fix(zod): union and intersection schema conversion

[dinwwwh]

Summary by CodeRabbit

• Refactor

  • Improved recursion depth handling for nested schema conversions to tighten depth tracking.
  • Unified union/intersection schema output to always produce a consistent anyOf array.

• Tests

  • Updated test expectations to match the new schema output format for unions including undefined.

[vercel]

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Project	Deployment	Preview	Comments	Updated (UTC)
orpc	Ready	Preview	Comment	Nov 1, 2025 9:48am

[coderabbitai]

Walkthrough

Recursive conversion now increments structureDepth for child items in Union, DiscriminatedUnion, and Intersection branches; the single-element anyOf short-circuit was removed so unions always emit an { anyOf: [...] } form. Tests were updated to expect the anyOf-wrapped output for single-item unions with undefined.

Changes

Cohort / File(s)	Summary
Tests updated packages/zod/src/converter.test.ts, packages/zod/src/zod4/converter.combination.test.ts	Expected JSON-schema for unions that previously produced a single type (e.g., { type: 'string' }) now expects the anyOf-wrapped form (e.g., { anyOf: [{ type: 'string' }] }).
Main converter depth & anyOf behavior packages/zod/src/converter.ts	Union, discriminated-union, and intersection branches now call child conversion with structureDepth + 1. Removed the optimization that returned a single anyOf item directly; unions always return an object with anyOf array.
Zod4 converter depth & standardized union format packages/zod/src/zod4/converter.ts	Union and intersection recursive calls increment depth (structureDepth + 1). Union return always uses { anyOf: [...] } rather than returning a single item when one option exists.

Sequence Diagram(s)

sequenceDiagram
    participant Caller as convert(schema, depth)
    participant Union as Union Handler
    participant Child as Child Converter

    rect rgb(240,248,255)
    Note over Caller,Child: Old behavior
    Caller->>Union: convert(unionSchema, depth=0)
    Union->>Child: convert(optionA, depth=0)
    Union->>Child: convert(optionB, depth=0)
    Union->>Caller: return anyOf[0] if length==1
    end

    rect rgb(255,245,240)
    Note over Caller,Child: New behavior
    Caller->>Union: convert(unionSchema, depth=0)
    Union->>Child: convert(optionA, depth=1)
    Union->>Child: convert(optionB, depth=1)
    Union->>Caller: return { anyOf: [ ... ] } always
    end

Loading

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

• Pay attention to depth-limit logic and any places that rely on previous depth values.
• Review callers/consumers that expected the old single-item return shape.
• Confirm tests cover discriminated unions and nested intersections for depth-related behavior.

Possibly related PRs

• unnoq/orpc#206 — Modifies the zod JSON-schema converter and tests; appears directly related to the converter changes and test expectations for unions/anyOf.

Suggested labels

size:M

Poem

🐇 I hopped through branches, depth in tow,
Each child now deeper, one step to grow.
AnyOf gathered in tidy array,
Tests now cheer for the standardized way. 🥕

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title Check	✅ Passed	The pull request title "fix(zod): union and intersection schema conversion" accurately reflects the main changes across the affected files. The PR modifies schema conversion behavior for unions, discriminated unions, and intersections by adjusting structureDepth tracking and removing the single-element anyOf short-circuit optimization. The title is specific and concise, clearly identifying the primary focus of the changes without being overly broad or misleading. While implementation details like recursion depth adjustments are not mentioned, the title appropriately captures the high-level objective.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix/zod/common-schema-not-workwell-in-union

---

📜 Recent review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 7d034bb and 75c8463.

📒 Files selected for processing (4)

• packages/zod/src/converter.test.ts (1 hunks)
• packages/zod/src/converter.ts (2 hunks)
• packages/zod/src/zod4/converter.combination.test.ts (1 hunks)
• packages/zod/src/zod4/converter.ts (3 hunks)

🚧 Files skipped from review as they are similar to previous changes (3)

• packages/zod/src/zod4/converter.ts
• packages/zod/src/zod4/converter.combination.test.ts
• packages/zod/src/converter.test.ts

🔇 Additional comments (1)

packages/zod/src/converter.ts (1)

533-550: LGTM: Intersection depth tracking fixed.

The change to increment structureDepth + 1 when recursing into intersection components (left and right) correctly tracks nesting depth and is consistent with the union fix at line 516.

---

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[gemini-code-assist]

Summary of Changes

Hello @unnoq, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a bug in the Zod to JSON Schema converter, specifically refining how union and intersection schemas are translated. The core improvement ensures that union types are always represented as anyOf arrays in the resulting JSON schema, even if they contain only one element, thereby preventing implicit type simplification. Additionally, it enhances the handling of nested schemas by correctly managing recursion depth during the conversion process, leading to more accurate and robust schema generation.

Highlights

• Union Schema Conversion Logic: The conversion of z.union schemas to JSON Schema has been updated to consistently produce an anyOf array, even when the union effectively simplifies to a single type (e.g., z.union([z.string(), z.undefined()])). This prevents unintended simplification and ensures a more explicit representation of union types.
• Recursion Depth Handling: The structureDepth parameter is now correctly incremented when recursively converting members of union and intersection schemas. This change improves the robustness of the converter, particularly for complex or deeply nested schema definitions, by ensuring proper tracking of recursion depth.
• Test Case Alignment: Relevant test cases that previously expected z.union([z.string(), z.undefined()]) to simplify to a basic string type in the JSON schema output have been removed, aligning the tests with the new, more explicit conversion behavior.

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[gemini-code-assist]

Code Review

This pull request fixes how Zod union and intersection schemas are converted. The changes correctly increment the structureDepth during recursive calls for unions and intersections, which is a great bug fix. Additionally, the logic for handling unions is updated to no longer simplify anyOf arrays that contain a single item. This improves consistency in the generated schema. My main feedback is to suggest updating the removed test cases to assert the new, correct behavior instead of deleting them, to maintain test coverage.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

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commit: 75c8463