Cleanup computation of default branch

scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/GitUtil.java

@@ -39,6 +39,8 @@ import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Strings;
 import com.google.common.collect.ArrayListMultimap;
 import com.google.common.collect.Multimap;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
 import org.eclipse.jgit.api.FetchCommand;
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.errors.GitAPIException;
@@ -66,9 +68,7 @@ import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 
-import static java.util.Optional.empty;
 import static java.util.Optional.of;
-import static java.util.Optional.ofNullable;
 
 //~--- JDK imports ------------------------------------------------------------
 
@@ -504,40 +504,12 @@ public final class GitUtil
     return ref;
   }
 
-  public static String getRepositoryHeadBranchName(org.eclipse.jgit.lib.Repository repo) {
-    return getRepositoryHeadRef(repo).map(GitUtil::getBranch).orElse(null);
-  }
-
   public static ObjectId getRepositoryHead(org.eclipse.jgit.lib.Repository repo) {
     return getRepositoryHeadRef(repo).map(Ref::getObjectId).orElse(null);
   }
 
   public static Optional<Ref> getRepositoryHeadRef(org.eclipse.jgit.lib.Repository repo) {
-    Map<String, Ref> refs = repo.getAllRefs();
+    Optional<Ref> foundRef = findMostAppropriateHead(repo.getAllRefs());
-    Optional<Ref> foundRef = empty();
-    Ref lastHeadRef = null;
-
-    for (Map.Entry<String, Ref> e : refs.entrySet()) {
-      String key = e.getKey();
-
-      if (REF_HEAD.equals(key)) {
-        if (e.getValue().isSymbolic() && isBranch(e.getValue().getTarget().getName())) {
-          foundRef = of(e.getValue().getTarget());
-          break;
-        }
-      } else if (key.startsWith(REF_HEAD_PREFIX)) {
-        if (REF_MASTER.equals(key.substring(REF_HEAD_PREFIX.length()))) {
-          foundRef = of(e.getValue());
-          break;
-        } else {
-          lastHeadRef = e.getValue();
-        }
-      }
-    }
-
-    if (!foundRef.isPresent()) {
-      foundRef = ofNullable(lastHeadRef);
-    }
 
     if (foundRef.isPresent()) {
       if (logger.isDebugEnabled()) {
@@ -553,6 +525,29 @@ public final class GitUtil
     return foundRef;
   }
 
+  private static Optional<Ref> findMostAppropriateHead(Map<String, Ref> refs) {
+    Ref refHead = refs.get(REF_HEAD);
+    if (refHead != null && refHead.isSymbolic() && isBranch(refHead.getTarget().getName())) {
+      return of(refHead);
+    }
+
+    Ref master = refs.get(REF_HEAD_PREFIX + REF_MASTER);
+    if (master != null) {
+      return of(master);
+    }
+
+    Ref defaultBranch = refs.get(REF_HEAD_PREFIX + "default");
+    if (defaultBranch != null) {
+      return of(defaultBranch);
+    }
+
+    return refs.entrySet()
+      .stream()
+      .filter(e -> e.getKey().startsWith(REF_HEAD_PREFIX))
+      .map(Map.Entry::getValue)
+      .findFirst();
+  }
+
   /**
    * Method description
    *

scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/AbstractGitCommand.java

@@ -35,11 +35,16 @@ package sonia.scm.repository.spi;
 //~--- non-JDK imports --------------------------------------------------------
 
 import com.google.common.base.Strings;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
 
 //~--- JDK imports ------------------------------------------------------------
 
 import java.io.IOException;
+import java.util.Optional;
+
 import org.eclipse.jgit.lib.ObjectId;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -97,30 +102,12 @@ public class AbstractGitCommand
     return commit;
   }
 
-  protected String getBranchNameOrDefault(Repository gitRepository, String requestedBranch) {
+  protected BranchWithId getBranchOrDefault(Repository gitRepository, String requestedBranch) throws IOException {
     if ( Strings.isNullOrEmpty(requestedBranch) ) {
-      return getDefaultBranchName(gitRepository);
+      Optional<Ref> repositoryHeadRef = GitUtil.getRepositoryHeadRef(gitRepository);
+      return repositoryHeadRef.map(r -> new BranchWithId(GitUtil.getBranch(r), r.getObjectId())).orElse(null);
     } else {
-      return requestedBranch;
+      return new BranchWithId(requestedBranch, GitUtil.getBranchId(gitRepository, requestedBranch));
-    }
-  }
-
-  protected ObjectId getBranchOrDefault(Repository gitRepository, String requestedBranch) throws IOException {
-    ObjectId head;
-    if ( Strings.isNullOrEmpty(requestedBranch) ) {
-      head = getDefaultBranch(gitRepository);
-    } else {
-      head = GitUtil.getBranchId(gitRepository, requestedBranch);
-    }
-    return head;
-  }
-
-  protected String getDefaultBranchName(Repository gitRepository) {
-    String defaultBranchName = repository.getProperty(GitConstants.PROPERTY_DEFAULT_BRANCH);
-    if (!Strings.isNullOrEmpty(defaultBranchName)) {
-      return defaultBranchName;
-    } else {
-      return GitUtil.getRepositoryHeadBranchName(gitRepository);
     }
   }
 
@@ -143,4 +130,10 @@ public class AbstractGitCommand
 
   /** Field description */
   protected sonia.scm.repository.Repository repository;
+
+  @Getter @AllArgsConstructor
+  static class BranchWithId {
+    private final String name;
+    private final ObjectId objectId;
+  }
 }

scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitLogCommand.java

@@ -207,14 +207,13 @@ public class GitLogCommand extends AbstractGitCommand implements LogCommand
               PathFilter.create(request.getPath()), TreeFilter.ANY_DIFF));
         }
 
-        ObjectId head = getBranchOrDefault(repository, request.getBranch());
+        BranchWithId branch = getBranchOrDefault(repository,request.getBranch());
-        String branch = getBranchNameOrDefault(repository,request.getBranch());
 
-        if (head != null) {
+        if (branch != null) {
           if (startId != null) {
             revWalk.markStart(revWalk.lookupCommit(startId));
           } else {
-            revWalk.markStart(revWalk.lookupCommit(head));
+            revWalk.markStart(revWalk.lookupCommit(branch.getObjectId()));
           }
 
           Iterator<RevCommit> iterator = revWalk.iterator();
@@ -236,7 +235,7 @@ public class GitLogCommand extends AbstractGitCommand implements LogCommand
         }
 
         if (branch != null) {
-          changesets = new ChangesetPagingResult(counter, changesetList, branch);
+          changesets = new ChangesetPagingResult(counter, changesetList, branch.getName());
         } else {
           changesets = new ChangesetPagingResult(counter, changesetList);
         }