tests/test-lock.py

lock: recognize parent locks while acquiring

This is part of a series that will allow locks to be inherited by subprocesses
in limited circumstances. This patch enables the logic introduced in previous
patches.

from __future__ import absolute_import

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

from mercurial import (
    lock,
    scmutil,
)

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 os.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 = scmutil.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
        lockname = parentlock.prepinherit()
        parentstate.assertreleasecalled(True)
        parentstate.assertpostreleasecalled(False)
        parentstate.assertlockexists(True)

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

        # release the child lock -- the lock file should still exist on disk
        childlock.release()
        childstate.assertreleasecalled(True)
        childstate.assertpostreleasecalled(True)
        childstate.assertlockexists(True)

        parentstate.resetacquirefn()
        parentlock.reacquire()
        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)

        lock0name = lock0.prepinherit()
        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
        lock1name = lock1.prepinherit()
        # 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(True)
        state2.assertlockexists(True)

        state1.resetacquirefn()
        lock1.reacquire()
        state1.assertacquirecalled(True)

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

        lock0.reacquire()
        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
        lockname = parentlock.prepinherit()
        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(True)
        childstate.assertlockexists(True)

        parentlock.reacquire()
        parentlock.release()

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