Fix for CONPY-278:

In case of an (automatic) reconnect the connection property
connection_id was not updated, since there is no callback
functionality in Connector/C available to notify the application
that a reconnect occured. Instead of obtaining the connection_id
via MemberDef, connection_id is now implemented as getter function.

include/mariadb_python.h

@@ -218,7 +218,6 @@ typedef struct {
     uint8_t status;
     uint8_t asynchronous;
     struct timespec last_used;
-    unsigned long thread_id;
     char *server_info;
     uint8_t closed;
 #if MARIADB_PACKAGE_VERSION_ID > 30301

mariadb/mariadb_connection.c

@@ -58,6 +58,9 @@ MrdbConnection_exception(PyObject *self, void *closure);
 static PyObject *
 MrdbConnection_getreconnect(MrdbConnection *self, void *closure);
 
+static PyObject *
+MrdbConnection_connection_id(MrdbConnection *self);
+
 static int
 MrdbConnection_setreconnect(MrdbConnection *self, PyObject *args,
                             void *closure);
@@ -89,6 +92,8 @@ MrdbConnection_sets[]=
     {"auto_reconnect", (getter)MrdbConnection_getreconnect,
         (setter)MrdbConnection_setreconnect,
         connection_auto_reconnect__doc__, NULL},
+    {"connection_id", (getter)MrdbConnection_connection_id,
+        NULL, "Id of current connection", NULL},
     {"warnings", (getter)MrdbConnection_warnings, NULL,
         connection_warnings__doc__, NULL},
     GETTER_EXCEPTION("Error", Mariadb_Error, ""),
@@ -166,11 +171,6 @@ MrdbConnection_Methods[] =
 static struct
 PyMemberDef MrdbConnection_Members[] =
 {
-    {"connection_id",
-        T_LONG,
-        offsetof(MrdbConnection, thread_id),
-        READONLY,
-        "Id of current connection."},
     {"dsn",
         T_OBJECT,
         offsetof(MrdbConnection, dsn),
@@ -454,7 +454,6 @@ MrdbConnection_Initialize(MrdbConnection *self,
         goto end;
     }
 
-    self->thread_id= mysql_thread_id(self->mysql);
     mariadb_get_infov(self->mysql, MARIADB_CONNECTION_HOST, (void *)&self->host);
 
     has_error= 0;
@@ -607,9 +606,6 @@ PyObject *MrdbConnection_ping(MrdbConnection *self)
         return NULL;
     }
 
-    /* in case a reconnect occurred, we need to obtain new thread_id */
-    self->thread_id= mysql_thread_id(self->mysql);
-
     Py_RETURN_NONE;
 }
 /* }}} */
@@ -777,7 +773,6 @@ PyObject *MrdbConnection_reconnect(MrdbConnection *self)
         return NULL;
     }
     /* get capabilities */
-    self->thread_id= mysql_thread_id(self->mysql);
     Py_RETURN_NONE;
 }
 /* }}} */
@@ -801,6 +796,15 @@ PyObject *MrdbConnection_reset(MrdbConnection *self)
 }
 /* }}} */
 
+/* {{{ MrdbConnection_connection_id */
+static PyObject *MrdbConnection_connection_id(MrdbConnection *self)
+{
+    MARIADB_CHECK_CONNECTION(self, NULL);
+
+    return PyLong_FromUnsignedLong(mysql_thread_id(self->mysql));
+}
+/* }}} */
+
 /* {{{ MrdbConnection_warnings */
 static PyObject *MrdbConnection_warnings(MrdbConnection *self)
 {

testing/test/integration/test_connection.py

@@ -268,6 +268,44 @@ class TestConnection(unittest.TestCase):
                             parse_version('3.3.0'))
             pass
 
+    def test_conpy278(self):
+         test_conf= conf()
+         test_conf["reconnect"]= True
+         conn= mariadb.connect(**test_conf)
+         old_id= conn.connection_id
+         try:
+             conn.kill(conn.connection_id)
+         except mariadb.OperationalError:
+             conn.ping()
+         self.assertNotEqual(old_id, conn.connection_id)
+         conn.close()
+         conn= mariadb.connect(**test_conf)
+         old_id= conn.connection_id
+         try:
+             conn.kill(conn.connection_id)
+         except mariadb.OperationalError:
+             conn.ping()
+         self.assertNotEqual(old_id, conn.connection_id)
+         conn.close()
+         conn= mariadb.connect(**test_conf)
+         old_id= conn.connection_id
+         try:
+             conn.kill(conn.connection_id)
+         except mariadb.OperationalError:
+             pass
+         cursor= conn.cursor()
+         try:
+             cursor.execute("set @a:=1")
+         except mariadb.InterfaceError:
+             pass
+         cursor.execute("set @a:=1")
+         self.assertNotEqual(old_id, conn.connection_id)
+
+         old_id= conn.connection_id
+         conn.reconnect()
+         self.assertNotEqual(old_id, conn.connection_id)
+         conn.close()
+
 
 if __name__ == '__main__':
     unittest.main()