Yeah, that should be relatively easy to do. We would just skip the "am I the goroutine under the debugger" check here [1] and add some kind of channel communication here [2]. The hardest thing is probably just the UI. How should that functionality work? I'm imagining something like this:

  >>> pause all
  All goroutines paused
  >>> show goroutines
  1: foo.go:16
  2: foo.go:24
  3. bar.go:10 [current]
  >>> next
  -> // some code from goroutine 3
  >>> goroutine 2
  Now tracing goroutine 2. Current location:
  /*
     Code listing from goroutine 2's current location
  */
  >>> next
  -> // some code from goroutine 2

Is this the kind of interface you were imagining?

[1] https://github.com/mailgun/godebug/blob/5c173f56b398bc13fd41... [2] https://github.com/mailgun/godebug/blob/5c173f56b398bc13fd41...

EDIT: formatting

Yep, something like gdb's threads interface.