`Readable` in new openapi-typescript-helpers is broken

[evrom]

openapi-fetch version

0.17.0

Description

it is broken using both the latest openapi-typescript package and using the previous version without re-generating the types.

I always use --immutable=true and almost all JsonSchemas in my openapi have:

      additionalProperties: false
      readOnly: true

In the latest 0.17.0 version, Arrays in the response bodies of openapi-fetch are iterable objects that remove methods for reading arrays, like .map.

 '{ readonly [x: number]: string; readonly length: number; toString: {}; toLocaleString: {}; concat: {}; join: {}; slice: {}; indexOf: {}; lastIndexOf: {}; every: {}; some: {}; forEach: {}; ... 20 more ...; readonly [Symbol.unscopables]: { ...; }; }' 

I can workaround this and get the old behavior before version 0.17.0, by putting this iterable object into Array.from, then typing it as readonly:

const openapiFetchArray = response.data.myArray; /* `Readable` object from openapi-typescript-helpers */
const desiredArray: readonly Item[] = Array.from(openapiFetchArray);

Reproduction

this is reproduced on type-checking a project using openapi-fetch after updating to 0.17.0

To reproduce in the unittests of this repo:

1. Add --immutable=true here:

   openapi-typescript/packages/openapi-fetch/package.json

   Line 49 in f3a3a19

   "generate-types": "openapi-typescript -c test/redocly.yaml",

2. add an array to the schemas in the tests (i.e. add an array as an attribute to either of these:

   openapi-typescript/packages/openapi-fetch/test/http-methods/schemas/get.yaml

   Line 46 in f3a3a19

   components:

3. in packages/openapi-fetch, run pnpm run generate-types

4. then try to call a method like .map on that array, it will break in lint:ts. However, the test may successfully run, because it is a typescript error only.

Expected result

I think this should be opt-in. I do not have --read-write-markers anywhere, or made any other changes to the code.

Extra

• I’m willing to open a PR (see CONTRIBUTING.md)

[albannurkollari]

Date in response bodies becomes a structural object and stops being assignable to Date, too!

It stems from openapi-fetch 0.17.0 update. I can confirm that I too have this issue. Right now I'm forced to lock the version to 0.15.0 (that was the safe one that worked for me).

[drwpow]

I think this should be opt-in. I do not have --read-write-markers anywhere

I agree. Given that this was less backwards-compatible than anticipated, we’ll add a flag to make this change opt-in. Sorry for the disruption here, this wasn’t as invisible as we’d hoped!

[evrom]

I have isolated this further. Removing "readOnly: true" has no effect on this bug. However, adding "--immutable=true" will re-create this, even in the unittests.

1. Add --immutable=true here:

   openapi-typescript/packages/openapi-fetch/package.json

   Line 49 in f3a3a19

   "generate-types": "openapi-typescript -c test/redocly.yaml",

2. add an array to the schemas in the tests (i.e. add an array as an attribute to either of these:

   openapi-typescript/packages/openapi-fetch/test/http-methods/schemas/get.yaml

   Line 46 in f3a3a19

   components:

3. in packages/openapi-fetch, run pnpm run generate-types

4. then try to call a method like .map on that array, it will break in lint:ts. However, the test may successfully run, because it is a typescript error only.

[evrom]

It further can be isolated by importing Readable directly from openapi-typescript-helpers.

import type {Readable} from "./index.js";
type NothingHappens = Readable<string[]>  // evaluates to `string[]`
type Broken = Readable<readonly string[]> // evaluates to strange object with every method being `{}`