Generated type definitions should not include the error case

[manuschillernordlb]

Models generated with openapi-typescript-codegen contain the correctly inferred types from our OpenAPI Spec, but also the structure for the error object.

That should probably not be the case adds unnecessary of guarding code when calling the api functions.

Example:

const { data: favorites, isLoading } = useQuery({
    queryKey: ["favorites"],
    queryFn: async () => {
      const result = await api.getFavorites();

      if ("status" in result) throw new Error(result.title, { cause: result });

      return result.favorites;
    },
    initialData: () => [],
  });

It seems like the generated client should throw (and therefore not resolve) in any case when response.ok is not true:

openapi-typescript-codegen/src/templates/core/functions/catchErrorCodes.hbs

Lines 20 to 33 in 9e475d9

	if (!result.ok) {
	const errorStatus = result.status ?? 'unknown';
	const errorStatusText = result.statusText ?? 'unknown';
	const errorBody = (() => {
	try {
	return JSON.stringify(result.body, null, 2);
	} catch (e) {
	return undefined;
	}
	})();
	throw new ApiError(options, result,
	`Generic Error: status: ${errorStatus}; status text: ${errorStatusText}; body: ${errorBody}`
	);

[mrlubos]

@manuschillernordlb can you share your OpenAPI spec and the generated vs expected type?

[awolden]

+1 also running into this pattern where I have to type check responses for Error typing even though it never seems to get returned as an error, it's always a thrown error. Is this an issue with the open api definition or something we can configure?

Our response definition looks something like:

        "204":
          description: Successfully updated status for issue
        "422":
          description: Invalid Status Transition
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
        "409":
          description: Unexpected Transition Result
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
        "404":
          description: Issue not found
        "400":
          description: Malformed Request
        default:
          description: Unexpected Error
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Error"
                ```

[mrlubos]

@awolden are you able to create a failing test case? I can look at it for you in our fork