[BUG][GO][Client] Returned err is never nil

Created by: thiagoarrais

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?

Description

When calling any generated Execute() function, a non-nil error is always returned. Instead of using the usual Go idiom:

result, _, err := r.Execute()
if err != nil {
	/* deal with error */
}

I need to check the actual error message in order to detect errors:

result, _, err := r.Execute()
if err != nil && err.Error() != "" {
	/* deal with error */
}

openapi-generator version

c3220848 (current main branch)

Related issues/PRs

I believe this was introduced by #8137. Maybe it is intended behaviour. Care to weigh in here, @code-lucidal58?

Suggest a fix

Successful execution of *Execute() should not return a non-nil error.