view tests/test-propertycache.py @ 32697:19b9fc40cc51

revlog: skeleton support for version 2 revlogs

There are a number of improvements we want to make to revlogs
that will require a new version - version 2. It is unclear what the
full set of improvements will be or when we'll be done with them.
What I do know is that the process will likely take longer than a
single release, will require input from various stakeholders to
evaluate changes, and will have many contentious debates and
bikeshedding.

It is unrealistic to develop revlog version 2 up front: there
are just too many uncertainties that we won't know until things
are implemented and experiments are run. Some changes will also
be invasive and prone to bit rot, so sitting on dozens of patches
is not practical.

This commit introduces skeleton support for version 2 revlogs in
a way that is flexible and not bound by backwards compatibility
concerns.

An experimental repo requirement for denoting revlog v2 has been
added. The requirement string has a sub-version component to it.
This will allow us to declare multiple requirements in the course
of developing revlog v2. Whenever we change the in-development
revlog v2 format, we can tweak the string, creating a new
requirement and locking out old clients. This will allow us to
make as many backwards incompatible changes and experiments to
revlog v2 as we want. In other words, we can land code and make
meaningful progress towards revlog v2 while still maintaining
extreme format flexibility up until the point we freeze the
format and remove the experimental labels.

To enable the new repo requirement, you must supply an experimental
and undocumented config option. But not just any boolean flag
will do: you need to explicitly use a value that no sane person
should ever type. This is an additional guard against enabling
revlog v2 on an installation it shouldn't be enabled on. The
specific scenario I'm trying to prevent is say a user with a
4.4 client with a frozen format enabling the option but then
downgrading to 4.3 and accidentally creating repos with an
outdated and unsupported repo format. Requiring a "challenge"
string should prevent this.

Because the format is not yet finalized and I don't want to take
any chances, revlog v2's version is currently 0xDEAD. I figure
squatting on a value we're likely never to use as an actual revlog
version to mean "internal testing only" is acceptable. And
"dead" is easily recognized as something meaningful.

There is a bunch of cleanup that is needed before work on revlog
v2 begins in earnest. I plan on doing that work once this patch
is accepted and we're comfortable with the idea of starting down
this path.

"""test behavior of propertycache and unfiltered propertycache

The repoview overlay is quite complex. We test the behavior of
property cache of both localrepo and repoview to prevent
regression."""

from __future__ import absolute_import, print_function
import os
import subprocess

from mercurial import (
    hg,
    localrepo,
    ui as uimod,
    util,
)

# create some special property cache that trace they call

calllog = []
@util.propertycache
def testcachedfoobar(repo):
    name = repo.filtername
    if name is None:
        name = ''
    val = len(name)
    calllog.append(val)
    return val

unficalllog = []
@localrepo.unfilteredpropertycache
def testcachedunfifoobar(repo):
    name = repo.filtername
    if name is None:
        name = ''
    val = 100 + len(name)
    unficalllog.append(val)
    return val

#plug them on repo
localrepo.localrepository.testcachedfoobar = testcachedfoobar
localrepo.localrepository.testcachedunfifoobar = testcachedunfifoobar


# Create an empty repo and instantiate it. It is important to run
# these tests on the real object to detect regression.
repopath = os.path.join(os.environ['TESTTMP'], 'repo')
assert subprocess.call(['hg', 'init', repopath]) == 0
ui = uimod.ui.load()
repo = hg.repository(ui, path=repopath).unfiltered()


print('')
print('=== property cache ===')
print('')
print('calllog:', calllog)
print('cached value (unfiltered):',
    vars(repo).get('testcachedfoobar', 'NOCACHE'))

print('')
print('= first access on unfiltered, should do a call')
print('access:', repo.testcachedfoobar)
print('calllog:', calllog)
print('cached value (unfiltered):',
    vars(repo).get('testcachedfoobar', 'NOCACHE'))

print('')
print('= second access on unfiltered, should not do call')
print('access', repo.testcachedfoobar)
print('calllog:', calllog)
print('cached value (unfiltered):',
    vars(repo).get('testcachedfoobar', 'NOCACHE'))

print('')
print('= first access on "visible" view, should do a call')
visibleview = repo.filtered('visible')
print('cached value ("visible" view):',
    vars(visibleview).get('testcachedfoobar', 'NOCACHE'))
print('access:', visibleview.testcachedfoobar)
print('calllog:', calllog)
print('cached value (unfiltered):',
    vars(repo).get('testcachedfoobar', 'NOCACHE'))
print('cached value ("visible" view):',
    vars(visibleview).get('testcachedfoobar', 'NOCACHE'))

print('')
print('= second access on "visible view", should not do call')
print('access:', visibleview.testcachedfoobar)
print('calllog:', calllog)
print('cached value (unfiltered):',
    vars(repo).get('testcachedfoobar', 'NOCACHE'))
print('cached value ("visible" view):',
    vars(visibleview).get('testcachedfoobar', 'NOCACHE'))

print('')
print('= no effect on other view')
immutableview = repo.filtered('immutable')
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedfoobar', 'NOCACHE'))
print('access:', immutableview.testcachedfoobar)
print('calllog:', calllog)
print('cached value (unfiltered):',
    vars(repo).get('testcachedfoobar', 'NOCACHE'))
print('cached value ("visible" view):',
    vars(visibleview).get('testcachedfoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedfoobar', 'NOCACHE'))

# unfiltered property cache test
print('')
print('')
print('=== unfiltered property cache ===')
print('')
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'))

print('')
print('= first access on unfiltered, should do a call')
print('access (unfiltered):', repo.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))

print('')
print('= second access on unfiltered, should not do call')
print('access (unfiltered):', repo.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))

print('')
print('= access on view should use the unfiltered cache')
print('access (unfiltered):      ', repo.testcachedunfifoobar)
print('access ("visible" view):  ', visibleview.testcachedunfifoobar)
print('access ("immutable" view):', immutableview.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'))

print('')
print('= even if we clear the unfiltered cache')
del repo.__dict__['testcachedunfifoobar']
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'))
print('unficalllog:', unficalllog)
print('access ("visible" view):  ', visibleview.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'))
print('access ("immutable" view):', immutableview.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'))
print('access (unfiltered):      ', repo.testcachedunfifoobar)
print('unficalllog:', unficalllog)
print('cached value (unfiltered):      ',
    vars(repo).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("visible" view):  ',
    vars(visibleview).get('testcachedunfifoobar', 'NOCACHE'))
print('cached value ("immutable" view):',
    vars(immutableview).get('testcachedunfifoobar', 'NOCACHE'))