Rev 4530: Change the fcntl locks so they are only exclusive with -Dlock. in lp:///~jameinel/bzr/1.18-lock-warnings

[John Arbash Meinel]

At lp:///~jameinel/bzr/1.18-lock-warnings

------------------------------------------------------------
revno: 4530
revision-id: john at arbash-meinel.com-20090730210106-7m4zs5bxl0cqgtn8
parent: john at arbash-meinel.com-20090730204645-w20f3wb8k480b5kc
committer: John Arbash Meinel <john at arbash-meinel.com>
branch nick: 1.18-lock-warnings
timestamp: Thu 2009-07-30 16:01:06 -0500
message:
  Change the fcntl locks so they are only exclusive with -Dlock.
  
  Update the tests to handle this fact.
-------------- next part --------------
=== modified file 'bzrlib/lock.py'
--- a/bzrlib/lock.py	2009-07-30 20:46:45 +0000
+++ b/bzrlib/lock.py	2009-07-30 21:01:06 +0000
@@ -188,7 +188,8 @@
             # Check we can grab a lock before we actually open the file.
             self.filename = osutils.realpath(filename)
             if (self.filename in _fcntl_WriteLock._open_locks
-                or self.filename in _fcntl_ReadLock._open_locks):
+                or ('lock' in debug.debug_flags
+                    and self.filename in _fcntl_ReadLock._open_locks)):
                 self._clear_f()
                 raise errors.LockContention(self.filename)
 
@@ -221,7 +222,8 @@
         def __init__(self, filename):
             super(_fcntl_ReadLock, self).__init__()
             self.filename = osutils.realpath(filename)
-            if self.filename in _fcntl_WriteLock._open_locks:
+            if ('lock' in debug.debug_flags and
+                self.filename in _fcntl_WriteLock._open_locks):
                 raise errors.LockContention(self.filename)
             _fcntl_ReadLock._open_locks.setdefault(self.filename, 0)
             _fcntl_ReadLock._open_locks[self.filename] += 1

=== modified file 'bzrlib/tests/test_lock.py'
--- a/bzrlib/tests/test_lock.py	2009-07-10 20:07:24 +0000
+++ b/bzrlib/tests/test_lock.py	2009-07-30 21:01:06 +0000
@@ -19,8 +19,9 @@
 
 
 from bzrlib import (
+    debug,
+    errors,
     lock,
-    errors,
     tests,
     )
 
@@ -73,16 +74,50 @@
     def test_read_locks_block_write_locks(self):
         r_lock = self.read_lock('a-lock-file')
         try:
-            self.assertRaises(errors.LockContention,
-                              self.write_lock, 'a-lock-file')
+            if lock.have_fcntl and self.write_lock is lock._fcntl_WriteLock:
+                # With -Dlock, fcntl locks are properly exclusive
+                debug.debug_flags.add('lock')
+                self.assertRaises(errors.LockContention,
+                                  self.write_lock, 'a-lock-file')
+                # But not without it
+                debug.debug_flags.remove('lock')
+                try:
+                    w_lock = self.write_lock('a-lock-file')
+                except errors.LockContention:
+                    self.fail('Unexpected success. fcntl read locks'
+                              ' do not usually block write locks')
+                else:
+                    w_lock.unlock()
+                    self.knownFailure('fcntl read locks don\'t'
+                                      ' block write locks without -Dlock')
+            else:
+                self.assertRaises(errors.LockContention,
+                                  self.write_lock, 'a-lock-file')
         finally:
             r_lock.unlock()
 
     def test_write_locks_block_read_lock(self):
         w_lock = self.write_lock('a-lock-file')
         try:
-            self.assertRaises(errors.LockContention,
-                              self.read_lock, 'a-lock-file')
+            if lock.have_fcntl and self.read_lock is lock._fcntl_ReadLock:
+                # With -Dlock, fcntl locks are properly exclusive
+                debug.debug_flags.add('lock')
+                self.assertRaises(errors.LockContention,
+                                  self.read_lock, 'a-lock-file')
+                # But not without it
+                debug.debug_flags.remove('lock')
+                try:
+                    r_lock = self.read_lock('a-lock-file')
+                except errors.LockContention:
+                    self.fail('Unexpected success. fcntl write locks'
+                              ' do not usually block read locks')
+                else:
+                    r_lock.unlock()
+                    self.knownFailure('fcntl write locks don\'t'
+                                      ' block read locks without -Dlock')
+            else:
+                self.assertRaises(errors.LockContention,
+                                  self.read_lock, 'a-lock-file')
         finally:
             w_lock.unlock()