Error: Excessive stack depth comparing types 'ParseMixedSchema<?, T>' and 'ParseMixedSchema<?, T>'.ts(2321)

As of version 1.6.5, I now get this error in several places in my code.

Excessive stack depth comparing types 'ParseMixedSchema<?, T>' and 'ParseMixedSchema<?, T>'.ts(2321)

It comes from this:

import type { FromSchema } from 'json-schema-to-ts';
import createHttpError, { NamedConstructors } from 'http-errors';
import { URLSearchParams } from 'url';

export type ValidatedAPIGatewayProxyEvent<S> = APIGatewayProxyEvent &
  FromSchema<S>;

which I adopted from the Serverless Framework TS template.

I create a JS/JSON API Gateway schema, e.g.:

const schema = {
  type: 'object',
  properties: {
    body: {
      type: 'object',
      properties: {
        coupon_id: { type: 'string' },
        end_of_term: { type: 'boolean' },
        plan_id: { type: 'string' },
        subscription_id: { type: 'string' },
        reactivate: { type: 'boolean' },
        first_payment: { type: 'boolean' },
      },
      required: ['end_of_term', 'plan_id', 'subscription_id'],
      additionalProperties: false,
    },
  },
} as const;

and pass it to Sentry’s wrapHandler:

export const handler = Sentry.AWSLambda.wrapHandler<
      ValidatedAPIGatewayProxyEvent<S>,
      APIGatewayProxyResult | undefined
    >(...

This has worked fine up until the latest release.

[daffl]

I’ve been seein the same error in the latest version in https://github.com/feathersjs/feathers/tree/dove/packages/schema. The smallest example I could come up with to reproduce looks like this:

class Test<S extends JSONSchema> {
  readonly type: FromSchema<S>;
}

const schemaA = {
  type: 'object',
  additionalProperties: false,
  properties: {
    name: { type: 'string' }
  }
} as const;

const schemaB = {
  type: 'object',
  additionalProperties: false,
  properties: {
    name: { type: 'string' }
  }
} as const;

const t: Test<typeof schemaB> = new Test<typeof schemaA>();

Maybe that helps, I can try and do some more digging if you think it’s worth investigating. Either way, this is a great project!

[ericvicenti]

I think this can be closed. I haven’t seen this weirdo error in a while

Now I just need to find workarounds for “Type instantiation is excessively deep and possibly infinite” 😤