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manifest: avoid corruption by dropping removed files with pure (issue5801)...
manifest: avoid corruption by dropping removed files with pure (issue5801) Previously, removed files would simply be marked by overwriting the first byte with NUL and dropping their entry in `self.position`. But no effort was made to ignore them when compacting the dictionary into text form. This allowed them to slip into the manifest revision, since the code seems to be trying to minimize the string operations by copying as large a chunk as possible. As part of this, compact() walks the existing text based on entries in the `positions` list, and consumed everything up to the next position entry. This typically resulted in a ValueError complaining about unsorted manifest entries. Sometimes it seems that files do get dropped in large repos- it seems to correspond to there being a new entry that would take the same slot. A much more trivial problem is that if the only changes were removals, `_compact()` didn't even run because `__delitem__` doesn't add anything to `self.extradata`. Now there's an explicit variable to flag this, both to allow `_compact()` to run, and to avoid searching the manifest in cases where there are no removals. In practice, this behavior was mostly obscured by the check in fastdelta() which takes a different path that explicitly drops removed files if there are fewer than 1000 changes. However, timeless has a repo where after rebasing tens of commits, a totally different path[1] is taken that bypasses the change count check and hits this problem. [1] https://www.mercurial-scm.org/repo/hg/file/2338bdea4474/mercurial/manifest.py#l1511

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contentstore.py
376 lines | 12.7 KiB | text/x-python | PythonLexer
from __future__ import absolute_import
import threading
from mercurial.node import hex, nullid
from mercurial import (
mdiff,
pycompat,
revlog,
)
from . import (
basestore,
constants,
shallowutil,
)
class ChainIndicies(object):
"""A static class for easy reference to the delta chain indicies.
"""
# The filename of this revision delta
NAME = 0
# The mercurial file node for this revision delta
NODE = 1
# The filename of the delta base's revision. This is useful when delta
# between different files (like in the case of a move or copy, we can delta
# against the original file content).
BASENAME = 2
# The mercurial file node for the delta base revision. This is the nullid if
# this delta is a full text.
BASENODE = 3
# The actual delta or full text data.
DATA = 4
class unioncontentstore(basestore.baseunionstore):
def __init__(self, *args, **kwargs):
super(unioncontentstore, self).__init__(*args, **kwargs)
self.stores = args
self.writestore = kwargs.get(r'writestore')
# If allowincomplete==True then the union store can return partial
# delta chains, otherwise it will throw a KeyError if a full
# deltachain can't be found.
self.allowincomplete = kwargs.get(r'allowincomplete', False)
def get(self, name, node):
"""Fetches the full text revision contents of the given name+node pair.
If the full text doesn't exist, throws a KeyError.
Under the hood, this uses getdeltachain() across all the stores to build
up a full chain to produce the full text.
"""
chain = self.getdeltachain(name, node)
if chain[-1][ChainIndicies.BASENODE] != nullid:
# If we didn't receive a full chain, throw
raise KeyError((name, hex(node)))
# The last entry in the chain is a full text, so we start our delta
# applies with that.
fulltext = chain.pop()[ChainIndicies.DATA]
text = fulltext
while chain:
delta = chain.pop()[ChainIndicies.DATA]
text = mdiff.patches(text, [delta])
return text
@basestore.baseunionstore.retriable
def getdelta(self, name, node):
"""Return the single delta entry for the given name/node pair.
"""
for store in self.stores:
try:
return store.getdelta(name, node)
except KeyError:
pass
raise KeyError((name, hex(node)))
def getdeltachain(self, name, node):
"""Returns the deltachain for the given name/node pair.
Returns an ordered list of:
[(name, node, deltabasename, deltabasenode, deltacontent),...]
where the chain is terminated by a full text entry with a nullid
deltabasenode.
"""
chain = self._getpartialchain(name, node)
while chain[-1][ChainIndicies.BASENODE] != nullid:
x, x, deltabasename, deltabasenode, x = chain[-1]
try:
morechain = self._getpartialchain(deltabasename, deltabasenode)
chain.extend(morechain)
except KeyError:
# If we allow incomplete chains, don't throw.
if not self.allowincomplete:
raise
break
return chain
@basestore.baseunionstore.retriable
def getmeta(self, name, node):
"""Returns the metadata dict for given node."""
for store in self.stores:
try:
return store.getmeta(name, node)
except KeyError:
pass
raise KeyError((name, hex(node)))
def getmetrics(self):
metrics = [s.getmetrics() for s in self.stores]
return shallowutil.sumdicts(*metrics)
@basestore.baseunionstore.retriable
def _getpartialchain(self, name, node):
"""Returns a partial delta chain for the given name/node pair.
A partial chain is a chain that may not be terminated in a full-text.
"""
for store in self.stores:
try:
return store.getdeltachain(name, node)
except KeyError:
pass
raise KeyError((name, hex(node)))
def add(self, name, node, data):
raise RuntimeError("cannot add content only to remotefilelog "
"contentstore")
def getmissing(self, keys):
missing = keys
for store in self.stores:
if missing:
missing = store.getmissing(missing)
return missing
def addremotefilelognode(self, name, node, data):
if self.writestore:
self.writestore.addremotefilelognode(name, node, data)
else:
raise RuntimeError("no writable store configured")
def markledger(self, ledger, options=None):
for store in self.stores:
store.markledger(ledger, options)
class remotefilelogcontentstore(basestore.basestore):
def __init__(self, *args, **kwargs):
super(remotefilelogcontentstore, self).__init__(*args, **kwargs)
self._threaddata = threading.local()
def get(self, name, node):
# return raw revision text
data = self._getdata(name, node)
offset, size, flags = shallowutil.parsesizeflags(data)
content = data[offset:offset + size]
ancestormap = shallowutil.ancestormap(data)
p1, p2, linknode, copyfrom = ancestormap[node]
copyrev = None
if copyfrom:
copyrev = hex(p1)
self._updatemetacache(node, size, flags)
# lfs tracks renames in its own metadata, remove hg copy metadata,
# because copy metadata will be re-added by lfs flag processor.
if flags & revlog.REVIDX_EXTSTORED:
copyrev = copyfrom = None
revision = shallowutil.createrevlogtext(content, copyfrom, copyrev)
return revision
def getdelta(self, name, node):
# Since remotefilelog content stores only contain full texts, just
# return that.
revision = self.get(name, node)
return revision, name, nullid, self.getmeta(name, node)
def getdeltachain(self, name, node):
# Since remotefilelog content stores just contain full texts, we return
# a fake delta chain that just consists of a single full text revision.
# The nullid in the deltabasenode slot indicates that the revision is a
# fulltext.
revision = self.get(name, node)
return [(name, node, None, nullid, revision)]
def getmeta(self, name, node):
self._sanitizemetacache()
if node != self._threaddata.metacache[0]:
data = self._getdata(name, node)
offset, size, flags = shallowutil.parsesizeflags(data)
self._updatemetacache(node, size, flags)
return self._threaddata.metacache[1]
def add(self, name, node, data):
raise RuntimeError("cannot add content only to remotefilelog "
"contentstore")
def _sanitizemetacache(self):
metacache = getattr(self._threaddata, 'metacache', None)
if metacache is None:
self._threaddata.metacache = (None, None) # (node, meta)
def _updatemetacache(self, node, size, flags):
self._sanitizemetacache()
if node == self._threaddata.metacache[0]:
return
meta = {constants.METAKEYFLAG: flags,
constants.METAKEYSIZE: size}
self._threaddata.metacache = (node, meta)
class remotecontentstore(object):
def __init__(self, ui, fileservice, shared):
self._fileservice = fileservice
# type(shared) is usually remotefilelogcontentstore
self._shared = shared
def get(self, name, node):
self._fileservice.prefetch([(name, hex(node))], force=True,
fetchdata=True)
return self._shared.get(name, node)
def getdelta(self, name, node):
revision = self.get(name, node)
return revision, name, nullid, self._shared.getmeta(name, node)
def getdeltachain(self, name, node):
# Since our remote content stores just contain full texts, we return a
# fake delta chain that just consists of a single full text revision.
# The nullid in the deltabasenode slot indicates that the revision is a
# fulltext.
revision = self.get(name, node)
return [(name, node, None, nullid, revision)]
def getmeta(self, name, node):
self._fileservice.prefetch([(name, hex(node))], force=True,
fetchdata=True)
return self._shared.getmeta(name, node)
def add(self, name, node, data):
raise RuntimeError("cannot add to a remote store")
def getmissing(self, keys):
return keys
def markledger(self, ledger, options=None):
pass
class manifestrevlogstore(object):
def __init__(self, repo):
self._store = repo.store
self._svfs = repo.svfs
self._revlogs = dict()
self._cl = revlog.revlog(self._svfs, '00changelog.i')
self._repackstartlinkrev = 0
def get(self, name, node):
return self._revlog(name).revision(node, raw=True)
def getdelta(self, name, node):
revision = self.get(name, node)
return revision, name, nullid, self.getmeta(name, node)
def getdeltachain(self, name, node):
revision = self.get(name, node)
return [(name, node, None, nullid, revision)]
def getmeta(self, name, node):
rl = self._revlog(name)
rev = rl.rev(node)
return {constants.METAKEYFLAG: rl.flags(rev),
constants.METAKEYSIZE: rl.rawsize(rev)}
def getancestors(self, name, node, known=None):
if known is None:
known = set()
if node in known:
return []
rl = self._revlog(name)
ancestors = {}
missing = set((node,))
for ancrev in rl.ancestors([rl.rev(node)], inclusive=True):
ancnode = rl.node(ancrev)
missing.discard(ancnode)
p1, p2 = rl.parents(ancnode)
if p1 != nullid and p1 not in known:
missing.add(p1)
if p2 != nullid and p2 not in known:
missing.add(p2)
linknode = self._cl.node(rl.linkrev(ancrev))
ancestors[rl.node(ancrev)] = (p1, p2, linknode, '')
if not missing:
break
return ancestors
def getnodeinfo(self, name, node):
cl = self._cl
rl = self._revlog(name)
parents = rl.parents(node)
linkrev = rl.linkrev(rl.rev(node))
return (parents[0], parents[1], cl.node(linkrev), None)
def add(self, *args):
raise RuntimeError("cannot add to a revlog store")
def _revlog(self, name):
rl = self._revlogs.get(name)
if rl is None:
revlogname = '00manifesttree.i'
if name != '':
revlogname = 'meta/%s/00manifest.i' % name
rl = revlog.revlog(self._svfs, revlogname)
self._revlogs[name] = rl
return rl
def getmissing(self, keys):
missing = []
for name, node in keys:
mfrevlog = self._revlog(name)
if node not in mfrevlog.nodemap:
missing.append((name, node))
return missing
def setrepacklinkrevrange(self, startrev, endrev):
self._repackstartlinkrev = startrev
self._repackendlinkrev = endrev
def markledger(self, ledger, options=None):
if options and options.get(constants.OPTION_PACKSONLY):
return
treename = ''
rl = revlog.revlog(self._svfs, '00manifesttree.i')
startlinkrev = self._repackstartlinkrev
endlinkrev = self._repackendlinkrev
for rev in pycompat.xrange(len(rl) - 1, -1, -1):
linkrev = rl.linkrev(rev)
if linkrev < startlinkrev:
break
if linkrev > endlinkrev:
continue
node = rl.node(rev)
ledger.markdataentry(self, treename, node)
ledger.markhistoryentry(self, treename, node)
for path, encoded, size in self._store.datafiles():
if path[:5] != 'meta/' or path[-2:] != '.i':
continue
treename = path[5:-len('/00manifest.i')]
rl = revlog.revlog(self._svfs, path)
for rev in pycompat.xrange(len(rl) - 1, -1, -1):
linkrev = rl.linkrev(rev)
if linkrev < startlinkrev:
break
if linkrev > endlinkrev:
continue
node = rl.node(rev)
ledger.markdataentry(self, treename, node)
ledger.markhistoryentry(self, treename, node)
def cleanup(self, ledger):
pass