feat: enhance fakeNonOptional to unwrap multiple inner optional layers and add test for nonoptional chain

[InfiniteXyy]

Hi, first of all thanks for the great lib!

We encountered a problem while using it. We always extend a new schema based on an existing schema, but we run into issues when generating nonoptional.

Specifically, nonoptional does not work (if the schema itself is optional). I tried to fix this issue; could you help take a look?

Example

const schema = z.object({ name: z.string(), age: z.number().optional() })

const requiredSchema = schema.required()

fake(requiredSchema)

// expected: age alwasy be a number
// actual: age sometimes is undefined

My fix still has potential issues. if the schema looks like z.string().optional().nullable().nonoptional()

But this is quite uncommon, and I feel like it's not easy to solve this

[Copilot]

Pull request overview

This PR updates the v4 Zod nonoptional faker behavior so fake() won’t accidentally generate undefined when nonoptional() is applied to a schema that still contains nested optional wrappers, and adds a regression test for an optional→nonoptional chain.

Changes:

• Enhance fakeNonOptional to unwrap multiple nested $ZodOptional layers before faking the inner schema.
• Add a nonoptional chain test to ensure z.string().optional().nonoptional() fakes to a string.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
tests/v4/zod.test.ts	Adds a regression test for optional→nonoptional chaining.
src/v4/internals/schemas/non-optional.ts	Unwraps repeated optional layers when faking nonoptional schemas.

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[Copilot]

The new test relies on randomness (via faker's boolean in optional handling) to catch the regression, so it may still pass even if the bug is reintroduced (i.e., it can be flaky/ineffective as a regression test). Consider making it deterministic by seeding (seed(...)) or stubbing getFaker().datatype.boolean() for the duration of the test, and optionally asserting schema.parse(data) as well.

Suggested change

	test('nonoptional chain', { repeats: 5 }, () => {
	const schema = z.string().optional().nonoptional()
	const data = fake(schema)
	test('nonoptional chain', { repeats: 5 }, () => {
	faker.seed(123)
	const schema = z.string().optional().nonoptional()
	const data = fake(schema)
	schema.parse(data)

[Copilot]

The inline comment has a grammatical issue: the clause after the comma should not start with a capitalized “But”, and it would read clearer as a separate sentence. Please adjust the punctuation/capitalization so the comment is easier to read.

Suggested change

	// A known issue is that this cannot handle `z.string().optional().nullable().nonoptional()`, But this should still solve most common cases
	// A known issue is that this cannot handle `z.string().optional().nullable().nonoptional()`. This should still solve most common cases.