unrecognised connection type {qualified_type_name(connection

Error message

unrecognised connection type {qualified_type_name(connection)!r}

What it means

Error "unrecognised connection type {qualified_type_name(connection)!r}" thrown in pola-rs/polars.

Source

Thrown at py-polars/src/polars/dataframe/frame.py:4514

                _import_optional_adbc_driver,
                _is_adbc_snowflake_conn,
                _open_adbc_connection,
            )

            conn, can_close_conn = (
                (_open_adbc_connection(connection), True)
                if isinstance(connection, str)
                else (connection, False)
            )

            driver_manager = import_optional("adbc_driver_manager")

            # base class for ADBC connections
            if not isinstance(conn, driver_manager.dbapi.Connection):
                msg = (
                    f"unrecognised connection type {qualified_type_name(connection)!r}"
                )
                raise TypeError(msg)

            driver_manager_str_version = getattr(driver_manager, "__version__", "0.0")
            driver_manager_version = parse_version(driver_manager_str_version)

            if if_table_exists == "fail":
                # if the table exists, 'create' will raise an error,
                # resulting in behaviour equivalent to 'fail'
                mode = "create"
            elif if_table_exists == "replace":
                if driver_manager_version < (0, 7):
                    msg = (
                        "`if_table_exists = 'replace'` requires ADBC version >= 0.7, "
                        f"found {driver_manager_str_version}"
                    )
                    raise ModuleUpgradeRequiredError(msg)
                mode = "replace"
            elif if_table_exists == "append":
                # 'append' inserts into an existing table; the table-existence

View on GitHub (pinned to df599052da)

When it happens

Trigger: Thrown at py-polars/src/polars/dataframe/frame.py:4514 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of pola-rs/polars@df599052da (2026-08-16). Data as JSON: /api/errors/9a538c18fef71275. Report an issue: GitHub.