[everdev]

In Go, chaining is not idiomatic. For one, it becomes more challenging to determine where the error occurred if you want to try to handle the error instead of failing. Also, it requires each function in the chain to detect if an error has already occurred.

Interfaces are generally a better solution.

[eternalban]

Clearly a fluid API can not return a 2+ tuple as its results so the error issue you note is a non-issue.

The clean way to deal with errors in fluid APIs is to have a terminal .init() that returns an error (which can also specifically note which options are "illegal", etc.)