make sure the activation is in state error when input is invalid for paral…

source/FingerBoard-Core-Tests/FBFlowTest.class.st

@@ -118,6 +118,19 @@ FBFlowTest >> testNodeWithIdError [
 		raise: FBNodeNotFound 
 ]
 
+{ #category : #tests }
+FBFlowTest >> testParallelNodeEmptyList [
+	| flow instance |
+	flow := FBFlow parallelFlowOpen.
+	instance := flow newInstance.
+	instance executeWith: { }.
+	self assert: instance atEnd.
+	self assert: instance state equals: #done.
+	"there should be one activation per node. The flow should have stopped at the parallel node because the collection was empty"
+	self assert: instance activations size equals:  2.
+
+]
+
 { #category : #tests }
 FBFlowTest >> testParallelNodeJoined [
 	| flow instance |

source/FingerBoard-Core/FBActivation.class.st

@@ -29,11 +29,6 @@ FBActivation >> events [
 	^ self flowInstance eventsOfActivation: self
 ]
 
-{ #category : #accessing }
-FBActivation >> instance [
-	^ executor flowInstance
-]
-
 { #category : #'as yet unclassified' }
 FBActivation >> isDone [
 	^ state = #done

source/FingerBoard-Core/FBBaseActivation.class.st

@@ -92,6 +92,11 @@ FBBaseActivation >> initialize [
 	state := #created
 ]
 
+{ #category : #accessing }
+FBBaseActivation >> instance [
+	^ executor flowInstance
+]
+
 { #category : #accessing }
 FBBaseActivation >> node [
 	^ node

source/FingerBoard-Core/FBParallelExecutor.class.st

@@ -87,12 +87,7 @@ FBParallelExecutor >> step [
 	transition := pending removeFirst.
 	values := transition source lastValueIn: self.
 	activation := self newActivation: transition.
-	(values isCollection and: [ values isSequenceable ]) ifFalse: [
-		self addEvent: (FBNodeActivationErrored new
-				 activation: activation;
-				 activationError:
-					 'Input for parallel execution has to be a collection.').
-		^ self ].
+	activation initializeValues: list size.
 	lastValue := values at: index.
 	activation argument: lastValue.
 	self activate: activation.

source/FingerBoard-Core/FBParallelNodeBehavior.class.st

@@ -5,9 +5,15 @@ Class {
 }
 
 { #category : #execution }
-FBParallelNodeBehavior >> execute [ 
-	activation flowInstance pushExecutor: (FBParallelExecutor new 
-		node: activation node;
-		list: activation argument ).
-	activation value: activation argument 
+FBParallelNodeBehavior >> execute [
+
+	(activation argument isCollection and: [
+		 activation argument isSequenceable ]) ifFalse: [
+		FBError signal:
+			'Input for parallel execution has to be a non empty collection.' ].
+	activation argument size > 0 ifFalse: [ ^ self ].
+	activation flowInstance pushExecutor: (FBParallelExecutor new
+			 node: activation node;
+			 list: activation argument).
+	activation value: activation argument
 ]