mergestate: reduce the number of attribute lookups

This code is called a lot during updates, this is a very small but also very
easy thing to do.

mercurial/mergestate.py

@@ -1,911 +1,908 b''
 from __future__ import annotations
 
 import collections
 import shutil
 import struct
 import weakref
 
 from .i18n import _
 from .node import (
     bin,
     hex,
     nullrev,
 )
 from . import (
     error,
     filemerge,
     util,
 )
 from .utils import hashutil
 
 _pack = struct.pack
 _unpack = struct.unpack
 
 
 def _droponode(data):
     # used for compatibility for v1
     bits = data.split(b'\0')
     bits = bits[:-2] + bits[-1:]
     return b'\0'.join(bits)
 
 
 def _filectxorabsent(hexnode, ctx, f):
     if hexnode == ctx.repo().nodeconstants.nullhex:
         return filemerge.absentfilectx(ctx, f)
     else:
         return ctx[f]
 
 
 # Merge state record types. See ``mergestate`` docs for more.
 
 ####
 # merge records which records metadata about a current merge
 # exists only once in a mergestate
 #####
 RECORD_LOCAL = b'L'
 RECORD_OTHER = b'O'
 # record merge labels
 RECORD_LABELS = b'l'
 
 #####
 # record extra information about files, with one entry containing info about one
 # file. Hence, multiple of them can exists
 #####
 RECORD_FILE_VALUES = b'f'
 
 #####
 # merge records which represents state of individual merges of files/folders
 # These are top level records for each entry containing merge related info.
 # Each record of these has info about one file. Hence multiple of them can
 # exists
 #####
 RECORD_MERGED = b'F'
 RECORD_CHANGEDELETE_CONFLICT = b'C'
 # the path was dir on one side of merge and file on another
 RECORD_PATH_CONFLICT = b'P'
 
 #####
 # possible state which a merge entry can have. These are stored inside top-level
 # merge records mentioned just above.
 #####
 MERGE_RECORD_UNRESOLVED = b'u'
 MERGE_RECORD_RESOLVED = b'r'
 MERGE_RECORD_UNRESOLVED_PATH = b'pu'
 MERGE_RECORD_RESOLVED_PATH = b'pr'
 # represents that the file was automatically merged in favor
 # of other version. This info is used on commit.
 # This is now deprecated and commit related information is now
 # stored in RECORD_FILE_VALUES
 MERGE_RECORD_MERGED_OTHER = b'o'
 
 #####
 # top level record which stores other unknown records. Multiple of these can
 # exists
 #####
 RECORD_OVERRIDE = b't'
 
 #####
 # legacy records which are no longer used but kept to prevent breaking BC
 #####
 # This record was release in 5.4 and usage was removed in 5.5
 LEGACY_RECORD_RESOLVED_OTHER = b'R'
 # This record was release in 3.7 and usage was removed in 5.6
 LEGACY_RECORD_DRIVER_RESOLVED = b'd'
 # This record was release in 3.7 and usage was removed in 5.6
 LEGACY_MERGE_DRIVER_STATE = b'm'
 # This record was release in 3.7 and usage was removed in 5.6
 LEGACY_MERGE_DRIVER_MERGE = b'D'
 
 CHANGE_ADDED = b'added'
 CHANGE_REMOVED = b'removed'
 CHANGE_MODIFIED = b'modified'
 
 
 class MergeAction:
     """represent an "action" merge need to take for a given file
 
     Attributes:
 
     _short: internal representation used to identify each action
 
     no_op:  True if the action does affect the file content or tracking status
 
     narrow_safe:
         True if the action can be safely used for a file outside of the narrow
         set
 
     changes:
         The types of changes that this actions involves. This is a work in
         progress and not all actions have one yet. In addition, some requires
         user changes and cannot be fully decided. The value currently available
         are:
 
         - ADDED: the files is new in both parents
         - REMOVED: the files existed in one parent and is getting removed
         - MODIFIED: the files existed in at least one parent and is getting changed
     """
 
     ALL_ACTIONS = weakref.WeakSet()
     NO_OP_ACTIONS = weakref.WeakSet()
 
     def __init__(self, short, no_op=False, narrow_safe=False, changes=None):
         self._short = short
         self.ALL_ACTIONS.add(self)
         self.no_op = no_op
         if self.no_op:
             self.NO_OP_ACTIONS.add(self)
         self.narrow_safe = narrow_safe
         self.changes = changes
 
     def __hash__(self):
         return hash(self._short)
 
     def __repr__(self):
         return 'MergeAction<%s>' % self._short.decode('ascii')
 
     def __bytes__(self):
         return self._short
 
     def __eq__(self, other):
         if other is None:
             return False
         assert isinstance(other, MergeAction)
         return self._short == other._short
 
     def __lt__(self, other):
         return self._short < other._short
 
 
 ACTION_FORGET = MergeAction(b'f', narrow_safe=True, changes=CHANGE_REMOVED)
 ACTION_REMOVE = MergeAction(b'r', narrow_safe=True, changes=CHANGE_REMOVED)
 ACTION_ADD = MergeAction(b'a', narrow_safe=True, changes=CHANGE_ADDED)
 ACTION_GET = MergeAction(b'g', narrow_safe=True, changes=CHANGE_MODIFIED)
 ACTION_PATH_CONFLICT = MergeAction(b'p')
 ACTION_PATH_CONFLICT_RESOLVE = MergeAction(b'pr')
 ACTION_ADD_MODIFIED = MergeAction(
     b'am', narrow_safe=True, changes=CHANGE_ADDED
 )  # not 100% about the changes value here
 ACTION_CREATED = MergeAction(b'c', narrow_safe=True, changes=CHANGE_ADDED)
 ACTION_DELETED_CHANGED = MergeAction(b'dc')
 ACTION_CHANGED_DELETED = MergeAction(b'cd')
 ACTION_MERGE = MergeAction(b'm')
 ACTION_LOCAL_DIR_RENAME_GET = MergeAction(b'dg')
 ACTION_DIR_RENAME_MOVE_LOCAL = MergeAction(b'dm')
 ACTION_KEEP = MergeAction(b'k', no_op=True)
 # the file was absent on local side before merge and we should
 # keep it absent (absent means file not present, it can be a result
 # of file deletion, rename etc.)
 ACTION_KEEP_ABSENT = MergeAction(b'ka', no_op=True)
 # the file is absent on the ancestor and remote side of the merge
 # hence this file is new and we should keep it
 ACTION_KEEP_NEW = MergeAction(b'kn', no_op=True)
 ACTION_EXEC = MergeAction(b'e', narrow_safe=True, changes=CHANGE_MODIFIED)
 ACTION_CREATED_MERGE = MergeAction(
     b'cm', narrow_safe=True, changes=CHANGE_ADDED
 )
 
 
 # Used by concert to detect situation it does not like, not sure what the exact
 # criteria is
 CONVERT_MERGE_ACTIONS = (
     ACTION_MERGE,
     ACTION_DIR_RENAME_MOVE_LOCAL,
     ACTION_CHANGED_DELETED,
     ACTION_DELETED_CHANGED,
 )
 
 
 class _mergestate_base:
     """track 3-way merge state of individual files
 
     The merge state is stored on disk when needed. Two files are used: one with
     an old format (version 1), and one with a new format (version 2). Version 2
     stores a superset of the data in version 1, including new kinds of records
     in the future. For more about the new format, see the documentation for
     `_readrecordsv2`.
 
     Each record can contain arbitrary content, and has an associated type. This
     `type` should be a letter. If `type` is uppercase, the record is mandatory:
     versions of Mercurial that don't support it should abort. If `type` is
     lowercase, the record can be safely ignored.
 
     Currently known records:
 
     L: the node of the "local" part of the merge (hexified version)
     O: the node of the "other" part of the merge (hexified version)
     F: a file to be merged entry
     C: a change/delete or delete/change conflict
     P: a path conflict (file vs directory)
     f: a (filename, dictionary) tuple of optional values for a given file
     l: the labels for the parts of the merge.
 
     Merge record states (stored in self._state, indexed by filename):
     u: unresolved conflict
     r: resolved conflict
     pu: unresolved path conflict (file conflicts with directory)
     pr: resolved path conflict
     o: file was merged in favor of other parent of merge (DEPRECATED)
 
     The resolve command transitions between 'u' and 'r' for conflicts and
     'pu' and 'pr' for path conflicts.
     """
 
     def __init__(self, repo):
         """Initialize the merge state.
 
         Do not use this directly! Instead call read() or clean()."""
         self._repo = repo
         self._state = {}
         self._stateextras = collections.defaultdict(dict)
         self._local = None
         self._other = None
         self._labels = None
         # contains a mapping of form:
         # {filename : (merge_return_value, action_to_be_performed}
         # these are results of re-running merge process
         # this dict is used to perform actions on dirstate caused by re-running
         # the merge
         self._results = {}
         self._dirty = False
 
     def reset(self):
         pass
 
     def start(self, node, other, labels=None):
         self._local = node
         self._other = other
         self._labels = labels
 
     @util.propertycache
     def local(self):
         if self._local is None:
             msg = b"local accessed but self._local isn't set"
             raise error.ProgrammingError(msg)
         return self._local
 
     @util.propertycache
     def localctx(self):
         return self._repo[self.local]
 
     @util.propertycache
     def other(self):
         if self._other is None:
             msg = b"other accessed but self._other isn't set"
             raise error.ProgrammingError(msg)
         return self._other
 
     @util.propertycache
     def otherctx(self):
         return self._repo[self.other]
 
     def active(self):
         """Whether mergestate is active.
 
         Returns True if there appears to be mergestate. This is a rough proxy
         for "is a merge in progress."
         """
         return bool(self._local) or bool(self._state)
 
     def commit(self):
         """Write current state on disk (if necessary)"""
 
     @staticmethod
     def getlocalkey(path):
         """hash the path of a local file context for storage in the .hg/merge
         directory."""
 
         return hex(hashutil.sha1(path).digest())
 
     def _make_backup(self, fctx, localkey):
         raise NotImplementedError()
 
     def _restore_backup(self, fctx, localkey, flags):
         raise NotImplementedError()
 
     def add(self, fcl, fco, fca, fd):
         """add a new (potentially?) conflicting file the merge state
         fcl: file context for local,
         fco: file context for remote,
         fca: file context for ancestors,
         fd:  file path of the resulting merge.
 
         note: also write the local version to the `.hg/merge` directory.
         """
         if fcl.isabsent():
             localkey = self._repo.nodeconstants.nullhex
         else:
             localkey = mergestate.getlocalkey(fcl.path())
             self._make_backup(fcl, localkey)
         self._state[fd] = [
             MERGE_RECORD_UNRESOLVED,
             localkey,
             fcl.path(),
             fca.path(),
             hex(fca.filenode()),
             fco.path(),
             hex(fco.filenode()),
             fcl.flags(),
         ]
         self._stateextras[fd][b'ancestorlinknode'] = hex(fca.node())
         self._dirty = True
 
     def addpathconflict(self, path, frename, forigin):
         """add a new conflicting path to the merge state
         path:    the path that conflicts
         frename: the filename the conflicting file was renamed to
         forigin: origin of the file ('l' or 'r' for local/remote)
         """
         self._state[path] = [MERGE_RECORD_UNRESOLVED_PATH, frename, forigin]
         self._dirty = True
 
     def addcommitinfo(self, path, data):
         """stores information which is required at commit
         into _stateextras"""
         self._stateextras[path].update(data)
         self._dirty = True
 
     def __contains__(self, dfile):
         return dfile in self._state
 
     def __getitem__(self, dfile):
         return self._state[dfile][0]
 
     def __iter__(self):
         return iter(sorted(self._state))
 
     def files(self):
         return self._state.keys()
 
     def mark(self, dfile, state):
         self._state[dfile][0] = state
         self._dirty = True
 
     def unresolved(self):
         """Obtain the paths of unresolved files."""
 
         for f, entry in self._state.items():
             if entry[0] in (
                 MERGE_RECORD_UNRESOLVED,
                 MERGE_RECORD_UNRESOLVED_PATH,
             ):
                 yield f
 
     def allextras(self):
         """return all extras information stored with the mergestate"""
         return self._stateextras
 
     def extras(self, filename):
         """return extras stored with the mergestate for the given filename"""
         return self._stateextras[filename]
 
     def resolve(self, dfile, wctx):
         """run merge process for dfile
 
         Returns the exit code of the merge."""
         if self[dfile] in (
             MERGE_RECORD_RESOLVED,
             LEGACY_RECORD_DRIVER_RESOLVED,
         ):
             return 0
         stateentry = self._state[dfile]
         state, localkey, lfile, afile, anode, ofile, onode, flags = stateentry
         octx = self._repo[self._other]
         extras = self.extras(dfile)
         anccommitnode = extras.get(b'ancestorlinknode')
         if anccommitnode:
             actx = self._repo[anccommitnode]
         else:
             actx = None
         fcd = _filectxorabsent(localkey, wctx, dfile)
         fco = _filectxorabsent(onode, octx, ofile)
         # TODO: move this to filectxorabsent
         fca = self._repo.filectx(afile, fileid=anode, changectx=actx)
         # "premerge" x flags
         flo = fco.flags()
         fla = fca.flags()
         if b'x' in flags + flo + fla and b'l' not in flags + flo + fla:
             if fca.rev() == nullrev and flags != flo:
                 self._repo.ui.warn(
                     _(
                         b'warning: cannot merge flags for %s '
                         b'without common ancestor - keeping local flags\n'
                     )
                     % afile
                 )
             elif flags == fla:
                 flags = flo
         # restore local
         if localkey != self._repo.nodeconstants.nullhex:
             self._restore_backup(wctx[dfile], localkey, flags)
         else:
             wctx[dfile].remove(ignoremissing=True)
 
         if not fco.cmp(fcd):  # files identical?
             # If return value of merge is None, then there are no real conflict
             del self._state[dfile]
             self._results[dfile] = None, None
             self._dirty = True
             return None
 
         merge_ret, deleted = filemerge.filemerge(
             self._repo,
             wctx,
             self._local,
             lfile,
             fcd,
             fco,
             fca,
             labels=self._labels,
         )
 
         if not merge_ret:
             self.mark(dfile, MERGE_RECORD_RESOLVED)
 
         action = None
         if deleted:
             if fcd.isabsent():
                 # dc: local picked. Need to drop if present, which may
                 # happen on re-resolves.
                 action = ACTION_FORGET
             else:
                 # cd: remote picked (or otherwise deleted)
                 action = ACTION_REMOVE
         else:
             if fcd.isabsent():  # dc: remote picked
                 action = ACTION_GET
             elif fco.isabsent():  # cd: local picked
                 if dfile in self.localctx:
                     action = ACTION_ADD_MODIFIED
                 else:
                     action = ACTION_ADD
             # else: regular merges (no action necessary)
         self._results[dfile] = merge_ret, action
 
         return merge_ret
 
     def counts(self):
         """return counts for updated, merged and removed files in this
         session"""
         updated, merged, removed = 0, 0, 0
         for r, action in self._results.values():
             if r is None:
                 updated += 1
             elif r == 0:
                 if action == ACTION_REMOVE:
                     removed += 1
                 else:
                     merged += 1
         return updated, merged, removed
 
     def unresolvedcount(self):
         """get unresolved count for this merge (persistent)"""
         return len(list(self.unresolved()))
 
     def actions(self):
         """return lists of actions to perform on the dirstate"""
         actions = {
             ACTION_REMOVE: [],
             ACTION_FORGET: [],
             ACTION_ADD: [],
             ACTION_ADD_MODIFIED: [],
             ACTION_GET: [],
         }
         for f, (r, action) in self._results.items():
             if action is not None:
                 actions[action].append((f, None, b"merge result"))
         return actions
 
 
 class mergestate(_mergestate_base):
     statepathv1 = b'merge/state'
     statepathv2 = b'merge/state2'
 
     @staticmethod
     def clean(repo):
         """Initialize a brand new merge state, removing any existing state on
         disk."""
         ms = mergestate(repo)
         ms.reset()
         return ms
 
     @staticmethod
     def read(repo):
         """Initialize the merge state, reading it from disk."""
         ms = mergestate(repo)
         ms._read()
         return ms
 
     def _read(self):
         """Analyse each record content to restore a serialized state from disk
 
         This function process "record" entry produced by the de-serialization
         of on disk file.
         """
         unsupported = set()
         records = self._readrecords()
         for rtype, record in records:
             if rtype == RECORD_LOCAL:
                 self._local = bin(record)
             elif rtype == RECORD_OTHER:
                 self._other = bin(record)
             elif rtype == LEGACY_MERGE_DRIVER_STATE:
                 pass
             elif rtype in (
                 RECORD_MERGED,
                 RECORD_CHANGEDELETE_CONFLICT,
                 RECORD_PATH_CONFLICT,
                 LEGACY_MERGE_DRIVER_MERGE,
                 LEGACY_RECORD_RESOLVED_OTHER,
             ):
                 bits = record.split(b'\0')
                 # merge entry type MERGE_RECORD_MERGED_OTHER is deprecated
                 # and we now store related information in _stateextras, so
                 # lets write to _stateextras directly
                 if bits[1] == MERGE_RECORD_MERGED_OTHER:
                     self._stateextras[bits[0]][b'filenode-source'] = b'other'
                 else:
                     self._state[bits[0]] = bits[1:]
             elif rtype == RECORD_FILE_VALUES:
                 filename, rawextras = record.split(b'\0', 1)
                 extraparts = rawextras.split(b'\0')
                 extras = {}
                 i = 0
                 while i < len(extraparts):
                     extras[extraparts[i]] = extraparts[i + 1]
                     i += 2
 
                 self._stateextras[filename] = extras
             elif rtype == RECORD_LABELS:
                 labels = record.split(b'\0', 2)
                 self._labels = [l for l in labels if len(l) > 0]
             elif not rtype.islower():
                 unsupported.add(rtype)
 
         if unsupported:
             raise error.UnsupportedMergeRecords(unsupported)
 
     def _readrecords(self):
         """Read merge state from disk and return a list of record (TYPE, data)
 
         We read data from both v1 and v2 files and decide which one to use.
 
         V1 has been used by version prior to 2.9.1 and contains less data than
         v2. We read both versions and check if no data in v2 contradicts
         v1. If there is not contradiction we can safely assume that both v1
         and v2 were written at the same time and use the extract data in v2. If
         there is contradiction we ignore v2 content as we assume an old version
         of Mercurial has overwritten the mergestate file and left an old v2
         file around.
 
         returns list of record [(TYPE, data), ...]"""
         v1records = self._readrecordsv1()
         v2records = self._readrecordsv2()
         if self._v1v2match(v1records, v2records):
             return v2records
         else:
             # v1 file is newer than v2 file, use it
             # we have to infer the "other" changeset of the merge
             # we cannot do better than that with v1 of the format
             mctx = self._repo[None].parents()[-1]
             v1records.append((RECORD_OTHER, mctx.hex()))
             # add place holder "other" file node information
             # nobody is using it yet so we do no need to fetch the data
             # if mctx was wrong `mctx[bits[-2]]` may fails.
             for idx, r in enumerate(v1records):
                 if r[0] == RECORD_MERGED:
                     bits = r[1].split(b'\0')
                     bits.insert(-2, b'')
                     v1records[idx] = (r[0], b'\0'.join(bits))
             return v1records
 
     def _v1v2match(self, v1records, v2records):
         oldv2 = set()  # old format version of v2 record
         for rec in v2records:
             if rec[0] == RECORD_LOCAL:
                 oldv2.add(rec)
             elif rec[0] == RECORD_MERGED:
                 # drop the onode data (not contained in v1)
                 oldv2.add((RECORD_MERGED, _droponode(rec[1])))
         for rec in v1records:
             if rec not in oldv2:
                 return False
         else:
             return True
 
     def _readrecordsv1(self):
         """read on disk merge state for version 1 file
 
         returns list of record [(TYPE, data), ...]
 
         Note: the "F" data from this file are one entry short
               (no "other file node" entry)
         """
         records = []
         try:
             f = self._repo.vfs(self.statepathv1)
             for i, l in enumerate(f):
                 if i == 0:
                     records.append((RECORD_LOCAL, l[:-1]))
                 else:
                     records.append((RECORD_MERGED, l[:-1]))
             f.close()
         except FileNotFoundError:
             pass
         return records
 
     def _readrecordsv2(self):
         """read on disk merge state for version 2 file
 
         This format is a list of arbitrary records of the form:
 
           [type][length][content]
 
         `type` is a single character, `length` is a 4 byte integer, and
         `content` is an arbitrary byte sequence of length `length`.
 
         Mercurial versions prior to 3.7 have a bug where if there are
         unsupported mandatory merge records, attempting to clear out the merge
         state with hg update --clean or similar aborts. The 't' record type
         works around that by writing out what those versions treat as an
         advisory record, but later versions interpret as special: the first
         character is the 'real' record type and everything onwards is the data.
 
         Returns list of records [(TYPE, data), ...]."""
         records = []
         try:
             f = self._repo.vfs(self.statepathv2)
             data = f.read()
             off = 0
             end = len(data)
             while off < end:
                 rtype = data[off : off + 1]
                 off += 1
                 length = _unpack(b'>I', data[off : (off + 4)])[0]
                 off += 4
                 record = data[off : (off + length)]
                 off += length
                 if rtype == RECORD_OVERRIDE:
                     rtype, record = record[0:1], record[1:]
                 records.append((rtype, record))
             f.close()
         except FileNotFoundError:
             pass
         return records
 
     def commit(self):
         if self._dirty:
             records = self._makerecords()
             self._writerecords(records)
             self._dirty = False
 
     def _makerecords(self):
         records = []
         records.append((RECORD_LOCAL, hex(self._local)))
         records.append((RECORD_OTHER, hex(self._other)))
         # Write out state items. In all cases, the value of the state map entry
         # is written as the contents of the record. The record type depends on
         # the type of state that is stored, and capital-letter records are used
         # to prevent older versions of Mercurial that do not support the feature
         # from loading them.
         for filename, v in self._state.items():
             if v[0] in (
                 MERGE_RECORD_UNRESOLVED_PATH,
                 MERGE_RECORD_RESOLVED_PATH,
             ):
                 # Path conflicts. These are stored in 'P' records.  The current
                 # resolution state ('pu' or 'pr') is stored within the record.
                 records.append(
                     (RECORD_PATH_CONFLICT, b'\0'.join([filename] + v))
                 )
             elif (
                 v[1] == self._repo.nodeconstants.nullhex
                 or v[6] == self._repo.nodeconstants.nullhex
             ):
                 # Change/Delete or Delete/Change conflicts. These are stored in
                 # 'C' records. v[1] is the local file, and is nullhex when the
                 # file is deleted locally ('dc'). v[6] is the remote file, and
                 # is nullhex when the file is deleted remotely ('cd').
                 records.append(
                     (RECORD_CHANGEDELETE_CONFLICT, b'\0'.join([filename] + v))
                 )
             else:
                 # Normal files.  These are stored in 'F' records.
                 records.append((RECORD_MERGED, b'\0'.join([filename] + v)))
         for filename, extras in sorted(self._stateextras.items()):
             rawextras = b'\0'.join(
                 b'%s\0%s' % (k, v) for k, v in extras.items()
             )
             records.append(
                 (RECORD_FILE_VALUES, b'%s\0%s' % (filename, rawextras))
             )
         if self._labels is not None:
             labels = b'\0'.join(self._labels)
             records.append((RECORD_LABELS, labels))
         return records
 
     def _writerecords(self, records):
         """Write current state on disk (both v1 and v2)"""
         self._writerecordsv1(records)
         self._writerecordsv2(records)
 
     def _writerecordsv1(self, records):
         """Write current state on disk in a version 1 file"""
         f = self._repo.vfs(self.statepathv1, b'wb')
         irecords = iter(records)
         lrecords = next(irecords)
         assert lrecords[0] == RECORD_LOCAL
         f.write(hex(self._local) + b'\n')
         for rtype, data in irecords:
             if rtype == RECORD_MERGED:
                 f.write(b'%s\n' % _droponode(data))
         f.close()
 
     def _writerecordsv2(self, records):
         """Write current state on disk in a version 2 file
 
         See the docstring for _readrecordsv2 for why we use 't'."""
         # these are the records that all version 2 clients can read
         allowlist = (RECORD_LOCAL, RECORD_OTHER, RECORD_MERGED)
         f = self._repo.vfs(self.statepathv2, b'wb')
         for key, data in records:
             assert len(key) == 1
             if key not in allowlist:
                 key, data = RECORD_OVERRIDE, b'%s%s' % (key, data)
             format = b'>sI%is' % len(data)
             f.write(_pack(format, key, len(data), data))
         f.close()
 
     def _make_backup(self, fctx, localkey):
         self._repo.vfs.write(b'merge/' + localkey, fctx.data())
 
     def _restore_backup(self, fctx, localkey, flags):
         with self._repo.vfs(b'merge/' + localkey) as f:
             fctx.write(f.read(), flags)
 
     def reset(self):
         shutil.rmtree(self._repo.vfs.join(b'merge'), True)
 
 
 class memmergestate(_mergestate_base):
     def __init__(self, repo):
         super(memmergestate, self).__init__(repo)
         self._backups = {}
 
     def _make_backup(self, fctx, localkey):
         self._backups[localkey] = fctx.data()
 
     def _restore_backup(self, fctx, localkey, flags):
         fctx.write(self._backups[localkey], flags)
 
 
 def recordupdates(repo, actions, branchmerge, getfiledata):
     """record merge actions to the dirstate"""
+    dirstate = repo.dirstate
+    update_file = dirstate.update_file
+
     # remove (must come first)
     for f, args, msg in actions.get(ACTION_REMOVE, []):
         if branchmerge:
-            repo.dirstate.update_file(f, p1_tracked=True, wc_tracked=False)
+            update_file(f, p1_tracked=True, wc_tracked=False)
         else:
-            repo.dirstate.update_file(f, p1_tracked=False, wc_tracked=False)
+            update_file(f, p1_tracked=False, wc_tracked=False)
 
     # forget (must come first)
     for f, args, msg in actions.get(ACTION_FORGET, []):
-        repo.dirstate.update_file(f, p1_tracked=False, wc_tracked=False)
+        update_file(f, p1_tracked=False, wc_tracked=False)
 
     # resolve path conflicts
     for f, args, msg in actions.get(ACTION_PATH_CONFLICT_RESOLVE, []):
         (f0, origf0) = args
-        repo.dirstate.update_file(f, p1_tracked=False, wc_tracked=True)
-        repo.dirstate.copy(origf0, f)
+        update_file(f, p1_tracked=False, wc_tracked=True)
+        dirstate.copy(origf0, f)
         if f0 == origf0:
-            repo.dirstate.update_file(f0, p1_tracked=True, wc_tracked=False)
+            update_file(f0, p1_tracked=True, wc_tracked=False)
         else:
-            repo.dirstate.update_file(f0, p1_tracked=False, wc_tracked=False)
+            update_file(f0, p1_tracked=False, wc_tracked=False)
 
     # re-add
     for f, args, msg in actions.get(ACTION_ADD, []):
-        repo.dirstate.update_file(f, p1_tracked=False, wc_tracked=True)
+        update_file(f, p1_tracked=False, wc_tracked=True)
 
     # re-add/mark as modified
     for f, args, msg in actions.get(ACTION_ADD_MODIFIED, []):
         if branchmerge:
-            repo.dirstate.update_file(
+            update_file(
                 f, p1_tracked=True, wc_tracked=True, possibly_dirty=True
             )
         else:
-            repo.dirstate.update_file(f, p1_tracked=False, wc_tracked=True)
+            update_file(f, p1_tracked=False, wc_tracked=True)
 
     # exec change
     for f, args, msg in actions.get(ACTION_EXEC, []):
-        repo.dirstate.update_file(
-            f, p1_tracked=True, wc_tracked=True, possibly_dirty=True
-        )
+        update_file(f, p1_tracked=True, wc_tracked=True, possibly_dirty=True)
 
     # keep
     for f, args, msg in actions.get(ACTION_KEEP, []):
         pass
 
     # keep deleted
     for f, args, msg in actions.get(ACTION_KEEP_ABSENT, []):
         pass
 
     # keep new
     for f, args, msg in actions.get(ACTION_KEEP_NEW, []):
         pass
 
     # get
     for f, args, msg in actions.get(ACTION_GET, []):
         if branchmerge:
             # tracked in p1 can be True also but update_file should not care
-            old_entry = repo.dirstate.get_entry(f)
+            old_entry = dirstate.get_entry(f)
             p1_tracked = old_entry.any_tracked and not old_entry.added
-            repo.dirstate.update_file(
+            update_file(
                 f,
                 p1_tracked=p1_tracked,
                 wc_tracked=True,
                 p2_info=True,
             )
         else:
             parentfiledata = getfiledata[f] if getfiledata else None
-            repo.dirstate.update_file(
+            update_file(
                 f,
                 p1_tracked=True,
                 wc_tracked=True,
                 parentfiledata=parentfiledata,
             )
 
     # merge
     for f, args, msg in actions.get(ACTION_MERGE, []):
         f1, f2, fa, move, anc = args
         if branchmerge:
             # We've done a branch merge, mark this file as merged
             # so that we properly record the merger later
             p1_tracked = f1 == f
-            repo.dirstate.update_file(
+            update_file(
                 f,
                 p1_tracked=p1_tracked,
                 wc_tracked=True,
                 p2_info=True,
             )
             if f1 != f2:  # copy/rename
                 if move:
-                    repo.dirstate.update_file(
-                        f1, p1_tracked=True, wc_tracked=False
-                    )
+                    update_file(f1, p1_tracked=True, wc_tracked=False)
                 if f1 != f:
-                    repo.dirstate.copy(f1, f)
+                    dirstate.copy(f1, f)
                 else:
-                    repo.dirstate.copy(f2, f)
+                    dirstate.copy(f2, f)
         else:
             # We've update-merged a locally modified file, so
             # we set the dirstate to emulate a normal checkout
             # of that file some time in the past. Thus our
             # merge will appear as a normal local file
             # modification.
             if f2 == f:  # file not locally copied/moved
-                repo.dirstate.update_file(
+                update_file(
                     f, p1_tracked=True, wc_tracked=True, possibly_dirty=True
                 )
             if move:
-                repo.dirstate.update_file(
-                    f1, p1_tracked=False, wc_tracked=False
-                )
+                update_file(f1, p1_tracked=False, wc_tracked=False)
 
     # directory rename, move local
     for f, args, msg in actions.get(ACTION_DIR_RENAME_MOVE_LOCAL, []):
         f0, flag = args
         if branchmerge:
-            repo.dirstate.update_file(f, p1_tracked=False, wc_tracked=True)
-            repo.dirstate.update_file(f0, p1_tracked=True, wc_tracked=False)
-            repo.dirstate.copy(f0, f)
+            update_file(f, p1_tracked=False, wc_tracked=True)
+            update_file(f0, p1_tracked=True, wc_tracked=False)
+            dirstate.copy(f0, f)
         else:
-            repo.dirstate.update_file(f, p1_tracked=True, wc_tracked=True)
-            repo.dirstate.update_file(f0, p1_tracked=False, wc_tracked=False)
+            update_file(f, p1_tracked=True, wc_tracked=True)
+            update_file(f0, p1_tracked=False, wc_tracked=False)
 
     # directory rename, get
     for f, args, msg in actions.get(ACTION_LOCAL_DIR_RENAME_GET, []):
         f0, flag = args
         if branchmerge:
-            repo.dirstate.update_file(f, p1_tracked=False, wc_tracked=True)
-            repo.dirstate.copy(f0, f)
+            update_file(f, p1_tracked=False, wc_tracked=True)
+            dirstate.copy(f0, f)
         else:
-            repo.dirstate.update_file(f, p1_tracked=True, wc_tracked=True)
+            update_file(f, p1_tracked=True, wc_tracked=True)