When an exception is thrown, Xdebug can intercept this and break on it, as it currently allows through Exception breakpoints.

At this state, PHP (and hence Xdebug) does not yet know whether the exception is being caught so there is no possibility of discerning whether it is a "caught" or "uncaught" exception.

@derick Thanks for the note.

We need a way to stop execution ONLY when the exception is left uncaught in the entire call hierarchy and reaches the top (bottom?) of the stack. There should be a difference between an exception that is handled gracefully in a try block (xdebug shouldn't care; maybe log them at most) and an exception the code does not handle and is going to crash the application (xdebug should catch it, pausing on the line on which the exception is thrown).

I understand in the latter case the stack is already unwound, and stopping at the exception line may sound weird, but both JS and C# debuggers seem to have found a way to do exactly that, which is what inspires this ticket (and the original PHPStorm ticket).

Please take my saying that other debuggers can stop on exactly that line with a grain of salt; it's been a while since I worked with both of the languages and I may be misremembering. Other parts of the tooling or the IDE may also be helping to find the exact exception line. For example, C# exceptions store the entire stack trace and that's how even after the stack is unwound the IDE can still find the exception line.