fix: surface 422 validation error messages in SendDraft and UpdateDraft

[AruneshDwivedi]

The generated client parses 422 responses into JSON422, but the service wrappers (UpdateDraft and SendDraft) discarded this and fell back to CheckResponse which returns a generic validation error string. Parse JSON422 and return specific messages from the response body instead.

---

Summary by cubic

UpdateDraft and SendDraft now return the specific validation error messages from HEY API 422 responses instead of a generic "validation error" string. The error keeps the HTTP status and X-Request-Id, and falls back to the generic message when the response body carries no reasons.

• Adds conformance tests for both operations answering 422 with a reasons list.

^{Written for commit cdae58e. Summary will update on new commits.}

[Copilot]

Pull request overview

Surfaces HEY API validation details from 422 responses in draft operations.

Changes:

• Parses JSON422 errors in UpdateDraft and SendDraft.
• Returns validation messages to callers.

Tip

If you aren't ready for review, convert to a draft PR.
Click "Convert to draft" or run gh pr ready --undo.
Click "Ready for review" or run gh pr ready to reengage.

Suppressed comments (2)

go/pkg/hey/messages.go:234

• This branch bypasses CheckResponse but only sets the code and message, so parsed 422 errors now report HTTPStatus == 0 and drop the response's X-Request-Id. That breaks the structured validation-error contract asserted in conformance/tests/error-mapping.json:64 and the request-ID handling in helpers.go:24-41. Construct the standard validation error and preserve the request ID.

			return &Error{
				Code:       CodeValidation,
				Message:    strings.Join(resp.JSON422.Errors, ", "),
			}

go/pkg/hey/messages.go:277

• As in UpdateDraft, this manually constructed error loses the actual 422 status and request ID because CheckResponse is skipped. Callers inspecting Error.HTTPStatus receive zero even though the server returned 422; use the shared validation constructor and copy the response request ID.

			return &Error{
				Code:       CodeValidation,
				Message:    strings.Join(resp.JSON422.Errors, ", "),
			}

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[jeremy]

Rebased onto main and pushed two commits on top.

4bdeb63 keeps the structured error contract on the parsed 422: the error built from the reasons list dropped the HTTP status and the X-Request-Id that CheckResponse puts on every other status, so a caller inspecting HTTPStatus saw zero for a request the server refused. draftWriteError builds it through ErrValidation (reasons joined with ; , as the rest of the SDK does) and copies the request id, falling back to the body's message when it carries no errors, and a bodyless 422 still maps by status. Unit tests cover UpdateDraft and SendDraft with a reasons list and a 422 with no body.

cdae58e adds the conformance case: both runners dispatch UpdateDraft and SendDraft through the HEY layer, so a 422 with a reasons list asserting code, status, retryability and request id holds Go and Rust to the same contract — against the wrapper as first pushed, both cases fail; with the fix they pass, and Rust already passed since its transport maps every 422 this way.

make check passes locally. The Test and Security runs are waiting on a maintainer to approve them for a first-time contributor, so CI is not green yet.