Mercurial > hg
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 |
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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)