[jira] [Resolved] (FELIX-6353) Constructor injection: activation with optional reference fails if service not available

["Tom Watson (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FELIX-6353?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Tom Watson resolved FELIX-6353.
-------------------------------
    Fix Version/s: scr-2.1.26
       Resolution: Fixed

Fixed with the commit https://github.com/apache/felix-dev/commit/d9236c80a4592a1e2b172fc330115b39bee3dc02

> Constructor injection: activation with optional reference fails if service not available
> ----------------------------------------------------------------------------------------
>
>                 Key: FELIX-6353
>                 URL: https://issues.apache.org/jira/browse/FELIX-6353
>             Project: Felix
>          Issue Type: Bug
>          Components: Declarative Services (SCR)
>    Affects Versions: scr-2.1.24
>            Reporter: Tobias Gunkel
>            Priority: Major
>             Fix For: scr-2.1.26
>
>         Attachments: constructorinjection.patch, optionalreferenceconstructor-example.zip
>
>
> A service that uses constructor injection for an optional service will crash with an "activation failed" exception if the optional service is not available.
> According to the OSGi R7 specification a "null" value should be injected instead.
>  
> Example:
> {code}
> @Activate
> public SomeService(
>   @Reference(cardinality = ReferenceCardinality.OPTIONAL)
>   OptionalService optionalService)
> {}
> {code}
> The above code works if an OptionalService instance is present but it fails and crashes if no OptionalService instance is present during activation time:
> Error message in log:
> {code}
> ERROR : bundle optionalreferenceconstructor:0.1.0.. (1)[optionalreferenceconstructor.SomeService(0)] : Error during instantiation of the implementation object: Unable to get service for reference optionalService
> {code}
> Stack trace shown with scr:info:
> {code}
> State:        FAILED ACTIVATION
> References:   (total 1)
>   - optionalService: optionalreferenceconstructor.OptionalService SATISFIED 0..1 static
>     target=(*) scope=bundle (no active bindings)
> Failure:      java.lang.InstantiationException: Unable to get service for reference optionalService
> java.lang.InstantiationException: Unable to get service for reference additionalSettingsStorage at org.apache.felix.scr.impl.inject.internal.ComponentConstructorImpl.newInstance(ComponentConstructorImpl.java:301) at org.apache.felix.scr.impl.manager.SingleComponentManager.createImplementationObject(SingleComponentManager.java:286) at org.apache.felix.scr.impl.manager.SingleComponentManager.createComponent(SingleComponentManager.java:115) at org.apache.felix.scr.impl.manager.SingleComponentManager.getService(SingleComponentManager.java:1000) at org.apache.felix.scr.impl.manager.SingleComponentManager.getServiceInternal(SingleComponentManager.java:973) at org.apache.felix.scr.impl.manager.AbstractComponentManager.activateInternal(AbstractComponentManager.java:785) at org.apache.felix.scr.impl.manager.DependencyManager$SingleStaticCustomizer.addedService(DependencyManager.java:1271) at org.apache.felix.scr.impl.manager.DependencyManager$SingleStaticCustomizer.addedService(DependencyManager.java:1222) at org.apache.felix.scr.impl.manager.ServiceTracker$Tracked.customizerAdded(ServiceTracker.java:1200) at org.apache.felix.scr.impl.manager.ServiceTracker$Tracked.customizerAdded(ServiceTracker.java:1121) at org.apache.felix.scr.impl.manager.ServiceTracker$AbstractTracked.trackAdding(ServiceTracker.java:928) at org.apache.felix.scr.impl.manager.ServiceTracker$AbstractTracked.track(ServiceTracker.java:864) at org.apache.felix.scr.impl.manager.ServiceTracker$Tracked.serviceChanged(ServiceTracker.java:1152) at org.apache.felix.scr.impl.BundleComponentActivator$ListenerInfo.serviceChanged(BundleComponentActivator.java:114) at org.apache.felix.framework.EventDispatcher.invokeServiceListenerCallback(EventDispatcher.java:990) at org.apache.felix.framework.EventDispatcher.fireEventImmediately(EventDispatcher.java:838) at org.apache.felix.framework.EventDispatcher.fireServiceEvent(EventDispatcher.java:545) at org.apache.felix.framework.Felix.fireServiceEvent(Felix.java:4833) at org.apache.felix.framework.Felix.registerService(Felix.java:3804) at org.apache.felix.framework.BundleContextImpl.registerService(BundleContextImpl.java:328) at
> ...
> {code}
> It seems that the ComponentConstructorImpl (line 301) does only check for multiple cardinality but not for optional cardinality.
> Propably ComponentConstructorImpl.java (line 299) should be:
> {code}
> if ( !refMetadata.isMultiple())
> {
> 	if ( !refMetadata.isOptional() && (ref == null) )
> 	{
> 		throw new InstantiationException("Unable to get service for reference " + refMetadata.getName());
> 	}
> }
> {code}
> Instead of:
> {code}
> if ( !refMetadata.isMultiple())
> {
> 	if ( ref == null )
> 	{
> 		throw new InstantiationException("Unable to get service for reference " + refMetadata.getName());
> 	}
> }
> {code}
> The change is also attached a patch file. Please note that I did not have the opportunity to test the change. It might not fix the problem or cause other crashes.



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