Fix Zod schema union deduplication by including validation constraints in type ID #2650

Copilot · 2025-09-17T13:30:04Z

The Zod plugin was incorrectly deduplicating schemas with different validation constraints when using anyOf, resulting in incomplete union schemas. For example:

{
  "anyOf": [
    {
      "type": "string",
      "minLength": 5,
      "maxLength": 5,
      "description": "Combination of ISO 639-1 and ISO 3166-1 alpha-2 separated by a hyphen."
    },
    {
      "type": "string",
      "minLength": 2,
      "maxLength": 2,
      "description": "ISO 639-1 language code."
    }
  ]
}

Before this fix:

export const zLocaleOrLanguage = z.string().length(5);

After this fix:

export const zLocaleOrLanguage = z.union([
    z.string().length(5),
    z.string().length(2)
]);

The issue was in the deduplicateSchema function which only considered $ref, type, const, and format when creating type identifiers, but ignored validation constraints like minLength, maxLength, minimum, maximum, pattern, etc. This caused schemas with different constraints to be treated as duplicates and incorrectly merged.

The fix enhances the type identification logic to include all validation constraints, ensuring that schemas with different validation rules are properly preserved in unions.

Changes:

Modified packages/openapi-ts/src/ir/schema.ts to include validation constraints in type ID generation
Added comprehensive test case validators-string-constraints-union.json to prevent regression
Verified compatibility across all Zod versions (v3, v4, mini)
Added changeset file for patch release

Fixes #2644.

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Copilot · 2025-09-17T13:30:06Z

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vercel · 2025-09-17T13:30:07Z

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bolt-new-by-stackblitz · 2025-09-17T13:30:07Z

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changeset-bot · 2025-09-17T13:30:08Z

🦋 Changeset detected

Latest commit: 8bd26d5

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@hey-api/openapi-ts	Patch

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Click here if you're a maintainer who wants to add another changeset to this PR

…s in type ID Co-authored-by: mrlubos <12529395+mrlubos@users.noreply.github.com>

pkg-pr-new · 2025-09-17T13:59:03Z

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npm i https://pkg.pr.new/hey-api/openapi-ts/@hey-api/codegen-core@2650

npm i https://pkg.pr.new/hey-api/openapi-ts/@hey-api/nuxt@2650

npm i https://pkg.pr.new/hey-api/openapi-ts/@hey-api/openapi-ts@2650

npm i https://pkg.pr.new/hey-api/openapi-ts/@hey-api/vite-plugin@2650

commit: 8bd26d5

codecov · 2025-09-17T13:59:32Z

Codecov Report

❌ Patch coverage is 87.50000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 23.83%. Comparing base (91bc2d0) to head (8bd26d5).
⚠️ Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/openapi-ts/src/ir/schema.ts	87.50%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2650      +/-   ##
==========================================
+ Coverage   23.81%   23.83%   +0.02%     
==========================================
  Files         379      379              
  Lines       36945    36960      +15     
  Branches     1623     1632       +9     
==========================================
+ Hits         8798     8811      +13     
- Misses      28134    28136       +2     
  Partials       13       13

Flag	Coverage Δ
unittests	`23.83% <87.50%> (+0.02%)`	⬆️

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mrlubos · 2025-09-17T14:27:44Z

@copilot add a changeset file with patch for the modified package. You can have a look at past releases or commits for the desired format. I'll let you know if I want any further changes

Co-authored-by: mrlubos <12529395+mrlubos@users.noreply.github.com>

Copilot · 2025-09-17T14:37:18Z

@copilot add a changeset file with patch for the modified package. You can have a look at past releases or commits for the desired format. I'll let you know if I want any further changes

Added changeset file with patch version bump for @hey-api/openapi-ts package in commit 31b3933. The changeset documents the Zod union deduplication fix and follows the standard format used in this repository.

Initial plan

e5b3a1e

Copilot AI assigned Copilot and mrlubos Sep 17, 2025

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Fix Zod schema union deduplication by including validation constraint…

29d2479

…s in type ID Co-authored-by: mrlubos <12529395+mrlubos@users.noreply.github.com>

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Copilot AI changed the title ~~[WIP] The generated Zod schema can be incorrect~~ Fix Zod schema union deduplication by including validation constraints in type ID Sep 17, 2025

Copilot AI requested a review from mrlubos September 17, 2025 13:52

Copilot finished work on behalf of mrlubos September 17, 2025 13:52

mrlubos marked this pull request as ready for review September 17, 2025 14:02

dosubot bot added size:L This PR changes 100-499 lines, ignoring generated files. bug 🔥 Something isn't working labels Sep 17, 2025

Copilot started work on behalf of mrlubos September 17, 2025 14:27 View session

Add changeset for Zod union deduplication fix

31b3933

Co-authored-by: mrlubos <12529395+mrlubos@users.noreply.github.com>

vercel bot deployed to Preview September 17, 2025 14:37 View deployment

Copilot stopped work on behalf of mrlubos due to an error September 17, 2025 14:38
Copilot has encountered an error. See logs for additional details.

Update fix-zod-union-deduplication.md

8bd26d5

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mrlubos approved these changes Sep 17, 2025

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dosubot bot added the lgtm This PR has been approved by a maintainer label Sep 17, 2025

mrlubos merged commit 10c13de into main Sep 17, 2025
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mrlubos deleted the copilot/fix-2644 branch September 17, 2025 15:20

This was referenced Sep 17, 2025

ci: release #2653

Merged

ci: release #2671

Merged

mrlubos mentioned this pull request Oct 6, 2025

Fix allOf in array items being generated as union instead of intersection in Zod plugins #2736

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