Mercurial > hg
view tests/test-filecache.py @ 33289:abd7dedbaa36
sparse: vendor Facebook-developed extension
Facebook has developed an extension to enable "sparse" checkouts -
a working directory with a subset of files. This feature is a critical
component in enabling repositories to scale to infinite number of
files while retaining reasonable performance. It's worth noting
that sparse checkout is only one possible solution to this problem:
another is virtual filesystems that realize files on first access.
But given that virtual filesystems may not be accessible to all
users, sparse checkout is necessary as a fallback.
Per mailing list discussion at
https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-March/095868.html
we want to add sparse checkout to the Mercurial distribution via
roughly the following mechanism:
1. Vendor extension as-is with minimal modifications (this patch)
2. Refactor extension so it is more clearly experimental and inline
with Mercurial practices
3. Move code from extension into core where possible
4. Drop experimental labeling and/or move feature into core
after sign-off from narrow clone feature owners
This commit essentially copies the sparse extension and tests
from revision 71e0a2aeca92a4078fe1b8c76e32c88ff1929737 of the
https://bitbucket.org/facebook/hg-experimental repository.
A list of modifications made as part of vendoring is as follows:
* "EXPERIMENTAL" added to module docstring
* Imports were changed to match Mercurial style conventions
* "testedwith" value was updated to core Mercurial special value and
comment boilerplate was inserted
* A "clone_sparse" function was renamed to "clonesparse" to appease
the style checker
* Paths to the sparse extension in tests reflect built-in location
* test-sparse-extensions.t was renamed to test-sparse-fsmonitor.t
and references to "simplecache" were removed. The test always skips
because it isn't trivial to run it given the way we currently run
fsmonitor tests
* A double empty line was removed from test-sparse-profiles.t
There are aspects of the added code that are obviously not ideal.
The goal is to make a minimal number of modifications as part of
the vendoring to make it easier to track changes from the original
implementation. Refactoring will occur in subsequent patches.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sat, 01 Jul 2017 10:43:29 -0700 |
parents | 74cbbd5420ba |
children | daa5f47558cf |
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from __future__ import absolute_import, print_function import os import subprocess import sys if subprocess.call(['python', '%s/hghave' % os.environ['TESTDIR'], 'cacheable']): sys.exit(80) from mercurial import ( extensions, hg, localrepo, ui as uimod, util, vfs as vfsmod, ) class fakerepo(object): def __init__(self): self._filecache = {} class fakevfs(object): def join(self, p): return p vfs = fakevfs() def unfiltered(self): return self def sjoin(self, p): return p @localrepo.repofilecache('x', 'y') def cached(self): print('creating') return 'string from function' def invalidate(self): for k in self._filecache: try: delattr(self, k) except AttributeError: pass def basic(repo): print("* neither file exists") # calls function repo.cached repo.invalidate() print("* neither file still exists") # uses cache repo.cached # create empty file f = open('x', 'w') f.close() repo.invalidate() print("* empty file x created") # should recreate the object repo.cached f = open('x', 'w') f.write('a') f.close() repo.invalidate() print("* file x changed size") # should recreate the object repo.cached repo.invalidate() print("* nothing changed with either file") # stats file again, reuses object repo.cached # atomic replace file, size doesn't change # hopefully st_mtime doesn't change as well so this doesn't use the cache # because of inode change f = vfsmod.vfs('.')('x', 'w', atomictemp=True) f.write('b') f.close() repo.invalidate() print("* file x changed inode") repo.cached # create empty file y f = open('y', 'w') f.close() repo.invalidate() print("* empty file y created") # should recreate the object repo.cached f = open('y', 'w') f.write('A') f.close() repo.invalidate() print("* file y changed size") # should recreate the object repo.cached f = vfsmod.vfs('.')('y', 'w', atomictemp=True) f.write('B') f.close() repo.invalidate() print("* file y changed inode") repo.cached f = vfsmod.vfs('.')('x', 'w', atomictemp=True) f.write('c') f.close() f = vfsmod.vfs('.')('y', 'w', atomictemp=True) f.write('C') f.close() repo.invalidate() print("* both files changed inode") repo.cached def fakeuncacheable(): def wrapcacheable(orig, *args, **kwargs): return False def wrapinit(orig, *args, **kwargs): pass originit = extensions.wrapfunction(util.cachestat, '__init__', wrapinit) origcacheable = extensions.wrapfunction(util.cachestat, 'cacheable', wrapcacheable) for fn in ['x', 'y']: try: os.remove(fn) except OSError: pass basic(fakerepo()) util.cachestat.cacheable = origcacheable util.cachestat.__init__ = originit def test_filecache_synced(): # test old behavior that caused filecached properties to go out of sync os.system('hg init && echo a >> a && hg ci -qAm.') repo = hg.repository(uimod.ui.load()) # first rollback clears the filecache, but changelog to stays in __dict__ repo.rollback() repo.commit('.') # second rollback comes along and touches the changelog externally # (file is moved) repo.rollback() # but since changelog isn't under the filecache control anymore, we don't # see that it changed, and return the old changelog without reconstructing # it repo.commit('.') def setbeforeget(repo): os.remove('x') os.remove('y') repo.cached = 'string set externally' repo.invalidate() print("* neither file exists") print(repo.cached) repo.invalidate() f = open('x', 'w') f.write('a') f.close() print("* file x created") print(repo.cached) repo.cached = 'string 2 set externally' repo.invalidate() print("* string set externally again") print(repo.cached) repo.invalidate() f = open('y', 'w') f.write('b') f.close() print("* file y created") print(repo.cached) def antiambiguity(): filename = 'ambigcheck' # try some times, because reproduction of ambiguity depends on # "filesystem time" for i in xrange(5): fp = open(filename, 'w') fp.write('FOO') fp.close() oldstat = os.stat(filename) if oldstat.st_ctime != oldstat.st_mtime: # subsequent changing never causes ambiguity continue repetition = 3 # repeat changing via checkambigatclosing, to examine whether # st_mtime is advanced multiple times as expected for i in xrange(repetition): # explicit closing fp = vfsmod.checkambigatclosing(open(filename, 'a')) fp.write('FOO') fp.close() # implicit closing by "with" statement with vfsmod.checkambigatclosing(open(filename, 'a')) as fp: fp.write('BAR') newstat = os.stat(filename) if oldstat.st_ctime != newstat.st_ctime: # timestamp ambiguity was naturally avoided while repetition continue # st_mtime should be advanced "repetition * 2" times, because # all changes occurred at same time (in sec) expected = (oldstat.st_mtime + repetition * 2) & 0x7fffffff if newstat.st_mtime != expected: print("'newstat.st_mtime %s is not %s (as %s + %s * 2)" % (newstat.st_mtime, expected, oldstat.st_mtime, repetition)) # no more examination is needed regardless of result break else: # This platform seems too slow to examine anti-ambiguity # of file timestamp (or test happened to be executed at # bad timing). Exit silently in this case, because running # on other faster platforms can detect problems pass print('basic:') print() basic(fakerepo()) print() print('fakeuncacheable:') print() fakeuncacheable() test_filecache_synced() print() print('setbeforeget:') print() setbeforeget(fakerepo()) print() print('antiambiguity:') print() antiambiguity()