* psycopg/cursor_type.c: add support for cyclic GC.
* psycopg/python.h: add definitions for Py_CLEAR() and Py_VISIT()
for compatibility with old versions of Python.
and change the Python level attribute to a getset.
* psycopg/lobject.h (lobjectObject): remove the closed member,
since "fd < 0" gives us the same information. Reorder the struct
members for better packing.
including behaviour on closed lobjects and stale lobjects.
* psycopg/lobject_type.c (psyco_lobj_close): don't mark the
connection closed here because it is done by
lobject_close_locked().
* psycopg/lobject_int.c (lobject_open): mark objects as not closed
if we successfully open them.
(lobject_close_locked): mark the lobject closed here.
(lobject_export): ensure we are in a transaction, since
lo_export() issues multiple queries.
* psycopg/lobject_type.c (lobject_setup): make lobjects start closed.
* tests/*.py: use the DSN constructed in tests/__init__.py.
* tests/__init__.py: allow setting the host, port and user for the
DSN used by the tests through the environment.
connection->encoding with free() instead of PyMem_Free().
* psycopg/connection_int.c (conn_connect): use malloc() to
allocate connection->encoding instead of PyMem_Malloc(), since it
is freed in other places with free() and assigned to with
strdup().
return value for partially parsed time values.
* psycopg/typecast_mxdatetime.c (typecast_MXDATE_cast): return
NULL after setting DataError. Also, don't treat it as an error if
typecast_parse_time() returns 0 (as might happen if the remainder
of the string is " BC").
* psycopg/typecast_datetime.c (typecast_PYDATE_cast): return NULL
after setting DataError.
(typecast_PYDATETIME_cast): same here.
(typecast_PYTIME_cast): same here.
* tests/test_dates.py
(CommonDatetimeTestsMixin.test_parse_incomplete_date): test that
parsing incomplete date values results in DataError.
(CommonDatetimeTestsMixin.test_parse_incomplete_time): same for
times.
(CommonDatetimeTestsMixin.test_parse_incomplete_time): same for
datetimes.
* psycopg/pqpath.c (pq_raise): if PSYCOPG_EXTENSIONS is not
defined, raise OperationalError rather than
TransactionRollbackError for deadlock or serialisation errors for
protocol versions less than 3.
