Fix ambiguous bean resolution for sub resource interfaces with multiple implementations

Author: Postremus

extensions/resteasy-reactive/rest/deployment/src/test/java/io/quarkus/resteasy/reactive/server/test/resource/basic/SubResourceAmbiguousInjectTest.java

@@ -0,0 +1,128 @@
+package io.quarkus.resteasy.reactive.server.test.resource.basic;
+
+import static io.restassured.RestAssured.given;
+import static org.hamcrest.CoreMatchers.is;
+
+import java.util.Map;
+import java.util.function.Supplier;
+
+import jakarta.enterprise.context.RequestScoped;
+import jakarta.inject.Inject;
+import jakarta.ws.rs.GET;
+import jakarta.ws.rs.Path;
+import jakarta.ws.rs.PathParam;
+import jakarta.ws.rs.Produces;
+import jakarta.ws.rs.core.MediaType;
+
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.resteasy.reactive.server.test.simple.PortProviderUtil;
+import io.quarkus.test.QuarkusUnitTest;
+
+class SubResourceAmbiguousInjectTest {
+    @RegisterExtension
+    static QuarkusUnitTest testExtension = new QuarkusUnitTest()
+            .setArchiveProducer(new Supplier<>() {
+                @Override
+                public JavaArchive get() {
+                    JavaArchive war = ShrinkWrap.create(JavaArchive.class);
+                    war.addClass(PortProviderUtil.class);
+                    war.addClass(EnglishGreeterResource.class);
+                    war.addClass(SpanishGreeterResource.class);
+                    war.addClass(GreeterResource.class);
+                    war.addClass(LanguageResource.class);
+                    war.addClass(LanguageResourceV2.class);
+                    war.addClass(GreeterResourceV2.class);
+                    war.addClass(EnglishGreeterResource.class);
+                    war.addClass(SpanishGreeterResource.class);
+                    return war;
+                }
+            });
+
+    @Test
+    void basicTest() {
+        given().when().get("/languages/en").then().statusCode(200).body(is("hello"));
+        given().when().get("/languages/v2/es").then().statusCode(200).body(is("hola"));
+    }
+
+    @RequestScoped
+    public static class EnglishGreeterResource implements GreeterResource {
+        @Override
+        public String greeting() {
+            return "hello";
+        }
+    }
+
+    @RequestScoped
+    public static class SpanishGreeterResource implements GreeterResource {
+        @Override
+        public String greeting() {
+            return "hola";
+        }
+    }
+
+    public interface GreeterResource {
+        @GET
+        @Produces(MediaType.TEXT_PLAIN)
+        String greeting();
+    }
+
+    @Path("languages")
+    public static class LanguageResource {
+
+        private final Map<String, GreeterResource> languages;
+
+        @Inject
+        public LanguageResource(
+                final EnglishGreeterResource english, final SpanishGreeterResource spanish) {
+            languages = Map.of("en", english, "es", spanish);
+        }
+
+        @Path("{language}")
+        public GreeterResource locateGreeter(@PathParam("language") final String language) {
+            return languages.get(language);
+        }
+    }
+
+    @Path("languages/v2")
+    public static class LanguageResourceV2 {
+
+        private final Map<String, GreeterResourceV2> languages;
+
+        @Inject
+        public LanguageResourceV2(
+                final EnglishGreeterResourceV2 english, final SpanishGreeterResourceV2 spanish) {
+            languages = Map.of("en", english, "es", spanish);
+        }
+
+        @Path("{language}")
+        public GreeterResourceV2 locateGreeter(@PathParam("language") final String language) {
+            return languages.get(language);
+        }
+    }
+
+    public abstract static class GreeterResourceV2 {
+        @GET
+        @Produces(MediaType.TEXT_PLAIN)
+        public abstract String greeting();
+    }
+
+    @RequestScoped
+    public static class EnglishGreeterResourceV2 extends GreeterResourceV2 {
+        @Override
+        public String greeting() {
+            return "hello";
+        }
+    }
+
+    @RequestScoped
+    public static class SpanishGreeterResourceV2 extends GreeterResourceV2 {
+        @Override
+        public String greeting() {
+            return "hola";
+        }
+    }
+}

independent-projects/resteasy-reactive/common/processor/src/main/java/org/jboss/resteasy/reactive/common/processor/EndpointIndexer.java

@@ -297,7 +297,10 @@ public Optional<ResourceClass> createEndpoints(ClassInfo classInfo, boolean cons
                 }
                 clazz.setPath(sanitizePath(path));
             }
-            if (factoryCreator != null) {
+            if (factoryCreator != null && !classInfo.isInterface()) {
+                // Most likely an interface for a sub resource. The ResourceLocatorHandler does not use the factory to create new instances, but uses the result of the sub resource locator method instead
+                // Interfaces therefore do not need a factory here
+                // Otherwise, when having multiple implementations of the interface, an Ambiguous Bean Resolution error occurs, since io.quarkus.arc.runtime.BeanContainerImpl.createFactory is run, even if the factory is never invoked
                 clazz.setFactory(factoryCreator.apply(classInfo.name().toString()));
             }
             Map<String, String> classLevelExceptionMappers = this.classLevelExceptionMappers.get(classInfo.name());