Maximum call stack size exceeded in zodToJsonSchema

[Rajavasanthan]

I am writing a backend API in Nextjs14

const topicSchema = z.object({
      topics: z
        .array(
          z.object({
            topic: z.string().describe("The topic of the position")
          })
        )
        .describe("An array of topics"),
    });
    const res = zodToJsonSchema(topicSchema)

this code return Maximum call stack size exceeded

RangeError: Maximum call stack size exceeded
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
    ...

I am using zod-to-json-schema with NextJS 14, langchain ^0.0.177

[StefanTerdell]

Can't reproduce. Please check if this looks right https://github.com/StefanTerdell/zod-to-json-schema/blob/master/test/issues.test.ts#L6

[Rajavasanthan]

I have re-produced the same issue. I have made a project in Stackblitz please take a look at it.

https://stackblitz.com/edit/stackblitz-starters-foddlw?description=The%20React%20framework%20for%20production&file=app%2Fapi%2Ftest%2Froute.ts&title=Next.js%20Starter

Steps npm install && npx next dev Visit :

/api/test

You can see the logs

[StefanTerdell]

[jhiester-shell]

I am seeing this issue as well. What version of node were used in the repo and your response @StefanTerdell @Rajavasanthan ?

[StefanTerdell]

@jhiester-shell It's 18.18.0 in the playground @Rajavasanthan provided

[jhiester-shell]

can you test on 20.10.0?

[StefanTerdell]

I just tested the provided example on 16.20.0, 18.18.0 and 20.10.0 with node commonjs, node esm and ts-node (10.9.1, defaults only) with no issue. closing until someone can reproduce this.

[rheaton64]

I have a very similar issue with node 18.18.0 and Next 14. Simple schema, same recursion error as above.

const zodSchema = z.object({
  questions: z.array(
    z.object({
      question: z.string().describe("One question on the test"),
    })
  ).length(5).describe("List of 5 questions on the test"),
});

Using with ai^2.2.20

const functionCallingModel = llm.bind({
    functions: [
        {
        name: "create_test",
        description: "Create a 5 question test. The questions should slowly increase in difficulty.",
        parameters: zodToJsonSchema(zodSchema, "Test"),
        },
    ],
    function_call: { name: "create_test" },
    });

error:

 ⨯ RangeError: Maximum call stack size exceeded
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
    at Module.zodToJsonSchema (webpack-internal:///(rsc)/./node_modules/zod-to-json-schema/dist/esm/index.js:43:107)
...

[dominics]

@StefanTerdell Reproduction is to use the link @Rajavasanthan posted, but change line 7 (the import) to use a named import:

import { zodToJsonSchema } from 'zod-to-json-schema';

Here is an updated StackBlitz. As before, visit /api/test, and now it breaks as described:

I suspect ESM weirdness in Webpack in my and @rheaton64's cases (I'm bundling for a Firebase function using Webpack 4), and whatever next is doing in @Rajavasanthan's case (swc, but then Stackblitz doesn't support it, so falls back to Webpack?).

Answer might just be: don't import it like that! But if so, that'd be a BC-break, no? (Unless the project doesn't consider bundled usage as part of API stability?). There's also third-party code I can't control that imports it like this (e.g. fastify-type-provider-zod) so those aren't easy to fix.

The issue test won't pick it up because it's not going through package.json nor bundling.

I think this is why packages usually add an ESM version at the next major version bump (because it's unpredictable which of the exports listed in package.json a bundler will choose, and it's hard to test a package under bundlers.)

[StefanTerdell]

Jesus christ

[kachkaev]

Same issue here when using Next.js 14 with monaco editor. The crash only happens in prod. I am using zod-to-json-schema for autocompletion in monaco. The code looks something like this:

    monaco.languages.json.jsonDefaults.setDiagnosticsOptions({
      ...monaco.languages.json.jsonDefaults.diagnosticsOptions,
      validate: true,
      schemas: [
        ...(monaco.languages.json.jsonDefaults.diagnosticsOptions.schemas ?? []),
        {
          uri: jsonSchemaUri,
          fileMatch: [modelPath],
          schema: zodToJsonSchema(schema),
        },
      ],

It used to work, but started crashing after I updated from 3.21.4 to 3.22.0.

[kachkaev]

This diff might fix it: https://github.com/StefanTerdell/zod-to-json-schema/commit/82d339ecfe0775b697b8e1643451cd3eaf9115c8#diff-a2a171449d862fe29692ce031981047d7ab755ae7f84c707aef80701b3ea0c80L2

Happy to try a canary release and report if I get the same crash in next start as for 3.22.0.

[StefanTerdell]

@kachkaev Sure, I just published 3.22.1@beta

[kachkaev]

It worked! After updating zod-to-json-schema to 3.22.1-beta.0, I can no longer observe a crash in next start 🎉

[StefanTerdell]

Nice. I just released it on @latest tag as well. Keeping this open for a bit in case we get stragglers, but fingers crossed it should be fixed

So I can understand why the recursive export caused an overflow... What I don't get is what it had to do with named/default exports