exewrapper: add comments about PYTHONHOME
This has been a repeating source of confusion for users of HackableMercurial.
Note that users of HackableMercurial should *not* and are *not* expected to set
PYTHONHOME.
# obsolete.py - obsolete markers handling
#
# Copyright 2012 Pierre-Yves David <pierre-yves.david@ens-lyon.org>
# Logilab SA <contact@logilab.fr>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""Obsolete marker handling
An obsolete marker maps an old changeset to a list of new
changesets. If the list of new changesets is empty, the old changeset
is said to be "killed". Otherwise, the old changeset is being
"replaced" by the new changesets.
Obsolete markers can be used to record and distribute changeset graph
transformations performed by history rewrite operations, and help
building new tools to reconcile conflicting rewrite actions. To
facilitate conflict resolution, markers include various annotations
besides old and news changeset identifiers, such as creation date or
author name.
The old obsoleted changeset is called a "precursor" and possible
replacements are called "successors". Markers that used changeset X as
a precursor are called "successor markers of X" because they hold
information about the successors of X. Markers that use changeset Y as
a successors are call "precursor markers of Y" because they hold
information about the precursors of Y.
Examples:
- When changeset A is replaced by changeset A', one marker is stored:
(A, (A',))
- When changesets A and B are folded into a new changeset C, two markers are
stored:
(A, (C,)) and (B, (C,))
- When changeset A is simply "pruned" from the graph, a marker is created:
(A, ())
- When changeset A is split into B and C, a single marker are used:
(A, (C, C))
We use a single marker to distinguish the "split" case from the "divergence"
case. If two independent operations rewrite the same changeset A in to A' and
A'', we have an error case: divergent rewriting. We can detect it because
two markers will be created independently:
(A, (B,)) and (A, (C,))
Format
------
Markers are stored in an append-only file stored in
'.hg/store/obsstore'.
The file starts with a version header:
- 1 unsigned byte: version number, starting at zero.
The header is followed by the markers. Marker format depend of the version. See
comment associated with each format for details.
"""
import errno, struct
import util, base85, node, parsers, error
import phases
from i18n import _
_pack = struct.pack
_unpack = struct.unpack
_calcsize = struct.calcsize
propertycache = util.propertycache
# the obsolete feature is not mature enough to be enabled by default.
# you have to rely on third party extension extension to enable this.
_enabled = False
# Options for obsolescence
createmarkersopt = 'createmarkers'
allowunstableopt = 'allowunstable'
exchangeopt = 'exchange'
### obsolescence marker flag
## bumpedfix flag
#
# When a changeset A' succeed to a changeset A which became public, we call A'
# "bumped" because it's a successors of a public changesets
#
# o A' (bumped)
# |`:
# | o A
# |/
# o Z
#
# The way to solve this situation is to create a new changeset Ad as children
# of A. This changeset have the same content than A'. So the diff from A to A'
# is the same than the diff from A to Ad. Ad is marked as a successors of A'
#
# o Ad
# |`:
# | x A'
# |'|
# o | A
# |/
# o Z
#
# But by transitivity Ad is also a successors of A. To avoid having Ad marked
# as bumped too, we add the `bumpedfix` flag to the marker. <A', (Ad,)>.
# This flag mean that the successors express the changes between the public and
# bumped version and fix the situation, breaking the transitivity of
# "bumped" here.
bumpedfix = 1
usingsha256 = 2
## Parsing and writing of version "0"
#
# The header is followed by the markers. Each marker is made of:
#
# - 1 uint8 : number of new changesets "N", can be zero.
#
# - 1 uint32: metadata size "M" in bytes.
#
# - 1 byte: a bit field. It is reserved for flags used in common
# obsolete marker operations, to avoid repeated decoding of metadata
# entries.
#
# - 20 bytes: obsoleted changeset identifier.
#
# - N*20 bytes: new changesets identifiers.
#
# - M bytes: metadata as a sequence of nul-terminated strings. Each
# string contains a key and a value, separated by a colon ':', without
# additional encoding. Keys cannot contain '\0' or ':' and values
# cannot contain '\0'.
_fm0version = 0
_fm0fixed = '>BIB20s'
_fm0node = '20s'
_fm0fsize = _calcsize(_fm0fixed)
_fm0fnodesize = _calcsize(_fm0node)
def _fm0readmarkers(data, off):
# Loop on markers
l = len(data)
while off + _fm0fsize <= l:
# read fixed part
cur = data[off:off + _fm0fsize]
off += _fm0fsize
numsuc, mdsize, flags, pre = _unpack(_fm0fixed, cur)
# read replacement
sucs = ()
if numsuc:
s = (_fm0fnodesize * numsuc)
cur = data[off:off + s]
sucs = _unpack(_fm0node * numsuc, cur)
off += s
# read metadata
# (metadata will be decoded on demand)
metadata = data[off:off + mdsize]
if len(metadata) != mdsize:
raise error.Abort(_('parsing obsolete marker: metadata is too '
'short, %d bytes expected, got %d')
% (mdsize, len(metadata)))
off += mdsize
metadata = _fm0decodemeta(metadata)
try:
when, offset = metadata.pop('date', '0 0').split(' ')
date = float(when), int(offset)
except ValueError:
date = (0., 0)
parents = None
if 'p2' in metadata:
parents = (metadata.pop('p1', None), metadata.pop('p2', None))
elif 'p1' in metadata:
parents = (metadata.pop('p1', None),)
elif 'p0' in metadata:
parents = ()
if parents is not None:
try:
parents = tuple(node.bin(p) for p in parents)
# if parent content is not a nodeid, drop the data
for p in parents:
if len(p) != 20:
parents = None
break
except TypeError:
# if content cannot be translated to nodeid drop the data.
parents = None
metadata = tuple(sorted(metadata.iteritems()))
yield (pre, sucs, flags, metadata, date, parents)
def _fm0encodeonemarker(marker):
pre, sucs, flags, metadata, date, parents = marker
if flags & usingsha256:
raise error.Abort(_('cannot handle sha256 with old obsstore format'))
metadata = dict(metadata)
time, tz = date
metadata['date'] = '%r %i' % (time, tz)
if parents is not None:
if not parents:
# mark that we explicitly recorded no parents
metadata['p0'] = ''
for i, p in enumerate(parents):
metadata['p%i' % (i + 1)] = node.hex(p)
metadata = _fm0encodemeta(metadata)
numsuc = len(sucs)
format = _fm0fixed + (_fm0node * numsuc)
data = [numsuc, len(metadata), flags, pre]
data.extend(sucs)
return _pack(format, *data) + metadata
def _fm0encodemeta(meta):
"""Return encoded metadata string to string mapping.
Assume no ':' in key and no '\0' in both key and value."""
for key, value in meta.iteritems():
if ':' in key or '\0' in key:
raise ValueError("':' and '\0' are forbidden in metadata key'")
if '\0' in value:
raise ValueError("':' is forbidden in metadata value'")
return '\0'.join(['%s:%s' % (k, meta[k]) for k in sorted(meta)])
def _fm0decodemeta(data):
"""Return string to string dictionary from encoded version."""
d = {}
for l in data.split('\0'):
if l:
key, value = l.split(':')
d[key] = value
return d
## Parsing and writing of version "1"
#
# The header is followed by the markers. Each marker is made of:
#
# - uint32: total size of the marker (including this field)
#
# - float64: date in seconds since epoch
#
# - int16: timezone offset in minutes
#
# - uint16: a bit field. It is reserved for flags used in common
# obsolete marker operations, to avoid repeated decoding of metadata
# entries.
#
# - uint8: number of successors "N", can be zero.
#
# - uint8: number of parents "P", can be zero.
#
# 0: parents data stored but no parent,
# 1: one parent stored,
# 2: two parents stored,
# 3: no parent data stored
#
# - uint8: number of metadata entries M
#
# - 20 or 32 bytes: precursor changeset identifier.
#
# - N*(20 or 32) bytes: successors changesets identifiers.
#
# - P*(20 or 32) bytes: parents of the precursors changesets.
#
# - M*(uint8, uint8): size of all metadata entries (key and value)
#
# - remaining bytes: the metadata, each (key, value) pair after the other.
_fm1version = 1
_fm1fixed = '>IdhHBBB20s'
_fm1nodesha1 = '20s'
_fm1nodesha256 = '32s'
_fm1nodesha1size = _calcsize(_fm1nodesha1)
_fm1nodesha256size = _calcsize(_fm1nodesha256)
_fm1fsize = _calcsize(_fm1fixed)
_fm1parentnone = 3
_fm1parentshift = 14
_fm1parentmask = (_fm1parentnone << _fm1parentshift)
_fm1metapair = 'BB'
_fm1metapairsize = _calcsize('BB')
def _fm1purereadmarkers(data, off):
# make some global constants local for performance
noneflag = _fm1parentnone
sha2flag = usingsha256
sha1size = _fm1nodesha1size
sha2size = _fm1nodesha256size
sha1fmt = _fm1nodesha1
sha2fmt = _fm1nodesha256
metasize = _fm1metapairsize
metafmt = _fm1metapair
fsize = _fm1fsize
unpack = _unpack
# Loop on markers
stop = len(data) - _fm1fsize
ufixed = struct.Struct(_fm1fixed).unpack
while off <= stop:
# read fixed part
o1 = off + fsize
t, secs, tz, flags, numsuc, numpar, nummeta, prec = ufixed(data[off:o1])
if flags & sha2flag:
# FIXME: prec was read as a SHA1, needs to be amended
# read 0 or more successors
if numsuc == 1:
o2 = o1 + sha2size
sucs = (data[o1:o2],)
else:
o2 = o1 + sha2size * numsuc
sucs = unpack(sha2fmt * numsuc, data[o1:o2])
# read parents
if numpar == noneflag:
o3 = o2
parents = None
elif numpar == 1:
o3 = o2 + sha2size
parents = (data[o2:o3],)
else:
o3 = o2 + sha2size * numpar
parents = unpack(sha2fmt * numpar, data[o2:o3])
else:
# read 0 or more successors
if numsuc == 1:
o2 = o1 + sha1size
sucs = (data[o1:o2],)
else:
o2 = o1 + sha1size * numsuc
sucs = unpack(sha1fmt * numsuc, data[o1:o2])
# read parents
if numpar == noneflag:
o3 = o2
parents = None
elif numpar == 1:
o3 = o2 + sha1size
parents = (data[o2:o3],)
else:
o3 = o2 + sha1size * numpar
parents = unpack(sha1fmt * numpar, data[o2:o3])
# read metadata
off = o3 + metasize * nummeta
metapairsize = unpack('>' + (metafmt * nummeta), data[o3:off])
metadata = []
for idx in xrange(0, len(metapairsize), 2):
o1 = off + metapairsize[idx]
o2 = o1 + metapairsize[idx + 1]
metadata.append((data[off:o1], data[o1:o2]))
off = o2
yield (prec, sucs, flags, tuple(metadata), (secs, tz * 60), parents)
def _fm1encodeonemarker(marker):
pre, sucs, flags, metadata, date, parents = marker
# determine node size
_fm1node = _fm1nodesha1
if flags & usingsha256:
_fm1node = _fm1nodesha256
numsuc = len(sucs)
numextranodes = numsuc
if parents is None:
numpar = _fm1parentnone
else:
numpar = len(parents)
numextranodes += numpar
formatnodes = _fm1node * numextranodes
formatmeta = _fm1metapair * len(metadata)
format = _fm1fixed + formatnodes + formatmeta
# tz is stored in minutes so we divide by 60
tz = date[1]//60
data = [None, date[0], tz, flags, numsuc, numpar, len(metadata), pre]
data.extend(sucs)
if parents is not None:
data.extend(parents)
totalsize = _calcsize(format)
for key, value in metadata:
lk = len(key)
lv = len(value)
data.append(lk)
data.append(lv)
totalsize += lk + lv
data[0] = totalsize
data = [_pack(format, *data)]
for key, value in metadata:
data.append(key)
data.append(value)
return ''.join(data)
def _fm1readmarkers(data, off):
native = getattr(parsers, 'fm1readmarkers', None)
if not native:
return _fm1purereadmarkers(data, off)
stop = len(data) - _fm1fsize
return native(data, off, stop)
# mapping to read/write various marker formats
# <version> -> (decoder, encoder)
formats = {_fm0version: (_fm0readmarkers, _fm0encodeonemarker),
_fm1version: (_fm1readmarkers, _fm1encodeonemarker)}
@util.nogc
def _readmarkers(data):
"""Read and enumerate markers from raw data"""
off = 0
diskversion = _unpack('>B', data[off:off + 1])[0]
off += 1
if diskversion not in formats:
raise error.Abort(_('parsing obsolete marker: unknown version %r')
% diskversion)
return diskversion, formats[diskversion][0](data, off)
def encodemarkers(markers, addheader=False, version=_fm0version):
# Kept separate from flushmarkers(), it will be reused for
# markers exchange.
encodeone = formats[version][1]
if addheader:
yield _pack('>B', version)
for marker in markers:
yield encodeone(marker)
class marker(object):
"""Wrap obsolete marker raw data"""
def __init__(self, repo, data):
# the repo argument will be used to create changectx in later version
self._repo = repo
self._data = data
self._decodedmeta = None
def __hash__(self):
return hash(self._data)
def __eq__(self, other):
if type(other) != type(self):
return False
return self._data == other._data
def precnode(self):
"""Precursor changeset node identifier"""
return self._data[0]
def succnodes(self):
"""List of successor changesets node identifiers"""
return self._data[1]
def parentnodes(self):
"""Parents of the precursors (None if not recorded)"""
return self._data[5]
def metadata(self):
"""Decoded metadata dictionary"""
return dict(self._data[3])
def date(self):
"""Creation date as (unixtime, offset)"""
return self._data[4]
def flags(self):
"""The flags field of the marker"""
return self._data[2]
@util.nogc
def _addsuccessors(successors, markers):
for mark in markers:
successors.setdefault(mark[0], set()).add(mark)
@util.nogc
def _addprecursors(precursors, markers):
for mark in markers:
for suc in mark[1]:
precursors.setdefault(suc, set()).add(mark)
@util.nogc
def _addchildren(children, markers):
for mark in markers:
parents = mark[5]
if parents is not None:
for p in parents:
children.setdefault(p, set()).add(mark)
def _checkinvalidmarkers(markers):
"""search for marker with invalid data and raise error if needed
Exist as a separated function to allow the evolve extension for a more
subtle handling.
"""
for mark in markers:
if node.nullid in mark[1]:
raise error.Abort(_('bad obsolescence marker detected: '
'invalid successors nullid'))
class obsstore(object):
"""Store obsolete markers
Markers can be accessed with two mappings:
- precursors[x] -> set(markers on precursors edges of x)
- successors[x] -> set(markers on successors edges of x)
- children[x] -> set(markers on precursors edges of children(x)
"""
fields = ('prec', 'succs', 'flag', 'meta', 'date', 'parents')
# prec: nodeid, precursor changesets
# succs: tuple of nodeid, successor changesets (0-N length)
# flag: integer, flag field carrying modifier for the markers (see doc)
# meta: binary blob, encoded metadata dictionary
# date: (float, int) tuple, date of marker creation
# parents: (tuple of nodeid) or None, parents of precursors
# None is used when no data has been recorded
def __init__(self, svfs, defaultformat=_fm1version, readonly=False):
# caches for various obsolescence related cache
self.caches = {}
self.svfs = svfs
self._version = defaultformat
self._readonly = readonly
def __iter__(self):
return iter(self._all)
def __len__(self):
return len(self._all)
def __nonzero__(self):
if not self._cached('_all'):
try:
return self.svfs.stat('obsstore').st_size > 1
except OSError as inst:
if inst.errno != errno.ENOENT:
raise
# just build an empty _all list if no obsstore exists, which
# avoids further stat() syscalls
pass
return bool(self._all)
def create(self, transaction, prec, succs=(), flag=0, parents=None,
date=None, metadata=None):
"""obsolete: add a new obsolete marker
* ensuring it is hashable
* check mandatory metadata
* encode metadata
If you are a human writing code creating marker you want to use the
`createmarkers` function in this module instead.
return True if a new marker have been added, False if the markers
already existed (no op).
"""
if metadata is None:
metadata = {}
if date is None:
if 'date' in metadata:
# as a courtesy for out-of-tree extensions
date = util.parsedate(metadata.pop('date'))
else:
date = util.makedate()
if len(prec) != 20:
raise ValueError(prec)
for succ in succs:
if len(succ) != 20:
raise ValueError(succ)
if prec in succs:
raise ValueError(_('in-marker cycle with %s') % node.hex(prec))
metadata = tuple(sorted(metadata.iteritems()))
marker = (str(prec), tuple(succs), int(flag), metadata, date, parents)
return bool(self.add(transaction, [marker]))
def add(self, transaction, markers):
"""Add new markers to the store
Take care of filtering duplicate.
Return the number of new marker."""
if self._readonly:
raise error.Abort('creating obsolete markers is not enabled on '
'this repo')
known = set(self._all)
new = []
for m in markers:
if m not in known:
known.add(m)
new.append(m)
if new:
f = self.svfs('obsstore', 'ab')
try:
offset = f.tell()
transaction.add('obsstore', offset)
# offset == 0: new file - add the version header
for bytes in encodemarkers(new, offset == 0, self._version):
f.write(bytes)
finally:
# XXX: f.close() == filecache invalidation == obsstore rebuilt.
# call 'filecacheentry.refresh()' here
f.close()
self._addmarkers(new)
# new marker *may* have changed several set. invalidate the cache.
self.caches.clear()
# records the number of new markers for the transaction hooks
previous = int(transaction.hookargs.get('new_obsmarkers', '0'))
transaction.hookargs['new_obsmarkers'] = str(previous + len(new))
return len(new)
def mergemarkers(self, transaction, data):
"""merge a binary stream of markers inside the obsstore
Returns the number of new markers added."""
version, markers = _readmarkers(data)
return self.add(transaction, markers)
@propertycache
def _all(self):
data = self.svfs.tryread('obsstore')
if not data:
return []
self._version, markers = _readmarkers(data)
markers = list(markers)
_checkinvalidmarkers(markers)
return markers
@propertycache
def successors(self):
successors = {}
_addsuccessors(successors, self._all)
return successors
@propertycache
def precursors(self):
precursors = {}
_addprecursors(precursors, self._all)
return precursors
@propertycache
def children(self):
children = {}
_addchildren(children, self._all)
return children
def _cached(self, attr):
return attr in self.__dict__
def _addmarkers(self, markers):
markers = list(markers) # to allow repeated iteration
self._all.extend(markers)
if self._cached('successors'):
_addsuccessors(self.successors, markers)
if self._cached('precursors'):
_addprecursors(self.precursors, markers)
if self._cached('children'):
_addchildren(self.children, markers)
_checkinvalidmarkers(markers)
def relevantmarkers(self, nodes):
"""return a set of all obsolescence markers relevant to a set of nodes.
"relevant" to a set of nodes mean:
- marker that use this changeset as successor
- prune marker of direct children on this changeset
- recursive application of the two rules on precursors of these markers
It is a set so you cannot rely on order."""
pendingnodes = set(nodes)
seenmarkers = set()
seennodes = set(pendingnodes)
precursorsmarkers = self.precursors
children = self.children
while pendingnodes:
direct = set()
for current in pendingnodes:
direct.update(precursorsmarkers.get(current, ()))
pruned = [m for m in children.get(current, ()) if not m[1]]
direct.update(pruned)
direct -= seenmarkers
pendingnodes = set([m[0] for m in direct])
seenmarkers |= direct
pendingnodes -= seennodes
seennodes |= pendingnodes
return seenmarkers
def commonversion(versions):
"""Return the newest version listed in both versions and our local formats.
Returns None if no common version exists.
"""
versions.sort(reverse=True)
# search for highest version known on both side
for v in versions:
if v in formats:
return v
return None
# arbitrary picked to fit into 8K limit from HTTP server
# you have to take in account:
# - the version header
# - the base85 encoding
_maxpayload = 5300
def _pushkeyescape(markers):
"""encode markers into a dict suitable for pushkey exchange
- binary data is base85 encoded
- split in chunks smaller than 5300 bytes"""
keys = {}
parts = []
currentlen = _maxpayload * 2 # ensure we create a new part
for marker in markers:
nextdata = _fm0encodeonemarker(marker)
if (len(nextdata) + currentlen > _maxpayload):
currentpart = []
currentlen = 0
parts.append(currentpart)
currentpart.append(nextdata)
currentlen += len(nextdata)
for idx, part in enumerate(reversed(parts)):
data = ''.join([_pack('>B', _fm0version)] + part)
keys['dump%i' % idx] = base85.b85encode(data)
return keys
def listmarkers(repo):
"""List markers over pushkey"""
if not repo.obsstore:
return {}
return _pushkeyescape(sorted(repo.obsstore))
def pushmarker(repo, key, old, new):
"""Push markers over pushkey"""
if not key.startswith('dump'):
repo.ui.warn(_('unknown key: %r') % key)
return 0
if old:
repo.ui.warn(_('unexpected old value for %r') % key)
return 0
data = base85.b85decode(new)
lock = repo.lock()
try:
tr = repo.transaction('pushkey: obsolete markers')
try:
repo.obsstore.mergemarkers(tr, data)
tr.close()
return 1
finally:
tr.release()
finally:
lock.release()
def getmarkers(repo, nodes=None):
"""returns markers known in a repository
If <nodes> is specified, only markers "relevant" to those nodes are are
returned"""
if nodes is None:
rawmarkers = repo.obsstore
else:
rawmarkers = repo.obsstore.relevantmarkers(nodes)
for markerdata in rawmarkers:
yield marker(repo, markerdata)
def relevantmarkers(repo, node):
"""all obsolete markers relevant to some revision"""
for markerdata in repo.obsstore.relevantmarkers(node):
yield marker(repo, markerdata)
def precursormarkers(ctx):
"""obsolete marker marking this changeset as a successors"""
for data in ctx.repo().obsstore.precursors.get(ctx.node(), ()):
yield marker(ctx.repo(), data)
def successormarkers(ctx):
"""obsolete marker making this changeset obsolete"""
for data in ctx.repo().obsstore.successors.get(ctx.node(), ()):
yield marker(ctx.repo(), data)
def allsuccessors(obsstore, nodes, ignoreflags=0):
"""Yield node for every successor of <nodes>.
Some successors may be unknown locally.
This is a linear yield unsuited to detecting split changesets. It includes
initial nodes too."""
remaining = set(nodes)
seen = set(remaining)
while remaining:
current = remaining.pop()
yield current
for mark in obsstore.successors.get(current, ()):
# ignore marker flagged with specified flag
if mark[2] & ignoreflags:
continue
for suc in mark[1]:
if suc not in seen:
seen.add(suc)
remaining.add(suc)
def allprecursors(obsstore, nodes, ignoreflags=0):
"""Yield node for every precursors of <nodes>.
Some precursors may be unknown locally.
This is a linear yield unsuited to detecting folded changesets. It includes
initial nodes too."""
remaining = set(nodes)
seen = set(remaining)
while remaining:
current = remaining.pop()
yield current
for mark in obsstore.precursors.get(current, ()):
# ignore marker flagged with specified flag
if mark[2] & ignoreflags:
continue
suc = mark[0]
if suc not in seen:
seen.add(suc)
remaining.add(suc)
def foreground(repo, nodes):
"""return all nodes in the "foreground" of other node
The foreground of a revision is anything reachable using parent -> children
or precursor -> successor relation. It is very similar to "descendant" but
augmented with obsolescence information.
Beware that possible obsolescence cycle may result if complex situation.
"""
repo = repo.unfiltered()
foreground = set(repo.set('%ln::', nodes))
if repo.obsstore:
# We only need this complicated logic if there is obsolescence
# XXX will probably deserve an optimised revset.
nm = repo.changelog.nodemap
plen = -1
# compute the whole set of successors or descendants
while len(foreground) != plen:
plen = len(foreground)
succs = set(c.node() for c in foreground)
mutable = [c.node() for c in foreground if c.mutable()]
succs.update(allsuccessors(repo.obsstore, mutable))
known = (n for n in succs if n in nm)
foreground = set(repo.set('%ln::', known))
return set(c.node() for c in foreground)
def successorssets(repo, initialnode, cache=None):
"""Return set of all latest successors of initial nodes
The successors set of a changeset A are the group of revisions that succeed
A. It succeeds A as a consistent whole, each revision being only a partial
replacement. The successors set contains non-obsolete changesets only.
This function returns the full list of successor sets which is why it
returns a list of tuples and not just a single tuple. Each tuple is a valid
successors set. Note that (A,) may be a valid successors set for changeset A
(see below).
In most cases, a changeset A will have a single element (e.g. the changeset
A is replaced by A') in its successors set. Though, it is also common for a
changeset A to have no elements in its successor set (e.g. the changeset
has been pruned). Therefore, the returned list of successors sets will be
[(A',)] or [], respectively.
When a changeset A is split into A' and B', however, it will result in a
successors set containing more than a single element, i.e. [(A',B')].
Divergent changesets will result in multiple successors sets, i.e. [(A',),
(A'')].
If a changeset A is not obsolete, then it will conceptually have no
successors set. To distinguish this from a pruned changeset, the successor
set will contain itself only, i.e. [(A,)].
Finally, successors unknown locally are considered to be pruned (obsoleted
without any successors).
The optional `cache` parameter is a dictionary that may contain precomputed
successors sets. It is meant to reuse the computation of a previous call to
`successorssets` when multiple calls are made at the same time. The cache
dictionary is updated in place. The caller is responsible for its life
span. Code that makes multiple calls to `successorssets` *must* use this
cache mechanism or suffer terrible performance.
"""
succmarkers = repo.obsstore.successors
# Stack of nodes we search successors sets for
toproceed = [initialnode]
# set version of above list for fast loop detection
# element added to "toproceed" must be added here
stackedset = set(toproceed)
if cache is None:
cache = {}
# This while loop is the flattened version of a recursive search for
# successors sets
#
# def successorssets(x):
# successors = directsuccessors(x)
# ss = [[]]
# for succ in directsuccessors(x):
# # product as in itertools cartesian product
# ss = product(ss, successorssets(succ))
# return ss
#
# But we can not use plain recursive calls here:
# - that would blow the python call stack
# - obsolescence markers may have cycles, we need to handle them.
#
# The `toproceed` list act as our call stack. Every node we search
# successors set for are stacked there.
#
# The `stackedset` is set version of this stack used to check if a node is
# already stacked. This check is used to detect cycles and prevent infinite
# loop.
#
# successors set of all nodes are stored in the `cache` dictionary.
#
# After this while loop ends we use the cache to return the successors sets
# for the node requested by the caller.
while toproceed:
# Every iteration tries to compute the successors sets of the topmost
# node of the stack: CURRENT.
#
# There are four possible outcomes:
#
# 1) We already know the successors sets of CURRENT:
# -> mission accomplished, pop it from the stack.
# 2) Node is not obsolete:
# -> the node is its own successors sets. Add it to the cache.
# 3) We do not know successors set of direct successors of CURRENT:
# -> We add those successors to the stack.
# 4) We know successors sets of all direct successors of CURRENT:
# -> We can compute CURRENT successors set and add it to the
# cache.
#
current = toproceed[-1]
if current in cache:
# case (1): We already know the successors sets
stackedset.remove(toproceed.pop())
elif current not in succmarkers:
# case (2): The node is not obsolete.
if current in repo:
# We have a valid last successors.
cache[current] = [(current,)]
else:
# Final obsolete version is unknown locally.
# Do not count that as a valid successors
cache[current] = []
else:
# cases (3) and (4)
#
# We proceed in two phases. Phase 1 aims to distinguish case (3)
# from case (4):
#
# For each direct successors of CURRENT, we check whether its
# successors sets are known. If they are not, we stack the
# unknown node and proceed to the next iteration of the while
# loop. (case 3)
#
# During this step, we may detect obsolescence cycles: a node
# with unknown successors sets but already in the call stack.
# In such a situation, we arbitrary set the successors sets of
# the node to nothing (node pruned) to break the cycle.
#
# If no break was encountered we proceed to phase 2.
#
# Phase 2 computes successors sets of CURRENT (case 4); see details
# in phase 2 itself.
#
# Note the two levels of iteration in each phase.
# - The first one handles obsolescence markers using CURRENT as
# precursor (successors markers of CURRENT).
#
# Having multiple entry here means divergence.
#
# - The second one handles successors defined in each marker.
#
# Having none means pruned node, multiple successors means split,
# single successors are standard replacement.
#
for mark in sorted(succmarkers[current]):
for suc in mark[1]:
if suc not in cache:
if suc in stackedset:
# cycle breaking
cache[suc] = []
else:
# case (3) If we have not computed successors sets
# of one of those successors we add it to the
# `toproceed` stack and stop all work for this
# iteration.
toproceed.append(suc)
stackedset.add(suc)
break
else:
continue
break
else:
# case (4): we know all successors sets of all direct
# successors
#
# Successors set contributed by each marker depends on the
# successors sets of all its "successors" node.
#
# Each different marker is a divergence in the obsolescence
# history. It contributes successors sets distinct from other
# markers.
#
# Within a marker, a successor may have divergent successors
# sets. In such a case, the marker will contribute multiple
# divergent successors sets. If multiple successors have
# divergent successors sets, a Cartesian product is used.
#
# At the end we post-process successors sets to remove
# duplicated entry and successors set that are strict subset of
# another one.
succssets = []
for mark in sorted(succmarkers[current]):
# successors sets contributed by this marker
markss = [[]]
for suc in mark[1]:
# cardinal product with previous successors
productresult = []
for prefix in markss:
for suffix in cache[suc]:
newss = list(prefix)
for part in suffix:
# do not duplicated entry in successors set
# first entry wins.
if part not in newss:
newss.append(part)
productresult.append(newss)
markss = productresult
succssets.extend(markss)
# remove duplicated and subset
seen = []
final = []
candidate = sorted(((set(s), s) for s in succssets if s),
key=lambda x: len(x[1]), reverse=True)
for setversion, listversion in candidate:
for seenset in seen:
if setversion.issubset(seenset):
break
else:
final.append(listversion)
seen.append(setversion)
final.reverse() # put small successors set first
cache[current] = final
return cache[initialnode]
# mapping of 'set-name' -> <function to compute this set>
cachefuncs = {}
def cachefor(name):
"""Decorator to register a function as computing the cache for a set"""
def decorator(func):
assert name not in cachefuncs
cachefuncs[name] = func
return func
return decorator
def getrevs(repo, name):
"""Return the set of revision that belong to the <name> set
Such access may compute the set and cache it for future use"""
repo = repo.unfiltered()
if not repo.obsstore:
return frozenset()
if name not in repo.obsstore.caches:
repo.obsstore.caches[name] = cachefuncs[name](repo)
return repo.obsstore.caches[name]
# To be simple we need to invalidate obsolescence cache when:
#
# - new changeset is added:
# - public phase is changed
# - obsolescence marker are added
# - strip is used a repo
def clearobscaches(repo):
"""Remove all obsolescence related cache from a repo
This remove all cache in obsstore is the obsstore already exist on the
repo.
(We could be smarter here given the exact event that trigger the cache
clearing)"""
# only clear cache is there is obsstore data in this repo
if 'obsstore' in repo._filecache:
repo.obsstore.caches.clear()
@cachefor('obsolete')
def _computeobsoleteset(repo):
"""the set of obsolete revisions"""
obs = set()
getrev = repo.changelog.nodemap.get
getphase = repo._phasecache.phase
for n in repo.obsstore.successors:
rev = getrev(n)
if rev is not None and getphase(repo, rev):
obs.add(rev)
return obs
@cachefor('unstable')
def _computeunstableset(repo):
"""the set of non obsolete revisions with obsolete parents"""
revs = [(ctx.rev(), ctx) for ctx in
repo.set('(not public()) and (not obsolete())')]
revs.sort(key=lambda x:x[0])
unstable = set()
for rev, ctx in revs:
# A rev is unstable if one of its parent is obsolete or unstable
# this works since we traverse following growing rev order
if any((x.obsolete() or (x.rev() in unstable))
for x in ctx.parents()):
unstable.add(rev)
return unstable
@cachefor('suspended')
def _computesuspendedset(repo):
"""the set of obsolete parents with non obsolete descendants"""
suspended = repo.changelog.ancestors(getrevs(repo, 'unstable'))
return set(r for r in getrevs(repo, 'obsolete') if r in suspended)
@cachefor('extinct')
def _computeextinctset(repo):
"""the set of obsolete parents without non obsolete descendants"""
return getrevs(repo, 'obsolete') - getrevs(repo, 'suspended')
@cachefor('bumped')
def _computebumpedset(repo):
"""the set of revs trying to obsolete public revisions"""
bumped = set()
# util function (avoid attribute lookup in the loop)
phase = repo._phasecache.phase # would be faster to grab the full list
public = phases.public
cl = repo.changelog
torev = cl.nodemap.get
for ctx in repo.set('(not public()) and (not obsolete())'):
rev = ctx.rev()
# We only evaluate mutable, non-obsolete revision
node = ctx.node()
# (future) A cache of precursors may worth if split is very common
for pnode in allprecursors(repo.obsstore, [node],
ignoreflags=bumpedfix):
prev = torev(pnode) # unfiltered! but so is phasecache
if (prev is not None) and (phase(repo, prev) <= public):
# we have a public precursors
bumped.add(rev)
break # Next draft!
return bumped
@cachefor('divergent')
def _computedivergentset(repo):
"""the set of rev that compete to be the final successors of some revision.
"""
divergent = set()
obsstore = repo.obsstore
newermap = {}
for ctx in repo.set('(not public()) - obsolete()'):
mark = obsstore.precursors.get(ctx.node(), ())
toprocess = set(mark)
seen = set()
while toprocess:
prec = toprocess.pop()[0]
if prec in seen:
continue # emergency cycle hanging prevention
seen.add(prec)
if prec not in newermap:
successorssets(repo, prec, newermap)
newer = [n for n in newermap[prec] if n]
if len(newer) > 1:
divergent.add(ctx.rev())
break
toprocess.update(obsstore.precursors.get(prec, ()))
return divergent
def createmarkers(repo, relations, flag=0, date=None, metadata=None):
"""Add obsolete markers between changesets in a repo
<relations> must be an iterable of (<old>, (<new>, ...)[,{metadata}])
tuple. `old` and `news` are changectx. metadata is an optional dictionary
containing metadata for this marker only. It is merged with the global
metadata specified through the `metadata` argument of this function,
Trying to obsolete a public changeset will raise an exception.
Current user and date are used except if specified otherwise in the
metadata attribute.
This function operates within a transaction of its own, but does
not take any lock on the repo.
"""
# prepare metadata
if metadata is None:
metadata = {}
if 'user' not in metadata:
metadata['user'] = repo.ui.username()
tr = repo.transaction('add-obsolescence-marker')
try:
for rel in relations:
prec = rel[0]
sucs = rel[1]
localmetadata = metadata.copy()
if 2 < len(rel):
localmetadata.update(rel[2])
if not prec.mutable():
raise error.Abort("cannot obsolete public changeset: %s"
% prec,
hint='see "hg help phases" for details')
nprec = prec.node()
nsucs = tuple(s.node() for s in sucs)
npare = None
if not nsucs:
npare = tuple(p.node() for p in prec.parents())
if nprec in nsucs:
raise error.Abort("changeset %s cannot obsolete itself" % prec)
repo.obsstore.create(tr, nprec, nsucs, flag, parents=npare,
date=date, metadata=localmetadata)
repo.filteredrevcache.clear()
tr.close()
finally:
tr.release()
def isenabled(repo, option):
"""Returns True if the given repository has the given obsolete option
enabled.
"""
result = set(repo.ui.configlist('experimental', 'evolution'))
if 'all' in result:
return True
# For migration purposes, temporarily return true if the config hasn't been
# set but _enabled is true.
if len(result) == 0 and _enabled:
return True
# createmarkers must be enabled if other options are enabled
if ((allowunstableopt in result or exchangeopt in result) and
not createmarkersopt in result):
raise error.Abort(_("'createmarkers' obsolete option must be enabled "
"if other obsolete options are enabled"))
return option in result