error when detecting is connection is custom

[edublancas]

(Note that this error can only be reproduced with #431, which hasn't been merged yet)

while improving some error messages, I encountered this:

Note that the error message doesn't accurately display the error in the df variable. Instead, if shows ''

I tracked down the error to this method:

jupysql/src/sql/connection.py

Line 362 in fcc74b0

def is_custom_connection(conn=None) -> bool:

Since int is not part of the list of checks:

jupysql/src/sql/connection.py

Line 381 in fcc74b0

conn, (sqlalchemy.engine.base.Connection, Connection, str, bool)

It fails. Which breaks the SQLCommand logic (the is_custom_connection is called there).

We need a more robust way to check whether a connection is custom or not. A better approach is to check if the connection object has all the attributes expected from the DB API: close, commit, rollback and cursor (https://peps.python.org/pep-0249/)

[tonykploomber]

I am trying to reproduce the error.
Do you mind to share how you make duckdb:// connection as custom?

[edublancas]

@tonykploomber: I just realized this could not be reproduced with the code in master. Let's wait until #431 is merged - I reproduced it while working on that PR