UPDATE SET date_column = '2026-02-14' fails without explicit ::date cast via simple protocol

[johannesdb]

When using simple protocol, assigning a date string literal to a DATE column fails with:

date: unhandled type: string

Standard PostgreSQL implicitly casts string literals to the target column's type in UPDATE SET assignments.

Reproduction

CREATE TABLE test_date (id UUID PRIMARY KEY, d DATE);
INSERT INTO test_date VALUES ('00000000-0000-0000-0000-000000000001', '2026-01-01'::date);
UPDATE test_date SET d = '2026-02-14' WHERE id = '00000000-0000-0000-0000-000000000001';
-- Expected: d updated to 2026-02-14
-- Actual: "date: unhandled type: string" error

Workaround

Use explicit cast '2026-02-14'::date.

Notes

INSERT with date literals may also be affected, but we haven't tested that path since we use the same workaround everywhere.