Hyrum’s Law in Golang

This is a good example of "stringly typed" software. Golang designers did not want exceptions (still have them with panic/recover), but untyped errors are evil. On the other hand, how would one process typed errors without pattern matching? Because "catch" in most languages is a [rudimentary] pattern matching.

https://learn.microsoft.com/en-us/dotnet/csharp/language-ref...

Go has typed errors, it just didn't use it in this case.

It has typed errors, except every function that returns an error returns the 'error' interface, which gives you no information on the set of errors you might have.

In other statically typed languages, you can do things like 'match err' and have the compiler tell you if you handled all the variants. In java you can `try { x } catch (SomeTypedException)` and have the compiler tell you if you missed any checked exceptions.

In go, you have to read the recursive call stack of the entire function you called to know if a certain error type is returned.

Can 'pgx.Connect' return an `io.EOF` error? Can it return a "tls: unknown certificate authority" (unexported string only error)?

The only way to know is to recursively read every line of code `pgx.Connect` calls and take note of every returned error.

In other languages, it's part of the type-signature.

Go doesn't have _useful_ typed errors since idiomatically they're type-erased into 'error' the second they're returned up from any method.

You actually should never return a specific error pointer because you can eventually break nil checks. I caused a production outage because interfaces are tuples of type and pointer and the literal nil turns to [nil, nil] when getting passed to a comparator whereas your struct return value will be [nil, *Type]