- make it easier for an admin to configure logging levels
  (by making the defaults more sane)
- refactor the tests a little, in preparation for more tests

- remove methods that aren't needed
- rename "resolved" to "instance" for readability

- de-tabify everything

_deadline to None, to prevent reporting the same timeout more than
once.  Added a helpful comment too. :-)

intent according to the comment.

- Get rid of _lock() and _unlock(); _lock() is inlined, and so is
  _unlock(), after factoring out some common code at the end of
  tpc_begin() and tpc_end().

- In the refactored _unlock() code, only call self.timeout.end() if
  self.locked was actually set.

In the TimeoutThread class:

- Add some comments.

- Add some assertions.

- Get rid of the stop() method; we're a daemon thread so we'll be
  killed anyway; close_server() is only used from the test suite.

- Switch from using a lock + an event to a condition variable.  Be
  religious about doing stuff only while holding the lock.

- Inline the timeout() function; it shouldn't reacquire the lock
  anyway.

--Guido & Jeremy

earlier in the loop.  Basically, once we've got a tid from the
transaction record, we check it against our stop tid, and we check the
status looking for a 'c' flag.

the middle of a transaction.  This test isn't totally helpful in its
own right, but run it with logging and you'll see the bogus warning
(before the fix is applied).

Fixed to correctly munge sys.path.

that we can get distutils install to munge the #! line to insert the
proper Python executable file name.  (/usr/local/bin/python would work
too, but may not be the Python version that you intended to use, so
IMO it's better to require that you use an explicit Python interpreter
when invoking the scripts before they are installed.

runzeo.py lives -- that didn't work when runzeo.py is installed in
/usr/local/bin.

activities these days.

Closes SF bug #659068.

This change adds a new method, setLocalTransaction(), to the
Connection class.  ZODB applications can call this method to bind
transactions to connections rather than threads.  This is especially
useful for GUI applications, which often have only one thread but
multiple independent activities within that thread (generally one per
window).  Thanks to Christian Reis for championing this feature.

Applications that take advantage of this feature should not use the
get_transaction() function.  Until now, ZODB itself sometimes assumed
get_transaction() was the only way to get the transaction.  Minor
corrections have been added.  The ZODB test suite, on the other hand,
can continue to use get_transaction(), since it is free to assume that
transactions are bound to threads.

+ Transaction T1 deletes some of the keys in bucket B,
  but not all of the keys.

+ Transaction T2 deletes (exactly) the keys in B that
  aren't deleted by T1.

The version of B each transaction sees is then non-empty,
but conflict resolution creates an empty bucket.  However,
conflict resolution doesn't have enough info to unlink an
empty bucket from its containing BTree correctly.

The result is that an empty bucket is left in the BTree,
which violates a BTree invariant.  The most probable
symptom is a segfault, when later & unrelated code tries
to access this bucket:  an empty bucket has NULL
pointers where the vectors of keys and values should be,
and accessing code tries to dereference the NULL pointers.

I don't know that this error has been seen in real life.
It was provoked by a randomized multithreaded simulation
program that was trying to provoke errors.  This error was
provoked frequently by that program; no other kinds of
errors have come out of it.

Fix likely bug where calling tpc_abort() after a client disconnected
did not properly clear the client's internal state about the
transaction.  The change means that tpc_abort() will never raise a
ClientDisconnected error, even when disconnected.

Added a new test that sort-of covers this case and deleted another
that was testing, in part, that you did get a ClientDisconnected
error.

run from Daemon.

Zope3/ZODB4.  Many test fixes from Jeremy (in particular,
most of the tests weren't getting run), and new tests from
Tim.  Note that the new testEmptyBucketConflict() actually
shows that a particular rare case of conflict resolution
doesn't work correctly now.  A fix for that comes next,
along with reversing the sense of this new test.