feat(rpc): runtime type validation for rpc calls #161

Gianthard-cyh · 2026-01-11T16:40:16Z

Description

Introduce valibot to rpc interface, for better type generation and API verification.

Linked Issues

#9

Introduce valibot to rpc interface, for better type generation and API verification.

Additional context

pkg-pr-new · 2026-01-11T16:42:15Z

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npm i https://pkg.pr.new/@vitejs/devtools@161

npm i https://pkg.pr.new/@vitejs/devtools-kit@161

npm i https://pkg.pr.new/@vitejs/devtools-rpc@161

npm i https://pkg.pr.new/@vitejs/devtools-vite@161

commit: f898497

…urn schemas

…n value checks

…configurations

Gianthard-cyh · 2026-01-14T16:43:02Z

I think this is mostly done. Before adding some tests, I wanted to check whether I’m heading in the right direction.

Since the definitions of RPC methods are scattered across multiple packages (devtools-vite and devtools-core), it seemed reasonable to me to colocate the schemas with the RPC function definitions. In the current implementation, I modified defineRpcFunction to accept argument and return schemas as options. These schemas are then collected and exported from devtools-vite and devtools-core, and devtools-kit imports them for runtime validation.

This approach, however, introduces some additional exports and also creates cyclic dependencies. As a result, vite ends up being pulled in as a dependency of devtools-vite, and lightningcss (a dependency of Vite) breaks when being bundled, since it is not supposed to be bundled. This seems to be related to Vite listing it as a regular dependency rather than a devDependency (see parcel-bundler/lightningcss#701).

I worked around this by marking lightningcss as external, which makes the bundle work again, but I’m not sure whether this aligns with the intended design.

To avoid the cyclic dependency, it looks like one option would be to move all schemas into devtools-kit, but that would separate the RPC function definitions from their schemas. That would mean adding or updating a method would require changes in two places, which feels a bit error-prone.

I might be missing something here, so I’d really appreciate some guidance on the intended architecture. In particular, I’d love to understand where you expect the schemas to live and how the dependency direction between devtools-vite, devtools-core, and devtools-kit is meant to be structured.

@antfu

Copilot

Pull request overview

This PR adds runtime type validation to RPC calls by integrating valibot for schema-based validation. The changes introduce schema definitions for RPC functions and validate both arguments and return values on the client side.

Changes:

Added valibot dependency and schema definitions for RPC functions
Created validation utilities for runtime type checking of RPC arguments and return values
Exported RPC schemas from core and vite packages for use in validation
Fixed build configuration to externalize lightningcss dependency

Reviewed changes

Copilot reviewed 16 out of 17 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
pnpm-workspace.yaml	Added valibot v1.2.0 to dependency catalog
pnpm-lock.yaml	Lock file update for valibot dependency
packages/kit/package.json	Added valibot as a dependency to the kit package
packages/kit/src/utils/define.ts	Enhanced defineRpcFunction to support optional schema definitions for args and return values
packages/kit/src/utils/rpc-validation.ts	New validation utility implementing runtime type checking for RPC calls
packages/kit/src/client/rpc.ts	Integrated validation into the RPC call method
packages/core/src/node/rpc/index.ts	Added builtinRpcSchemas export containing schema mappings
packages/core/src/index.ts	Exported builtinRpcSchemas for external use
packages/vite/src/node/rpc/index.ts	Added serverRpcSchemas export containing schema mappings
packages/vite/src/node/index.ts	Exported serverRpcSchemas for external use
packages/core/src/node/rpc/internal/docks-on-launch.ts	Example implementation adding schema definitions to an RPC function
packages/core/src/node/cli-commands.ts	Refactored to use rpc.definitions instead of rpc.functions
packages/vite/tsdown.config.ts	Added lightningcss to external dependencies
packages/vite/src/nuxt.config.ts	Added lightningcss to Rolldown external dependencies
test/exports/*.yaml	Updated export snapshots with new schema exports
packages/core/playground/vite.config.ts	Added debug dock entry to test RPC calls

Files not reviewed (1)

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Copilot · 2026-01-16T15:46:38Z

packages/core/src/index.ts

@@ -1,3 +1,4 @@
+export { builtinRpcSchemas } from '../../core/src/node/rpc'


The import path is incorrect. It should be './node/rpc' instead of '../../core/src/node/rpc'. The current path goes up two directories to packages/, then back down to core/src/node/rpc, which is unnecessarily complex and could cause issues if the directory structure changes.

Suggested change

export { builtinRpcSchemas } from '../../core/src/node/rpc'

export { builtinRpcSchemas } from './node/rpc'

Copilot · 2026-01-16T15:46:39Z

packages/kit/src/utils/rpc-validation.ts

+  const schema = getSchema(method)
+  if (!schema)
+    throw new Error(`RPC method "${method}" is not defined.`)


The schema existence check on lines 29-30 is redundant because getSchema() already throws an error if the schema is not found (lines 22-23). This duplicate check can be removed.

Copilot · 2026-01-16T15:46:39Z

packages/kit/src/client/rpc.ts

    call: (...args: any): any => {
-      return serverRpc.$call(
+      validateRpcArgs(args[0], args.slice(1))
+      const ret = serverRpc.$call(
        // @ts-expect-error casting
        ...args,
      )
+      validateRpcReturn(args[0], ret)
    },


The call method has three issues: (1) Missing return statement - the function should return 'ret', (2) The validation of return value should happen after the promise resolves since $call returns a Promise, requiring async/await or .then(), (3) The function signature should be async if validating async return values. Consider: call: async (...args: any): Promise<any> => { validateRpcArgs(args[0], args.slice(1)); const ret = await serverRpc.$call(...args); validateRpcReturn(args[0], ret); return ret; }

Copilot · 2026-01-16T15:46:39Z

packages/kit/src/utils/rpc-validation.ts

+export function validateRpcReturn(method: string, data: any) {
+  const schema = getSchema(method)
+  if (!schema)
+    throw new Error(`RPC method "${method}" is not defined.`)


The schema existence check on lines 49-50 is redundant because getSchema() already throws an error if the schema is not found (lines 22-23). This duplicate check can be removed.

Copilot · 2026-01-16T15:46:39Z

packages/core/src/node/rpc/index.ts


 declare module '@vitejs/devtools-kit' {
-  export interface DevToolsRpcServerFunctions extends BuiltinServerFunctions {}
+  export interface DevToolsRpcServerFunctions extends BuiltinServerFunctions { }


There is an unnecessary space before the closing brace. While this doesn't affect functionality, it's inconsistent with TypeScript formatting conventions. Should be extends BuiltinServerFunctions {}

Suggested change

export interface DevToolsRpcServerFunctions extends BuiltinServerFunctions { }

export interface DevToolsRpcServerFunctions extends BuiltinServerFunctions {}

antfu · 2026-01-17T05:13:18Z

Thanks! But I think it might be better to do it in birpc-x. I also want to have the schema optional, where it skips the validation when not provided.

WIP

fbfc375

Gianthard-cyh changed the title ~~feat(rpc):~~ feat(rpc): valibot verification for rpc Jan 11, 2026

Gianthard-cyh mentioned this pull request Jan 11, 2026

TODO #9

Open

41 tasks

Gianthard-cyh added 9 commits January 14, 2026 00:56

chore: update args type in defineRpcFunction

fed5b20

restore changes

31d18dd

fix: correct args and return properties in defineRpcFunction

e015103

fix: enhance return type in defineRpcFunction to include args and ret…

7ae96aa

…urn schemas

fix: update RPC dump to use definitions instead of functions

13805f2

feat: add RPC validation functions and schemas for argument and retur…

bf6906d

…n value checks

fix: add 'lightningcss' to external dependencies in tsdown config

85690dd

fix: add 'lightningcss' as an external dependency in nuxt and tsdown …

cb9c320

…configurations

feat: add serverRpcSchemas and builtinRpcSchemas to YAML configurations

f898497

Gianthard-cyh changed the title ~~feat(rpc): valibot verification for rpc~~ feat(rpc): runtime type verification for rpc calls Jan 14, 2026

Gianthard-cyh changed the title ~~feat(rpc): runtime type verification for rpc calls~~ feat(rpc): runtime type validation for rpc calls Jan 14, 2026

Gianthard-cyh marked this pull request as ready for review January 16, 2026 15:43

Copilot AI review requested due to automatic review settings January 16, 2026 15:43

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		@@ -1,3 +1,4 @@
		export { builtinRpcSchemas } from '../../core/src/node/rpc'

	export { builtinRpcSchemas } from '../../core/src/node/rpc'
	export { builtinRpcSchemas } from './node/rpc'

	export interface DevToolsRpcServerFunctions extends BuiltinServerFunctions { }
	export interface DevToolsRpcServerFunctions extends BuiltinServerFunctions {}

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Gianthard-cyh commented Jan 11, 2026

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