[NS 6] Migrations: handle mounted submodule tables, views, and indexes

[aasoni]

Description of Changes

Handle module migrations for modules that have mounted sub-modules. This required major surgery on the the migration step types which used "Identifier" which doesn't allow for dots or slashes.
It also required significant changes in the code that gathers and compares changes between the old and new module to correctly compare namespaced types with the corresponding mounted types.

API and ABI breaking changes

No

Expected complexity level and risk

4 - Significant change to migration code and logic. This shouldn't effect any logic for migrations that affect modules that don't have mounts, but the change is extensive enough that I think 4 is warrented.

Testing

Beyond the rust tests in the codebase that test various auto-migration cases for mounted modules I also did the following tests on sample module that had a mounted sub-module library:

• Module migrates without issue from having a submodule to not having a submodule
• Module migrates without issue from not having a submodule to having a submodule
• Module migrates without issue when having a submodule and root module change occurs (change reducer signature, add table, add column with default, change reducer function body, change index)
• Module migrates without issue when having a submodule and a submodule change occurs (change reducer signature, add table, add column with default, change reducer function body, change index)

[coolreader18]

LGTM, though it'd probably be good to have someone more familiar with automigration also take a look.

[coolreader18]

I'd rather have the validation logic in Identifier::new pulled out into a separate function that returns Result<(), IdentifierError>, so we're not doing a bunch of unnecessary allocation here.

[JasonAtClockwork]

I've run through and ran into two problems which I'll list out as separate comments here, I've used AI to minify the repro to hopefully make this easier to check on your end:

1. Call a child submodule reducer from inside its parent submodule reducer using ctx.as.child, and that call fails at runtime.

  // src/index.ts
  import { schema } from 'spacetimedb/server';
  import * as nested from './nested';

  const root = schema({ nested });
  export default root;

  // src/nested/index.ts
  import { schema, t } from 'spacetimedb/server';
  import * as child from './child';

  const nested = schema({ child });
  export default nested;

  export const parent_calls_child = nested.reducer(
    { value: t.string() },
    (ctx, { value }) => {
      child.child_insert(ctx.as.child, { value });
    }
  );

  // src/nested/child.ts
  import { schema, table, t } from 'spacetimedb/server';

  const child_events = table(
    { name: 'child_events', public: true },
    { id: t.u64().primaryKey().autoInc(), value: t.string() }
  );

  const child = schema({ child_events });
  export default child;

  export const child_insert = child.reducer(
    { value: t.string() },
    (ctx, { value }) => {
      ctx.db.child_events.insert({ id: 0n, value });
    }
  );

Then:

  spacetimedb-cli call <db> nested.child.child_insert direct-child
  spacetimedb-cli call <db> nested.parent_calls_child hello

  Expected broken-runtime result:

  nested.child.child_insert succeeds

  nested.parent_calls_child fails:
  Cannot read properties of undefined (reading 'db')
  at child_insert
  at parent_calls_child

[JasonAtClockwork]

2. Procedure in parent submodule fails if the submodule has child namespaces

  // src/index.ts
  import { schema } from 'spacetimedb/server';
  import * as nested from './nested';

  const root = schema({ nested });
  export default root;

  // src/nested/index.ts
  import { schema, table, t } from 'spacetimedb/server';
  import * as child from './child';

  const parent_events = table(
    { name: 'parent_events', public: true },
    { id: t.u64().primaryKey().autoInc(), value: t.string() }
  );

  const nested = schema({ parent_events, child });
  export default nested;

  export const parent_count = nested.procedure(t.u64(), ctx =>
    ctx.withTx(tx => tx.db.parent_events.count())
  );

  // src/nested/child.ts
  import { schema, table, t } from 'spacetimedb/server';

  const child_events = table(
    { name: 'child_events', public: true },
    { id: t.u64().primaryKey().autoInc(), value: t.string() }
  );

  const child = schema({ child_events });
  export default child;

Then:

  spacetimedb-cli call <db> nested.parent_count

  fails with:

  Uncaught No such table
  at makeTableView
  at buildDbViewForDispatch
  at buildAliasCtx
  at buildAliasCtxMap
  at assignTxAliasViews
  at withTx
  at src/nested/index.ts