I tried to reproduce (note that you have to -Dgatling.simulation, not -Dgatling.simulations) but it worked fine.
Are you sure that you properly renamed the file AND the class name inside the file (those don’t have to be the same in scala)?
In your file MySimulation.scala the package is simulations.basic, so if you want to launch this simulation the full class name is simulations.basic.MySimulation. Be careful, class name and package in scala are not correlated to the file name and directory.
This is a Zinc bug (the incremental scala compiler we’ve been using recently): it doesn’t properly refresh.
The good news is that it has already been fixed!
You can:
use the 1.4.0 snapshot that ships a more recent version of Zinc
perform a clean (but you lose incremental compiling) mvn clean gatling:execute
If that’s really a blocker, we’ll have a 1.3.5 with the new Zinc.
I don’t think this is a Zinc related bug. In the file MySimulation.scala the package is simulations.basic, so the full class name is simulations.basic.MySimulation not basic.MySimulation