tests: perform a shallow copy instead of a deep copy

Python 3 can't perform a deep copy because it looks like symbols
in the locals() namespace are not deep-copyable. For the curious,
somehow the deepcopy() is attempting to copy objects attached to
the unittest.* functions for the running test!

We don't use deepcopy() anywhere in the code base and a shallow
object copy should be sufficient to test lock copying.

Actually, I'm not sure why we even test this, as I couldn't find
copy.copy() being used for lock copying either. Who knows.

Differential Revision: https://phab.mercurial-scm.org/D5770

tests/test-lock.py

@@ -1,297 +1,297 b''
 from __future__ import absolute_import
 
 import copy
 import errno
 import tempfile
 import types
 import unittest
 
 import silenttestrunner
 
 from mercurial import (
     encoding,
     error,
     lock,
     vfs as vfsmod,
 )
 
 testlockname = b'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.__func__, copy.deepcopy(x.__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=encoding.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=encoding.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=encoding.getcwd()))
         lock = state.makelock()
         state.assertacquirecalled(True)
 
         # fake a fork
-        forklock = copy.deepcopy(lock)
+        forklock = copy.copy(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=encoding.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=encoding.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=encoding.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 = copy.copy(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=encoding.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=encoding.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__)