push: rework the computation of fallbackheads to be correct
The previous computation tried to be smart but ended up being wrong. This was
caught by phase movement test while reworking the phase discovery logic to be
faster.
The previous logic was failing to catch case where the pushed set was not based
on a common heads (i.e. when the discovery seemed to have "over discovered"
content, outside the pushed set)
In the following graph, `e` is a common head and we `hg push -r f`. We need to
detect `c` as a fallback heads and we previous failed to do so::
e
|
d f
|/
c
|
b
|
a
The performance impact of the change seems minimal. On the most impacted
repository at hand (mozilla-try), the slowdown seems mostly mixed in the
overall noise `hg push` but seems to be in the hundred of milliseconds order of
magnitude. When using rust, we seems to be a bit faster, probably because we
leverage more accelaratd internals.
I added a couple of performance related common for further investigation later
on.
# 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.
import contextlib
from mercurial import (
localrepo,
pycompat,
wireprotov1peer,
)
def bprint(*bs):
print(*[pycompat.sysstr(b) for b in bs])
# equivalent of repo.repository
class thing:
def hello(self):
return b"Ready."
# equivalent of localrepo.localrepository
class localthing(thing):
def foo(self, one, two=None):
if one:
return b"%s and %s" % (
one,
two,
)
return b"Nope"
def bar(self, b, a):
return b"%s und %s" % (
b,
a,
)
def greet(self, name=None):
return b"Hello, %s" % name
@contextlib.contextmanager
def commandexecutor(self):
e = localrepo.localcommandexecutor(self)
try:
yield e
finally:
e.close()
# usage of "thing" interface
def use(it):
# Direct call to base method shared between client and server.
bprint(it.hello())
# Direct calls to proxied methods. They cause individual roundtrips.
bprint(it.foo(b"Un", two=b"Deux"))
bprint(it.bar(b"Eins", b"Zwei"))
# Batched call to a couple of proxied methods.
with it.commandexecutor() as e:
ffoo = e.callcommand(b'foo', {b'one': b'One', b'two': b'Two'})
fbar = e.callcommand(b'bar', {b'b': b'Eins', b'a': b'Zwei'})
fbar2 = e.callcommand(b'bar', {b'b': b'Uno', b'a': b'Due'})
bprint(ffoo.result())
bprint(fbar.result())
bprint(fbar2.result())
# local usage
mylocal = localthing()
print()
bprint(b"== Local")
use(mylocal)
# demo remoting; mimicks what wireproto and HTTP/SSH do
# shared
def escapearg(plain):
return (
plain.replace(b':', b'::')
.replace(b',', b':,')
.replace(b';', b':;')
.replace(b'=', b':=')
)
def unescapearg(escaped):
return (
escaped.replace(b':=', b'=')
.replace(b':;', b';')
.replace(b':,', b',')
.replace(b'::', b':')
)
# server side
# equivalent of wireproto's global functions
class server:
def __init__(self, local):
self.local = local
def _call(self, name, args):
args = dict(arg.split(b'=', 1) for arg in args)
return getattr(self, name)(**args)
def perform(self, req):
bprint(b"REQ:", req)
name, args = req.split(b'?', 1)
args = args.split(b'&')
vals = dict(arg.split(b'=', 1) for arg in args)
res = getattr(self, pycompat.sysstr(name))(**pycompat.strkwargs(vals))
bprint(b" ->", res)
return res
def batch(self, cmds):
res = []
for pair in cmds.split(b';'):
name, args = pair.split(b':', 1)
vals = {}
for a in args.split(b','):
if a:
n, v = a.split(b'=')
vals[n] = unescapearg(v)
res.append(
escapearg(
getattr(self, pycompat.sysstr(name))(
**pycompat.strkwargs(vals)
)
)
)
return b';'.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 b''.join(pycompat.bytechr(ord(c) + 1) for c in pycompat.bytestr(s))
def unmangle(s):
return b''.join(pycompat.bytechr(ord(c) - 1) for c in pycompat.bytestr(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 + b'?' + b'&'.join([b'%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 = b','.join(n + b'=' + escapearg(v) for n, v in args)
req.append(name + b':' + args)
req = b';'.join(req)
res = self._submitone(
b'batch',
[
(
b'cmds',
req,
)
],
)
for r in res.split(b';'):
yield r
@contextlib.contextmanager
def commandexecutor(self):
e = wireprotov1peer.peerexecutor(self)
try:
yield e
finally:
e.close()
@wireprotov1peer.batchable
def foo(self, one, two=None):
encoded_args = [
(
b'one',
mangle(one),
),
(
b'two',
mangle(two),
),
]
return encoded_args, unmangle
@wireprotov1peer.batchable
def bar(self, b, a):
return [
(
b'b',
mangle(b),
),
(
b'a',
mangle(a),
),
], unmangle
# 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(
b'greet',
[
(
b'name',
mangle(name),
)
],
)
)
# demo remote usage
myproxy = remotething(myserver)
print()
bprint(b"== Remote")
use(myproxy)