ADD COLUMN REFERENCES with a non-NULL default

Warning — it works, but holds the single write lock or breaks the previous release.

What it catches

When foreign keys are enforced (PRAGMA foreign_keys=ON, which most applications set on every connection), a column added with a REFERENCES clause must default to NULL — anything else fails with "Cannot add a REFERENCES column with non-NULL default value". Whether it fails depends on a per-connection pragma, so the same file passes in one runner and stops in another.

Fires on

ALTER TABLE orders ADD COLUMN warehouse_id INTEGER REFERENCES warehouses(id) DEFAULT 1;

Do this instead

ALTER TABLE orders ADD COLUMN warehouse_id INTEGER REFERENCES warehouses(id);
-- backfill from the application, in batches