Hi Alistair чт, 19 дек. 2019 г. в 07:19, Alistair Grant <akgrant0...@gmail.com>:
> On Wed, 18 Dec 2019 at 21:45, Denis Kudriashov <dionisi...@gmail.com> > wrote: > > > > Following script demonstrates the difference in the error processing > logic when there is an outer handler: > > > > [ > > > > [MyTestError signal ] on: UnhandledError do: [ :e | self halt ] > > > > ] on: MyTestError do: [ :z | z pass] > > > > > > Try it from playground. Second line separately will show the halt while > all together it will stop at MyTestError signal. > > > > Debugging shows that when the outer handler is processed it sets the > handler context into the exception and it skips the existing handler for > UnhandledError. > > It isn't skipping the UnhandledError handler. MyTestError isn't a > subclass of UnhandledError, it's a subclass of Error, so we expect the > first exception handler that is triggered in the code above to be the > MyTestError handler. > Hm. It forces me to think that I did not explain the problem. If your sentence is correct then the following code would not halt: [[MyTestError signal ] on: UnhandledError do: [ :e | self halt ]] fork Notice that I use fork to avoid any "garbage" of outer handlers from the doIt processing machinery. With the handler we #pass the caught error (on: MyTestError do: [ :z | z pass]) which should be equivalent to "not caught scenario" (it should be to my view) but it doesn't (there will be MyTestError instead of halt). > > > > The question: is it a feature or a bug? > > Setting aside whether it is a feature or a bug, it is clearly the > defined behaviour. > Do you still think it is clear semantics? > > > > Think also how following code should work (unrelated to UnhandledError > logic): > > > > [ > > > > [ 1/0 ] on: MyTestError do: [ :e | self halt ] > > > > ] on: ZeroDivide do: [ :z | MyTestError signal ] > > In this case the behaviour should be the same for both the browser and > the playground: the 0 divide exception handler catches 1/0 and signals > MyTestError, which doesn't have a handler, and a debugger is opened. > > Cheers, > Alistair > >
