z.pipe can create impossible validation schemas

[ciscoheat]

I noticed that z.pipe can create conflicting schemas due to the allOf inclusion of the types. A crude example:

const schema = z.object({
  len: z.string().transform((val) => val.length).pipe(z.number().min(5))
});

{
  type: 'object',
  properties: {
    // Can never validate, conflicting types
    len: { allOf: [ { type: 'string' }, { type: 'number', minimum: 5 } ] }
  },
  required: [ 'len' ],
  additionalProperties: false,
  '$schema': 'http://json-schema.org/draft-07/schema#'
}

I saw that pipeStrategy can be used to only get the input type, so would you be open to an output option for that, if possible? If it's relatively simple, I'll make a PR for it.

[StefanTerdell]

That's the thing, short of using a compiler you can't get the output type to serialize it. But I guess an option to pick the last schema in the pipe could work.

[StefanTerdell]

🚀 3.22.2

[ciscoheat]

Thank you for a very quick merge! :)