Mercurial > hg
view tests/test-filecache.py @ 30521:86cd09bc13ba
worker: use os._exit for posix worker in all cases
Like commandserver, the worker should never run other resource cleanup logic.
Previously this is not true for workers if they have exceptions other than
KeyboardInterrupt.
This actually caused a real-world deadlock with remotefilelog:
1. remotefilelog/fileserverclient creates a sshpeer. pipei/o/e get created.
2. worker inherits that sshpeer's pipei/o/e.
3. worker runs sshpeer.cleanup (only happens without os._exit)
4. worker closes pipeo/i, which will normally make the sshpeer read EOF from
its stdin and exit. But the master process still have pipeo, so no EOF.
5. worker reads pipee (stderr of sshpeer), which never completes because
the ssh process does not exit, does not close its stderr.
6. master waits for all workers, which never completes because they never
complete sshpeer.cleanup.
This could also be addressed by closing these fds after fork, which is not
easy because Python 2.x does not have an official "afterfork" hook. Hacking
os.fork is also ugly. Besides, sshpeer is probably not the only troublemarker.
The patch changes _posixworker so all its code paths will use os._exit to
avoid running unwanted resource clean-ups.
author | Jun Wu <quark@fb.com> |
---|---|
date | Thu, 24 Nov 2016 01:15:34 +0000 |
parents | 318a24b52eeb |
children | d83ca854fa21 |
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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, scmutil, ui as uimod, util, ) filecache = scmutil.filecache class fakerepo(object): def __init__(self): self._filecache = {} def join(self, p): return p def sjoin(self, p): return p @filecache('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 = scmutil.opener('.')('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 = scmutil.opener('.')('y', 'w', atomictemp=True) f.write('B') f.close() repo.invalidate() print("* file y changed inode") repo.cached f = scmutil.opener('.')('x', 'w', atomictemp=True) f.write('c') f.close() f = scmutil.opener('.')('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()) # 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 = scmutil.checkambigatclosing(open(filename, 'a')) fp.write('FOO') fp.close() # implicit closing by "with" statement with scmutil.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()