Module namespace 

Namespace-Scoped Query API (Task 2)

This module enforces mandatory namespace scoping at the type level, making cross-workspace data leakage impossible by construction.

The Problem

When namespace/tenant scoping is treated as an optional filter parameter, developers can accidentally:

• Query across workspaces by forgetting to add the namespace filter
• Reuse a handle across workspaces in local-first scenarios
• Mix data from different tenants in multi-tenant deployments

The Solution

Make namespace a required part of the query identity, not an optional filter. The type system enforces:

1. Namespace is required in every query request
2. Namespace must be validated against the capability token
3. “No namespace” is not a valid state

Multi-Namespace Queries

For legitimate multi-namespace queries, use NamespaceScope::Multiple which requires explicit authorization for each namespace.

Example

// This compiles - namespace is required
let query = ScopedQuery::new(
    Namespace::new("production"),
    QueryOp::VectorSearch { ... }
);

// This won't compile - no namespace
let query = ScopedQuery::new(QueryOp::VectorSearch { ... });  // ERROR!

Structs

DatabaseId

A database within a namespace.

Namespace

A validated namespace identifier

NamespaceRegistry

Registry tracking the namespace → database → table hierarchy.

QualifiedTable

A fully qualified table path: namespace/database/table.

QueryRequest

A complete query request with authentication

ScopedQuery

A query that is always scoped to a namespace

Enums

NamespaceError

Errors that can occur when creating a namespace

NamespaceScope

Scope for a query - either single namespace or explicitly multiple

ScopeError

Errors related to namespace scope

Functions

ns

Create a namespace (shorthand)

scope

Create a single-namespace scope (shorthand)