Make Insert<> respect .db.auto()/.db.inserted(), and typecheck the public API

package.json

@@ -55,7 +55,7 @@
     "test": "bun test && npm run test:node",
     "test:bun": "bun test",
     "test:node": "node --import tsx --test src/impl/*.node-test.ts",
-    "typecheck": "tsc --noEmit",
+    "typecheck": "tsc --noEmit -p tsconfig.typecheck.json",
     "lint": "eslint --ext .js,.jsx,.ts,.tsx .",
     "prepublishOnly": "echo 'ERROR: Cannot publish from root directory. Use libuild publish instead.' && exit 1"
   },

src/impl/table.ts

@@ -2849,19 +2849,55 @@ export type FullTableOnly<T> = T extends {meta: {isPartial: true}}
 		? never
 		: T;
 
+/**
+ * Phantom brand applied by `.db.auto()`, `.db.inserted()` and `.db.upserted()`.
+ *
+ * These methods mean "the value is supplied for you on INSERT", so the field
+ * must not be required in `Insert<T>`. The metadata itself lives in a runtime
+ * side-channel, which the type system cannot see — hence the brand. It rides on
+ * the Zod field type in the table's shape, and because `db` is typed as
+ * `ZodDBMethods<this>`, it survives further chaining in any order
+ * (`.db.auto().db.primary()` and `.db.primary().db.auto()` both keep it).
+ */
+export interface DBInsertOptional {
+	readonly __dbInsertOptional: true;
+}
+
+/** Keys of a table shape whose values are generated on INSERT. */
+type InsertOptionalKeys<Shape extends ZodRawShape> = {
+	[K in keyof Shape]: Shape[K] extends DBInsertOptional ? K : never;
+}[keyof Shape];
+
+/** Make the given keys of `O` optional, leaving the rest required. */
+type OptionalizeKeys<O, K extends PropertyKey> = Omit<O, K> &
+	Partial<Pick<O, Extract<K, keyof O>>>;
+
+/** Flatten an intersection so hovers and errors read as a single object. */
+type Flatten<O> = {[K in keyof O]: O[K]} & {};
+
 /**
  * Infer the insert type (respects defaults and .db.auto() fields).
  * Returns `never` for partial or derived tables to prevent insert at compile time.
  *
+ * Fields marked `.db.auto()`, `.db.inserted()` or `.db.upserted()` are optional,
+ * because the value is generated for you. Everything else stays required.
+ *
  * @example
- * const Users = table("users", {...});
- * type NewUser = Insert<typeof Users>;
+ * const Users = table("users", {
+ *   id: z.string().uuid().db.primary().db.auto(),
+ *   email: z.string().email(),
+ * });
+ * type NewUser = Insert<typeof Users>; // {id?: string; email: string}
  */
 export type Insert<T extends Table<any>> = T extends {meta: {isPartial: true}}
 	? never
 	: T extends {meta: {isDerived: true}}
 		? never
-		: z.input<T["schema"]>;
+		: T extends Table<infer Shape, any, any>
+			? Flatten<
+					OptionalizeKeys<z.input<ZodObject<Shape>>, InsertOptionalKeys<Shape>>
+				>
+			: z.input<T["schema"]>;
 
 /**
  * Infer the update type (all fields optional, excludes primary key and insert-only fields).
@@ -3025,8 +3061,11 @@ export interface ZodDBMethods<Schema extends ZodType> {
 	 */
 	inserted(
 		value: import("./database.js").SQLBuiltin | (() => z.infer<Schema>),
-	): Schema;
-	inserted(strings: TemplateStringsArray, ...values: unknown[]): Schema;
+	): Schema & DBInsertOptional;
+	inserted(
+		strings: TemplateStringsArray,
+		...values: unknown[]
+	): Schema & DBInsertOptional;
 
 	/**
 	 * Set a value to apply on UPDATE only.
@@ -3059,8 +3098,11 @@ export interface ZodDBMethods<Schema extends ZodType> {
 	 */
 	upserted(
 		value: import("./database.js").SQLBuiltin | (() => z.infer<Schema>),
-	): Schema;
-	upserted(strings: TemplateStringsArray, ...values: unknown[]): Schema;
+	): Schema & DBInsertOptional;
+	upserted(
+		strings: TemplateStringsArray,
+		...values: unknown[]
+	): Schema & DBInsertOptional;
 
 	/**
 	 * Auto-generate value on insert based on field type.
@@ -3084,7 +3126,7 @@ export interface ZodDBMethods<Schema extends ZodType> {
 	 * createdAt: z.date().db.auto()
 	 * // → NOW on insert
 	 */
-	auto(): Schema;
+	auto(): Schema & DBInsertOptional;
 }
 
 declare module "zod" {

test/types/public-api.ts

@@ -0,0 +1,118 @@
+/**
+ * Compile-time tests for the public API.
+ *
+ * This file is never executed. It exists because nothing else typechecks the
+ * public surface: `bun test` does not typecheck at all, and `tsconfig.json`
+ * used to include only `src/**`. That gap is how `db.insert()` shipped unable
+ * to compile the README's own Quick Start — the runtime generated the id
+ * correctly, but TypeScript rejected the call.
+ *
+ * Anything asserted here is checked by `npm run typecheck`. Type errors in this
+ * file are test failures.
+ */
+import {
+	z,
+	table,
+	Database,
+	NOW,
+	type Insert,
+	type Row,
+	type Update,
+} from "../../src/zen.js";
+
+declare const db: Database;
+
+// ============================================================================
+// The README Quick Start, verbatim. This must compile.
+// ============================================================================
+
+const Users = table("users", {
+	id: z.string().uuid().db.primary().db.auto(),
+	email: z.string().email().db.unique(),
+	name: z.string(),
+});
+
+const Posts = table("posts", {
+	id: z.string().uuid().db.primary().db.auto(),
+	authorId: z.string().uuid().db.references(Users, "author"),
+	title: z.string(),
+	published: z.boolean().db.inserted(() => false),
+});
+
+export async function readmeQuickStart() {
+	// `id` is omitted: it is .db.auto().
+	const user = await db.insert(Users, {
+		email: "alice@example.com",
+		name: "Alice",
+	});
+
+	// `id` and `published` are omitted: .db.auto() and .db.inserted().
+	await db.insert(Posts, {authorId: user.id, title: "Hello"});
+
+	// The generated id is present on the returned row.
+	const id: string = user.id;
+	return id;
+}
+
+// ============================================================================
+// Insert: generated fields optional, everything else still required.
+// ============================================================================
+
+export const Timestamps = table("timestamps", {
+	id: z.string().uuid().db.primary().db.auto(),
+	title: z.string(),
+	createdAt: z.date().db.inserted(NOW),
+	updatedAt: z.date().db.upserted(NOW),
+});
+
+// Every generated field may be omitted...
+export const minimalInsert: Insert<typeof Timestamps> = {title: "Hello"};
+
+// ...and may still be supplied explicitly.
+export const explicitInsert: Insert<typeof Timestamps> = {
+	id: "e5b7c1f0-0000-4000-8000-000000000000",
+	title: "Hello",
+	createdAt: new Date(),
+	updatedAt: new Date(),
+};
+
+// A field with no .db generator stays required.
+// @ts-expect-error - `title` is required
+export const missingRequired: Insert<typeof Timestamps> = {};
+
+// @ts-expect-error - `name` is required
+export const missingName: Insert<typeof Users> = {email: "a@b.com"};
+
+// Unknown fields are still rejected. (The excess-property error is reported on
+// the offending property, so the directive has to sit directly above it.)
+export const unknownField: Insert<typeof Users> = {
+	email: "a@b.com",
+	name: "Alice",
+	// @ts-expect-error - `nope` is not a field
+	nope: true,
+};
+
+// The brand must survive chaining in either order.
+export const EitherOrder = table("either_order", {
+	a: z.string().uuid().db.primary().db.auto(),
+	b: z.string().uuid().db.auto().db.unique(),
+	c: z.string(),
+});
+export const chainOrder: Insert<typeof EitherOrder> = {c: "required"};
+
+// ============================================================================
+// Row: generated fields are present after a read, not optional.
+// ============================================================================
+
+export function rowKeepsGeneratedFields(row: Row<typeof Timestamps>) {
+	const id: string = row.id;
+	const createdAt: Date = row.createdAt;
+	return {id, createdAt};
+}
+
+// ============================================================================
+// Update: still all-optional.
+// ============================================================================
+
+export const emptyUpdate: Update<typeof Users> = {};
+export const partialUpdate: Update<typeof Users> = {name: "Bob"};

tsconfig.typecheck.json

@@ -0,0 +1,18 @@
+{
+  // Typecheck-only config. The base tsconfig drives the build (rootDir: ./src),
+  // so it cannot include files outside src/. This one adds the compile-time
+  // tests in test/types/ — which assert things `bun test` cannot, because
+  // `bun test` does not typecheck.
+  //
+  // test/*.test.ts is deliberately NOT included: those files have pre-existing
+  // type errors, and folding them in would make this check useless.
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "noEmit": true,
+    "rootDir": ".",
+    "declaration": false,
+    "declarationMap": false
+  },
+  "include": ["src/**/*", "test/types/**/*"],
+  "exclude": ["node_modules", "dist"]
+}