view tests/test-lock.py @ 33766:4c706037adef

wireproto: overhaul iterating batcher code (API)

The remote batching code is difficult to read. Let's improve it.

As part of the refactor, the future returned by method calls on
batchiter() instances is now populated. However, you still need to
consume the results() generator for the future to be set.  But at
least now we can stuff the future somewhere and not have to worry
about aligning method call order with result order since you can
use a future to hold the result.

Also as part of the change, we now verify that @batchable generators
yield exactly 2 values. In other words, we enforce their API.

The non-iter batcher has been unused since b6e71f8af5b8. And to my
surprise we had no explicit unit test coverage of it! test-batching.py
has been overhauled to use the iterating batcher.

Since the iterating batcher doesn't allow non-batchable method
calls nor local calls, tests have been updated to reflect reality.
The iterating batcher has been used for multiple releases apparently
without major issue. So this shouldn't cause alarm.

.. api::

   @peer.batchable functions must now yield exactly 2 values

Differential Revision: https://phab.mercurial-scm.org/D319

from __future__ import absolute_import

import copy
import errno
import os
import silenttestrunner
import tempfile
import types
import unittest

from mercurial import (
    error,
    lock,
    vfs as vfsmod,
)

testlockname = 'testlock'

# work around http://bugs.python.org/issue1515
if types.MethodType not in copy._deepcopy_dispatch:
    def _deepcopy_method(x, memo):
        return type(x)(x.im_func, copy.deepcopy(x.im_self, memo), x.im_class)
    copy._deepcopy_dispatch[types.MethodType] = _deepcopy_method

class lockwrapper(lock.lock):
    def __init__(self, pidoffset, *args, **kwargs):
        # lock.lock.__init__() calls lock(), so the pidoffset assignment needs
        # to be earlier
        self._pidoffset = pidoffset
        super(lockwrapper, self).__init__(*args, **kwargs)
    def _getpid(self):
        return super(lockwrapper, self)._getpid() + self._pidoffset

class teststate(object):
    def __init__(self, testcase, dir, pidoffset=0):
        self._testcase = testcase
        self._acquirecalled = False
        self._releasecalled = False
        self._postreleasecalled = False
        self.vfs = vfsmod.vfs(dir, audit=False)
        self._pidoffset = pidoffset

    def makelock(self, *args, **kwargs):
        l = lockwrapper(self._pidoffset, self.vfs, testlockname,
                        releasefn=self.releasefn, acquirefn=self.acquirefn,
                        *args, **kwargs)
        l.postrelease.append(self.postreleasefn)
        return l

    def acquirefn(self):
        self._acquirecalled = True

    def releasefn(self):
        self._releasecalled = True

    def postreleasefn(self):
        self._postreleasecalled = True

    def assertacquirecalled(self, called):
        self._testcase.assertEqual(
            self._acquirecalled, called,
            'expected acquire to be %s but was actually %s' % (
                self._tocalled(called),
                self._tocalled(self._acquirecalled),
            ))

    def resetacquirefn(self):
        self._acquirecalled = False

    def assertreleasecalled(self, called):
        self._testcase.assertEqual(
            self._releasecalled, called,
            'expected release to be %s but was actually %s' % (
                self._tocalled(called),
                self._tocalled(self._releasecalled),
            ))

    def assertpostreleasecalled(self, called):
        self._testcase.assertEqual(
            self._postreleasecalled, called,
            'expected postrelease to be %s but was actually %s' % (
                self._tocalled(called),
                self._tocalled(self._postreleasecalled),
            ))

    def assertlockexists(self, exists):
        actual = self.vfs.lexists(testlockname)
        self._testcase.assertEqual(
            actual, exists,
            'expected lock to %s but actually did %s' % (
                self._toexists(exists),
                self._toexists(actual),
            ))

    def _tocalled(self, called):
        if called:
            return 'called'
        else:
            return 'not called'

    def _toexists(self, exists):
        if exists:
            return 'exist'
        else:
            return 'not exist'

class testlock(unittest.TestCase):
    def testlock(self):
        state = teststate(self, tempfile.mkdtemp(dir=os.getcwd()))
        lock = state.makelock()
        state.assertacquirecalled(True)
        lock.release()
        state.assertreleasecalled(True)
        state.assertpostreleasecalled(True)
        state.assertlockexists(False)

    def testrecursivelock(self):
        state = teststate(self, tempfile.mkdtemp(dir=os.getcwd()))
        lock = state.makelock()
        state.assertacquirecalled(True)

        state.resetacquirefn()
        lock.lock()
        # recursive lock should not call acquirefn again
        state.assertacquirecalled(False)

        lock.release() # brings lock refcount down from 2 to 1
        state.assertreleasecalled(False)
        state.assertpostreleasecalled(False)
        state.assertlockexists(True)

        lock.release() # releases the lock
        state.assertreleasecalled(True)
        state.assertpostreleasecalled(True)
        state.assertlockexists(False)

    def testlockfork(self):
        state = teststate(self, tempfile.mkdtemp(dir=os.getcwd()))
        lock = state.makelock()
        state.assertacquirecalled(True)

        # fake a fork
        forklock = copy.deepcopy(lock)
        forklock._pidoffset = 1
        forklock.release()
        state.assertreleasecalled(False)
        state.assertpostreleasecalled(False)
        state.assertlockexists(True)

        # release the actual lock
        lock.release()
        state.assertreleasecalled(True)
        state.assertpostreleasecalled(True)
        state.assertlockexists(False)

    def testinheritlock(self):
        d = tempfile.mkdtemp(dir=os.getcwd())
        parentstate = teststate(self, d)
        parentlock = parentstate.makelock()
        parentstate.assertacquirecalled(True)

        # set up lock inheritance
        with parentlock.inherit() as lockname:
            parentstate.assertreleasecalled(True)
            parentstate.assertpostreleasecalled(False)
            parentstate.assertlockexists(True)

            childstate = teststate(self, d, pidoffset=1)
            childlock = childstate.makelock(parentlock=lockname)
            childstate.assertacquirecalled(True)

            childlock.release()
            childstate.assertreleasecalled(True)
            childstate.assertpostreleasecalled(False)
            childstate.assertlockexists(True)

            parentstate.resetacquirefn()

        parentstate.assertacquirecalled(True)

        parentlock.release()
        parentstate.assertreleasecalled(True)
        parentstate.assertpostreleasecalled(True)
        parentstate.assertlockexists(False)

    def testmultilock(self):
        d = tempfile.mkdtemp(dir=os.getcwd())
        state0 = teststate(self, d)
        lock0 = state0.makelock()
        state0.assertacquirecalled(True)

        with lock0.inherit() as lock0name:
            state0.assertreleasecalled(True)
            state0.assertpostreleasecalled(False)
            state0.assertlockexists(True)

            state1 = teststate(self, d, pidoffset=1)
            lock1 = state1.makelock(parentlock=lock0name)
            state1.assertacquirecalled(True)

            # from within lock1, acquire another lock
            with lock1.inherit() as lock1name:
                # since the file on disk is lock0's this should have the same
                # name
                self.assertEqual(lock0name, lock1name)

                state2 = teststate(self, d, pidoffset=2)
                lock2 = state2.makelock(parentlock=lock1name)
                state2.assertacquirecalled(True)

                lock2.release()
                state2.assertreleasecalled(True)
                state2.assertpostreleasecalled(False)
                state2.assertlockexists(True)

                state1.resetacquirefn()

            state1.assertacquirecalled(True)

            lock1.release()
            state1.assertreleasecalled(True)
            state1.assertpostreleasecalled(False)
            state1.assertlockexists(True)

        lock0.release()

    def testinheritlockfork(self):
        d = tempfile.mkdtemp(dir=os.getcwd())
        parentstate = teststate(self, d)
        parentlock = parentstate.makelock()
        parentstate.assertacquirecalled(True)

        # set up lock inheritance
        with parentlock.inherit() as lockname:
            childstate = teststate(self, d, pidoffset=1)
            childlock = childstate.makelock(parentlock=lockname)
            childstate.assertacquirecalled(True)

            # fork the child lock
            forkchildlock = copy.deepcopy(childlock)
            forkchildlock._pidoffset += 1
            forkchildlock.release()
            childstate.assertreleasecalled(False)
            childstate.assertpostreleasecalled(False)
            childstate.assertlockexists(True)

            # release the child lock
            childlock.release()
            childstate.assertreleasecalled(True)
            childstate.assertpostreleasecalled(False)
            childstate.assertlockexists(True)

        parentlock.release()

    def testinheritcheck(self):
        d = tempfile.mkdtemp(dir=os.getcwd())
        state = teststate(self, d)
        def check():
            raise error.LockInheritanceContractViolation('check failed')
        lock = state.makelock(inheritchecker=check)
        state.assertacquirecalled(True)

        with self.assertRaises(error.LockInheritanceContractViolation):
            with lock.inherit():
                pass

        lock.release()

    def testfrequentlockunlock(self):
        """This tests whether lock acquisition fails as expected, even if
        (1) lock can't be acquired (makelock fails by EEXIST), and
        (2) locker info can't be read in (readlock fails by ENOENT) while
        retrying 5 times.
        """

        d = tempfile.mkdtemp(dir=os.getcwd())
        state = teststate(self, d)

        def emulatefrequentlock(*args):
            raise OSError(errno.EEXIST, "File exists")
        def emulatefrequentunlock(*args):
            raise OSError(errno.ENOENT, "No such file or directory")

        state.vfs.makelock = emulatefrequentlock
        state.vfs.readlock = emulatefrequentunlock

        try:
            state.makelock(timeout=0)
            self.fail("unexpected lock acquisition")
        except error.LockHeld as why:
            self.assertTrue(why.errno == errno.ETIMEDOUT)
            self.assertTrue(why.locker == "")
            state.assertlockexists(False)

if __name__ == '__main__':
    silenttestrunner.main(__name__)