Stop on unhandled exception. Is it possible, is it planned?

[miroshQa]

Is it possible for the debugger to stop on the line when an exception occurs, so I can inspect scopes and figure out what went wrong? (In this case, in the file "Tree.lua" on line 78.)

abc.mp4

Is this feature planned?

[jbyuki]

Yes agreed. This feature could be really beneficial to track down exceptions more quickly.

[jbyuki]

On the technical side, I don't see an easy solution at the moment. osv is attached to the running instance via the debug hook debug.sethook which monitors each executed line and optionally execute some code. However for exception catching, the only solution I see right now is to use a pcall and wrap the executed line but this is not how osv works.

A possible solution would be to somehow hook into the neovim exception handler (by having a breakpoint inside it), and then return the exception to the dap client. But i'm not sure any of that code is lua. If it is, then it could be possible.

[jbyuki]

[...]

That's lucky, there seems to be a way to hook into the error handler by redefining the debug.tracebook function!

[jbyuki]

Created an issue #73 here to discuss the implementation.