Revert "Fix default port for mongosrv DSNs (#6827)"

This reverts commit 05341d3.

pydantic/networks.py

@@ -4,7 +4,7 @@
 import dataclasses as _dataclasses
 import re
 from ipaddress import IPv4Address, IPv4Interface, IPv4Network, IPv6Address, IPv6Interface, IPv6Network
-from typing import TYPE_CHECKING, Any, Union
+from typing import TYPE_CHECKING, Any
 
 from pydantic_core import MultiHostUrl, PydanticCustomError, Url, core_schema
 from typing_extensions import Annotated, TypeAlias
@@ -124,10 +124,7 @@ def __hash__(self) -> int:
     UrlConstraints(allowed_schemes=['redis', 'rediss'], default_host='localhost', default_port=6379, default_path='/0'),
 ]
 """A type that will accept any Redis DSN."""
-MongoDsn = Union[
-    Annotated[MultiHostUrl, UrlConstraints(allowed_schemes=['mongodb'], default_port=27017)],
-    Annotated[MultiHostUrl, UrlConstraints(allowed_schemes=['mongodb+srv'])],
-]
+MongoDsn = Annotated[MultiHostUrl, UrlConstraints(allowed_schemes=['mongodb', 'mongodb+srv'], default_port=27017)]
 """A type that will accept any MongoDB DSN."""
 KafkaDsn = Annotated[Url, UrlConstraints(allowed_schemes=['kafka'], default_host='localhost', default_port=9092)]
 """A type that will accept any Kafka DSN."""

tests/test_networks.py

@@ -615,16 +615,6 @@ class Model(BaseModel):
     assert m.a.hosts() == [{'username': None, 'password': None, 'host': 'localhost', 'port': 27017}]
 
 
-def test_mongodsn_default_ports():
-    class Model(BaseModel):
-        a: MongoDsn
-
-    m1 = Model(a='mongodb://user:pass@localhost/app')
-    m2 = Model(a='mongodb+srv://user:pass@localhost/app')
-    assert str(m1.a) == 'mongodb://user:pass@localhost:27017/app'
-    assert str(m2.a) == 'mongodb+srv://user:pass@localhost/app'
-
-
 def test_kafka_dsns():
     class Model(BaseModel):
         a: KafkaDsn