fix: Django and SQLAlchemy APIs are failing to use rowcount (#654)

* fix: Django and SQLAlchemy APIs are failing to use rowcount * lint fix Co-authored-by: Vikash Singh <3116482+vi3k6i5@users.noreply.github.com>

Author: Ilya Gurov

google/cloud/spanner_dbapi/cursor.py

@@ -14,7 +14,6 @@
 
 """Database cursor for Google Cloud Spanner DB API."""
 
-import warnings
 from collections import namedtuple
 
 import sqlparse
@@ -137,15 +136,11 @@ def description(self):
  def rowcount(self):
  """The number of rows produced by the last `execute()` call.
 
- :raises: :class:`NotImplemented`.
+ The property is non-operational and always returns -1. Request
+ resulting rows are streamed by the `fetch*()` methods and
+ can't be counted before they are all streamed.
  """
- warnings.warn(
- "The `rowcount` property is non-operational. Request "
- "resulting rows are streamed by the `fetch*()` methods "
- "and can't be counted before they are all streamed.",
- UserWarning,
- stacklevel=2,
- )
+ return -1
 
  @check_not_closed
  def callproc(self, procname, args=None):

tests/unit/spanner_dbapi/test_cursor.py

@@ -61,19 +61,11 @@ def test_property_description(self):
  self.assertIsNotNone(cursor.description)
  self.assertIsInstance(cursor.description[0], ColumnInfo)
 
- @mock.patch("warnings.warn")
- def test_property_rowcount(self, warn_mock):
+ def test_property_rowcount(self):
  connection = self._make_connection(self.INSTANCE, self.DATABASE)
  cursor = self._make_one(connection)
 
- cursor.rowcount
- warn_mock.assert_called_once_with(
- "The `rowcount` property is non-operational. Request "
- "resulting rows are streamed by the `fetch*()` methods "
- "and can't be counted before they are all streamed.",
- UserWarning,
- stacklevel=2,
- )
+ assert cursor.rowcount == -1
 
  def test_callproc(self):
  from google.cloud.spanner_dbapi.exceptions import InterfaceError