docs(changelog): upgrade notes of interface-database 0.4.0

CHANGELOG.md

@@ -4,6 +4,57 @@
 
 [compare changes](https://github.com/AntelopeJS/interface-database/compare/v0.3.3...v0.4.0)
 
+### Upgrade notes
+
+- **A query is no longer a promise.** `Query` has no `then()`, and `QueryExecution` no longer extends `PromiseLike`. `await query` gives back the query object and sends nothing to the provider. Run a query with `run()`, or read it with `cursor()` or `for await`. A query in `Promise.all([...])`, or returned from an `async` function, is no longer run either. TypeScript rejects a query passed where a `PromiseLike` is expected, and the `typescript/await-thenable` lint rule reports `await` on a query and a query passed to `Promise.all`, `Promise.race` or another promise aggregator. The conformance suite in `dist/tests` runs every query with `run()`. A database module implements nothing new.
+
+  ```ts
+  // Before
+  const adults = await users.filter((u) => u.key("age").ge(18));
+  // After
+  const adults = await users.filter((u) => u.key("age").ge(18)).run();
+  ```
+
+- **`cast()` returns a new object.** `Datum#cast`, `Stream#cast` and `ValueProxy#cast` return a new object with the same stages, built by the new `StagedObject` constructor form `new X(undefined, previous)`, which records no stage. `cast()` on a `Table`, a `Selection` or a `SingleSelection` returns a plain `Stream` or `Datum`, the class its type already declared. Code that compared the result with its receiver, or relied on it keeping the subclass methods at runtime, such as a table's `insert` or `getAll`, keeps the receiver instead.
+
+  ```ts
+  // Before: the same object, still a Table at runtime
+  table.cast<Row>() === table; // true
+  // After: a new Stream with the same stages
+  table.cast<Row>() === table; // false
+  table.cast<Row>().build(); // equal to table.build()
+  ```
+
+- **`Schema.get()` takes no type arguments.** The registry keeps none, so `Schema.get(id)` returns `Schema<any, unknown> | undefined`: tables hold `any` documents, and the definition is typed `unknown`. A typed lookup such as `Schema.get<{ users: User }>(id)` fails to compile (TS2558). Query typed tables through the schema object the constructor returned. On the runtime entry, `Schema.list().get(id)` returns the schema with its definition typed `SchemaDefinition`.
+
+  ```ts
+  // Before
+  const schema = Schema.get<{ users: User }>("myapp")!;
+  // After: export the schema you define, and import it
+  export const schema = new Schema<{ users: User }>("myapp", definition);
+  ```
+
+- **The build-only `Query<T>` keeps its result type.** Loaded from `@antelopejs/interface-database/staged-query` alone, `Query<T>` now uses `T`, so `ExtractType` reads the result type of a `Datum` or a `Stream` a mapper returns, and a `Query<string>` is no longer assignable to a `Query<number>`. Code that relied on that assignment fails to compile.
+
+  ```ts
+  // Before, build-only entry: compiled, typed unknown
+  const q: Query<number> = schema.createInstance(); // Query<string>
+  // After: TS2322
+  ```
+
+- **`StagedObject#callfunc` checks its argument classes.** The protected method takes one or two `StagedConstructor`s, and each must build the parameter type `func` declares. A subclass that passed `ValueProxy<unknown>` for a parameter typed `ValueProxy<T>` passes `ValueProxy<T>`.
+
+  ```ts
+  // Before
+  this.callfunc(mapper, Stream<T>, ValueProxy<unknown>);
+  // After
+  this.callfunc(
+    mapper,
+    Stream<T>,
+    ValueProxy<K extends keyof T ? T[K] : unknown>,
+  );
+  ```
+
 ### 🚀 Enhancements
 
 - **staged-query:** ⚠️  Drop casts, thenable queries and caller-typed schema lookups ([#91](https://github.com/AntelopeJS/interface-database/pull/91))