Re: [RFC] Throwable Hierarchy Policy for Extensions

Hi On 4/28/25 23:09, Larry Garfield wrote:

* Would allowing an extension-tagging interface instead of a base class be an option? It still allows for catching "anything thrown by this extension", which I presume is the goal. If not, why?

See the “Choice of Base Exception” section in https://github.com/php/php-src/pull/9220.

That seems to be about not having a common interface for both the Error and the Exception, which makes sense. I'm talking about interface ExampleException {} and interface ExampleError {}, instead of class ExampleException extends Exception {}, etc.

Besides not following the de facto standard (which is what this proposal is trying to codify), I'm also not sure what benefit an interface would have over a base exception for the problem we're trying to solve here? So I can return the “why (interface)?”. It would just make it tempting to extend some SPL exception :-) I see the value of using interfaces for exceptions when the functionality implements an interface that defines specific types of exception (e.g. PSR-18), but this is (literally) orthogonal to base exceptions that group exceptions by “library” [1]. Best regards Tim Düsterhus [1] Writing down these words, it would probably made sense for ext/random to define a Random\EngineFailureExceptionInterface and specifying that Random\Engine::generate() must throw that one, rather than directly throwing the Random\RandomException base exception - especially for userland engines. But on the other hand an engine failure is not really programmatically recoverable anyways, so that's probably why I used the "simplification" back when I designed the hierarchy.