fix(studio): allow replacing the whole state, catch unhandled promises (#1122)

### TL;DR

Removed database dependencies from the counter example and simplified the actor state structure.

### What changed?

- Removed database integration from the counter example:
  - Deleted `dizzle.config.ts` and `schema.ts` files
  - Removed database-related dependencies from `package.json` (drizzle-orm, better-sqlite3, drizzle-kit)
  - Removed `@rivetkit/db` dependency
- Simplified the counter example's actor state to only include the essential `count` property
- Removed the database initialization and unused code in the registry
- Updated the file system global state implementation to improve actor state loading
- Enhanced the inspector API to support both patching and replacing state
- Updated Zod import to use v4
- Added error handling for actor fetching in the manager inspector

### How to test?

1. Run the counter example to verify it works without database dependencies:
   ```
   cd examples/counter
   pnpm install
   pnpm start
   ```
2. Test the inspector API's new state replacement functionality by making a PATCH request with a `replace` property
3. Verify that actor state loading works correctly with the updated implementation

### Why make this change?

This change simplifies the counter example by removing unnecessary database dependencies, making it more focused on demonstrating the core actor functionality. It also improves the state management implementation and enhances the inspector API with better error handling and the ability to completely replace state, providing more flexibility for debugging and development.

Author: jog1t

examples/counter/dizzle.config.ts

@@ -10,16 +10,10 @@
   },
   "devDependencies": {
     "@rivetkit/actor": "workspace:*",
-    "@rivetkit/db": "workspace:*",
     "@types/node": "^22.13.9",
     "tsx": "^3.12.7",
     "typescript": "^5.7.3",
     "vitest": "^3.1.1"
   },
-  "stableVersion": "0.8.0",
-  "dependencies": {
-    "better-sqlite3": "^11.10.0",
-    "drizzle-kit": "^0.31.2",
-    "drizzle-orm": "^0.44.2"
-  }
+  "stableVersion": "0.8.0"
 }

examples/counter/package.json

@@ -1,59 +1,14 @@
 import { actor, setup } from "@rivetkit/actor";
-import { db } from "@rivetkit/db/drizzle";
-import * as schema from "./schema";
 
 const counter = actor({
-	db: db({ schema }),
 	state: {
 		count: 0,
-		boolean: false,
-		string: "",
-		number: 0,
-		array: [{ id: 1, value: "value", object: { key: "value" } }],
-		object: { key: "value" },
-		nestedObject: { nestedKey: "nestedValue" },
-		nestedArray: [{ id: 1, value: "value", object: { key: "value" } }],
-		nestedObjectArray: [{ id: 1, value: "value", object: { key: "value" } }],
-		nestedArrayObject: [{ id: 1, value: "value", object: { key: "value" } }],
-		nestedArrays: [
-			[
-				{
-					id: 1,
-					value: "value",
-					object: { key: "value" },
-					array: [{ key: "value", array: [{ key: "value" }] }],
-				},
-			],
-			[
-				{
-					id: 2,
-					value: "value2",
-					object: { key: "value2" },
-					array: [{ key: "value", array: [{ key: "value" }] }],
-				},
-			],
-		],
-		undefined: undefined,
-		date: new Date(),
-		dateArray: [new Date(), new Date()],
-		dateObject: { date: new Date() },
-		null: null,
 	},
 	onAuth: () => {
 		return true;
 	},
-	onStart: (c) => {
-		c.schedule.after(1000, "increment", 1);
-
-		c.state.count = 0;
-	},
 	actions: {
 		increment: (c, x: number) => {
-			// c.db.insert(schema.usersTable).values({
-			// 	name: "John Doe",
-			// 	age: 30,
-			// 	email: "john.doe@example.com",
-			// });
 			c.state.count += x;
 			c.broadcast("newCount", c.state.count);
 			return c.state.count;

examples/counter/src/registry.ts

@@ -37,7 +37,7 @@ interface ActorEntry {
 
 	state?: ActorState;
 	/** Promise for loading the actor state. */
-	loadPromise?: PromiseWithResolvers<void>;
+	loadPromise?: Promise<ActorEntry>;
 
 	actor?: AnyActorInstance;
 	/** Promise for starting the actor. */
@@ -202,24 +202,18 @@ export class FileSystemGlobalState {
 
 		// If state is currently being loaded, wait for it
 		if (entry.loadPromise) {
-			await entry.loadPromise.promise;
+			await entry.loadPromise;
 			return entry;
 		}
 
 		// Start loading state
-		entry.loadPromise = Promise.withResolvers();
+		entry.loadPromise = this.loadActorState(entry);
+		return entry.loadPromise;
+	}
 
+	private async loadActorState(entry: ActorEntry) {
 		const stateFilePath = getActorDataPath(this.#storagePath, entry.id);
 
-		// Check if file exists
-		try {
-			await fs.access(stateFilePath);
-		} catch {
-			// Actor does not exist
-			entry.loadPromise.resolve(undefined);
-			return entry;
-		}
-
 		// Read & parse file
 		try {
 			const stateData = await fs.readFile(stateFilePath);
@@ -230,15 +224,11 @@ export class FileSystemGlobalState {
 
 			// Cache the loaded state in handler
 			entry.state = state;
-			entry.loadPromise.resolve();
-			entry.loadPromise = undefined;
 
 			return entry;
 		} catch (innerError) {
 			// Failed to read actor, so reset promise to retry next time
 			const error = new Error(`Failed to load actor state: ${innerError}`);
-			entry.loadPromise?.reject(error);
-			entry.loadPromise = undefined;
 			throw error;
 		}
 	}

examples/counter/src/schema.ts

@@ -79,6 +79,7 @@ export class FileSystemManagerDriver implements ManagerDriver {
 					getAllActors: async ({ cursor, limit }) => {
 						const itr = this.#state.getActorsIterator({ cursor });
 						const actors: Actor[] = [];
+
 						for await (const actor of itr) {
 							actors.push(transformActor(actor));
 							if (limit && actors.length >= limit) {

packages/core/src/drivers/file-system/global-state.ts

@@ -3,7 +3,7 @@ import jsonPatch from "fast-json-patch";
 import { Hono } from "hono";
 import { streamSSE } from "hono/streaming";
 import { createNanoEvents, type Unsubscribe } from "nanoevents";
-import z from "zod";
+import z from "zod/v4";
 import type {
 	AnyDatabaseProvider,
 	InferDatabaseClient,
@@ -45,22 +45,42 @@ export function createActorInspectorRouter() {
 			}
 			return c.json({ enabled: false, state: null }, 200);
 		})
-		.patch("/state", sValidator("json", PatchSchema), async (c) => {
-			if (!(await c.var.inspector.accessors.isStateEnabled())) {
-				return c.json({ enabled: false }, 200);
-			}
+		.patch(
+			"/state",
+			sValidator(
+				"json",
+				z.object({ patch: PatchSchema }).or(z.object({ replace: z.any() })),
+			),
+			async (c) => {
+				if (!(await c.var.inspector.accessors.isStateEnabled())) {
+					return c.json({ enabled: false }, 200);
+				}
 
-			const patch = c.req.valid("json");
-			const state = await c.var.inspector.accessors.getState();
+				const body = c.req.valid("json");
+				if ("replace" in body) {
+					await c.var.inspector.accessors.setState(body.replace);
+					return c.json(
+						{
+							enabled: true,
+							state: await c.var.inspector.accessors.getState(),
+						},
+						200,
+					);
+				}
+				const state = await c.var.inspector.accessors.getState();
 
-			const { newDocument: newState } = jsonPatch.applyPatch(state, patch);
-			await c.var.inspector.accessors.setState(newState);
+				const { newDocument: newState } = jsonPatch.applyPatch(
+					state,
+					body.patch,
+				);
+				await c.var.inspector.accessors.setState(newState);
 
-			return c.json(
-				{ enabled: true, state: await c.var.inspector.accessors.getState() },
-				200,
-			);
-		})
+				return c.json(
+					{ enabled: true, state: await c.var.inspector.accessors.getState() },
+					200,
+				);
+			},
+		)
 		.get("/state/stream", async (c) => {
 			if (!(await c.var.inspector.accessors.isStateEnabled())) {
 				return c.json({ enabled: false }, 200);
@@ -71,9 +91,9 @@ export function createActorInspectorRouter() {
 			return streamSSE(
 				c,
 				async (stream) => {
-					unsub = c.var.inspector.emitter.on("stateUpdated", (state) => {
+					unsub = c.var.inspector.emitter.on("stateUpdated", async (state) => {
 						stream.writeSSE({
-							data: JSON.stringify(state),
+							data: JSON.stringify(state) || "",
 							event: "state-update",
 							id: String(id++),
 						});

packages/core/src/drivers/file-system/manager.ts

@@ -26,11 +26,16 @@ export function createManagerInspectorRouter() {
 
 			invariant(limit && limit > 0, "Limit must be a positive integer");
 
-			const actors = await c.var.inspector.accessors.getAllActors({
-				limit,
-				cursor,
-			});
-			return c.json(actors, 200);
+			try {
+				const actors = await c.var.inspector.accessors.getAllActors({
+					limit,
+					cursor,
+				});
+				return c.json(actors, 200);
+			} catch (error) {
+				inspectorLogger().error("Failed to fetch actors", error);
+				return c.json("Failed to fetch actors", 500);
+			}
 		})
 
 		.post("/actors", sValidator("json", CreateActorSchema), async (c) => {