Fix Zod and Valibot plugins missing u flag on regex patterns with unicode property escapes

[Copilot]

• Update patternNode in v3/toAst/string.ts to detect unicode property escapes and add u flag
• Update patternNode in v4/toAst/string.ts similarly
• Update patternNode in mini/toAst/string.ts similarly
• Update patternNode in valibot/v1/toAst/string.ts similarly
• Add unicode pattern test case to spec files (2.0.x, 3.0.x, 3.1.x)
• Update test snapshots (zod + valibot + client snapshots)
• Run pnpm examples:generate to update all example output
• Run tests and verify (all tests pass)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Zod plugin doesn't work with regexes that contain unicode patterns</issue_title>
<issue_description>### Description

I have an Open API spec with a property defined as:

type: string
pattern: ^[\p{L} `\-'^.]{1,35}$

The zod plugin generates the following output for this type:z.string().regex(/^[\p{L} `\-'^.]{1,35}$/);

However the \p{L} segment of this code flags with the error "Property escape sequences are not supported in this regex dialect", and does not successfully match valid inputs.

Additional details

I am have been able to work around this issue by manually adding the unicode flag to this regex in the generated code - i.e. z.string().regex(/^[\p{L} `\-'^.]{1,35}$/u);

Digging into the Hey API code, it looks like this could be handled by passing a "u" value the optional second param of the $.regexp call in the patternNode function(s).

Proposed solution

As far as I can see, the options for addressing this are:

1. Just set the "u" flag all the time
2. Add logic to determine whether to enable the flag based on whether the pattern contains elements that require it
3. Add a config option to specify flags that will be set for regexp validation

Reproducible example or configuration

No response

OpenAPI specification (optional)

No response

System information (optional)

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Zod plugin doesn't work with regexes that contain unicode patterns #3460

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🦋 Changeset detected

Latest commit: 02d0ed9

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Project	Deployment	Actions	Updated (UTC)
hey-api-docs	Ready	Preview, Comment	Feb 27, 2026 9:28am

[mrlubos]

@copilot make sure regex works with Valibot as well. I'm not sure if the fix is the same there.

[Copilot]

@copilot make sure regex works with Valibot as well. I'm not sure if the fix is the same there.

Yes, Valibot had the same issue. Applied the same fix to valibot/v1/toAst/string.ts in commit 022960f — now v.regex(/^\p{L}+$/u) is generated when unicode property escapes are detected.

[pullfrog]

Leaping into action...

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[mrlubos]

@copilot CI fails, you probably didn't run pnpm test:update and pnpm examples:generate

[Copilot]

@copilot CI fails, you probably didn't run pnpm test:update and pnpm examples:generate

Fixed in commit 02d0ed9. Ran vitest run --update to update the clients test snapshots and pnpm examples:generate to regenerate all example output — 93 snapshot files updated.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 40.10%. Comparing base (75d9833) to head (02d0ed9).
⚠️ Report is 15 commits behind head on main.

Files with missing lines	Patch %	Lines
.../openapi-ts/src/plugins/valibot/v1/toAst/string.ts	0.00%	1 Missing and 1 partial ⚠️
...es/openapi-ts/src/plugins/zod/mini/toAst/string.ts	0.00%	1 Missing and 1 partial ⚠️
...ages/openapi-ts/src/plugins/zod/v3/toAst/string.ts	0.00%	1 Missing and 1 partial ⚠️
...ages/openapi-ts/src/plugins/zod/v4/toAst/string.ts	0.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3468      +/-   ##
==========================================
- Coverage   40.11%   40.10%   -0.02%     
==========================================
  Files         478      478              
  Lines       17488    17494       +6     
  Branches     5294     5299       +5     
==========================================
  Hits         7016     7016              
- Misses       8425     8426       +1     
- Partials     2047     2052       +5     

Flag	Coverage Δ
unittests	40.10% <0.00%> (-0.02%)	⬇️

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commit: 748780f