> you'll probably return your own VisionResult (extends Object) unless it throws your TooCloudedException (extends Exception).
> When someone else writes a wrapper or higher-level layer that uses your code, then it'll be up to them to convert or wrap those results and exceptions into something suitable for their level of abstraction.
Why though? What do you gain other than longer stacktraces with all those wrappers? People always trot out some theoretical notion that a caller is going to catch that framework's different exceptions and handle them differently, but have you ever seen calling code that actually did that?
> In other words, suppose all Java methods always returned Object [0]. That would also ensure that a new return type is "always a local change" to the compiler, but I think most developers would be rightly horrified if they came across code that worked that way.
There are many different kinds of values. There really aren't that many different kinds of error - there's "transient error that you might want to retry", "programmer called the API wrong", and that's about it, most other cases (like bad user input) probably shouldn't be exceptions.
> When someone else writes a wrapper or higher-level layer that uses your code, then it'll be up to them to convert or wrap those results and exceptions into something suitable for their level of abstraction.
Why though? What do you gain other than longer stacktraces with all those wrappers? People always trot out some theoretical notion that a caller is going to catch that framework's different exceptions and handle them differently, but have you ever seen calling code that actually did that?
> In other words, suppose all Java methods always returned Object [0]. That would also ensure that a new return type is "always a local change" to the compiler, but I think most developers would be rightly horrified if they came across code that worked that way.
There are many different kinds of values. There really aren't that many different kinds of error - there's "transient error that you might want to retry", "programmer called the API wrong", and that's about it, most other cases (like bad user input) probably shouldn't be exceptions.