Issue #20484 has been updated by jfrisby (Jon Frisby). zverok (Victor Shepelev) wrote in #note-3:
Honestly, it is no different than any name used in a branch that wasn’t tested. E.g. if you have this: ```ruby if foo OneClass.new else OtherClass.new end ``` ...and the `else` branch wasn’t covered by tests, and the `OtherClass` isn’t defined, then it will struck in production. The rescue clauses can be seen as kind of “syntax sugar” upon this: ```ruby # ... rescue => e case e when SomeClass # ... when OtherClass # ... else # ... end end ``` Which makes it more obvious that unless you ran into the `rescue` branch, any name inside it wouldn’t be evaluated, and no name errors would be caught.
So the common answer is “it should be covered by testing and/or static code analysis.”
Though theoretically, “opt-in forced resolution of everything that looks like a module name” might be an interesting idea to play with (but it probably shouldn’t be limited to `rescue` blocks).
I would agree that any such opt-in feature should probably catch other cases. I'd say that there's a bit of nuance here about the testing situation: I feel like, in practice, rescue blocks are much more likely to be neglected in test coverage than else blocks. That is mostly an ergonomic issue around testing, of course. Of course, bigger picture, anything that can be detected at parse-time is one less than for which a test case needs to be written. That constitutes a win for programmer productivity. To address byroot's comments: I don't follow how it could lead to circular dependency issues, but I confess I have probably not thought it through as deeply so I defer to your thinking on that. I _do_ see how it could make load ordering concerns more in absence of autoload, which is why I suggested it be a purely opt-in feature. Certainly if autoload adds another dimension of complexity, that could make even an opt-in feature useful in significantly fewer cases -- to the point that it might not be worth implementing. That said, I was unaware that sorbet (and potentially steep) addressed this. Thank you! I will check those out. ---------------------------------------- Feature #20484: A new pragma for eager resolution of classes referenced in rescue clauses. https://bugs.ruby-lang.org/issues/20484#change-108318 * Author: jfrisby (Jon Frisby) * Status: Feedback ---------------------------------------- I've been using Ruby for 20 years, and just today learned (the hard way) that the class name(s) referenced in a `rescue` clause are not resolved until an exception occurs. Upon reflection, this behavior probably makes sense in a lot of situations. Late resolution may simplify code loading for the developer. I would, however, love to see an opt-in feature (a la `frozen-string-literal`) to force resolution when the code is loaded/parsed. -- https://bugs.ruby-lang.org/