### Prerequisites - [X] I have written a descriptive issue title - [X] I have searched existing issues to ensure the bug has not already been reported ### Fastify version 4.28.0 (latest) ### Plugin version 5.16.1 (latest) ### Node.js version 20.11.0 (LTS) ### Operating system macOS Sonoma 14.5 ### Description When defining a schema with at least two anyOf fields or oneOf fields with self ref like so : ``` import fastJson from 'fast-json-stringify'; const schema = { $schema: 'http://json-schema.org/draft-07/schema#', type: 'object', properties: { field: { type: 'string' }, field1: { anyOf: [{ $ref: '#' }, { type: 'null' }] }, field2: { anyOf: [{ $ref: '#' }, { type: 'null' }] }, }, }; fastJson(schema.valueOf()); ``` I'm getting this following error : ``` RangeError: Maximum call stack size exceeded at RefResolver.#addSchema (../../node_modules/.pnpm/json-schema-ref-resolver@1.0.1/node_modules/json-schema-ref-resolver/index.js:143:14) at RefResolver.#addSchema (../../node_modules/.pnpm/json-schema-ref-resolver@1.0.1/node_modules/json-schema-ref-resolver/index.js:165:24) at RefResolver.#addSchema (../../node_modules/.pnpm/json-schema-ref-resolver@1.0.1/node_modules/json-schema-ref-resolver/index.js:165:24) at RefResolver.#addSchema (../../node_modules/.pnpm/json-schema-ref-resolver@1.0.1/node_modules/json-schema-ref-resolver/index.js:165:24) at RefResolver.#addSchema (../../node_modules/.pnpm/json-schema-ref-resolver@1.0.1/node_modules/json-schema-ref-resolver/index.js:165:24) at RefResolver.addSchema (../../node_modules/.pnpm/json-schema-ref-resolver@1.0.1/node_modules/json-schema-ref-resolver/index.js:30:20) at mergeLocations (../../node_modules/.pnpm/fast-json-stringify@5.16.1/node_modules/fast-json-stringify/index.js:433:23) at buildOneOf (../../node_modules/.pnpm/fast-json-stringify@5.16.1/node_modules/fast-json-stringify/index.js:868:24) at buildValue (../../node_modules/.pnpm/fast-json-stringify@5.16.1/node_modules/fast-json-stringify/index.js:979:12) at buildInnerObject (../../node_modules/.pnpm/fast-json-stringify@5.16.1/node_modules/fast-json-stringify/index.js:380:11) at buildObject (../../node_modules/.pnpm/fast-json-stringify@5.16.1/node_modules/fast-json-stringify/index.js:501:9) at buildSingleTypeSerializer (../../node_modules/.pnpm/fast-json-stringify@5.16.1/node_modules/fast-json-stringify/index.js:768:24) at buildValue (../../node_modules/.pnpm/fast-json-stringify@5.16.1/node_modules/fast-json-stringify/index.js:1010:13) at buildOneOf (../../node_modules/.pnpm/fast-json-stringify@5.16.1/node_modules/fast-json-stringify/index.js:874:26) at buildValue (../../node_modules/.pnpm/fast-json-stringify@5.16.1/node_modules/fast-json-stringify/index.js:979:12) at buildInnerObject (../../node_modules/.pnpm/fast-json-stringify@5.16.1/node_modules/fast-json-stringify ``` (output truncated for readability) Fastify fails to start when using this schema in routes Is this kind of schema possible ? in my case, anyOf / oneOf + self reference & null are required.