[Shubham8287]

Description of Changes

Macro side changes taken out from: #6001.
Based on #6375

Adds Rust outbox declarations for intermodule reducer calls using generated receiver bindings.

It can be reviewed through commits:

• Add outbox macros and runtime registration as described in the proposal.
• Map outbox columns to receiver parameters using #[param(name = ...)], with compile-time type checking.
• Make outbox tables insert-only by removing update and delete APIs.
• Accept receiver dependencies in publish configuration.
• Add end-to-end smoke tests covering generation, publishing, delivery, callbacks, receiver updates, and two dependencies with identical type names.

API and ABI breaking changes

Additive module API. Update and delete APIs are unavailable on outbox tables.

No host ABI changes.

Rollback safety impact

N/A.

Expected complexity level and risk

Proposal drift

The outbox! convenience macro is not implemented yet.

Source-based local reducer references and self-referential outboxes are handled in a separate PR.

Testing

• Compile-pass and compile-fail tests for parameter mapping, receiver types, table shape, and mutation restrictions.
• Generated receiver-bindings fixture validation.
• End-to-end IDC delivery smoke tests.

[joshua-spacetime]

Is this a breaking change? Table is technically part of the public api.

[Shubham8287]

You mean, If someone were doing:

fn do_something<T: spacetimedb::Table>(table: &T) {
    table.clear();
}

that would break?

[joshua-spacetime]

I believe so, yes.

[Shubham8287]

yeah, I overlooked Table trait to be as public api itself, only cared to not break methods.
I fixed this by adding struct OutboxTable<T: Table> wrapper type around Table.

[joshua-spacetime]

Same here.