force all loops to handle not having goals

Change-Id: I630f98d3b373f4c5e8fc6dec589dd5b077a9a391
diff --git a/frc971/control_loops/claw/claw_lib_test.cc b/frc971/control_loops/claw/claw_lib_test.cc
index 4f86697..49205d9 100644
--- a/frc971/control_loops/claw/claw_lib_test.cc
+++ b/frc971/control_loops/claw/claw_lib_test.cc
@@ -174,6 +174,17 @@
               2.0 * M_PI / 180.0);*/
 }
 
+// Tests that not having a goal doesn't break anything.
+TEST_F(ClawTest, NoGoal) {
+  for (int i = 0; i < 10; ++i) {
+    claw_plant_.SendPositionMessage();
+    claw_.Iterate();
+    claw_plant_.Simulate();
+
+    TickTime();
+  }
+}
+
 }  // namespace testing
 }  // namespace control_loops
 }  // namespace frc971
diff --git a/frc971/control_loops/drivetrain/drivetrain.cc b/frc971/control_loops/drivetrain/drivetrain.cc
index 395f8b9..bcfc6a1 100644
--- a/frc971/control_loops/drivetrain/drivetrain.cc
+++ b/frc971/control_loops/drivetrain/drivetrain.cc
@@ -689,19 +689,28 @@
   }
   no_position_.Print();
 
-  double wheel = goal->steering;
-  double throttle = goal->throttle;
-  bool quickturn = goal->quickturn;
+  bool control_loop_driving = false;
+  if (goal) {
+    double wheel = goal->steering;
+    double throttle = goal->throttle;
+    bool quickturn = goal->quickturn;
 #if HAVE_SHIFTERS
-  bool highgear = goal->highgear;
+    bool highgear = goal->highgear;
 #endif
 
-  bool control_loop_driving = goal->control_loop_driving;
-  double left_goal = goal->left_goal;
-  double right_goal = goal->right_goal;
+    control_loop_driving = goal->control_loop_driving;
+    double left_goal = goal->left_goal;
+    double right_goal = goal->right_goal;
 
-  dt_closedloop.SetGoal(left_goal, goal->left_velocity_goal, right_goal,
-                        goal->right_velocity_goal);
+    dt_closedloop.SetGoal(left_goal, goal->left_velocity_goal, right_goal,
+                          goal->right_velocity_goal);
+#if HAVE_SHIFTERS
+    dt_openloop.SetGoal(wheel, throttle, quickturn, highgear);
+#else
+    dt_openloop.SetGoal(wheel, throttle, quickturn, false);
+#endif
+  }
+
   if (!bad_pos) {
     const double left_encoder = position->left_encoder;
     const double right_encoder = position->right_encoder;
@@ -714,11 +723,6 @@
     }
   }
   dt_openloop.SetPosition(position);
-#if HAVE_SHIFTERS
-  dt_openloop.SetGoal(wheel, throttle, quickturn, highgear);
-#else
-  dt_openloop.SetGoal(wheel, throttle, quickturn, false);
-#endif
   dt_openloop.Update();
 
   if (control_loop_driving) {
@@ -732,7 +736,7 @@
     }
     dt_closedloop.Update(output == NULL, false);
   }
-  
+
   // set the output status of the control loop state
   if (status) {
     bool done = false;
diff --git a/frc971/control_loops/drivetrain/drivetrain_lib_test.cc b/frc971/control_loops/drivetrain/drivetrain_lib_test.cc
index 96583da..7e14cf0 100644
--- a/frc971/control_loops/drivetrain/drivetrain_lib_test.cc
+++ b/frc971/control_loops/drivetrain/drivetrain_lib_test.cc
@@ -170,6 +170,26 @@
   VerifyNearGoal();
 }
 
+// Tests that never having a goal doesn't break.
+TEST_F(DrivetrainTest, NoGoalStart) {
+  for (int i = 0; i < 20; ++i) {
+    drivetrain_motor_plant_.SendPositionMessage();
+    drivetrain_motor_.Iterate();
+    drivetrain_motor_plant_.Simulate();
+  }
+}
+
+// Tests that never having a goal, but having driver's station messages, doesn't
+// break.
+TEST_F(DrivetrainTest, NoGoalWithRobotState) {
+  for (int i = 0; i < 20; ++i) {
+    drivetrain_motor_plant_.SendPositionMessage();
+    drivetrain_motor_.Iterate();
+    drivetrain_motor_plant_.Simulate();
+    SimulateTimestep(true);
+  }
+}
+
 ::aos::controls::HPolytope<2> MakeBox(double x1_min, double x1_max,
                                       double x2_min, double x2_max) {
   Eigen::Matrix<double, 4, 2> box_H;
diff --git a/frc971/control_loops/fridge/fridge.cc b/frc971/control_loops/fridge/fridge.cc
index 9533ddf..65ee72e 100644
--- a/frc971/control_loops/fridge/fridge.cc
+++ b/frc971/control_loops/fridge/fridge.cc
@@ -56,7 +56,7 @@
 }
 
 Fridge::Fridge(control_loops::FridgeQueue *fridge)
-    : aos::controls::ControlLoop<control_loops::FridgeQueue, false>(fridge),
+    : aos::controls::ControlLoop<control_loops::FridgeQueue>(fridge),
       arm_loop_(new CappedStateFeedbackLoop(
           StateFeedbackLoop<4, 2, 2>(MakeArmLoop()))),
       elevator_loop_(new CappedStateFeedbackLoop(
diff --git a/frc971/control_loops/fridge/fridge.h b/frc971/control_loops/fridge/fridge.h
index eecfe1b..87dbfa4 100644
--- a/frc971/control_loops/fridge/fridge.h
+++ b/frc971/control_loops/fridge/fridge.h
@@ -40,7 +40,7 @@
 };
 
 class Fridge
-    : public aos::controls::ControlLoop<control_loops::FridgeQueue, false> {
+    : public aos::controls::ControlLoop<control_loops::FridgeQueue> {
  public:
   explicit Fridge(
       control_loops::FridgeQueue *fridge_queue = &control_loops::fridge_queue);