[JENKINS-61290] hard to see why a branch was not inspected - log them

src/main/java/org/jenkinsci/plugins/github_branch_source/BranchDiscoveryTrait.java

@@ -26,6 +26,8 @@
 import edu.umd.cs.findbugs.annotations.NonNull;
 import hudson.Extension;
 import hudson.util.ListBoxModel;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 import jenkins.scm.api.SCMHead;
 import jenkins.scm.api.SCMHeadCategory;
 import jenkins.scm.api.SCMHeadOrigin;
@@ -52,6 +54,8 @@
  * @since 2.2.0
  */
 public class BranchDiscoveryTrait extends SCMSourceTrait {
+    private static final Logger LOGGER = Logger.getLogger(Connector.class.getName());
+
     /**
      * The strategy encoded as a bit-field.
      */
@@ -239,6 +243,9 @@ public boolean isExcluded(@NonNull SCMSourceRequest request, @NonNull SCMHead he
                     if (headRepo != null // head repo can be null if the PR is from a repo that has been deleted
                             && p.getBase().getRepository().getFullName().equalsIgnoreCase(headRepo.getFullName())
                             && p.getHead().getRef().equals(head.getName())) {
+                        LOGGER.log(Level.WARNING, "Ignoring {} because "
+                                + "current strategy excludes branches that ARE also filed as a pull request"
+                                , new Object[]{head.toString()});
                         return true;
                     }
                 }
@@ -262,9 +269,13 @@ public boolean isExcluded(@NonNull SCMSourceRequest request, @NonNull SCMHead he
                     if (headRepo != null // head repo can be null if the PR is from a repo that has been deleted
                             && p.getBase().getRepository().getFullName().equalsIgnoreCase(headRepo.getFullName())
                             && p.getHead().getRef().equals(head.getName())) {
+
                         return false;
                     }
                 }
+                LOGGER.log(Level.WARNING, "Ignoring {} because "
+                        + "current strategy excludes branches that ARE NOT also filed as a pull request"
+                        , new Object[]{head.toString()});
                 return true;
             }
             return false;