v4: cannot use empty object as default for schema with defaults - regression?

[radiosilence]

In v3, you could do:

import { z } from 'zod';

const MyChildSchema = z.object({
  num: z.number().default(1),
  text: z.string().default('blah'),
});

const MyParentSchema = z.object({
  child: MyChildSchema.default({}),
});

This made doing deeply nested defaults with overrides very simple.

In v4, you get a TypeScript error on the child: MyChildSchema.default({}), line:

ts: No overload matches this call.
  Overload 1 of 2, '(def: { num: number; text: string; }, params?: string | { error?: undefined; } | undefined): ZodDefault<ZodObject<{ num: ZodDefault<ZodNumber>; text: ZodDefault<ZodString>; }, {}>>', gave the following error.
    Argument of type '{}' is not assignable to parameter of type '{ num: number; text: string; }'.
      Type '{}' is missing the following properties from type '{ num: number; text: string; }': num, text
  Overload 2 of 2, '(def: () => { num: number; text: string; }, params?: string | { error?: undefined; } | undefined): ZodDefault<ZodObject<{ num: ZodDefault<ZodNumber>; text: ZodDefault<ZodString>; }, {}>>', gave the following error.
    Argument of type '{}' is not assignable to parameter of type '() => { num: number; text: string; }'.
      Type '{}' provides no match for the signature '(): { num: number; text: string; }'.

This feels like unwanted behaviour, because surely the defaults mean that the empty object {} would be valid (IE uses child's default).

If there's a better way to do this I am interested.

[bobhigs]

I just ran into this myself. I use default({}) all time time. It looks like the issue is that zod v3 default(...) was defined using the Input type:

zod/src/types.ts

Line 519 in e62341b

default(def: util.noUndefined<Input>): ZodDefault<this>;

While in v4 the default(...) is defined using this output type in both zod and @zod/mini:

zod/packages/zod/src/schemas.ts

Line 73 in 62d7232

default(def: util.NoUndefined<core.output<this>>, params?: string | core.$ZodDefaultParams): ZodDefault<this>;

zod/packages/mini/src/schemas.ts

Lines 1234 to 1238 in 62d7232

	export function _default<T extends SomeType>(
	innerType: T,
	defaultValue: util.NoUndefined<core.output<T>> | (() => util.NoUndefined<core.output<T>>),
	params?: string | core.$ZodDefaultParams
	): ZodMiniDefault<T> {

I believe the version is zod v3 is correct and that this should be switch back to the input type