api: exception rethrow in crud

Before this patch, all DatabaseError exception, except for
ER_NO_SUCH_PROC and ER_ACCESS_DENIED ones, were silently ignored.
It resulted in "UnboundLocalError: local variable 'crud_resp' referenced
before assignment" instead of a proper error.

Author: DifferentialOrange

CHANGELOG.md

@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Fixed
+- Exception rethrow in crud API (PR #310).
+
 ## 1.1.1 - 2023-07-19
 
 ### Changed

tarantool/crud.py

@@ -69,5 +69,6 @@ def call_crud(conn, *args):
         if exc.code in (ER_NO_SUCH_PROC, ER_ACCESS_DENIED):
             exc_msg = ". Ensure that you're calling crud.router and user has sufficient grants"
             raise DatabaseError(exc.code, exc.message + exc_msg, extra_info=exc.extra_info) from exc
+        raise exc
 
     return crud_resp

test/suites/crud_mock_server.lua

@@ -0,0 +1,21 @@
+#!/usr/bin/env tarantool
+
+local admin_listen = os.getenv("ADMIN")
+local primary_listen = os.getenv("LISTEN")
+
+require('console').listen(admin_listen)
+box.cfg{
+    listen       = primary_listen,
+    memtx_memory = 0.1 * 1024^3, -- 0.1 GiB
+    pid_file     = "box.pid",
+}
+
+box.schema.user.grant('guest', 'execute', 'universe', nil, {if_not_exists = true})
+
+local function mock_replace()
+    error('Unexpected connection error')
+end
+
+rawset(_G, 'crud', {replace = mock_replace})
+
+rawset(_G, 'ready', true)

test/suites/test_crud.py

@@ -22,6 +22,14 @@ def create_server():
     return srv
 
 
+def create_mock_server():
+    srv = TarantoolServer()
+    srv.script = 'test/suites/crud_mock_server.lua'
+    srv.start()
+
+    return srv
+
+
 @unittest.skipIf(sys.platform.startswith("win"),
                  "Crud tests on windows platform are not supported: "
                  "complexity of the vshard replicaset configuration")
@@ -33,14 +41,19 @@ def setUpClass(cls):
         print('-' * 70, file=sys.stderr)
         # Create server and extract helpful fields for tests.
         cls.srv = create_server()
+        cls.mock_srv = create_mock_server()
         cls.host = cls.srv.host
         cls.port = cls.srv.args['primary']
+        cls.mock_host = cls.mock_srv.host
+        cls.mock_port = cls.mock_srv.args['primary']
 
     def setUp(self):
         time.sleep(1)
         # Open connections to instance.
         self.conn = tarantool.Connection(host=self.host, port=self.port,
                                          user='guest', password='', fetch_schema=False)
+        self.mock_conn = tarantool.Connection(host=self.mock_host, port=self.mock_port,
+                                              user='guest', password='', fetch_schema=False)
         self.conn_mesh = tarantool.MeshConnection(host=self.host, port=self.port,
                                                   user='guest', password='', fetch_schema=False)
         self.conn_pool = tarantool.ConnectionPool([{'host': self.host, 'port': self.port}],
@@ -736,9 +749,15 @@ def test_crud_module_via_pool_connection(self):
                 # Exception try testing.
                 self._exception_operation_with_crud(testing_function, case, mode=tarantool.Mode.RW)
 
+    def test_error_rethrow(self):
+        self.assertRaisesRegex(
+            DatabaseError, "Unexpected connection error",
+            lambda: self.mock_conn.crud_replace('tester', [2, 100, 'Alice'], {'timeout': 10}))
+
     def tearDown(self):
         # Close connections to instance.
         self.conn.close()
+        self.mock_conn.close()
         self.conn_mesh.close()
         self.conn_pool.close()
 
@@ -747,3 +766,5 @@ def tearDownClass(cls):
         # Stop instance.
         cls.srv.stop()
         cls.srv.clean()
+        cls.mock_srv.stop()
+        cls.mock_srv.clean()