PYTHON-5306 - Fix use of public MongoClient attributes before connection (#2285)

Author: NoahStapp

doc/changelog.rst

@@ -10,10 +10,13 @@ Version 4.12.1 is a bug fix release.
 - Fixed a bug that could raise ``UnboundLocalError`` when creating asynchronous connections over SSL.
 - Fixed a bug causing SRV hostname validation to fail when resolver and resolved hostnames are identical with three domain levels.
 - Fixed a bug that caused direct use of ``pymongo.uri_parser`` to raise an ``AttributeError``.
+- Fixed a bug where clients created with connect=False and a "mongodb+srv://" connection string
+  could cause public ``pymongo.MongoClient`` and ``pymongo.AsyncMongoClient`` attributes (topology_description,
+  nodes, address, primary, secondaries, arbiters) to incorrectly return a Database, leading to type
+  errors such as: "NotImplementedError: Database objects do not implement truth value testing or bool()".
 - Removed Eventlet testing against Python versions newer than 3.9 since
   Eventlet is actively being sunset by its maintainers and has compatibility issues with PyMongo's dnspython dependency.
 
-
 Issues Resolved
 ...............
 

pymongo/asynchronous/mongo_client.py

@@ -109,6 +109,7 @@
 )
 from pymongo.read_preferences import ReadPreference, _ServerMode
 from pymongo.results import ClientBulkWriteResult
+from pymongo.server_description import ServerDescription
 from pymongo.server_selectors import writable_server_selector
 from pymongo.server_type import SERVER_TYPE
 from pymongo.topology_description import TOPOLOGY_TYPE, TopologyDescription
@@ -779,7 +780,7 @@ def __init__(
         keyword_opts["document_class"] = doc_class
         self._resolve_srv_info: dict[str, Any] = {"keyword_opts": keyword_opts}
 
-        seeds = set()
+        self._seeds = set()
         is_srv = False
         username = None
         password = None
@@ -804,18 +805,18 @@ def __init__(
                     srv_max_hosts=srv_max_hosts,
                 )
                 is_srv = entity.startswith(SRV_SCHEME)
-                seeds.update(res["nodelist"])
+                self._seeds.update(res["nodelist"])
                 username = res["username"] or username
                 password = res["password"] or password
                 dbase = res["database"] or dbase
                 opts = res["options"]
                 fqdn = res["fqdn"]
             else:
-                seeds.update(split_hosts(entity, self._port))
-        if not seeds:
+                self._seeds.update(split_hosts(entity, self._port))
+        if not self._seeds:
             raise ConfigurationError("need to specify at least one host")
 
-        for hostname in [node[0] for node in seeds]:
+        for hostname in [node[0] for node in self._seeds]:
             if _detect_external_db(hostname):
                 break
 
@@ -838,7 +839,7 @@ def __init__(
             srv_service_name = opts.get("srvServiceName", common.SRV_SERVICE_NAME)
 
         srv_max_hosts = srv_max_hosts or opts.get("srvmaxhosts")
-        opts = self._normalize_and_validate_options(opts, seeds)
+        opts = self._normalize_and_validate_options(opts, self._seeds)
 
         # Username and password passed as kwargs override user info in URI.
         username = opts.get("username", username)
@@ -857,7 +858,7 @@ def __init__(
                 "username": username,
                 "password": password,
                 "dbase": dbase,
-                "seeds": seeds,
+                "seeds": self._seeds,
                 "fqdn": fqdn,
                 "srv_service_name": srv_service_name,
                 "pool_class": pool_class,
@@ -873,8 +874,7 @@ def __init__(
             self._options.read_concern,
         )
 
-        if not is_srv:
-            self._init_based_on_options(seeds, srv_max_hosts, srv_service_name)
+        self._init_based_on_options(self._seeds, srv_max_hosts, srv_service_name)
 
         self._opened = False
         self._closed = False
@@ -975,6 +975,7 @@ def _init_based_on_options(
             srv_service_name=srv_service_name,
             srv_max_hosts=srv_max_hosts,
             server_monitoring_mode=self._options.server_monitoring_mode,
+            topology_id=self._topology_settings._topology_id if self._topology_settings else None,
         )
         if self._options.auto_encryption_opts:
             from pymongo.asynchronous.encryption import _Encrypter
@@ -1205,6 +1206,16 @@ def topology_description(self) -> TopologyDescription:
 
         .. versionadded:: 4.0
         """
+        if self._topology is None:
+            servers = {(host, port): ServerDescription((host, port)) for host, port in self._seeds}
+            return TopologyDescription(
+                TOPOLOGY_TYPE.Unknown,
+                servers,
+                None,
+                None,
+                None,
+                self._topology_settings,
+            )
         return self._topology.description
 
     @property
@@ -1218,6 +1229,8 @@ def nodes(self) -> FrozenSet[_Address]:
           to any servers, or a network partition causes it to lose connection
           to all servers.
         """
+        if self._topology is None:
+            return frozenset()
         description = self._topology.description
         return frozenset(s.address for s in description.known_servers)
 
@@ -1576,6 +1589,8 @@ async def address(self) -> Optional[tuple[str, int]]:
 
         .. versionadded:: 3.0
         """
+        if self._topology is None:
+            await self._get_topology()
         topology_type = self._topology._description.topology_type
         if (
             topology_type == TOPOLOGY_TYPE.Sharded
@@ -1598,6 +1613,8 @@ async def primary(self) -> Optional[tuple[str, int]]:
         .. versionadded:: 3.0
            AsyncMongoClient gained this property in version 3.0.
         """
+        if self._topology is None:
+            await self._get_topology()
         return await self._topology.get_primary()  # type: ignore[return-value]
 
     @property
@@ -1611,6 +1628,8 @@ async def secondaries(self) -> set[_Address]:
         .. versionadded:: 3.0
            AsyncMongoClient gained this property in version 3.0.
         """
+        if self._topology is None:
+            await self._get_topology()
         return await self._topology.get_secondaries()
 
     @property
@@ -1621,6 +1640,8 @@ async def arbiters(self) -> set[_Address]:
         connected to a replica set, there are no arbiters, or this client was
         created without the `replicaSet` option.
         """
+        if self._topology is None:
+            await self._get_topology()
         return await self._topology.get_arbiters()
 
     @property

pymongo/asynchronous/settings.py

@@ -51,6 +51,7 @@ def __init__(
         srv_service_name: str = common.SRV_SERVICE_NAME,
         srv_max_hosts: int = 0,
         server_monitoring_mode: str = common.SERVER_MONITORING_MODE,
+        topology_id: Optional[ObjectId] = None,
     ):
         """Represent MongoClient's configuration.
 
@@ -78,8 +79,10 @@ def __init__(
         self._srv_service_name = srv_service_name
         self._srv_max_hosts = srv_max_hosts or 0
         self._server_monitoring_mode = server_monitoring_mode
-
-        self._topology_id = ObjectId()
+        if topology_id is not None:
+            self._topology_id = topology_id
+        else:
+            self._topology_id = ObjectId()
         # Store the allocation traceback to catch unclosed clients in the
         # test suite.
         self._stack = "".join(traceback.format_stack()[:-2])

pymongo/synchronous/mongo_client.py

@@ -101,6 +101,7 @@
 )
 from pymongo.read_preferences import ReadPreference, _ServerMode
 from pymongo.results import ClientBulkWriteResult
+from pymongo.server_description import ServerDescription
 from pymongo.server_selectors import writable_server_selector
 from pymongo.server_type import SERVER_TYPE
 from pymongo.synchronous import client_session, database, uri_parser
@@ -777,7 +778,7 @@ def __init__(
         keyword_opts["document_class"] = doc_class
         self._resolve_srv_info: dict[str, Any] = {"keyword_opts": keyword_opts}
 
-        seeds = set()
+        self._seeds = set()
         is_srv = False
         username = None
         password = None
@@ -802,18 +803,18 @@ def __init__(
                     srv_max_hosts=srv_max_hosts,
                 )
                 is_srv = entity.startswith(SRV_SCHEME)
-                seeds.update(res["nodelist"])
+                self._seeds.update(res["nodelist"])
                 username = res["username"] or username
                 password = res["password"] or password
                 dbase = res["database"] or dbase
                 opts = res["options"]
                 fqdn = res["fqdn"]
             else:
-                seeds.update(split_hosts(entity, self._port))
-        if not seeds:
+                self._seeds.update(split_hosts(entity, self._port))
+        if not self._seeds:
             raise ConfigurationError("need to specify at least one host")
 
-        for hostname in [node[0] for node in seeds]:
+        for hostname in [node[0] for node in self._seeds]:
             if _detect_external_db(hostname):
                 break
 
@@ -836,7 +837,7 @@ def __init__(
             srv_service_name = opts.get("srvServiceName", common.SRV_SERVICE_NAME)
 
         srv_max_hosts = srv_max_hosts or opts.get("srvmaxhosts")
-        opts = self._normalize_and_validate_options(opts, seeds)
+        opts = self._normalize_and_validate_options(opts, self._seeds)
 
         # Username and password passed as kwargs override user info in URI.
         username = opts.get("username", username)
@@ -855,7 +856,7 @@ def __init__(
                 "username": username,
                 "password": password,
                 "dbase": dbase,
-                "seeds": seeds,
+                "seeds": self._seeds,
                 "fqdn": fqdn,
                 "srv_service_name": srv_service_name,
                 "pool_class": pool_class,
@@ -871,8 +872,7 @@ def __init__(
             self._options.read_concern,
         )
 
-        if not is_srv:
-            self._init_based_on_options(seeds, srv_max_hosts, srv_service_name)
+        self._init_based_on_options(self._seeds, srv_max_hosts, srv_service_name)
 
         self._opened = False
         self._closed = False
@@ -973,6 +973,7 @@ def _init_based_on_options(
             srv_service_name=srv_service_name,
             srv_max_hosts=srv_max_hosts,
             server_monitoring_mode=self._options.server_monitoring_mode,
+            topology_id=self._topology_settings._topology_id if self._topology_settings else None,
         )
         if self._options.auto_encryption_opts:
             from pymongo.synchronous.encryption import _Encrypter
@@ -1203,6 +1204,16 @@ def topology_description(self) -> TopologyDescription:
 
         .. versionadded:: 4.0
         """
+        if self._topology is None:
+            servers = {(host, port): ServerDescription((host, port)) for host, port in self._seeds}
+            return TopologyDescription(
+                TOPOLOGY_TYPE.Unknown,
+                servers,
+                None,
+                None,
+                None,
+                self._topology_settings,
+            )
         return self._topology.description
 
     @property
@@ -1216,6 +1227,8 @@ def nodes(self) -> FrozenSet[_Address]:
           to any servers, or a network partition causes it to lose connection
           to all servers.
         """
+        if self._topology is None:
+            return frozenset()
         description = self._topology.description
         return frozenset(s.address for s in description.known_servers)
 
@@ -1570,6 +1583,8 @@ def address(self) -> Optional[tuple[str, int]]:
 
         .. versionadded:: 3.0
         """
+        if self._topology is None:
+            self._get_topology()
         topology_type = self._topology._description.topology_type
         if (
             topology_type == TOPOLOGY_TYPE.Sharded
@@ -1592,6 +1607,8 @@ def primary(self) -> Optional[tuple[str, int]]:
         .. versionadded:: 3.0
            MongoClient gained this property in version 3.0.
         """
+        if self._topology is None:
+            self._get_topology()
         return self._topology.get_primary()  # type: ignore[return-value]
 
     @property
@@ -1605,6 +1622,8 @@ def secondaries(self) -> set[_Address]:
         .. versionadded:: 3.0
            MongoClient gained this property in version 3.0.
         """
+        if self._topology is None:
+            self._get_topology()
         return self._topology.get_secondaries()
 
     @property
@@ -1615,6 +1634,8 @@ def arbiters(self) -> set[_Address]:
         connected to a replica set, there are no arbiters, or this client was
         created without the `replicaSet` option.
         """
+        if self._topology is None:
+            self._get_topology()
         return self._topology.get_arbiters()
 
     @property

pymongo/synchronous/settings.py

@@ -51,6 +51,7 @@ def __init__(
         srv_service_name: str = common.SRV_SERVICE_NAME,
         srv_max_hosts: int = 0,
         server_monitoring_mode: str = common.SERVER_MONITORING_MODE,
+        topology_id: Optional[ObjectId] = None,
     ):
         """Represent MongoClient's configuration.
 
@@ -78,8 +79,10 @@ def __init__(
         self._srv_service_name = srv_service_name
         self._srv_max_hosts = srv_max_hosts or 0
         self._server_monitoring_mode = server_monitoring_mode
-
-        self._topology_id = ObjectId()
+        if topology_id is not None:
+            self._topology_id = topology_id
+        else:
+            self._topology_id = ObjectId()
         # Store the allocation traceback to catch unclosed clients in the
         # test suite.
         self._stack = "".join(traceback.format_stack()[:-2])

test/asynchronous/test_client.py

@@ -850,6 +850,58 @@ async def test_init_disconnected_with_auth(self):
         with self.assertRaises(ConnectionFailure):
             await c.pymongo_test.test.find_one()
 
+    @async_client_context.require_no_standalone
+    @async_client_context.require_no_load_balancer
+    @async_client_context.require_tls
+    async def test_init_disconnected_with_srv(self):
+        c = await self.async_rs_or_single_client(
+            "mongodb+srv://test1.test.build.10gen.cc", connect=False, tlsInsecure=True
+        )
+        # nodes returns an empty set if not connected
+        self.assertEqual(c.nodes, frozenset())
+        # topology_description returns the initial seed description if not connected
+        topology_description = c.topology_description
+        self.assertEqual(topology_description.topology_type, TOPOLOGY_TYPE.Unknown)
+        self.assertEqual(
+            {
+                ("test1.test.build.10gen.cc", None): ServerDescription(
+                    ("test1.test.build.10gen.cc", None)
+                )
+            },
+            topology_description.server_descriptions(),
+        )
+
+        # address causes client to block until connected
+        self.assertIsNotNone(await c.address)
+        # Initial seed topology and connected topology have the same ID
+        self.assertEqual(
+            c._topology._topology_id, topology_description._topology_settings._topology_id
+        )
+        await c.close()
+
+        c = await self.async_rs_or_single_client(
+            "mongodb+srv://test1.test.build.10gen.cc", connect=False, tlsInsecure=True
+        )
+        # primary causes client to block until connected
+        await c.primary
+        self.assertIsNotNone(c._topology)
+        await c.close()
+
+        c = await self.async_rs_or_single_client(
+            "mongodb+srv://test1.test.build.10gen.cc", connect=False, tlsInsecure=True
+        )
+        # secondaries causes client to block until connected
+        await c.secondaries
+        self.assertIsNotNone(c._topology)
+        await c.close()
+
+        c = await self.async_rs_or_single_client(
+            "mongodb+srv://test1.test.build.10gen.cc", connect=False, tlsInsecure=True
+        )
+        # arbiters causes client to block until connected
+        await c.arbiters
+        self.assertIsNotNone(c._topology)
+
     async def test_equality(self):
         seed = "{}:{}".format(*list(self.client._topology_settings.seeds)[0])
         c = await self.async_rs_or_single_client(seed, connect=False)