What happens?

When reading a csv header=true, and also explicitly supplying columns, when they don't match an InternalException is thrown. Similar to:

  File "/Users/thijs/DuckDBLabs/duckdb/tmp/mismatch_csv.py", line 13, in <module>
    data = con.execute(q2).fetchall()
duckdb.InternalException: INTERNAL Error: Assertion triggered in file "/Users/thijs/DuckDBLabs/duckdb/src/function/table/read_csv.cpp" on line 113: return_types.size() == names.size()

Note: I'm sure this can also be reproduced as a .test file, for convenience I've supplied the example using the python client.

To Reproduce

test.csv

a, b, c, d
1, 2, 3, 4

import duckdb

con=duckdb.connect()
columns="{'a':'varchar','b':'varchar','c':'varchar','d':'varchar','e':'varchar'}"
q2=f"""
	SELECT * FROM read_csv_auto(
		'test.csv',
		delim='/t',
		header=True,
		columns={columns}
	)
	"""
data = con.execute(q2).fetchall()
print(data)

OS:

MacOS

DuckDB Version:

master

DuckDB Client:

Python

Full Name:

Thijs Bruineman

Affiliation:

DuckDB Labs

Have you tried this on the latest master branch?

• I agree

Have you tried the steps to reproduce? Do they include all relevant data and configuration? Does the issue you report still appear there?

• I agree