[Bug Bash] P3: bb-data: Aurora error message shown on the Supabase path

[vishaalmehrishi]

Priority: P3 · Package: bb-data

Env-var validation surfaces an Aurora-specific error message on the Supabase path. Not a functional bug on the correctly-generated Supabase app — keeping open for the polish fix below.

Verified still present on main (e98bab4, 2026-06-19). The env-var prefix is now BLOCKS_ (renamed from KIT_).

What happens

The only Aurora-specific runtime error is thrown by createDataApiEngine():

packages/bb-data/src/index.aws.ts#L88-L91

Missing environment variables: BLOCKS_{id}_CLUSTER_ARN and/or BLOCKS_{id}_SECRET_ARN. These are injected by the CDK layer — ensure the Database is provisioned.

This branch is reached only when the connection has no connectionString. _initBase() routes any connectionString connection to PgClientEngine, and the generated Supabase supabase.ts always uses connection: fromExisting({ connectionString: dbUrl }) — so a correctly-generated Supabase app never hits the Aurora message (not reproducible on the generated path):

packages/bb-data/src/index.aws.ts#L65-L71

if (conn && 'connectionString' in conn) {
  // ... → PgClientEngine (Supabase / external Postgres path)
  return new RLSEnabledDatabase(new PgClientEngine({ connectionString, ssl: { rejectUnauthorized: false } }));
}
return new RLSEnabledDatabase(this.createDataApiEngine(envName, conn)); // ← Aurora-only branch

Residual & fix

The message/JSDoc is Aurora-centric and would be confusing if a misconfiguration routed a Supabase user down the Data API branch.

Fix: detect the external/connectionString intent and emit a Supabase-appropriate error message.