bugfix: exceptions must terminate atomic blocks

src/swarm-engine/Swarm/Game/Step.hs

@@ -19,8 +19,6 @@
 -- See <https://github.com/swarm-game/swarm/issues/495>.
 module Swarm.Game.Step where
 
-import Debug.Trace
-
 import Control.Applicative (Applicative (..))
 import Control.Carrier.Error.Either (ErrorC, runError)
 import Control.Carrier.State.Lazy
@@ -497,7 +495,6 @@ tickRobotRec r = do
 stepRobot :: HasGameStepState sig m => Robot -> m Robot
 stepRobot r = do
   (r', cesk') <- runState (r & activityCounts . tickStepBudget -~ 1) (stepCESK (r ^. machine))
-  -- sendIO $ appendFile "out.txt" (prettyString cesk' ++ "\n")
   t <- use $ temporal . ticks
 
   isCreative <- use creativeMode
@@ -775,9 +772,7 @@ stepCESK cesk = case cesk of
   -- Otherwise, if we're suspended with nothing else left to do,
   -- return the machine unchanged (but throw away the rest of the
   -- continuation stack).
-  Suspended v e s k -> do
-    traceM ("Suspended killing stack: " ++ show k)
-    return $ Suspended v e s []
+  Suspended v e s _ -> return $ Suspended v e s []
   ------------------------------------------------------------
   -- Exception handling
   ------------------------------------------------------------
@@ -791,6 +786,10 @@ stepCESK cesk = case cesk of
   -- it appropriately.
   Up exn s [] -> handleException exn s Nothing
   Up exn s (FRestoreEnv e : _) -> handleException exn s (Just e)
+  -- If an atomic block threw an exception, we should terminate it.
+  Up exn s (FFinishAtomic : k) -> do
+    runningAtomic .= False
+    return $ Up exn s k
   -- If we are raising a catchable exception up the continuation
   -- stack and come to a Try frame, force and then execute the associated catch
   -- block.