snapshot: introduce an intermediate `_refinedgroups` generator
This method will be used to improve the search for a good snapshot base. To
keep things simpler, we introduce the necessary function before doing any
delta base logic change. The next handful of commits will focus on refactoring
the code to let that new logic land as clearly as possible.
# General Idea
Right now, the search for a good delta base stop whenever we found a good one.
However, when using sparse-revlog, we should probably try a bit harder.
We do significant effort to increase delta re-use by jumping on "unrelated"
delta chains that provide better results. Moving to another chain for a better
result is good, but we have no guarantee we jump at a reasonable point in that
new chain. When we consider over the chains related to the parents, we start
from the higher-level snapshots. This is a way to consider the snapshot closer
to the current revision that has the best chance to produce a small delta. We
do benefit from this walk order when jumping to a better "unrelated" stack.
To counter-balance this, we'll introduce a way to "refine" the result. After a
good delta have been found, we'll keep searching for a better delta, using the
current best one as a starting point.
# Target Setup
The `finddeltainfo` method is responsible for the general search for a good
delta. It requests candidates base from `_candidategroups` and decides which
one are usable.
The `_candidategroups` generator act as a top-level filter, it does not care
about how we pick candidates, it just does basic filtering, excluding
revisions that have been tested already or that are an obvious misfit.
The `_rawgroups` generator is the one with the actual ancestors walking logic,
It does not care about what would do a good delta and what was already tested,
it just issues the initial candidates.
We introduce a new `_refinedgroup` function to bridge the gap between
`_candidategroups` and `_rawgroups`. It delegates the initial iteration logic
and then performing relevant refining of the valid base once found. (This
logic is yet to be added to function)
All these logics are fairly independent and easier to understand when standing
alone, not mixed with each other. It also makes it easy to test and try
different approaches for one of those four layers without affecting the other
ones.
# Technical details
To communicate `finddeltainfo` choice of "current best delta base" to the
`_refinegroup` logic, we plan to use python co-routine feature. The
`_candidategroups` and `_refinegroup` generators will become co-routine. This
will allow `_refinegroup` to detect when a good delta have been found and
triggers various refining steps.
For now, `_candidategroups` will just pass the value down the stack.
After poking at various option, the co-routine appears the best to keep each
layers focus on its duty, without the need to spread implementation details
across layers.
# Since it's not easy to write a test that portably deals
# with files from different users/groups, we cheat a bit by
# monkey-patching some functions in the util module
from __future__ import absolute_import, print_function
import os
from mercurial import (
error,
ui as uimod,
util,
)
hgrc = os.environ['HGRCPATH']
f = open(hgrc)
basehgrc = f.read()
f.close()
def testui(user='foo', group='bar', tusers=(), tgroups=(),
cuser='foo', cgroup='bar', debug=False, silent=False,
report=True):
# user, group => owners of the file
# tusers, tgroups => trusted users/groups
# cuser, cgroup => user/group of the current process
# write a global hgrc with the list of trusted users/groups and
# some setting so that we can be sure it was read
f = open(hgrc, 'w')
f.write(basehgrc)
f.write('\n[paths]\n')
f.write('global = /some/path\n\n')
if tusers or tgroups:
f.write('[trusted]\n')
if tusers:
f.write('users = %s\n' % ', '.join(tusers))
if tgroups:
f.write('groups = %s\n' % ', '.join(tgroups))
f.close()
# override the functions that give names to uids and gids
def username(uid=None):
if uid is None:
return cuser
return user
util.username = username
def groupname(gid=None):
if gid is None:
return 'bar'
return group
util.groupname = groupname
def isowner(st):
return user == cuser
util.isowner = isowner
# try to read everything
#print '# File belongs to user %s, group %s' % (user, group)
#print '# trusted users = %s; trusted groups = %s' % (tusers, tgroups)
kind = ('different', 'same')
who = ('', 'user', 'group', 'user and the group')
trusted = who[(user in tusers) + 2*(group in tgroups)]
if trusted:
trusted = ', but we trust the ' + trusted
print('# %s user, %s group%s' % (kind[user == cuser], kind[group == cgroup],
trusted))
u = uimod.ui.load()
# disable the configuration registration warning
#
# the purpose of this test is to check the old behavior, not to validate the
# behavior from registered item. so we silent warning related to unregisted
# config.
u.setconfig('devel', 'warn-config-unknown', False, 'test')
u.setconfig('devel', 'all-warnings', False, 'test')
u.setconfig('ui', 'debug', str(bool(debug)))
u.setconfig('ui', 'report_untrusted', str(bool(report)))
u.readconfig('.hg/hgrc')
if silent:
return u
print('trusted')
for name, path in u.configitems('paths'):
print(' ', name, '=', util.pconvert(path))
print('untrusted')
for name, path in u.configitems('paths', untrusted=True):
print('.', end=' ')
u.config('paths', name) # warning with debug=True
print('.', end=' ')
u.config('paths', name, untrusted=True) # no warnings
print(name, '=', util.pconvert(path))
print()
return u
os.mkdir('repo')
os.chdir('repo')
os.mkdir('.hg')
f = open('.hg/hgrc', 'w')
f.write('[paths]\n')
f.write('local = /another/path\n\n')
f.close()
#print '# Everything is run by user foo, group bar\n'
# same user, same group
testui()
# same user, different group
testui(group='def')
# different user, same group
testui(user='abc')
# ... but we trust the group
testui(user='abc', tgroups=['bar'])
# different user, different group
testui(user='abc', group='def')
# ... but we trust the user
testui(user='abc', group='def', tusers=['abc'])
# ... but we trust the group
testui(user='abc', group='def', tgroups=['def'])
# ... but we trust the user and the group
testui(user='abc', group='def', tusers=['abc'], tgroups=['def'])
# ... but we trust all users
print('# we trust all users')
testui(user='abc', group='def', tusers=['*'])
# ... but we trust all groups
print('# we trust all groups')
testui(user='abc', group='def', tgroups=['*'])
# ... but we trust the whole universe
print('# we trust all users and groups')
testui(user='abc', group='def', tusers=['*'], tgroups=['*'])
# ... check that users and groups are in different namespaces
print("# we don't get confused by users and groups with the same name")
testui(user='abc', group='def', tusers=['def'], tgroups=['abc'])
# ... lists of user names work
print("# list of user names")
testui(user='abc', group='def', tusers=['foo', 'xyz', 'abc', 'bleh'],
tgroups=['bar', 'baz', 'qux'])
# ... lists of group names work
print("# list of group names")
testui(user='abc', group='def', tusers=['foo', 'xyz', 'bleh'],
tgroups=['bar', 'def', 'baz', 'qux'])
print("# Can't figure out the name of the user running this process")
testui(user='abc', group='def', cuser=None)
print("# prints debug warnings")
u = testui(user='abc', group='def', cuser='foo', debug=True)
print("# report_untrusted enabled without debug hides warnings")
u = testui(user='abc', group='def', cuser='foo', report=False)
print("# report_untrusted enabled with debug shows warnings")
u = testui(user='abc', group='def', cuser='foo', debug=True, report=False)
print("# ui.readconfig sections")
filename = 'foobar'
f = open(filename, 'w')
f.write('[foobar]\n')
f.write('baz = quux\n')
f.close()
u.readconfig(filename, sections=['foobar'])
print(u.config('foobar', 'baz'))
print()
print("# read trusted, untrusted, new ui, trusted")
u = uimod.ui.load()
# disable the configuration registration warning
#
# the purpose of this test is to check the old behavior, not to validate the
# behavior from registered item. so we silent warning related to unregisted
# config.
u.setconfig('devel', 'warn-config-unknown', False, 'test')
u.setconfig('devel', 'all-warnings', False, 'test')
u.setconfig('ui', 'debug', 'on')
u.readconfig(filename)
u2 = u.copy()
def username(uid=None):
return 'foo'
util.username = username
u2.readconfig('.hg/hgrc')
print('trusted:')
print(u2.config('foobar', 'baz'))
print('untrusted:')
print(u2.config('foobar', 'baz', untrusted=True))
print()
print("# error handling")
def assertraises(f, exc=error.Abort):
try:
f()
except exc as inst:
print('raised', inst.__class__.__name__)
else:
print('no exception?!')
print("# file doesn't exist")
os.unlink('.hg/hgrc')
assert not os.path.exists('.hg/hgrc')
testui(debug=True, silent=True)
testui(user='abc', group='def', debug=True, silent=True)
print()
print("# parse error")
f = open('.hg/hgrc', 'w')
f.write('foo')
f.close()
try:
testui(user='abc', group='def', silent=True)
except error.ParseError as inst:
print(inst)
try:
testui(debug=True, silent=True)
except error.ParseError as inst:
print(inst)
print()
print('# access typed information')
with open('.hg/hgrc', 'w') as f:
f.write('''\
[foo]
sub=main
sub:one=one
sub:two=two
path=monty/python
bool=true
int=42
bytes=81mb
list=spam,ham,eggs
''')
u = testui(user='abc', group='def', cuser='foo', silent=True)
def configpath(section, name, default=None, untrusted=False):
path = u.configpath(section, name, default, untrusted)
if path is None:
return None
return util.pconvert(path)
print('# suboptions, trusted and untrusted')
trusted = u.configsuboptions('foo', 'sub')
untrusted = u.configsuboptions('foo', 'sub', untrusted=True)
print(
(trusted[0], sorted(trusted[1].items())),
(untrusted[0], sorted(untrusted[1].items())))
print('# path, trusted and untrusted')
print(configpath('foo', 'path'), configpath('foo', 'path', untrusted=True))
print('# bool, trusted and untrusted')
print(u.configbool('foo', 'bool'), u.configbool('foo', 'bool', untrusted=True))
print('# int, trusted and untrusted')
print(
u.configint('foo', 'int', 0),
u.configint('foo', 'int', 0, untrusted=True))
print('# bytes, trusted and untrusted')
print(
u.configbytes('foo', 'bytes', 0),
u.configbytes('foo', 'bytes', 0, untrusted=True))
print('# list, trusted and untrusted')
print(
u.configlist('foo', 'list', []),
u.configlist('foo', 'list', [], untrusted=True))