Describe the bug

sqlalchemy.engine.url.URL's render_as_string function url encodes some but not all characters for passwords.

I expect the output of render_as_string to url encode all necessary characters for a db url.

Optional link from https://docs.sqlalchemy.org which documents the behavior that is expected

No response

SQLAlchemy Version in Use

1.4.41

DBAPI (i.e. the database driver)

n/a

Database Vendor and Major Version

n/a

Python Version

3.8

Operating system

Linux

To Reproduce

from sqlalchemy import create_engine
import urllib

password = urllib.parse.quote_plus("notareal[password]")
db_url = f"postgresql+pg8000://scott:{password}@localhost:5432/mydatabase"
print(db_url)
# postgresql+pg8000://scott:notareal%5Bpassword%5D@localhost:5432/mydatabase

engine = create_engine(db_url)
print(engine.url.render_as_string(hide_password=False))
# postgresql+pg8000://scott:notareal[password]@localhost:5432/mydatabase
# The password is no longer url encoded.

Error

I am using AWS xray which monkey patches Session. The monkey patched code uses urllib.parse.urlparse on the string returned by URL's render_as_string.

One of my passwords included a square bracket. Because square brackets are not url encoded by render_as_string, this leads to urlparse interpreting the db url as an invalid IPv6 url. This breaks xray functionality and logs an error:

[ERROR] Error parsing sql metadata.
Traceback (most recent call last):
  File "/var/task/aws_xray_sdk/ext/sqlalchemy_core/patch.py", line 22, in _sql_meta
    url = urlparse(str(engine_instance.engine.url))
  File "/var/lang/lib/python3.8/urllib/parse.py", line 384, in urlparse
    splitresult = urlsplit(url, scheme, allow_fragments)
  File "/var/lang/lib/python3.8/urllib/parse.py", line 486, in urlsplit
    raise ValueError("Invalid IPv6 URL")

Additional context

Is there any reason why sqlalchemy is only url encoding specific characters instead of using urllib.parse.quoteplus?