view tests/test-propertycache.py @ 32558:aa91085cadf3

transaction: delete callbacks after use

Before this change, localrepository instances that performed multiple
transactions would leak transaction objects. This could occur when
running `hg convert`. When running `hg convert`, the leak would be
~90 MB per 10,000 changesets as measured with the Mercurial repo itself.

The leak I tracked down involved the "validate" closure from
localrepository.transaction(). It appeared to be keeping a
reference to the original transaction via __closure__. __del__
semantics and a circular reference involving the repo object
may have also come into play.

Attempting to refactor the "validate" closure proved to be
difficult because the "tr" reference in that closure may
reference an object that isn't created until transaction.__init__
is called. And the "validate" closure is passed as an argument to
transaction.__init__. Plus there is a giant warning comment in
"validate" about how hacky it is. I did not want to venture into
the dragon den.

Anyway, we've had problems with transactions causing leaks before.
The solution then (14e683d6b273) is the same as the solution in this
patch: drop references to callbacks after they are called. This
not only breaks cycles in core Mercurial but can help break cycles
in extensions that accidentally introduce them.

While I only tracked down a leak due to self.validator, since this is
the 2nd time I've tracked down leaks due to transaction callbacks I
figure enough is enough and we should prevent the class of leak from
occurring regardless of the variable. That's why all callback variables
are now nuked.

"""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'))