rebase: turn rebaseskipobsolete on by default
Consider the following use case. User has a set of commits he wants to rebase
onto some destination. Some of the commits in the set are already rebased
and their new versions are now among the ancestors of destination. Traditional
rebase behavior would make the rebase and effectively try to apply older
versions of these commits on top of newer versions, like this:
a` --> b --> a`
(where both 'a`' and 'a``' are rebased versions of 'a')
This is not desired since 'b' might have made changes to 'a`' which can now
result in merge conflicts. We can avoid these merge conflicts since we know
that 'a``' is an older version of 'a`', so we don't even need to put it on top
of 'b'. Rebaseskipobsolete allows us to do exactly that.
Another undesired effect of a pure rebase is that now 'a`' and 'a``' are both
successors to 'a' which is a divergence. We don't want that and not rebasing
'a' the second time allows to avoid it.
This was not enabled by default initially because we wanted to have some more
experience with it. After months of painless usages in multiple places, we are
confident enough to turn it on my default.
# 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.peer import localbatch, batchable, future
from mercurial.wireproto import remotebatch
# 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)