[cmd/opampsupervisor] Fix early exits not shutting down client/server in bootstrapping

[BinaryFissionGames]

Description:

• Fix early exits not shutting down client/server in bootstrapping

Link to tracking Issue: Closes #31943

Testing:
I tested manually adding errors into the code. There isn't a good, consistent way to add e.g. the timeout error as-is.

[crobert-1]

Just a couple wording nits, feel free to ignore if they're not helpful. Looks good!

[evan-bradley]

Thanks for submitting a fix for this, and sorry for the long delay. Could you explain the flow of what is returned to me? If we execute return errors.New("..."), is err set to the return value in the deferred functions?

[BinaryFissionGames]

Thanks for submitting a fix for this, and sorry for the long delay. Could you explain the flow of what is returned to me? If we execute return errors.New("..."), is err set to the return value in the deferred functions?

Yes, that's exactly right. In the defer statements, err will be the value that will be returned (the errors.New value). Then, the defers can further modify that value in cases where it has it's own error.

Here's an example: https://go.dev/play/p/hT6HZSK62NH

[evan-bradley]

Yes, that's exactly right. In the defer statements, err will be the value that will be returned (the errors.New value). Then, the defers can further modify that value in cases where it has its own error.

Great, thank you. That's straightforward, just hadn't seen that pattern before.