Tommy Svensson created GROOVY-9413:
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Summary: Groovy 3.0 seem to have a problem with <?>, can't handle
it in Java interface method when called from Groovy.
Key: GROOVY-9413
URL: https://issues.apache.org/jira/browse/GROOVY-9413
Project: Groovy
Issue Type: Bug
Components: Compiler
Affects Versions: 3.0.1
Environment: OSX Crapalina
Reporter: Tommy Svensson
With the following code:
{{ public interface APSBusRouter {
boolean send( @NotNull String target, @NotNull Map<String, Object>
message,
@Optional @Nullable APSHandler<APSResult<?>> resultHandler );
}
void send( @NotNull String target, @NotNull Map<String, Object> message,
@Optional @Nullable APSHandler<APSResult<?>> resultHandler ) {
if ( validateBaseMessageStructure( message ) ) {
boolean valid = false
this.routerTracker.withAllAvailableServices() { APSBusRouter
apsBusRouter, @NotUsed Object[] args ->
---> if ( apsBusRouter.send( target.trim(), message, resultHandler ) ) {
valid = true
}
}
...
}}
There will be a compilation error:
Error:(236, 22) Groovyc: [Static type checking] - Cannot call
se.natusoft.osgi.aps.api.messaging.APSBusRouter#send(java.lang.String,
java.util.Map <java.lang.String, java.lang.Object>,
se.natusoft.osgi.aps.types.APSHandler <se.natusoft.osgi.aps.types.APSResult>)
with arguments [java.lang.String, java.util.Map <String, Object>,
se.natusoft.osgi.aps.types.APSHandler <APSResult>]
This because the resultHandler in the interface (APSBusRouter) for send method
is declared identical to the argument of same name in method, and this
argument is just passed on. Here the Groovy compiler cannot find the send
method called.
But if the APSBusRouter interface is changed and the <?> part after APSResult
is removed (making IDEA complain and correctly so !!) then this compiles
perfectly! This even though the passed resultHandler in this case is not
identical to the APSBusRouter.send(...) declaration of the resultHandler
argument.
Example on github:
APSBusRouter.java:
https://github.com/tombensve/APS/blob/4a0e5d56d61d218e55c1eb3b5edec1c6d44a40ba/APS-APIs/src/main/java/se/natusoft/osgi/aps/api/messaging/APSBusRouter.java#L106
APSBusProvider.groovy:
https://github.com/tombensve/APS/blob/4a0e5d56d61d218e55c1eb3b5edec1c6d44a40ba/APS-Libraries/APSCoreLib/src/main/groovy/se/natusoft/osgi/aps/core/service/APSBusProvider.groovy#L227
Both of these links are on Branch "Groovy-3_0_1-Issue". Ignore the annotations
in methods, they are purely for documentation purpose, and yes there is clearly
a bug in this method :-), but it has nothing to do with this issue.
The workaround for this is to remove the <?> part in APSBusRouter.send(...)
method declaration.
Personally I'm starting to think that maybe it is the "<?>" expression Groovy
has a problem with. The interface is in this case done in Java! But then again
in APSBusProvider.groovy it does allow this in the send(...) method
declaration. Maybe Groovy sees <?> differently than Java ? That is, Groovy code
accepts this, but it does not mean the same thing as in Java ?
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