Connect with passwordless DSN does not work

还没有人认领这个 Issue。

Basically as the title says: Trying to connect with a DSN that contains no password does not work

DSN in question:

`
@property
def dsn(self) -> str:
return f"postgresql+asyncpg://{self.pguser}@{self.pghost}:{self.pgport}/{self.pgdatabase}"
`

results, when used with

`
def get_db_url() -> str:
config = get_config()
return config.postgres.dsn

engine = create_async_engine(
get_db_url(),
echo=True,
future=True,
)
`

in the error:

`
ERROR: Traceback (most recent call last): File "asyncpg/protocol/coreproto.pyx", line 168, in asyncpg.protocol.protocol.CoreProtocol._process__auth File "asyncpg/protocol/coreproto.pyx", line 577, in asyncpg.protocol.protocol.CoreProtocol._parse_msg_authentication File "asyncpg/protocol/coreproto.pyx", line 672, in asyncpg.protocol.protocol.CoreProtocol._auth_password_message_cleartext AttributeError: 'NoneType' object has no attribute 'encode'
`

使用所示的无密码 PostgreSQL DSN 和 create_async_engine 入口点重现该故障。跟踪所报告的 traceback _auth_password_message_cleartext 附近的密码认证路径；当无密码连接不再引发 NoneType encode error，且此情况有测试覆盖时，即视为完成。

由索引模型根据 Issue 内容生成。