Panic (unwrap on None) reading sqlite-vec vec0 KNN results — SELECT ... WHERE embedding MATCH ?

[klueless-io]

Summary

Loading the sqlite-vec extension into a libsql database works, and a vec0 virtual table can be created, inserted into, and counted — but the KNN search query (... WHERE embedding MATCH ? ORDER BY distance) panics the native driver with called Option::unwrap() on a None value, aborting the process. This is the one operation that makes a vector extension useful, so sqlite-vec is effectively unusable via libsql.

Reproduced on both the latest stable libsql@0.5.29 and the latest prerelease libsql@0.6.0-pre.41.

Environment

• libsql: 0.5.29 (and 0.6.0-pre.41)
• sqlite-vec: 0.1.9
• Node.js: v25.8.0
• OS: macOS, arm64

Minimal reproduction

const Database = require('libsql');
const sqliteVec = require('sqlite-vec');

const db = new Database(':memory:');
sqliteVec.load(db);

console.log(db.prepare('select vec_version() v').get());          // ✓ works
db.exec('CREATE VIRTUAL TABLE t USING vec0(embedding float[4])'); // ✓ works
const f = a => Buffer.from(new Float32Array(a).buffer);
db.prepare('INSERT INTO t(rowid, embedding) VALUES (?, ?)').run(1n, f([1, 0, 0, 0])); // ✓ works
console.log(db.prepare('SELECT count(*) c FROM t').get());        // ✓ works -> { c: 1 }

// ✗ PANICS:
db.prepare('SELECT rowid, distance FROM t WHERE embedding MATCH ? ORDER BY distance LIMIT 1')
  .all(f([1, 0, 0, 0]));

Expected

The KNN query returns the nearest rows with their distance values (as it does under better-sqlite3 with the same extension).

Actual

thread '<unnamed>' panicked at src/statement.rs:396:62:
called `Option::unwrap()` on a `None` value

On 0.6.0-pre.41 the same query panics at src/lib.rs:1354:58 (fatal runtime error: failed to initiate panic, error 5, aborting).

Notes

• load / CREATE VIRTUAL TABLE vec0 / INSERT / SELECT count(*) all succeed — only the vec0 KNN result (which surfaces the hidden distance column via the MATCH constraint) fails. The panic looks like the driver assuming column metadata that a vec0 virtual-table result doesn't provide.
• The identical extension + query works under better-sqlite3.
• A panic::catch_unwind (or graceful SqliteError) instead of an unwrap() would at least keep it recoverable, but the underlying goal is to read vec0 KNN results.