[TS] Error publishing init reducer with insert' return string

[rubnfelix]

Using spacetimedb 1.9.0

const a = table(
    { name: 'A' },
    { id: t.u32().primaryKey().autoInc() }
);
const b = table(
    { name: 'B' },
    { id: t.string().primaryKey() }
);
const c = table(
    { name: 'C' },
    {
        id: t.u32().primaryKey().autoInc()
        aId: t.u32(),
        bId: t.string(),
    }
);
const db = schema(a, b, c);

✅ Works

db.init(ctx => {
    const { id: aId } = ctx.db.A.insert({ id: 0 });
    const bId = 'B_ID';
    ctx.db.B.insert({ id: bId });
    ctx.db.C.insert({ id: 0, aId, bId });
});

db.init(ctx => {
    const { id: aId } = ctx.db.A.insert({ id: 0 });
    const { id: bId } = ctx.db.B.insert({ id: 'B_ID' });
    ctx.db.C.insert({ id: 0, aId, bId: 'B_ID' });
});

❌ Fails

db.init(ctx => {
    const { id: aId } = ctx.db.A.insert({ id: 0 });
    const { id: bId } = ctx.db.B.insert({ id: 'B_ID' });
    ctx.db.C.insert({ id: 0, aId, bId });
});

DB logs

2025-11-26T16:14:42.210906Z  INFO crates\core\src\host\v8\error.rs:401: reducer "init" runtime error: js error Uncaught TypeError: Cannot read properties of undefined (reading 'length')
        at F (spacetimedb_module:181:26)
        at v.encode (spacetimedb_module:215:49)
        at writeString (spacetimedb_module:480:43)
        at serializeValue (spacetimedb_module:1029:12)
        at serializeValue (spacetimedb_module:1097:54)
        at serializeValue (spacetimedb_module:970:20)
        at insert (spacetimedb_module:3677:20)
        at <anonymous> (spacetimedb_module:4223:21)
        at __call_reducer__ (spacetimedb_module:3615:30)


2025-11-26T16:14:42.211313Z  INFO crates\core\src\host\v8\error.rs:403: js error Uncaught TypeError: Cannot read properties of undefined (reading 'length')
2025-11-26T16:14:42.211619Z  INFO crates\core\src\host\v8\error.rs:405:   Frame #0: at F (spacetimedb_module:181:26)
2025-11-26T16:14:42.211849Z  INFO crates\core\src\host\v8\error.rs:405:   Frame #1: at v.encode (spacetimedb_module:215:49)
2025-11-26T16:14:42.212099Z  INFO crates\core\src\host\v8\error.rs:405:   Frame #2: at writeString (spacetimedb_module:480:43)
2025-11-26T16:14:42.212333Z  INFO crates\core\src\host\v8\error.rs:405:   Frame #3: at serializeValue (spacetimedb_module:1029:12)
2025-11-26T16:14:42.212558Z  INFO crates\core\src\host\v8\error.rs:405:   Frame #4: at serializeValue (spacetimedb_module:1097:54)
2025-11-26T16:14:42.212785Z  INFO crates\core\src\host\v8\error.rs:405:   Frame #5: at serializeValue (spacetimedb_module:970:20)
2025-11-26T16:14:42.213014Z  INFO crates\core\src\host\v8\error.rs:405:   Frame #6: at insert (spacetimedb_module:3677:20)
2025-11-26T16:14:42.213192Z  INFO crates\core\src\host\v8\error.rs:405:   Frame #7: at <anonymous> (spacetimedb_module:4223:21)
2025-11-26T16:14:42.213357Z  INFO crates\core\src\host\v8\error.rs:405:   Frame #8: at __call_reducer__ (spacetimedb_module:3615:30)
2025-11-26T16:14:42.214702Z ERROR D:\a\SpacetimeDB\SpacetimeDB\crates\client-api\src\lib.rs:546: internal error: The instance encountered a fatal error.

cli publish logs

Publishing module...
JavaScript / TypeScript support is currently in BETA.
There may be bugs. Please file issues if you encounter any.
<https://github.com/clockworklabs/SpacetimeDB/issues/new>
Error: The instance encountered a fatal error.

Caused by:
    HTTP status server error (500 Internal Server Error) for url (http://127.0.0.1:3000/v1/database/entourage-server?clear=true&host_type=Js)

Notice the error doesn't happen with aId, which is a number.

[coolreader18]

Thanks for reporting! This is a known issue, will be resolved by #3775.

[rubnfelix]

great, thanks for letting me know