALL_REVLOGS:
-        incompatible = RECLONES_REQUIREMENTS & (removedreqs | addedreqs)
-        if incompatible:
-            msg = _(
-                b'ignoring revlogs selection flags, format requirements '
-                b'change: %s\n'
-            )
-            ui.warn(msg % b', '.join(sorted(incompatible)))
-            revlogs = upgrade_engine.UPGRADE_ALL_REVLOGS
-
-    def write_labeled(l, label):
-        first = True
-        for r in sorted(l):
-            if not first:
-                ui.write(b', ')
-            ui.write(r, label=label)
-            first = False
-
-    def printrequirements():
-        ui.write(_(b'requirements\n'))
-        ui.write(_(b'   preserved: '))
-        write_labeled(
-            newreqs & repo.requirements, "upgrade-repo.requirement.preserved"
-        )
-        ui.write((b'\n'))
-        removed = repo.requirements - newreqs
-        if repo.requirements - newreqs:
-            ui.write(_(b'   removed: '))
-            write_labeled(removed, "upgrade-repo.requirement.removed")
-            ui.write((b'\n'))
-        added = newreqs - repo.requirements
-        if added:
-            ui.write(_(b'   added: '))
-            write_labeled(added, "upgrade-repo.requirement.added")
-            ui.write((b'\n'))
-        ui.write(b'\n')
-
-    def printoptimisations():
-        optimisations = [a for a in actions if a.type == OPTIMISATION]
-        optimisations.sort(key=lambda a: a.name)
-        if optimisations:
-            ui.write(_(b'optimisations: '))
-            write_labeled(
-                [a.name for a in optimisations],
-                "upgrade-repo.optimisation.performed",
-            )
-            ui.write(b'\n\n')
-
-    def printupgradeactions():
-        for a in actions:
-            ui.status(b'%s\n   %s\n\n' % (a.name, a.upgrademessage))
-
-    def print_affected_revlogs():
-        if not revlogs:
-            ui.write((b'no revlogs to process\n'))
-        else:
-            ui.write((b'processed revlogs:\n'))
-            for r in sorted(revlogs):
-                ui.write((b'  - %s\n' % r))
-        ui.write((b'\n'))
-
-    if not run:
-        fromconfig = []
-        onlydefault = []
-
-        for d in deficiencies:
-            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 feature deficiencies found in existing '
-                    b'repository)\n'
-                )
-            )
-
-        ui.status(
-            _(
-                b'performing an upgrade with "--run" will make the following '
-                b'changes:\n\n'
-            )
-        )
-
-        printrequirements()
-        printoptimisations()
-        printupgradeactions()
-        print_affected_revlogs()
-
-        unusedoptimize = [i for i in alloptimizations if i not in actions]
-
-        if unusedoptimize:
-            ui.status(
-                _(
-                    b'additional optimizations are available by specifying '
-                    b'"--optimize <name>":\n\n'
-                )
-            )
-            for i in unusedoptimize:
-                ui.status(_(b'%s\n   %s\n\n') % (i.name, i.description))
-        return
-
-    # Else we're in the run=true case.
-    ui.write(_(b'upgrade will perform the following actions:\n\n'))
-    printrequirements()
-    printoptimisations()
-    printupgradeactions()
-    print_affected_revlogs()
-
-    upgradeactions = [a.name for a in actions]
-
-    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 migrated '
-                    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, newreqs, upgradeactions, revlogs=revlogs
-                )
-            if not (backup or backuppath is None):
-                ui.status(
-                    _(b'removing old repository content%s\n') % backuppath
-                )
-                repo.vfs.rmtree(backuppath, forcibly=True)
-                backuppath = None
-
-        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'
-                    )
-                )
diff --git a/mercurial/upgrade.py b/mercurial/upgrade.py
--- a/mercurial/upgrade.py
+++ b/mercurial/upgrade.py
@@ -13,514 +13,14 @@ 
     hg,
     localrepo,
     pycompat,
-    requirements,
-    util,
 )
 
 from .upgrade_utils import (
+    actions as upgrade_actions,
     engine as upgrade_engine,
 )
 
-from .utils import compression
-
-# list of requirements that request a clone of all revlog if added/removed
-RECLONES_REQUIREMENTS = {
-    b'generaldelta',
-    requirements.SPARSEREVLOG_REQUIREMENT,
-}
-
-
-def requiredsourcerequirements(repo):
-    """Obtain requirements required to be present to upgrade a repo.
-
-    An upgrade will not be allowed if the repository doesn't have the
-    requirements returned by this function.
-    """
-    return {
-        # Introduced in Mercurial 0.9.2.
-        b'revlogv1',
-        # Introduced in Mercurial 0.9.2.
-        b'store',
-    }
-
-
-def blocksourcerequirements(repo):
-    """Obtain requirements that will prevent an upgrade from occurring.
-
-    An upgrade cannot be performed if the source repository contains a
-    requirements in the returned set.
-    """
-    return {
-        # The upgrade code does not yet support these experimental features.
-        # This is an artificial limitation.
-        requirements.TREEMANIFEST_REQUIREMENT,
-        # This was a precursor to generaldelta and was never enabled by default.
-        # It should (hopefully) not exist in the wild.
-        b'parentdelta',
-        # Upgrade should operate on the actual store, not the shared link.
-        requirements.SHARED_REQUIREMENT,
-    }
-
-
-def supportremovedrequirements(repo):
-    """Obtain requirements that can be removed during an upgrade.
-
-    If an upgrade were to create a repository that dropped a requirement,
-    the dropped requirement must appear in the returned set for the upgrade
-    to be allowed.
-    """
-    supported = {
-        requirements.SPARSEREVLOG_REQUIREMENT,
-        requirements.SIDEDATA_REQUIREMENT,
-        requirements.COPIESSDC_REQUIREMENT,
-        requirements.NODEMAP_REQUIREMENT,
-    }
-    for name in compression.compengines:
-        engine = compression.compengines[name]
-        if engine.available() and engine.revlogheader():
-            supported.add(b'exp-compression-%s' % name)
-            if engine.name() == b'zstd':
-                supported.add(b'revlog-compression-zstd')
-    return supported
-
-
-def supporteddestrequirements(repo):
-    """Obtain requirements that upgrade supports in the destination.
-
-    If the result of the upgrade would create requirements not in this set,
-    the upgrade is disallowed.
-
-    Extensions should monkeypatch this to add their custom requirements.
-    """
-    supported = {
-        b'dotencode',
-        b'fncache',
-        b'generaldelta',
-        b'revlogv1',
-        b'store',
-        requirements.SPARSEREVLOG_REQUIREMENT,
-        requirements.SIDEDATA_REQUIREMENT,
-        requirements.COPIESSDC_REQUIREMENT,
-        requirements.NODEMAP_REQUIREMENT,
-        requirements.SHARESAFE_REQUIREMENT,
-    }
-    for name in compression.compengines:
-        engine = compression.compengines[name]
-        if engine.available() and engine.revlogheader():
-            supported.add(b'exp-compression-%s' % name)
-            if engine.name() == b'zstd':
-                supported.add(b'revlog-compression-zstd')
-    return supported
-
-
-def allowednewrequirements(repo):
-    """Obtain requirements that can be added to a repository during upgrade.
-
-    This is used to disallow proposed requirements from being added when
-    they weren't present before.
-
-    We use a list of allowed requirement additions instead of a list of known
-    bad additions because the whitelist approach is safer and will prevent
-    future, unknown requirements from accidentally being added.
-    """
-    supported = {
-        b'dotencode',
-        b'fncache',
-        b'generaldelta',
-        requirements.SPARSEREVLOG_REQUIREMENT,
-        requirements.SIDEDATA_REQUIREMENT,
-        requirements.COPIESSDC_REQUIREMENT,
-        requirements.NODEMAP_REQUIREMENT,
-    }
-    for name in compression.compengines:
-        engine = compression.compengines[name]
-        if engine.available() and engine.revlogheader():
-            supported.add(b'exp-compression-%s' % name)
-            if engine.name() == b'zstd':
-                supported.add(b'revlog-compression-zstd')
-    return supported
-
-
-def preservedrequirements(repo):
-    return set()
-
-
-DEFICIENCY = b'deficiency'
-OPTIMISATION = b'optimization'
-
-
-class improvement(object):
-    """Represents an improvement that can be made as part of an upgrade.
-
-    The following attributes are defined on each instance:
-
-    name
-       Machine-readable string uniquely identifying this improvement. It
-       will be mapped to an action later in the upgrade process.
-
-    type
-       Either ``DEFICIENCY`` or ``OPTIMISATION``. A deficiency is an obvious
-       problem. An optimization is an action (sometimes optional) that
-       can be taken to further improve the state of the repository.
-
-    description
-       Message intended for humans explaining the improvement in more detail,
-       including the implications of it. For ``DEFICIENCY`` types, should be
-       worded in the present tense. For ``OPTIMISATION`` types, should be
-       worded in the future tense.
-
-    upgrademessage
-       Message intended for humans explaining what an upgrade addressing this
-       issue will do. Should be worded in the future tense.
-    """
-
-    def __init__(self, name, type, description, upgrademessage):
-        self.name = name
-        self.type = type
-        self.description = description
-        self.upgrademessage = upgrademessage
-
-    def __eq__(self, other):
-        if not isinstance(other, improvement):
-            # This is what python tell use to do
-            return NotImplemented
-        return self.name == other.name
-
-    def __ne__(self, other):
-        return not (self == other)
-
-    def __hash__(self):
-        return hash(self.name)
-
-
-allformatvariant = []
-
-
-def registerformatvariant(cls):
-    allformatvariant.append(cls)
-    return cls
-
-
-class formatvariant(improvement):
-    """an improvement subclass dedicated to repository format"""
-
-    type = DEFICIENCY
-    ### The following attributes should be defined for each class:
-
-    # machine-readable string uniquely identifying this improvement. it will be
-    # mapped to an action later in the upgrade process.
-    name = None
-
-    # message intended for humans explaining the improvement in more detail,
-    # including the implications of it ``DEFICIENCY`` types, should be worded
-    # in the present tense.
-    description = None
-
-    # message intended for humans explaining what an upgrade addressing this
-    # issue will do. should be worded in the future tense.
-    upgrademessage = None
-
-    # value of current Mercurial default for new repository
-    default = None
-
-    def __init__(self):
-        raise NotImplementedError()
-
-    @staticmethod
-    def fromrepo(repo):
-        """current value of the variant in the repository"""
-        raise NotImplementedError()
-
-    @staticmethod
-    def fromconfig(repo):
-        """current value of the variant in the configuration"""
-        raise NotImplementedError()
-
-
-class requirementformatvariant(formatvariant):
-    """formatvariant based on a 'requirement' name.
-
-    Many format variant are controlled by a 'requirement'. We define a small
-    subclass to factor the code.
-    """
-
-    # the requirement that control this format variant
-    _requirement = None
-
-    @staticmethod
-    def _newreporequirements(ui):
-        return localrepo.newreporequirements(
-            ui, localrepo.defaultcreateopts(ui)
-        )
-
-    @classmethod
-    def fromrepo(cls, repo):
-        assert cls._requirement is not None
-        return cls._requirement in repo.requirements
-
-    @classmethod
-    def fromconfig(cls, repo):
-        assert cls._requirement is not None
-        return cls._requirement in cls._newreporequirements(repo.ui)
-
-
-@registerformatvariant
-class fncache(requirementformatvariant):
-    name = b'fncache'
-
-    _requirement = b'fncache'
-
-    default = True
-
-    description = _(
-        b'long and reserved filenames may not work correctly; '
-        b'repository performance is sub-optimal'
-    )
-
-    upgrademessage = _(
-        b'repository will be more resilient to storing '
-        b'certain paths and performance of certain '
-        b'operations should be improved'
-    )
-
-
-@registerformatvariant
-class dotencode(requirementformatvariant):
-    name = b'dotencode'
-
-    _requirement = b'dotencode'
-
-    default = True
-
-    description = _(
-        b'storage of filenames beginning with a period or '
-        b'space may not work correctly'
-    )
-
-    upgrademessage = _(
-        b'repository will be better able to store files '
-        b'beginning with a space or period'
-    )
-
-
-@registerformatvariant
-class generaldelta(requirementformatvariant):
-    name = b'generaldelta'
-
-    _requirement = b'generaldelta'
-
-    default = True
-
-    description = _(
-        b'deltas within internal storage are unable to '
-        b'choose optimal revisions; repository is larger and '
-        b'slower than it could be; interaction with other '
-        b'repositories may require extra network and CPU '
-        b'resources, making "hg push" and "hg pull" slower'
-    )
-
-    upgrademessage = _(
-        b'repository storage will be able to create '
-        b'optimal deltas; new repository data will be '
-        b'smaller and read times should decrease; '
-        b'interacting with other repositories using this '
-        b'storage model should require less network and '
-        b'CPU resources, making "hg push" and "hg pull" '
-        b'faster'
-    )
-
-
-@registerformatvariant
-class sparserevlog(requirementformatvariant):
-    name = b'sparserevlog'
-
-    _requirement = requirements.SPARSEREVLOG_REQUIREMENT
-
-    default = True
-
-    description = _(
-        b'in order to limit disk reading and memory usage on older '
-        b'version, the span of a delta chain from its root to its '
-        b'end is limited, whatever the relevant data in this span. '
-        b'This can severly limit Mercurial ability to build good '
-        b'chain of delta resulting is much more storage space being '
-        b'taken and limit reusability of on disk delta during '
-        b'exchange.'
-    )
-
-    upgrademessage = _(
-        b'Revlog supports delta chain with more unused data '
-        b'between payload. These gaps will be skipped at read '
-        b'time. This allows for better delta chains, making a '
-        b'better compression and faster exchange with server.'
-    )
-
-
-@registerformatvariant
-class sidedata(requirementformatvariant):
-    name = b'sidedata'
-
-    _requirement = requirements.SIDEDATA_REQUIREMENT
-
-    default = False
-
-    description = _(
-        b'Allows storage of extra data alongside a revision, '
-        b'unlocking various caching options.'
-    )
-
-    upgrademessage = _(b'Allows storage of extra data alongside a revision.')
-
-
-@registerformatvariant
-class persistentnodemap(requirementformatvariant):
-    name = b'persistent-nodemap'
-
-    _requirement = requirements.NODEMAP_REQUIREMENT
-
-    default = False
-
-    description = _(
-        b'persist the node -> rev mapping on disk to speedup lookup'
-    )
-
-    upgrademessage = _(b'Speedup revision lookup by node id.')
-
-
-@registerformatvariant
-class copiessdc(requirementformatvariant):
-    name = b'copies-sdc'
-
-    _requirement = requirements.COPIESSDC_REQUIREMENT
-
-    default = False
-
-    description = _(b'Stores copies information alongside changesets.')
-
-    upgrademessage = _(
-        b'Allows to use more efficient algorithm to deal with ' b'copy tracing.'
-    )
-
-
-@registerformatvariant
-class removecldeltachain(formatvariant):
-    name = b'plain-cl-delta'
-
-    default = True
-
-    description = _(
-        b'changelog storage is using deltas instead of '
-        b'raw entries; changelog reading and any '
-        b'operation relying on changelog data are slower '
-        b'than they could be'
-    )
-
-    upgrademessage = _(
-        b'changelog storage will be reformated to '
-        b'store raw entries; changelog reading will be '
-        b'faster; changelog size may be reduced'
-    )
-
-    @staticmethod
-    def fromrepo(repo):
-        # Mercurial 4.0 changed changelogs to not use delta chains. Search for
-        # changelogs with deltas.
-        cl = repo.changelog
-        chainbase = cl.chainbase
-        return all(rev == chainbase(rev) for rev in cl)
-
-    @staticmethod
-    def fromconfig(repo):
-        return True
-
-
-@registerformatvariant
-class compressionengine(formatvariant):
-    name = b'compression'
-    default = b'zlib'
-
-    description = _(
-        b'Compresion algorithm used to compress data. '
-        b'Some engine are faster than other'
-    )
-
-    upgrademessage = _(
-        b'revlog content will be recompressed with the new algorithm.'
-    )
-
-    @classmethod
-    def fromrepo(cls, repo):
-        # we allow multiple compression engine requirement to co-exist because
-        # strickly speaking, revlog seems to support mixed compression style.
-        #
-        # The compression used for new entries will be "the last one"
-        compression = b'zlib'
-        for req in repo.requirements:
-            prefix = req.startswith
-            if prefix(b'revlog-compression-') or prefix(b'exp-compression-'):
-                compression = req.split(b'-', 2)[2]
-        return compression
-
-    @classmethod
-    def fromconfig(cls, repo):
-        compengines = repo.ui.configlist(b'format', b'revlog-compression')
-        # return the first valid value as the selection code would do
-        for comp in compengines:
-            if comp in util.compengines:
-                return comp
-
-        # no valide compression found lets display it all for clarity
-        return b','.join(compengines)
-
-
-@registerformatvariant
-class compressionlevel(formatvariant):
-    name = b'compression-level'
-    default = b'default'
-
-    description = _(b'compression level')
-
-    upgrademessage = _(b'revlog content will be recompressed')
-
-    @classmethod
-    def fromrepo(cls, repo):
-        comp = compressionengine.fromrepo(repo)
-        level = None
-        if comp == b'zlib':
-            level = repo.ui.configint(b'storage', b'revlog.zlib.level')
-        elif comp == b'zstd':
-            level = repo.ui.configint(b'storage', b'revlog.zstd.level')
-        if level is None:
-            return b'default'
-        return bytes(level)
-
-    @classmethod
-    def fromconfig(cls, repo):
-        comp = compressionengine.fromconfig(repo)
-        level = None
-        if comp == b'zlib':
-            level = repo.ui.configint(b'storage', b'revlog.zlib.level')
-        elif comp == b'zstd':
-            level = repo.ui.configint(b'storage', b'revlog.zstd.level')
-        if level is None:
-            return b'default'
-        return bytes(level)
-
-
-def finddeficiencies(repo):
-    """returns a list of deficiencies that the repo suffer from"""
-    deficiencies = []
-
-    # We could detect lack of revlogv1 and store here, but they were added
-    # in 0.9.2 and we don't support upgrading repos without these
-    # requirements, so let's not bother.
-
-    for fv in allformatvariant:
-        if not fv.fromrepo(repo):
-            deficiencies.append(fv)
-
-    return deficiencies
-
+allformatvariant = upgrade_actions.allformatvariant
 
 # search without '-' to support older form on newer client.
 #
@@ -535,134 +35,6 @@ 
     b'redeltafulladd': b're-delta-fulladd',
 }
 
-ALL_OPTIMISATIONS = []
-
-
-def register_optimization(obj):
-    ALL_OPTIMISATIONS.append(obj)
-    return obj
-
-
-register_optimization(
-    improvement(
-        name=b're-delta-parent',
-        type=OPTIMISATION,
-        description=_(
-            b'deltas within internal storage will be recalculated to '
-            b'choose an optimal base revision where this was not '
-            b'already done; the size of the repository may shrink and '
-            b'various operations may become faster; the first time '
-            b'this optimization is performed could slow down upgrade '
-            b'execution considerably; subsequent invocations should '
-            b'not run noticeably slower'
-        ),
-        upgrademessage=_(
-            b'deltas within internal storage will choose a new '
-            b'base revision if needed'
-        ),
-    )
-)
-
-register_optimization(
-    improvement(
-        name=b're-delta-multibase',
-        type=OPTIMISATION,
-        description=_(
-            b'deltas within internal storage will be recalculated '
-            b'against multiple base revision and the smallest '
-            b'difference will be used; the size of the repository may '
-            b'shrink significantly when there are many merges; this '
-            b'optimization will slow down execution in proportion to '
-            b'the number of merges in the repository and the amount '
-            b'of files in the repository; this slow down should not '
-            b'be significant unless there are tens of thousands of '
-            b'files and thousands of merges'
-        ),
-        upgrademessage=_(
-            b'deltas within internal storage will choose an '
-            b'optimal delta by computing deltas against multiple '
-            b'parents; may slow down execution time '
-            b'significantly'
-        ),
-    )
-)
-
-register_optimization(
-    improvement(
-        name=b're-delta-all',
-        type=OPTIMISATION,
-        description=_(
-            b'deltas within internal storage will always be '
-            b'recalculated without reusing prior deltas; this will '
-            b'likely make execution run several times slower; this '
-            b'optimization is typically not needed'
-        ),
-        upgrademessage=_(
-            b'deltas within internal storage will be fully '
-            b'recomputed; this will likely drastically slow down '
-            b'execution time'
-        ),
-    )
-)
-
-register_optimization(
-    improvement(
-        name=b're-delta-fulladd',
-        type=OPTIMISATION,
-        description=_(
-            b'every revision will be re-added as if it was new '
-            b'content. It will go through the full storage '
-            b'mechanism giving extensions a chance to process it '
-            b'(eg. lfs). This is similar to "re-delta-all" but even '
-            b'slower since more logic is involved.'
-        ),
-        upgrademessage=_(
-            b'each revision will be added as new content to the '
-            b'internal storage; this will likely drastically slow '
-            b'down execution time, but some extensions might need '
-            b'it'
-        ),
-    )
-)
-
-
-def findoptimizations(repo):
-    """Determine optimisation that could be used during upgrade"""
-    # These are unconditionally added. There is logic later that figures out
-    # which ones to apply.
-    return list(ALL_OPTIMISATIONS)
-
-
-def determineactions(repo, deficiencies, sourcereqs, destreqs):
-    """Determine upgrade actions that will be performed.
-
-    Given a list of improvements as returned by ``finddeficiencies`` and
-    ``findoptimizations``, determine the list of upgrade actions that
-    will be performed.
-
-    The role of this function is to filter improvements if needed, apply
-    recommended optimizations from the improvements list that make sense,
-    etc.
-
-    Returns a list of action names.
-    """
-    newactions = []
-
-    for d in deficiencies:
-        name = d._requirement
-
-        # If the action is a requirement that doesn't show up in the
-        # destination requirements, prune the action.
-        if name is not None and name not in destreqs:
-            continue
-
-        newactions.append(d)
-
-    # FUTURE consider adding some optimizations here for certain transitions.
-    # e.g. adding generaldelta could schedule parent redeltas.
-
-    return newactions
-
 
 def upgraderepo(
     ui,
@@ -700,14 +72,18 @@ 
                 revlogs.discard(upgrade)
 
     # Ensure the repository can be upgraded.
-    missingreqs = requiredsourcerequirements(repo) - repo.requirements
+    missingreqs = (
+        upgrade_actions.requiredsourcerequirements(repo) - repo.requirements
+    )
     if missingreqs:
         raise error.Abort(
             _(b'cannot upgrade repository; requirement missing: %s')
             % _(b', ').join(sorted(missingreqs))
         )
 
-    blockedreqs = blocksourcerequirements(repo) & repo.requirements
+    blockedreqs = (
+        upgrade_actions.blocksourcerequirements(repo) & repo.requirements
+    )
     if blockedreqs:
         raise error.Abort(
             _(
@@ -722,10 +98,12 @@ 
     newreqs = localrepo.newreporequirements(
         repo.ui, localrepo.defaultcreateopts(repo.ui)
     )
-    newreqs.update(preservedrequirements(repo))
+    newreqs.update(upgrade_actions.preservedrequirements(repo))
 
     noremovereqs = (
-        repo.requirements - newreqs - supportremovedrequirements(repo)
+        repo.requirements
+        - newreqs
+        - upgrade_actions.supportremovedrequirements(repo)
     )
     if noremovereqs:
         raise error.Abort(
@@ -736,7 +114,11 @@ 
             % _(b', ').join(sorted(noremovereqs))
         )
 
-    noaddreqs = newreqs - repo.requirements - allowednewrequirements(repo)
+    noaddreqs = (
+        newreqs
+        - repo.requirements
+        - upgrade_actions.allowednewrequirements(repo)
+    )
     if noaddreqs:
         raise error.Abort(
             _(
@@ -746,7 +128,7 @@ 
             % _(b', ').join(sorted(noaddreqs))
         )
 
-    unsupportedreqs = newreqs - supporteddestrequirements(repo)
+    unsupportedreqs = newreqs - upgrade_actions.supporteddestrequirements(repo)
     if unsupportedreqs:
         raise error.Abort(
             _(
@@ -757,7 +139,7 @@ 
         )
 
     # Find and validate all improvements that can be made.
-    alloptimizations = findoptimizations(repo)
+    alloptimizations = upgrade_actions.findoptimizations(repo)
 
     # Apply and Validate arguments.
     optimizations = []
@@ -773,8 +155,10 @@ 
             hint=_(b'run without arguments to see valid optimizations'),
         )
 
-    deficiencies = finddeficiencies(repo)
-    actions = determineactions(repo, deficiencies, repo.requirements, newreqs)
+    deficiencies = upgrade_actions.finddeficiencies(repo)
+    actions = upgrade_actions.determineactions(
+        repo, deficiencies, repo.requirements, newreqs
+    )
     actions.extend(
         o
         for o in sorted(optimizations)
@@ -786,7 +170,9 @@ 
     addedreqs = newreqs - repo.requirements
 
     if revlogs != upgrade_engine.UPGRADE_ALL_REVLOGS:
-        incompatible = RECLONES_REQUIREMENTS & (removedreqs | addedreqs)
+        incompatible = upgrade_actions.RECLONES_REQUIREMENTS & (
+            removedreqs | addedreqs
+        )
         if incompatible:
             msg = _(
                 b'ignoring revlogs selection flags, format requirements '
@@ -823,7 +209,9 @@ 
         ui.write(b'\n')
 
     def printoptimisations():
-        optimisations = [a for a in actions if a.type == OPTIMISATION]
+        optimisations = [
+            a for a in actions if a.type == upgrade_actions.OPTIMISATION
+        ]
         optimisations.sort(key=lambda a: a.name)
         if optimisations:
             ui.write(_(b'optimisations: '))
diff --git a/hgext/lfs/wrapper.py b/hgext/lfs/wrapper.py
--- a/hgext/lfs/wrapper.py
+++ b/hgext/lfs/wrapper.py
@@ -28,13 +28,15 @@ 
     pycompat,
     revlog,
     scmutil,
-    upgrade,
     util,
     vfs as vfsmod,
     wireprotov1server,
 )
 
-from mercurial.upgrade_utils import engine as upgrade_engine
+from mercurial.upgrade_utils import (
+    actions as upgrade_actions,
+    engine as upgrade_engine,
+)
 
 from mercurial.interfaces import repository
 
@@ -539,8 +541,8 @@ 
                 lfutil.link(srclfsvfs.join(oid), dstlfsvfs.join(oid))
 
 
-@eh.wrapfunction(upgrade, b'preservedrequirements')
-@eh.wrapfunction(upgrade, b'supporteddestrequirements')
+@eh.wrapfunction(upgrade_actions, b'preservedrequirements')
+@eh.wrapfunction(upgrade_actions, b'supporteddestrequirements')
 def upgraderequirements(orig, repo):
     reqs = orig(repo)
     if b'lfs' in repo.requirements:
diff --git a/hgext/largefiles/overrides.py b/hgext/largefiles/overrides.py
--- a/hgext/largefiles/overrides.py
+++ b/hgext/largefiles/overrides.py
@@ -37,11 +37,14 @@ 
     scmutil,
     smartset,
     subrepo,
-    upgrade,
     url as urlmod,
     util,
 )
 
+from mercurial.upgrade_utils import (
+    actions as upgrade_actions,
+)
+
 from . import (
     lfcommands,
     lfutil,
@@ -1837,8 +1840,8 @@ 
     return result
 
 
-@eh.wrapfunction(upgrade, b'preservedrequirements')
-@eh.wrapfunction(upgrade, b'supporteddestrequirements')
+@eh.wrapfunction(upgrade_actions, b'preservedrequirements')
+@eh.wrapfunction(upgrade_actions, b'supporteddestrequirements')
 def upgraderequirements(orig, repo):
     reqs = orig(repo)
     if b'largefiles' in repo.requirements: