Fix for CONPY-150:

Since Python complains about invalid date types (year, month or day=0),
they need to converted to NULL instead of PyDate* object.

mariadb/mariadb_codecs.c

@@ -666,11 +666,11 @@ field_fetch_callback(void *data, unsigned int column, unsigned char **row)
                 uint8_t len= 0;
                 int year= 0, month= 0, day= 0,
                     hour= 0, minute= 0, second= 0, second_part= 0;
-
                 len= (uint8_t)mysql_net_field_length(row);
                 if (!len)
                 {
-                    self->values[column]= PyDateTime_FromDateAndTime(0,0,0,0,0,0,0);
+                    Py_INCREF(Py_None);
+                    self->values[column]= Py_None;
                     break;
                 }
                 year= uint2korr(*row);
@@ -698,7 +698,8 @@ field_fetch_callback(void *data, unsigned int column, unsigned char **row)
 
                 if (!len)
                 {
-                    self->values[column]= PyDate_FromDate(0,0,0);
+                    Py_INCREF(Py_None);
+                    self->values[column]= Py_None;
                     break;
                 }
                 year= uint2korr(*row);

testing/test/integration/test_cursor.py

@@ -1152,6 +1152,22 @@ def test_conpy139(self):
         del c1, c2
         connection.close()
 
+    def test_conpy150(self):
+        connection= create_connection()
+        cursor= connection.cursor()
+        cursor.execute("create temporary table t1 (id int, a datetime not null default '0000-00-00 00:00:00', b date not null default '0000-00-00')")
+        cursor.execute("insert into t1 (id) values (1)");
+        cursor.execute("select * from t1")
+        row= cursor.fetchone()
+        self.assertEqual(row[1], None)
+        self.assertEqual(row[2], None)
+        cursor.execute("select * from t1 WHERE 1=?", (1,))
+        row= cursor.fetchone()
+        self.assertEqual(row[1], None)
+        self.assertEqual(row[2], None)
+        del cursor
+        connection.close()
+
     def test_conpy91(self):
         with create_connection() as connection:
             with connection.cursor() as cursor: