TRPC generated `create` mutation fails in basic polymorphic use case with zod error `invalid_union`

[diesal11]

Description and expected behavior

I'm using Zenstack with the TRPC generator & react-query plugin in a NextJS app.

Given the following zmodel:

plugin trpc {
    provider = '@zenstackhq/trpc'
    output = 'src/server/api/routers/generated'
    version = 'v11'
    importCreateRouter = "@/server/api/trpc"
    importProcedure = "@/server/api/trpc"
    zodSchemasImport = "@/lib/zenstack/zod"
    generateClientHelpers = 'react'
}

generator client {
    provider = "prisma-client-js"
}

datasource db {
    provider = "postgresql"
    url      = env("DATABASE_URL")
}

enum UserType {
    UserLocal
    UserGoogle
}

model User {
    id          String       @id @default(cuid())
    type        UserType

    @@delegate(type)

    userFolders UserFolder[]
}

model UserLocal extends User {
    email    String
    password String
}

model UserGoogle extends User {
    googleId String
}

model UserFolder {
    id     String @id @default(cuid())
    userId String
    path   String

    user   User   @relation(fields: [userId], references: [id])
}

When calling the autogenerated UserFolder.create TRPC mutation as such:

    const createUserFolderMutation = api.userFolder.create.useMutation();
    ....
    await createUserFolderMutation.mutateAsync({
      data: {
        path: "/",
        userId: localUser.id,
      },
    });

The request then fails with a Zod validation error:

❌ tRPC failed on userFolder.create: [
  {
    "code": "invalid_union",
    "unionErrors": [
      {
        "issues": [
          {
            "code": "invalid_type",
            "expected": "object",
            "received": "undefined",
            "path": [
              "data",
              "user"
            ],
            "message": "Required"
          },
          {
            "code": "invalid_type",
            "expected": "object",
            "received": "undefined",
            "path": [
              "data",
              "delegate_aux_UserFolder_user_UserLocal"
            ],
            "message": "Required"
          },
          {
            "code": "invalid_type",
            "expected": "object",
            "received": "undefined",
            "path": [
              "data",
              "delegate_aux_UserFolder_user_UserGoogl_0"
            ],
            "message": "Required"
          },
          {
            "code": "unrecognized_keys",
            "keys": [
              "userId"
            ],
            "path": [
              "data"
            ],
            "message": "Unrecognized key(s) in object: 'userId'"
          }
        ],
        "name": "ZodError"
      },
      {
        "issues": [
          {
            "code": "invalid_type",
            "expected": "string",
            "received": "undefined",
            "path": [
              "data",
              "delegate_aux_UserFolder_userId_UserLoc_0"
            ],
            "message": "Required"
          },
          {
            "code": "invalid_type",
            "expected": "string",
            "received": "undefined",
            "path": [
              "data",
              "delegate_aux_UserFolder_userId_UserGoo_0"
            ],
            "message": "Required"
          }
        ],
        "name": "ZodError"
      }
    ],
    "path": [
      "data"
    ],
    "message": "Invalid input"
  }
]

Environment (please complete the following information):

• ZenStack version: 2.11.6
• Prisma version: 6.3.1
• Database type: Postgresql

Additional context

I can work around this issue by creating my own TRPC mutation, which uses the simpler UserFolderCreateSchema as the input schema.

export default function createFixedRouter() {
  return createTRPCRouter({
    userFolderFixed: createTRPCRouter({
      create: procedure
        .input(z.object({ data: UserFolderCreateSchema }))
        .mutation(({ ctx, input }) => getDb(ctx).userFolder.create(input)),
    }),
  });
}

I have created an example repo with the issue here:
https://github.com/diesal11/zenstack-trpc-zod-bug

[ymc9]

Thanks for the repro. Very helpful! It seems the zod schemas it not completely cleaned up for auxiliary declarations introduced by delegate models. I'll do some further debugging.

[MaxmaxmaximusFree]

for now I have to do something like this

const CreatePost = PostCreateSchema.merge(ContentCreateSchema)