Some more review feedback

Author: breskeby

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/ProjectSubscribeBuildService.java

@@ -23,16 +23,24 @@
 
 public abstract class ProjectSubscribeBuildService implements BuildService<BuildServiceParameters.None> {
 
-    public static final String TRANSPORT_REFERENCES_TOPIC = "transportReferences";
     private final ProviderFactory providerFactory;
 
+    /**
+     * The filling of this map depends on the order of #registerProjectForTopic being called.
+     * This is usually done during configuration phase, but we do not enforce yet the time of this method call.
+     * The values are LinkedHashSet to preserve the order of registration mostly to provide a predicatable order
+     * when running consecutive builds.
+     * */
     private Map<String, Collection<String>> versionsByTopic = new HashMap<>();
 
     @Inject
     public ProjectSubscribeBuildService(ProviderFactory providerFactory) {
         this.providerFactory = providerFactory;
     }
 
+    /**
+     * Returning a provider so the evaluation of the map value is deferred to when the provider is queried.
+     * */
     public Provider<Collection<String>> getProjectsByTopic(String topic) {
         return providerFactory.provider(() -> versionsByTopic.computeIfAbsent(topic, k -> new java.util.LinkedHashSet<>()));
     }

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/transport/TransportVersionReferencesPlugin.java

@@ -16,7 +16,7 @@
 import org.gradle.api.tasks.SourceSet;
 import org.gradle.language.base.plugins.LifecycleBasePlugin;
 
-import static org.elasticsearch.gradle.internal.ProjectSubscribeBuildService.TRANSPORT_REFERENCES_TOPIC;
+import static org.elasticsearch.gradle.internal.transport.TransportVersionResourcesPlugin.TRANSPORT_REFERENCES_TOPIC;
 
 public class TransportVersionReferencesPlugin implements Plugin<Project> {
 

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/transport/TransportVersionResourcesPlugin.java

@@ -19,10 +19,10 @@
 
 import java.util.Map;
 
-import static org.elasticsearch.gradle.internal.ProjectSubscribeBuildService.TRANSPORT_REFERENCES_TOPIC;
-
 public class TransportVersionResourcesPlugin implements Plugin<Project> {
 
+    public static final String TRANSPORT_REFERENCES_TOPIC = "transportReferences";
+
     @Override
     public void apply(Project project) {
         project.getPluginManager().apply(LifecycleBasePlugin.class);