Alright, so forget my comparison with other languages. My other points remain:
Presently, "throw new" is treated as though it was one statement. That's not the case. We have deferred throws and factory methods for exceptions, and we have re-throws, so collecting the stack-trace at construction time doesn't work. The construction site would only be relevant if "throw new" was in deed a single statement. Recording the actual throw site is clearly the goal - the current implementation is betting on "throw" and "new" happening at the same site, which is merely circumstance. Ideally, an Exception should collect another stack trace for each successive throw, which would enable you to trace not only the original site, but the flow through any exception-handlers that might have re-thrown the same Exception. As is, there is no information collected on throw, and thereby no evidence or record of possible re-throws - on top of the fact that you may be collecting and looking at bogus stack-traces from factory methods or exception mappers. On Fri, May 20, 2016 at 11:06 AM, Rowan Collins <rowan.coll...@gmail.com> wrote: > On 20/05/2016 08:22, Niklas Keller wrote: >> >> 2016-05-20 4:13 GMT+02:00 Jesse Schalken <m...@jesseschalken.com>: >>> >>> The top frame is the construction (get_error) and the site of the throw >>> (do_throw) doesn't appear in the stack at all. >>> >> >> The comparison with JavaScript isn't a good one, since you can throw >> everything in JS. If they didn't provide the stack trace upon throw, you >> would not have a stack trace at all if you throw a plain string. >> > > > That explanation justifies completely the opposite behaviour to what Jesse > described. > > According to MDN [1] the "stack" property is completley unstandardised, and > some engines may indeed populate it on throw, but there's no hint on that > page that they'll attach it to anything not constructed as an Error. > > So it's not a great comparison for either side (note that it was originally > brought up by Rasmus as an example where it *does* come from the throw site) > because the language doesn't actually guarantee you a stack trace at all. > > [1] > https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/stack > > Regards, > -- > Rowan Collins > [IMSoP] > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
