view tests/test-batching.py @ 25757:4d1382fd96ff

context: write dirstate out explicitly at the end of markcommitted To detect change of a file without redundant comparison of file content, dirstate recognizes a file as certainly clean, if: (1) it is already known as "normal", (2) dirstate entry for it has valid (= not "-1") timestamp, and (3) mode, size and timestamp of it on the filesystem are as same as ones expected in dirstate This works as expected in many cases, but doesn't in the corner case that changing a file keeps mode, size and timestamp of it on the filesystem. The timetable below shows steps in one of typical such situations: ---- ----------------------------------- ---------------- timestamp of "f" ---------------- dirstate file- time action mem file system ---- ----------------------------------- ---- ----- ----- * *** *** - 'hg transplant REV1 REV2 ...' - transplanting REV1 .... N - change "f", but keep size N (via 'patch.patch()') - 'dirstate.normal("f")' N *** (via 'repo.commit()') - transplanting REV2 - change "f", but keep size N (via 'patch.patch()') - aborted while patching N+1 - release wlock - 'dirstate.write()' N N N - 'hg status' shows "r1" as "clean" N N N ---- ----------------------------------- ---- ----- ----- The most important point is that 'dirstate.write()' is executed at N+1 or later. This causes writing dirstate timestamp N of "f" out successfully. If it is executed at N, 'parsers.pack_dirstate()' replaces timestamp N with "-1" before actual writing dirstate out. This issue can occur when 'hg transplant' satisfies conditions below: - multiple revisions to be transplanted change the same file - those revisions don't change mode and size of the file, and - the 2nd or later revision of them fails after changing the file The root cause of this issue is that files are changed without flushing in-memory dirstate changes via 'repo.commit()' (even though omitting 'dirstate.normallookup()' on files changed by 'patch.patch()' for efficiency also causes this issue). To detect changes of files correctly, this patch writes in-memory dirstate changes out explicitly after marking files as clean in 'committablectx.markcommitted()', which is invoked via 'repo.commit()'. After this change, timetable is changed as below: ---- ----------------------------------- ---------------- timestamp of "f" ---------------- dirstate file- time action mem file system ---- ----------------------------------- ---- ----- ----- * *** *** - 'hg transplant REV1 REV2 ...' - transplanting REV1 .... N - change "f", but keep size N (via 'patch.patch()') - 'dirstate.normal("f")' N *** (via 'repo.commit()') ----------------------------------- ---- ----- ----- - 'dirsttate.write()' -1 -1 ----------------------------------- ---- ----- ----- - transplanting REV2 - change "f", but keep size N (via 'patch.patch()') - aborted while patching N+1 - release wlock - 'dirstate.write()' -1 -1 N - 'hg status' shows "r1" as "clean" -1 -1 N ---- ----------------------------------- ---- ----- ----- To reproduce this issue in tests certainly, this patch emulates some timing critical actions as below: - change "f" at N 'patch.patch()' with 'fakepatchtime.py' explicitly changes mtime of patched files to "2000-01-01 00:00" (= N). - 'dirstate.write()' via 'repo.commit()' at N 'fakedirstatewritetime.py' forces 'pack_dirstate()' to use "2000-01-01 00:00" as "now", only if 'pack_dirstate()' is invoked via 'committablectx.markcommitted()'. - 'dirstate.write()' via releasing wlock at N+1 (or "not at N") 'pack_dirstate()' via releasing wlock uses actual timestamp at runtime as "now", and it should be different from the "2000-01-01 00:00" of "f". BTW, this patch doesn't test cases below, even though 'patch.patch()' is used similarly in these cases: 1. failure of 'hg import' or 'hg qpush' 2. success of 'hg import', 'hg qpush' or 'hg transplant' Case (1) above doesn't cause this kind of issue, because: - if patching is aborted by conflicts, changed files are committed changed files are marked as CLEAN, even though they are partially patched. - otherwise, dirstate are fully restored by 'dirstateguard' For example in timetable above, timestamp of "f" in .hg/dirstate is restored to -1 (or less than N), and subsequent 'hg status' can detect changes correctly. Case (2) always causes 'repo.status()' invocation via 'repo.commit()' just after changing files inside same wlock scope. ---- ----------------------------------- ---------------- timestamp of "f" ---------------- dirstate file- time action mem file system ---- ----------------------------------- ---- ----- ----- N *** *** - make file "f" clean N - execute 'hg foobar' .... - 'dirstate.normal("f")' N *** (e.g. via dirty check or previous 'repo.commit()') - change "f", but keep size N - 'repo.status()' (*1) (via 'repo.commit()') ---- ----------------------------------- ---- ----- ----- At a glance, 'repo.status()' at (*1) seems to cause similar issue (= "changed files are treated as clean"), but actually doesn't. 'dirstate._lastnormaltime' should be N at (*1) above, because 'dirstate.normal()' via dirty check is finished at N. Therefore, "f" changed at N (= 'dirstate._lastnormaltime') is forcibly treated as "unsure" at (*1), and changes are detected as expected (see 'dirstate.status()' for detail). If 'hg import' is executed with '--no-commit', 'repo.status()' isn't invoked just after changing files inside same wlock scope. But preceding 'dirstate.normal()' is invoked inside another wlock scope via 'cmdutil.bailifchanged()', and in-memory changes should be flushed at the end of that scope. Therefore, timestamp N of clean "f" should be replaced by -1, if 'dirstate.write()' is invoked at N. It means that condition of this issue isn't satisfied.
author FUJIWARA Katsunori <foozy@lares.dti.ne.jp>
date Wed, 08 Jul 2015 17:01:09 +0900
parents a7d5816087a9
children cbbdd085c991
line wrap: on
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# test-batching.py - tests for transparent command batching
#
# Copyright 2011 Peter Arrenbrecht <peter@arrenbrecht.ch>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from mercurial.wireproto import localbatch, remotebatch, batchable, future

# equivalent of repo.repository
class thing(object):
    def hello(self):
        return "Ready."

# equivalent of localrepo.localrepository
class localthing(thing):
    def foo(self, one, two=None):
        if one:
            return "%s and %s" % (one, two,)
        return "Nope"
    def bar(self, b, a):
        return "%s und %s" % (b, a,)
    def greet(self, name=None):
        return "Hello, %s" % name
    def batch(self):
        '''Support for local batching.'''
        return localbatch(self)

# usage of "thing" interface
def use(it):

    # Direct call to base method shared between client and server.
    print it.hello()

    # Direct calls to proxied methods. They cause individual roundtrips.
    print it.foo("Un", two="Deux")
    print it.bar("Eins", "Zwei")

    # Batched call to a couple of (possibly proxied) methods.
    batch = it.batch()
    # The calls return futures to eventually hold results.
    foo = batch.foo(one="One", two="Two")
    foo2 = batch.foo(None)
    bar = batch.bar("Eins", "Zwei")
    # We can call non-batchable proxy methods, but the break the current batch
    # request and cause additional roundtrips.
    greet = batch.greet(name="John Smith")
    # We can also add local methods into the mix, but they break the batch too.
    hello = batch.hello()
    bar2 = batch.bar(b="Uno", a="Due")
    # Only now are all the calls executed in sequence, with as few roundtrips
    # as possible.
    batch.submit()
    # After the call to submit, the futures actually contain values.
    print foo.value
    print foo2.value
    print bar.value
    print greet.value
    print hello.value
    print bar2.value

# local usage
mylocal = localthing()
print
print "== Local"
use(mylocal)

# demo remoting; mimicks what wireproto and HTTP/SSH do

# shared

def escapearg(plain):
    return (plain
            .replace(':', '::')
            .replace(',', ':,')
            .replace(';', ':;')
            .replace('=', ':='))
def unescapearg(escaped):
    return (escaped
            .replace(':=', '=')
            .replace(':;', ';')
            .replace(':,', ',')
            .replace('::', ':'))

# server side

# equivalent of wireproto's global functions
class server(object):
    def __init__(self, local):
        self.local = local
    def _call(self, name, args):
        args = dict(arg.split('=', 1) for arg in args)
        return getattr(self, name)(**args)
    def perform(self, req):
        print "REQ:", req
        name, args = req.split('?', 1)
        args = args.split('&')
        vals = dict(arg.split('=', 1) for arg in args)
        res = getattr(self, name)(**vals)
        print "  ->", res
        return res
    def batch(self, cmds):
        res = []
        for pair in cmds.split(';'):
            name, args = pair.split(':', 1)
            vals = {}
            for a in args.split(','):
                if a:
                    n, v = a.split('=')
                    vals[n] = unescapearg(v)
            res.append(escapearg(getattr(self, name)(**vals)))
        return ';'.join(res)
    def foo(self, one, two):
        return mangle(self.local.foo(unmangle(one), unmangle(two)))
    def bar(self, b, a):
        return mangle(self.local.bar(unmangle(b), unmangle(a)))
    def greet(self, name):
        return mangle(self.local.greet(unmangle(name)))
myserver = server(mylocal)

# local side

# equivalent of wireproto.encode/decodelist, that is, type-specific marshalling
# here we just transform the strings a bit to check we're properly en-/decoding
def mangle(s):
    return ''.join(chr(ord(c) + 1) for c in s)
def unmangle(s):
    return ''.join(chr(ord(c) - 1) for c in s)

# equivalent of wireproto.wirerepository and something like http's wire format
class remotething(thing):
    def __init__(self, server):
        self.server = server
    def _submitone(self, name, args):
        req = name + '?' + '&'.join(['%s=%s' % (n, v) for n, v in args])
        return self.server.perform(req)
    def _submitbatch(self, cmds):
        req = []
        for name, args in cmds:
            args = ','.join(n + '=' + escapearg(v) for n, v in args)
            req.append(name + ':' + args)
        req = ';'.join(req)
        res = self._submitone('batch', [('cmds', req,)])
        return res.split(';')

    def batch(self):
        return remotebatch(self)

    @batchable
    def foo(self, one, two=None):
        if not one:
            yield "Nope", None
        encargs = [('one', mangle(one),), ('two', mangle(two),)]
        encresref = future()
        yield encargs, encresref
        yield unmangle(encresref.value)

    @batchable
    def bar(self, b, a):
        encresref = future()
        yield [('b', mangle(b),), ('a', mangle(a),)], encresref
        yield unmangle(encresref.value)

    # greet is coded directly. It therefore does not support batching. If it
    # does appear in a batch, the batch is split around greet, and the call to
    # greet is done in its own roundtrip.
    def greet(self, name=None):
        return unmangle(self._submitone('greet', [('name', mangle(name),)]))

# demo remote usage

myproxy = remotething(myserver)
print
print "== Remote"
use(myproxy)