zero-value of `mysql.Result` was expected by `server.WriteValue`, breaks in `v1.11.0`

[stgarrity]

d02e79a introduced new constructors for mysql.Result that always initializes Result.Resultset to be non-nil, but this breaks the logic in server.WriteValue that differentiates between a resultset response and an OK response. This in turn breaks responses to things like INSERT statements.

This is missed in tests because server/server_test.go creates Results without the constructors, and with nil Resultsets

I have a fix https://github.com/userclouds/go-mysql/tree/stg/server_missed_ok that I'm happy to PR if it makes sense and I'm not mis-understanding the intent here.

Thanks!

[lance6716]

Thanks for reporting, we have this fix PR #983 please check if it's correct

[stgarrity]

yep, looks right to me! I think worth fixing the tests in server/server_test.go as well, happy to open a PR if you're OK with it.

[lance6716]

I think unit test can also be improved. Welcome to open PR