I tried today rc_climb with v4.0 beta. The thrust becomes negative when switching.
What exactly are you referring to with thrust?
stabilization_cmd[COMMAND_THRUST] is set to guidance_v_delta_t in RC_CLIMB, which is bound between 0 and MAX_PPRZ, hence can't become negative.
I suppose this is due to integer overflows as well?
Need a bit more info...
Is the floating point supervision commited in the v4.0 beta or do i need to pull the fix from dev branch?
Yes, was merged into 4.0_beta yesterday.
Cheers, Felix