Working on issue #246

src/Molecule-Tests/MolComponentImplTest.class.st

@@ -234,6 +234,8 @@ MolComponentImplTest >> testForEventsRemoveProducer [
 
 	| component |
 	component := MolCompleteComponentImpl start: #myComponentA.
+	"initial state"
+	self assert: (component eventsSubscribers at: MolUsedEvents) equals: MolUtils defaultComponentName.
 
 	component forEvents: MolUsedEvents useAllProducers: #(#producerA #producerB #producerC).	
 
@@ -247,7 +249,8 @@ MolComponentImplTest >> testForEventsRemoveProducer [
 
 	component forEvents: MolUsedEvents removeProducer: #producerC.
 	self assert: component eventsSubscribers size equals: 1.
-	self assert: (component eventsSubscribers at: MolUsedEvents) equals: nil.
+	"back to initial state"
+	self assert: (component eventsSubscribers at: MolUsedEvents) equals: MolUtils defaultComponentName.
 ]
 
 { #category : #'tests - connecting - events producers' }
@@ -673,6 +676,37 @@ MolComponentImplTest >> testStart2 [
 	self assert: component componentName equals: #compA.
 ]
 
+{ #category : #'tests - connecting - events producers' }
+MolComponentImplTest >> testStartAndStopComponentWithRemoveProducerSeveralTimes [
+	"This test reproduce issue #246: Exception after several starts and stops of same component"
+
+	| compA compB |
+	"start first implemention of a component contract"
+	compA := MolCompleteComponentImpl start: #compA.
+	compB := MolCompleteComponentImpl start: #compB.
+
+	"link compB to compA"
+	compB forServices: MolUsedServices useProvider: #compA. 
+	compB forEvents: MolUsedEvents useProducer: #compA. 
+	compB getMolUsedEventsSubscriber subscribe: compB.
+
+	"call the service of the first component, it answer #service"
+	self assert: compB getMolUsedServicesProvider service equals: #service.
+
+	"stop and start component several times"
+	1 to: 10 do:[ :i |
+		compB forEvents: MolUsedEvents removeProducer: #compA.
+		compB class stop: #compB.
+		compB := MolCompleteComponentImpl start: #compB.
+		compB forServices: MolUsedServices useProvider: #compA. 
+		compB forEvents: MolUsedEvents useProducer: #compA. 
+		compB getMolUsedEventsSubscriber subscribe: compB.
+		self assert: compB getMolUsedServicesProvider service equals: #service.
+	].
+
+
+]
+
 { #category : #'tests - component creation' }
 MolComponentImplTest >> testStartWithGeneratedName [
 

src/Molecule/MolComponentImpl.trait.st

@@ -348,7 +348,10 @@ MolComponentImpl >> forEvents: anEventsTrait removeProducer: aComponentName [
 
 		producers := self eventsSubscribers at: anEventsTrait.
 		producers ifNil:[ ^self ].
-		producers = aComponentName ifTrue:[ self eventsSubscribers at: anEventsTrait put: nil. ^ self ].
+		producers = aComponentName ifTrue:[ 
+			"Molecule issue #242: store the default component name when a producer is removed to going back to the initial state"
+			self eventsSubscribers at: anEventsTrait put: MolUtils defaultComponentName. ^ self 
+		].
 		(producers isArray and:[producers includes: aComponentName]) ifTrue: [ | newProducers |
 			newProducers := producers asOrderedCollection copy.
 			newProducers remove: aComponentName.

src/Molecule/MolEventSubscriber.class.st

@@ -61,15 +61,20 @@ MolEventSubscriber >> connectOriginator: componentName to: aComponent [
 	"Connect a component to event pipeline"
 
 	| key connect |
-	key := aComponent eventsSubscribers at: self events ifAbsent: [ nil ].
-	connect := key isSymbol ifTrue:[  componentName = key ] ifFalse:[ key includes: componentName ].
-
-	connect ifTrue: [
-			self events allSelectors do: [ :event |
-					| originator |
-					originator := self originatorsLinks at: componentName.
-					originator ifNil: [ ^ self error: 'Component originator is nil' ].
-					originator when: event send: event to: aComponent ] ]
+	key := aComponent eventsSubscribers at: self events ifAbsent: [ MolUtils defaultComponentName ].
+
+	connect := key isSymbol 
+		ifTrue:[ componentName = key ] 
+		ifFalse:[ key includes: componentName ].
+
+	"Cannot connect, stop here"
+	connect ifFalse:[ ^ self ].
+
+	self events allSelectors do: [ :event |
+		| originator |
+		originator := self originatorsLinks at: componentName.
+		originator ifNil: [ ^ self error: 'Component originator is nil' ].
+		originator when: event send: event to: aComponent ]
 ]
 
 { #category : #private }