Mercurial > hg
view mercurial/wireprotov1peer.py @ 48687:f8f2ecdde4b5
branchmap: skip obsolete revisions while computing heads
It's time to make this part of core Mercurial obsolescence-aware.
Not considering obsolete revisions when computing heads is clearly what
Mercurial should do. But there are a couple of small issues:
- Let's say tip of the repo is obsolete. There are two ways of finding tiprev
for branchcache (both are in use): looking at input data for update() and
looking at computed heads after update(). Previously, repo tip would be
tiprev of the branchcache. With this patch, an obsolete revision can no
longer be tiprev. And depending on what way we use for finding tiprev (input
data vs computed heads) we'll get a different result. This is relevant when
recomputing cache key from cache contents, and may lead to updating cache for
obsolete revisions multiple times (not from scratch, because it still would
be considered valid for a subset of revisions in the repo).
- If all commits on a branch are obsolete, the branchcache will include that
branch, but the list of heads will be empty (that's why there's now `if not
heads` when recomputing tiprev/tipnode from cache contents). Having an entry
for every branch is currently required for notify extension (and
test-notify.t to pass), because notify doesn't handle revsets in its
subscription config very well and will throw an error if e.g. a branch
doesn't exist.
- Cloning static HTTP repos may try to stat() a non-existent obsstore file. The
issue is that we now care about obsolescence during clone, but statichttpvfs
doesn't implement a stat method, so a regular vfs.stat() is used, and it
assumes that file is local and calls os.stat(). During a clone, we're trying
to stat() .hg/store/obsstore, but in static HTTP case we provide a literal
URL to the obsstore file on the remote as if it were a local file path. On
windows it actually results in a failure in test-static-http.t.
The first issue is going to be addressed in a series dedicated to making sure
branchcache is properly and timely written on disk (it wasn't perfect even
before this patch, but there aren't enough tests to demonstrate that). The
second issue will be addressed in a future patch for notify extension that will
make it not raise an exception if a branch doesn't exist. And the third one was
partially addressed in the previous patch in this series and will be properly
fixed in a future patch when this series is accepted.
filteredhash() grows a keyword argument to make sure that branchcache is also
invalidated when there are new obsolete revisions in its repo view. This way
the on-disk cache format is unchanged and compatible between versions (although
it will obviously be recomputed when switching versions before/after this patch
and the repo has obsolete revisions).
There's one test that uses plain `hg up` without arguments while updated to a
pruned commit. To make this test pass, simply return current working directory
parent. Later in this series this code will be replaced by what prune command
does: updating to the closest non-obsolete ancestor.
Test changes:
test-branch-change.t: update branch head and cache update message. The head of
default listed in hg heads is changed because revision 2 was rewritten as 7,
and 1 is the closest ancestor on the same branch, so it's the head of default
now.
The cache invalidation message appears now because of the cache hash change,
since we're now accounting for obsolete revisions. Here's some context:
"served.hidden" repo filter means everything is visible (no filtered
revisions), so before this series branch2-served.hidden file would not contain
any cache hash, only revnum and node. Now it also has a hash when there are
obsolete changesets in the repo. The command that the message appears for is
changing branch of 5 and 6, which are now obsolete, so the cache hash changes.
In general, when cache is simply out-of-date, it can be updated using the old
version as a base. But if cache hash differs, then the cache for that
particular repo filter is recomputed (at least with the current
implementation). This is what happens here.
test-obsmarker-template.t: the pull reports 2 heads changed, but after that the
repo correctly sees only 1. The new message could be better, but it's still an
improvement over the previous one where hg pull suggested merging with an
obsolete revision.
test-obsolete.t: we can see these revisions in hg log --hidden, but they
shouldn't be considered heads even with --hidden.
test-rebase-obsolete{,2}.t: there were new heads created previously after
making new orphan changesets, but they weren't detected. Now we are properly
detecting and reporting them.
test-rebase-obsolete4.t: there's only one head now because the other head is
pruned and was falsely reported before.
test-static-http.t: add obsstore to the list of requested files. This file
doesn't exist on the remotes, but clients want it anyway (they get 404). This
is fine, because there are other nonexistent files that clients request, like
.hg/bookmarks or .hg/cache/tags2-served.
Differential Revision: https://phab.mercurial-scm.org/D12097
author | Anton Shestakov <av6@dwimlabs.net> |
---|---|
date | Fri, 07 Jan 2022 11:53:23 +0300 |
parents | c424ff4807e6 |
children | a0da5075bca3 |
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# wireprotov1peer.py - Client-side functionality for wire protocol version 1. # # Copyright 2005-2010 Olivia Mackall <olivia@selenic.com> # # 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 import sys import weakref from .i18n import _ from .node import bin from .pycompat import ( getattr, setattr, ) from . import ( bundle2, changegroup as changegroupmod, encoding, error, pushkey as pushkeymod, pycompat, util, wireprototypes, ) from .interfaces import ( repository, util as interfaceutil, ) from .utils import hashutil urlreq = util.urlreq def batchable(f): """annotation for batchable methods Such methods must implement a coroutine as follows: @batchable def sample(self, one, two=None): # Build list of encoded arguments suitable for your wire protocol: encoded_args = [('one', encode(one),), ('two', encode(two),)] # Return it, along with a function that will receive the result # from the batched request. return encoded_args, decode The decorator returns a function which wraps this coroutine as a plain method, but adds the original method as an attribute called "batchable", which is used by remotebatch to split the call into separate encoding and decoding phases. """ def plain(*args, **opts): encoded_args_or_res, decode = f(*args, **opts) if not decode: return encoded_args_or_res # a local result in this case self = args[0] cmd = pycompat.bytesurl(f.__name__) # ensure cmd is ascii bytestr encoded_res = self._submitone(cmd, encoded_args_or_res) return decode(encoded_res) setattr(plain, 'batchable', f) setattr(plain, '__name__', f.__name__) return plain def encodebatchcmds(req): """Return a ``cmds`` argument value for the ``batch`` command.""" escapearg = wireprototypes.escapebatcharg cmds = [] for op, argsdict in req: # Old servers didn't properly unescape argument names. So prevent # the sending of argument names that may not be decoded properly by # servers. assert all(escapearg(k) == k for k in argsdict) args = b','.join( b'%s=%s' % (escapearg(k), escapearg(v)) for k, v in pycompat.iteritems(argsdict) ) cmds.append(b'%s %s' % (op, args)) return b';'.join(cmds) class unsentfuture(pycompat.futures.Future): """A Future variation to represent an unsent command. Because we buffer commands and don't submit them immediately, calling ``result()`` on an unsent future could deadlock. Futures for buffered commands are represented by this type, which wraps ``result()`` to call ``sendcommands()``. """ def result(self, timeout=None): if self.done(): return pycompat.futures.Future.result(self, timeout) self._peerexecutor.sendcommands() # This looks like it will infinitely recurse. However, # sendcommands() should modify __class__. This call serves as a check # on that. return self.result(timeout) @interfaceutil.implementer(repository.ipeercommandexecutor) class peerexecutor(object): def __init__(self, peer): self._peer = peer self._sent = False self._closed = False self._calls = [] self._futures = weakref.WeakSet() self._responseexecutor = None self._responsef = None def __enter__(self): return self def __exit__(self, exctype, excvalee, exctb): self.close() def callcommand(self, command, args): if self._sent: raise error.ProgrammingError( b'callcommand() cannot be used after commands are sent' ) if self._closed: raise error.ProgrammingError( b'callcommand() cannot be used after close()' ) # Commands are dispatched through methods on the peer. fn = getattr(self._peer, pycompat.sysstr(command), None) if not fn: raise error.ProgrammingError( b'cannot call command %s: method of same name not available ' b'on peer' % command ) # Commands are either batchable or they aren't. If a command # isn't batchable, we send it immediately because the executor # can no longer accept new commands after a non-batchable command. # If a command is batchable, we queue it for later. But we have # to account for the case of a non-batchable command arriving after # a batchable one and refuse to service it. def addcall(): f = pycompat.futures.Future() self._futures.add(f) self._calls.append((command, args, fn, f)) return f if getattr(fn, 'batchable', False): f = addcall() # But since we don't issue it immediately, we wrap its result() # to trigger sending so we avoid deadlocks. f.__class__ = unsentfuture f._peerexecutor = self else: if self._calls: raise error.ProgrammingError( b'%s is not batchable and cannot be called on a command ' b'executor along with other commands' % command ) f = addcall() # Non-batchable commands can never coexist with another command # in this executor. So send the command immediately. self.sendcommands() return f def sendcommands(self): if self._sent: return if not self._calls: return self._sent = True # Unhack any future types so caller seens a clean type and to break # cycle between us and futures. for f in self._futures: if isinstance(f, unsentfuture): f.__class__ = pycompat.futures.Future f._peerexecutor = None calls = self._calls # Mainly to destroy references to futures. self._calls = None # Simple case of a single command. We call it synchronously. if len(calls) == 1: command, args, fn, f = calls[0] # Future was cancelled. Ignore it. if not f.set_running_or_notify_cancel(): return try: result = fn(**pycompat.strkwargs(args)) except Exception: pycompat.future_set_exception_info(f, sys.exc_info()[1:]) else: f.set_result(result) return # Batch commands are a bit harder. First, we have to deal with the # @batchable coroutine. That's a bit annoying. Furthermore, we also # need to preserve streaming. i.e. it should be possible for the # futures to resolve as data is coming in off the wire without having # to wait for the final byte of the final response. We do this by # spinning up a thread to read the responses. requests = [] states = [] for command, args, fn, f in calls: # Future was cancelled. Ignore it. if not f.set_running_or_notify_cancel(): continue try: encoded_args_or_res, decode = fn.batchable( fn.__self__, **pycompat.strkwargs(args) ) except Exception: pycompat.future_set_exception_info(f, sys.exc_info()[1:]) return if not decode: f.set_result(encoded_args_or_res) else: requests.append((command, encoded_args_or_res)) states.append((command, f, batchable, decode)) if not requests: return # This will emit responses in order they were executed. wireresults = self._peer._submitbatch(requests) # The use of a thread pool executor here is a bit weird for something # that only spins up a single thread. However, thread management is # hard and it is easy to encounter race conditions, deadlocks, etc. # concurrent.futures already solves these problems and its thread pool # executor has minimal overhead. So we use it. self._responseexecutor = pycompat.futures.ThreadPoolExecutor(1) self._responsef = self._responseexecutor.submit( self._readbatchresponse, states, wireresults ) def close(self): self.sendcommands() if self._closed: return self._closed = True if not self._responsef: return # We need to wait on our in-flight response and then shut down the # executor once we have a result. try: self._responsef.result() finally: self._responseexecutor.shutdown(wait=True) self._responsef = None self._responseexecutor = None # If any of our futures are still in progress, mark them as # errored. Otherwise a result() could wait indefinitely. for f in self._futures: if not f.done(): f.set_exception( error.ResponseError( _(b'unfulfilled batch command response'), None ) ) self._futures = None def _readbatchresponse(self, states, wireresults): # Executes in a thread to read data off the wire. for command, f, batchable, decode in states: # Grab raw result off the wire and teach the internal future # about it. try: remoteresult = next(wireresults) except StopIteration: # This can happen in particular because next(batchable) # in the previous iteration can call peer._abort, which # may close the peer. f.set_exception( error.ResponseError( _(b'unfulfilled batch command response'), None ) ) else: try: result = decode(remoteresult) except Exception: pycompat.future_set_exception_info(f, sys.exc_info()[1:]) else: f.set_result(result) @interfaceutil.implementer( repository.ipeercommands, repository.ipeerlegacycommands ) class wirepeer(repository.peer): """Client-side interface for communicating with a peer repository. Methods commonly call wire protocol commands of the same name. See also httppeer.py and sshpeer.py for protocol-specific implementations of this interface. """ def commandexecutor(self): return peerexecutor(self) # Begin of ipeercommands interface. def clonebundles(self): self.requirecap(b'clonebundles', _(b'clone bundles')) return self._call(b'clonebundles') @batchable def lookup(self, key): self.requirecap(b'lookup', _(b'look up remote revision')) def decode(d): success, data = d[:-1].split(b" ", 1) if int(success): return bin(data) else: self._abort(error.RepoError(data)) return {b'key': encoding.fromlocal(key)}, decode @batchable def heads(self): def decode(d): try: return wireprototypes.decodelist(d[:-1]) except ValueError: self._abort(error.ResponseError(_(b"unexpected response:"), d)) return {}, decode @batchable def known(self, nodes): def decode(d): try: return [bool(int(b)) for b in pycompat.iterbytestr(d)] except ValueError: self._abort(error.ResponseError(_(b"unexpected response:"), d)) return {b'nodes': wireprototypes.encodelist(nodes)}, decode @batchable def branchmap(self): def decode(d): try: branchmap = {} for branchpart in d.splitlines(): branchname, branchheads = branchpart.split(b' ', 1) branchname = encoding.tolocal(urlreq.unquote(branchname)) branchheads = wireprototypes.decodelist(branchheads) branchmap[branchname] = branchheads return branchmap except TypeError: self._abort(error.ResponseError(_(b"unexpected response:"), d)) return {}, decode @batchable def listkeys(self, namespace): if not self.capable(b'pushkey'): return {}, None self.ui.debug(b'preparing listkeys for "%s"\n' % namespace) def decode(d): self.ui.debug( b'received listkey for "%s": %i bytes\n' % (namespace, len(d)) ) return pushkeymod.decodekeys(d) return {b'namespace': encoding.fromlocal(namespace)}, decode @batchable def pushkey(self, namespace, key, old, new): if not self.capable(b'pushkey'): return False, None self.ui.debug(b'preparing pushkey for "%s:%s"\n' % (namespace, key)) def decode(d): d, output = d.split(b'\n', 1) try: d = bool(int(d)) except ValueError: raise error.ResponseError( _(b'push failed (unexpected response):'), d ) for l in output.splitlines(True): self.ui.status(_(b'remote: '), l) return d return { b'namespace': encoding.fromlocal(namespace), b'key': encoding.fromlocal(key), b'old': encoding.fromlocal(old), b'new': encoding.fromlocal(new), }, decode def stream_out(self): return self._callstream(b'stream_out') def getbundle(self, source, **kwargs): kwargs = pycompat.byteskwargs(kwargs) self.requirecap(b'getbundle', _(b'look up remote changes')) opts = {} bundlecaps = kwargs.get(b'bundlecaps') or set() for key, value in pycompat.iteritems(kwargs): if value is None: continue keytype = wireprototypes.GETBUNDLE_ARGUMENTS.get(key) if keytype is None: raise error.ProgrammingError( b'Unexpectedly None keytype for key %s' % key ) elif keytype == b'nodes': value = wireprototypes.encodelist(value) elif keytype == b'csv': value = b','.join(value) elif keytype == b'scsv': value = b','.join(sorted(value)) elif keytype == b'boolean': value = b'%i' % bool(value) elif keytype != b'plain': raise KeyError(b'unknown getbundle option type %s' % keytype) opts[key] = value f = self._callcompressable(b"getbundle", **pycompat.strkwargs(opts)) if any((cap.startswith(b'HG2') for cap in bundlecaps)): return bundle2.getunbundler(self.ui, f) else: return changegroupmod.cg1unpacker(f, b'UN') def unbundle(self, bundle, heads, url): """Send cg (a readable file-like object representing the changegroup to push, typically a chunkbuffer object) to the remote server as a bundle. When pushing a bundle10 stream, return an integer indicating the result of the push (see changegroup.apply()). When pushing a bundle20 stream, return a bundle20 stream. `url` is the url the client thinks it's pushing to, which is visible to hooks. """ if heads != [b'force'] and self.capable(b'unbundlehash'): heads = wireprototypes.encodelist( [b'hashed', hashutil.sha1(b''.join(sorted(heads))).digest()] ) else: heads = wireprototypes.encodelist(heads) if util.safehasattr(bundle, b'deltaheader'): # this a bundle10, do the old style call sequence ret, output = self._callpush(b"unbundle", bundle, heads=heads) if ret == b"": raise error.ResponseError(_(b'push failed:'), output) try: ret = int(ret) except ValueError: raise error.ResponseError( _(b'push failed (unexpected response):'), ret ) for l in output.splitlines(True): self.ui.status(_(b'remote: '), l) else: # bundle2 push. Send a stream, fetch a stream. stream = self._calltwowaystream(b'unbundle', bundle, heads=heads) ret = bundle2.getunbundler(self.ui, stream) return ret # End of ipeercommands interface. # Begin of ipeerlegacycommands interface. def branches(self, nodes): n = wireprototypes.encodelist(nodes) d = self._call(b"branches", nodes=n) try: br = [tuple(wireprototypes.decodelist(b)) for b in d.splitlines()] return br except ValueError: self._abort(error.ResponseError(_(b"unexpected response:"), d)) def between(self, pairs): batch = 8 # avoid giant requests r = [] for i in pycompat.xrange(0, len(pairs), batch): n = b" ".join( [ wireprototypes.encodelist(p, b'-') for p in pairs[i : i + batch] ] ) d = self._call(b"between", pairs=n) try: r.extend( l and wireprototypes.decodelist(l) or [] for l in d.splitlines() ) except ValueError: self._abort(error.ResponseError(_(b"unexpected response:"), d)) return r def changegroup(self, nodes, source): n = wireprototypes.encodelist(nodes) f = self._callcompressable(b"changegroup", roots=n) return changegroupmod.cg1unpacker(f, b'UN') def changegroupsubset(self, bases, heads, source): self.requirecap(b'changegroupsubset', _(b'look up remote changes')) bases = wireprototypes.encodelist(bases) heads = wireprototypes.encodelist(heads) f = self._callcompressable( b"changegroupsubset", bases=bases, heads=heads ) return changegroupmod.cg1unpacker(f, b'UN') # End of ipeerlegacycommands interface. def _submitbatch(self, req): """run batch request <req> on the server Returns an iterator of the raw responses from the server. """ ui = self.ui if ui.debugflag and ui.configbool(b'devel', b'debug.peer-request'): ui.debug(b'devel-peer-request: batched-content\n') for op, args in req: msg = b'devel-peer-request: - %s (%d arguments)\n' ui.debug(msg % (op, len(args))) unescapearg = wireprototypes.unescapebatcharg rsp = self._callstream(b"batch", cmds=encodebatchcmds(req)) chunk = rsp.read(1024) work = [chunk] while chunk: while b';' not in chunk and chunk: chunk = rsp.read(1024) work.append(chunk) merged = b''.join(work) while b';' in merged: one, merged = merged.split(b';', 1) yield unescapearg(one) chunk = rsp.read(1024) work = [merged, chunk] yield unescapearg(b''.join(work)) def _submitone(self, op, args): return self._call(op, **pycompat.strkwargs(args)) def debugwireargs(self, one, two, three=None, four=None, five=None): # don't pass optional arguments left at their default value opts = {} if three is not None: opts['three'] = three if four is not None: opts['four'] = four return self._call(b'debugwireargs', one=one, two=two, **opts) def _call(self, cmd, **args): """execute <cmd> on the server The command is expected to return a simple string. returns the server reply as a string.""" raise NotImplementedError() def _callstream(self, cmd, **args): """execute <cmd> on the server The command is expected to return a stream. Note that if the command doesn't return a stream, _callstream behaves differently for ssh and http peers. returns the server reply as a file like object. """ raise NotImplementedError() def _callcompressable(self, cmd, **args): """execute <cmd> on the server The command is expected to return a stream. The stream may have been compressed in some implementations. This function takes care of the decompression. This is the only difference with _callstream. returns the server reply as a file like object. """ raise NotImplementedError() def _callpush(self, cmd, fp, **args): """execute a <cmd> on server The command is expected to be related to a push. Push has a special return method. returns the server reply as a (ret, output) tuple. ret is either empty (error) or a stringified int. """ raise NotImplementedError() def _calltwowaystream(self, cmd, fp, **args): """execute <cmd> on server The command will send a stream to the server and get a stream in reply. """ raise NotImplementedError() def _abort(self, exception): """clearly abort the wire protocol connection and raise the exception""" raise NotImplementedError()