view tests/test-propertycache.py @ 49000:dd6b67d5c256 stable

rust: fix unsound `OwningDirstateMap`

As per the previous patch, `OwningDirstateMap` is unsound. Self-referential
structs are difficult to implement correctly in Rust since the compiler is
free to move structs around as much as it wants to. They are also very rarely
needed in practice, so the state-of-the-art on how they should be done within
the Rust rules is still a bit new.

The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense)
of declaring self-referential structs. It is getting a lot attention and was
improved very quickly when soundness issues were found in the past: rather than
relying on our own (limited) review circle, we might as well use the de-facto
common crate to fix this problem. This will give us a much better chance of
finding issues should any new ones be discovered as well as the benefit of
fewer `unsafe` APIs of our own.

I was starting to think about how I would present a safe API to the old struct
but soon realized that the callback-based approach was already done in
`ouroboros`, along with a lot more care towards refusing incorrect structs.

In short: we don't return a mutable reference to the `DirstateMap` anymore, we
expect users of its API to pass a `FnOnce` that takes the map as an argument.
This allows our `OwningDirstateMap` to control the input and output lifetimes
of the code that modifies it to prevent such issues.

Changing to `ouroboros` meant changing every API with it, but it is relatively
low churn in the end. It correctly identified the example buggy modification of
`copy_map_insert` outlined in the previous patch as violating the borrow rules.

Differential Revision: https://phab.mercurial-scm.org/D12429

"""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,
    pycompat,
    ui as uimod,
    util,
)

from mercurial.utils import procutil

# 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 = pycompat.fsencode(os.path.join(os.environ['TESTTMP'], 'repo'))
assert (
    subprocess.call(
        pycompat.rapply(procutil.tonativestr, [b'hg', b'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'),
)