Hono•6mo ago

Types issue in zod-openapi in v0.19.4, .5, & .6 (repro attached)

Maybe I'm holding it wrong, but this minimal file reproduces the type error:

import {OpenAPIHono, createRoute, z} from '@hono/zod-openapi'

interface AppBindings { Variables: { userId: string } }

const route = createRoute({
  method: 'get',
  path: '/widget/{widgetId}',
  request: {
    params: z.object({ widgetId: z.string() }),
  },
  responses: {
    200: {
      content: {
        'application/json': {
          schema: z.object({ widgetId: z.string() }),
        },
      },
      description: 'Success',
    },
    404: {
      content: {
        'application/json': {
          schema: z.object({
            error: z.object({
              code: z.string(),
              message: z.string(),
            }),
          }),
        },
      },
      description: 'Not Found',
    },
  },
})

const app = new OpenAPIHono<AppBindings>()

app.openapi(route, async (c) => { // <-- type error
  const {widgetId} = c.req.valid('param')
  const userId = c.get('userId')

  if (widgetId === 'not-found') {
    return c.json(
      {
        error: {
          code: 'NOT_FOUND',
          message: 'Not found',
        },
      },
      404,
    )
  }

  return c.json({widgetId}, 200)
})

import {OpenAPIHono, createRoute, z} from '@hono/zod-openapi'

interface AppBindings { Variables: { userId: string } }

const route = createRoute({
  method: 'get',
  path: '/widget/{widgetId}',
  request: {
    params: z.object({ widgetId: z.string() }),
  },
  responses: {
    200: {
      content: {
        'application/json': {
          schema: z.object({ widgetId: z.string() }),
        },
      },
      description: 'Success',
    },
    404: {
      content: {
        'application/json': {
          schema: z.object({
            error: z.object({
              code: z.string(),
              message: z.string(),
            }),
          }),
        },
      },
      description: 'Not Found',
    },
  },
})

const app = new OpenAPIHono<AppBindings>()

app.openapi(route, async (c) => { // <-- type error
  const {widgetId} = c.req.valid('param')
  const userId = c.get('userId')

  if (widgetId === 'not-found') {
    return c.json(
      {
        error: {
          code: 'NOT_FOUND',
          message: 'Not found',
        },
      },
      404,
    )
  }

  return c.json({widgetId}, 200)
})

12 Replies

tbesedaOP•6mo ago

Here's the text of the type error

Argument of type '(c: Context<AppBindings, "/widget/:widgetId", { in: { param: { widgetId?: string; }; }; out: { param: { widgetId?: string; }; }; }>) => Promise<JSONRespondReturn<{ error: { code: string; message: string; }; }, 404> | JSONRespondReturn<...>>' is not assignable to parameter of type 'Handler<AppBindings, "/widget/:widgetId", { in: { param: { widgetId?: string; }; }; out: { param: { widgetId?: string; }; }; }, Promise<never>>'.
  Type 'Promise<JSONRespondReturn<{ error: { code: string; message: string; }; }, 404> | JSONRespondReturn<{ widgetId: string; }, 200>>' is not assignable to type 'Promise<never>'.
    Type 'JSONRespondReturn<{ error: { code: string; message: string; }; }, 404> | JSONRespondReturn<{ widgetId: string; }, 200>' is not assignable to type 'never'.
      Type 'JSONRespondReturn<{ error: { code: string; message: string; }; }, 404>' is not assignable to type 'never'.ts(2345)

Argument of type '(c: Context<AppBindings, "/widget/:widgetId", { in: { param: { widgetId?: string; }; }; out: { param: { widgetId?: string; }; }; }>) => Promise<JSONRespondReturn<{ error: { code: string; message: string; }; }, 404> | JSONRespondReturn<...>>' is not assignable to parameter of type 'Handler<AppBindings, "/widget/:widgetId", { in: { param: { widgetId?: string; }; }; out: { param: { widgetId?: string; }; }; }, Promise<never>>'.
  Type 'Promise<JSONRespondReturn<{ error: { code: string; message: string; }; }, 404> | JSONRespondReturn<{ widgetId: string; }, 200>>' is not assignable to type 'Promise<never>'.
    Type 'JSONRespondReturn<{ error: { code: string; message: string; }; }, 404> | JSONRespondReturn<{ widgetId: string; }, 200>' is not assignable to type 'never'.
      Type 'JSONRespondReturn<{ error: { code: string; message: string; }; }, 404>' is not assignable to type 'never'.ts(2345)

tbesedaOP•6mo ago

perhaps there's a bug in the fix for this issue 🤔 https://github.com/honojs/middleware/issues/1102

GitHub

Variables are of type never when there's a middleware with @hono/...

Which middleware has the bug? @hono/zod-openapi What version of the middleware? 0.19.2 What version of Hono are you using? 4.7.5 What runtime/platform is your app running on? (with version if possi...

ambergristle•6mo ago

i can't repro on 0.19.4 have you tried restarting your ts server, and/or reinstalling dependencies?

tbesedaOP•6mo ago

$ npm ls @hono/zod-openapi

myProject@0.0.1 /Users/my-project
├── @hono/zod-openapi@0.19.4

$ npm ls @hono/zod-openapi

myProject@0.0.1 /Users/my-project
├── @hono/zod-openapi@0.19.4

$ tsc repro.ts

repro.ts:42:20 - error TS2345: Argument of type '(c: Context<AppBindings, "/widget/:widgetId", { in: { param: { widgetId?: string; }; }; out: { param: { widgetId?: string; }; }; }>) => Promise<JSONRespondReturn<{ error: { code: string; message: string; }; }, 404> | JSONRespondReturn<...>>' is not assignable to parameter of type 'Handler<AppBindings, "/widget/:widgetId", { in: { param: { widgetId?: string; }; }; out: { param: { widgetId?: string; }; }; }, Promise<never>>'.
  Type 'Promise<JSONRespondReturn<{ error: { code: string; message: string; }; }, 404> | JSONRespondReturn<{ widgetId: string; }, 200>>' is not assignable to type 'Promise<never>'.
    Type 'JSONRespondReturn<{ error: { code: string; message: string; }; }, 404> | JSONRespondReturn<{ widgetId: string; }, 200>' is not assignable to type 'never'.
      Type 'JSONRespondReturn<{ error: { code: string; message: string; }; }, 404>' is not assignable to type 'never'.

42 app.openapi(route, async (c) => {
                      ~~~~~~~~~~~~~~

$ tsc repro.ts

repro.ts:42:20 - error TS2345: Argument of type '(c: Context<AppBindings, "/widget/:widgetId", { in: { param: { widgetId?: string; }; }; out: { param: { widgetId?: string; }; }; }>) => Promise<JSONRespondReturn<{ error: { code: string; message: string; }; }, 404> | JSONRespondReturn<...>>' is not assignable to parameter of type 'Handler<AppBindings, "/widget/:widgetId", { in: { param: { widgetId?: string; }; }; out: { param: { widgetId?: string; }; }; }, Promise<never>>'.
  Type 'Promise<JSONRespondReturn<{ error: { code: string; message: string; }; }, 404> | JSONRespondReturn<{ widgetId: string; }, 200>>' is not assignable to type 'Promise<never>'.
    Type 'JSONRespondReturn<{ error: { code: string; message: string; }; }, 404> | JSONRespondReturn<{ widgetId: string; }, 200>' is not assignable to type 'never'.
      Type 'JSONRespondReturn<{ error: { code: string; message: string; }; }, 404>' is not assignable to type 'never'.

42 app.openapi(route, async (c) => {
                      ~~~~~~~~~~~~~~

and with 0.19.2 it builds. (0.19.3 has the yarn workspace bug mentioned here - fixed in 0.19.4) (bump) I still see this issue in 0.19.5 Only way I see to fix it is using

as unknown as Promise<never>

as unknown as Promise<never>

😬

tbesedaOP•6mo ago

got this down to a minimal reproduction sandbox on Stackblitz Run npm run typecheck to see the error (the editor doesn't immediately show the issue until the file is edited)

Taylor Beseda

StackBlitz

hono-zod-type-error - StackBlitz

A TypeScript project based on @hono/zod-openapi, @types/node and typescript

ambergristle•6mo ago

Dope. Thanks for putting this together!

tbesedaOP•3mo ago

Still an issue in v0.19.6 -- I updated the reproduction above ☝️ and made it even simpler. npm test runs a simple typecheck tsc --noEmit --skipLibCheck main.ts and it complains with the same error that my response shapes are

not assignable to type 'Promise<never>

not assignable to type 'Promise<never>

Maybe if someone can make that pass with a change to the tsc flags/settings? It seems strange that others wouldn't have this issue, so I must have too simple of a TS setup. maybe? This is actually an issue with the example in the hono/zod-openapi/README.md too. I added the example to my test env. you can run npm t to see both files error in the same way. (The Stackblitz built-in typechecker doesn't always catch it, but if you edit the file (add a new line) it fires up.) https://stackblitz.com/edit/hono-zod-type-error-7phbanny?file=zod-openapi_README.ts&view=editor I must be doing something really dumb here. It's stripped back to the most minimal setup but I'm still getting a type error for the most important type: the handler response matches the route definition. Any help appreciated.

ambergristle•3mo ago

try strict that works for me https://www.typescriptlang.org/tsconfig/#strict

tbesedaOP•3mo ago

welp that did it! I added --strict to my reproduction and the types pass. thanks for the tip! wonder why that is

ambergristle•3mo ago

no idea. looks like some pretty significant updates were made to the typing though i'd open an issue, if you haven't already

tbesedaOP•3mo ago

Cool yeah I can do that. I hadn't yet because i figured it was something dumb I was doing, but it does seem like it should work (or error differently) without strict

ambergristle•3mo ago

it did until ~0.19.3, so worth calling out at least

Gaming

Programming

Types issue in zod-openapi in v0.19.4, .5, & .6 (repro attached)

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