If you set the mask to none (DEBUGDRAW_NONE) and you have not already set the mask your program will terminate.
The following code is safe
function gameClass:debugNone()
local pw = cc.Director:getInstance():getRunningScene():getPhysicsWorld()
if pw:getDebugDrawMask() ~= cc.PhysicsWorld.DEBUGDRAW_NONE then
pw:setDebugDrawMask(cc.PhysicsWorld.DEBUGDRAW_NONE)
end
end
Good luck
Andre