gh workflow run returns HTTP 500 for non-ASCII branch names

[yamachu]

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Bug

Body

Summary

Triggering a workflow dispatch against a branch whose name contains non-ASCII characters (e.g., Japanese) returns HTTP 500 from the GitHub REST API. This happens both via gh CLI and direct curl.

Steps to Reproduce

gh CLI

GH_DEBUG=api gh workflow run script-worker.yml --ref "テスト" -R yamachu/play-actions

curl (same result)

curl -i -X POST
-H "Authorization: token ***"
-H "Content-Type: application/json"
-d '{"inputs":{},"ref":"テスト"}'
https://api.github.com/repos/yamachu/play-actions/actions/workflows/51017169/dispatches

Expected Behavior

• Workflow dispatch should succeed

Actual Behavior

• HTTP 500 Internal Server Error
• Empty response body

HTTP/2 500
date: Mon, 26 Jan 2026 23:40:42 GMT
content-type: application/json; charset=utf-8
content-length: 0
x-oauth-scopes: gist, read:org, repo, workflow
x-accepted-oauth-scopes:
x-oauth-client-id: 178c6fc778ccc68e1d6a
x-github-media-type: github.v3; format=json
x-github-api-version-selected: 2022-11-28
x-ratelimit-limit: 5000
x-ratelimit-remaining: 4948
x-ratelimit-reset: 1769473123
x-ratelimit-used: 52
x-ratelimit-resource: core
access-control-expose-headers: ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Used, X-RateLimit-Resource, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type, X-GitHub-SSO, X-GitHub-Request-Id, Deprecation, Sunset
access-control-allow-origin: *
strict-transport-security: max-age=31536000; includeSubdomains; preload
x-frame-options: deny
x-content-type-options: nosniff
x-xss-protection: 0
referrer-policy: origin-when-cross-origin, strict-origin-when-cross-origin
content-security-policy: default-src 'none'
vary: Accept-Encoding, Accept, X-Requested-With
server: github.com
x-github-request-id: F6F5:C80EB:3FF2BE:547278:6977FB7A

Environment

• GitHub CLI: 2.83.2 (2025-12-10)
• OS: macOS
• Branch ref: any non-ASCII branch name (e.g., "テスト")

Notes

• The same workflow dispatch works from the GitHub UI using the same non-ASCII branch name.
• Behavior suggests the API endpoint rejects non-ASCII refs.

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