upgrade: take lock only for part where it's required

The final config calculation code does not require a lock, only writing it back
does require one.

Differential Revision: https://phab.mercurial-scm.org/D9783

mercurial/upgrade.py

@@ -1,303 +1,304 b''
 # 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 = {}
     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.
     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)
 
     removedreqs = repo.requirements - newreqs
     addedreqs = newreqs - repo.requirements
 
     if revlogs != upgrade_engine.UPGRADE_ALL_REVLOGS:
         incompatible = upgrade_actions.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
 
     upgrade_op = upgrade_actions.UpgradeOperation(
         ui,
         newreqs,
         repo.requirements,
         up_actions,
         removed_actions,
         revlogs,
     )
 
     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
                 )
             if not backup:
                 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'
                     )
                 )
 
             upgrade_op.print_post_op_messages()
 
 
 def upgrade_share_to_safe(ui, hgvfs, storevfs, current_requirements):
     """Upgrades a share to use share-safe mechanism"""
     wlock = None
+    store_requirements = localrepo._readrequires(storevfs, False)
+    # 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)
     try:
         wlock = lockmod.trylock(ui, hgvfs, b'wlock', 0, 0)
-        store_requirements = localrepo._readrequires(storevfs, False)
-        # 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)
         scmutil.writerequires(hgvfs, diffrequires)
-        current_requirements.add(requirementsmod.SHARESAFE_REQUIREMENT)
         ui.warn(_(b'repository upgraded to use share-safe mode\n'))
     except error.LockError as e:
         if ui.configbool(b'experimental', b'sharesafe-auto-upgrade-fail-error'):
             raise error.Abort(
                 _(b'failed to upgrade share, got error: %s')
                 % stringutil.forcebytestr(e.strerror)
             )
         elif ui.configbool(b'experimental', b'sharesafe-warn-outdated-shares'):
             ui.warn(
                 _(b'failed to upgrade share, got error: %s\n')
                 % stringutil.forcebytestr(e.strerror)
             )
     finally:
         if wlock:
             wlock.release()
 
 
 def downgrade_share_to_non_safe(
     ui,
     hgvfs,
     sharedvfs,
     current_requirements,
 ):
     """Downgrades a share which use share-safe to not use it"""
     wlock = None
+    source_requirements = localrepo._readrequires(sharedvfs, True)
+    # 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)
+
     try:
         wlock = lockmod.trylock(ui, hgvfs, b'wlock', 0, 0)
-        source_requirements = localrepo._readrequires(sharedvfs, True)
-        # 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)
         scmutil.writerequires(hgvfs, current_requirements)
         ui.warn(_(b'repository downgraded to not use share-safe mode\n'))
     except error.LockError as e:
         # raise error right away because if downgrade failed, we cannot load
         # the repository because it does not have complete set of requirements
         raise error.Abort(
             _(b'failed to downgrade share, got error: %s')
             % stringutil.forcebytestr(e.strerror)
         )
     finally:
         if wlock:
             wlock.release()