fix(sdk): handle empty JSON response bodies gracefully

[coleleavitt]

Fixes #7889
Fixes #7715

Summary

• Fix "Unexpected end of JSON input" error at client.gen.ts:167 when server returns empty response body

Root Cause

Two issues causing the JSON parsing error:

1. Server-side: OPTIONS handler in /packages/console/app/src/routes/zen/v1/models.ts returned status: 200 with null body
2. Client-side: SDK only handled empty responses with status: 204 or Content-Length: "0", but didn't handle empty body with 200 status and no Content-Length header

Changes

Server (packages/console/app/src/routes/zen/v1/models.ts)

• Changed OPTIONS response from status: 200 → status: 204 (proper "No Content" status)

SDK Client (both v1 and v2 client.gen.ts)

• Read response as text first, only parse JSON if non-empty
• Added try-catch with contextual error messages for malformed JSON:

case "json": {
  const text = await response.text()
  if (!text) {
    data = {}
  } else {
    try {
      data = JSON.parse(text)
    } catch (parseError) {
      const errorMessage = parseError instanceof Error ? parseError.message : String(parseError)
      throw new Error(
        `Failed to parse JSON response: ${errorMessage}. Status: ${response.status}, URL: ${response.url}`
      )
    }
  }
  break
}

Comparison with #7618

Aspect	#7618	This PR
Empty body handling	Still crashes (better message)	Returns {} gracefully
Malformed JSON	Better error message	Better error message
Server fix	No	Yes (204 status)
Lines added	+64	+39

This PR prevents the crash entirely AND provides good error messages for actual malformed JSON.

Note

These files are auto-generated by @hey-api/openapi-ts. This fix will need to be reapplied after regeneration, or ideally contributed upstream to @hey-api/client-fetch.

[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

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[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Potential Duplicate Found:

PR #7618: fix(sdk): improve JSON parsing error handling with contextual messages
#7618

Why it's related: This PR also addresses JSON parsing errors in the SDK. Both PRs are fixing issues with JSON parsing in the SDK client, though PR #7618 appears to focus on error handling with contextual messages while PR #7888 (the current PR) specifically handles empty response bodies. These may be tackling related or overlapping issues in the same codebase area.

[coleleavitt]

Created issue #7889 to track this bug. PR description updated with Fixes #7889.