[zod-mock]: add recursion depth control feature

[akkonrad]

Pull Request: Prevent infinite recursion in zod-mock with levelLimit option

• Scope: packages/zod-mock
• Type: Feature/Fix

Summary

Adds a recursion guard to generateMock to prevent infinite loops for self-referential schemas. Introduces a new option levelLimit (default: 1) to control how many times the same schema instance can expand along a single generation path.

Motivation

Self-referential schemas (e.g., via z.lazy) could cause infinite recursion during mock generation. This change provides a safe default and a configurable limit to support controlled depth.

Changes

• Add levelLimit?: number to GenerateMockOptions (default = 1).
• Add internal __levelsMap__?: WeakMap<ZodTypeAny, number> to track per-call expansion counts.
• Return undefined when the limit is exceeded at a specific node to stop further expansion.
• Tests:
  • Default behavior prevents recursion (stops at one level).
  • Custom depth when levelLimit is increased.
• Docs:
  • Add “Controlling recursion depth for self-referential schemas” section to README.md with examples.

Usage

const Node: z.ZodType<any> = z.lazy(() =>
  z.object({ value: z.string(), next: Node.optional() })
);

// default: stops at one expansion (next is undefined)
const mock1 = generateMock(Node);

// allow one nested node (two levels total)
const mock2 = generateMock(Node, { levelLimit: 2 });

Backwards Compatibility

• No breaking changes. Default behavior is safe for self-referential schemas and does not affect non-recursive schemas.

Tests

• Added unit tests to validate default and custom recursion depth behaviors.

Documentation

• Updated packages/zod-mock/README.md with a new section describing levelLimit, rationale, and examples.

If there’s a preferred default depth or alternative handling strategy (e.g., truncating with a sentinel value), I can adjust accordingly.

[nx-cloud]

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☁️ Nx Cloud last updated this comment at 2025-09-11 13:12:17 UTC