Fix CommitCommand to be able to skip writing to RefLog

CommitCommand already provided a method to set the comment which should
be written into the reflog. The underlying RefUpdate class supported to
skip writing a reflog entry. But through the CommitCommand API it was
not possible to prevent writing a reflog entry. Fix this and allow
creating commits which don't occur in the reflog.

Change-Id: I193c53de71fb5958ea749c4bfa8360a51acc9b58

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CommitCommandTest.java

@@ -68,6 +68,7 @@ import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.RefUpdate.Result;
+import org.eclipse.jgit.lib.ReflogEntry;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.lib.StoredConfig;
 import org.eclipse.jgit.revwalk.RevCommit;
@@ -436,6 +437,36 @@ public class CommitCommandTest extends RepositoryTestCase {
 		}
 	}
 
+	@Test
+	public void testReflogs() throws Exception {
+		try (Git git = new Git(db)) {
+			writeTrashFile("f", "1");
+			git.add().addFilepattern("f").call();
+			git.commit().setMessage("c1").call();
+			writeTrashFile("f", "2");
+			git.commit().setMessage("c2").setAll(true).setReflogComment(null)
+					.call();
+			writeTrashFile("f", "3");
+			git.commit().setMessage("c3").setAll(true)
+					.setReflogComment("testRl").call();
+
+			db.getReflogReader(Constants.HEAD).getReverseEntries();
+
+			assertEquals("testRl;commit (initial): c1;", reflogComments(
+					db.getReflogReader(Constants.HEAD).getReverseEntries()));
+			assertEquals("testRl;commit (initial): c1;", reflogComments(
+					db.getReflogReader(db.getBranch()).getReverseEntries()));
+		}
+	}
+
+	private static String reflogComments(List<ReflogEntry> entries) {
+		StringBuffer b = new StringBuffer();
+		for (ReflogEntry e : entries) {
+			b.append(e.getComment()).append(";");
+		}
+		return b.toString();
+	}
+
 	@Test(expected = WrongRepositoryStateException.class)
 	public void commitAmendOnInitialShouldFail() throws Exception {
 		try (Git git = new Git(db)) {

org.eclipse.jgit/src/org/eclipse/jgit/api/CommitCommand.java

@@ -124,6 +124,8 @@ public class CommitCommand extends GitCommand<RevCommit> {
 
 	private String reflogComment;
 
+	private boolean useDefaultReflogMessage = true;
+
 	/**
 	 * Setting this option bypasses the pre-commit and commit-msg hooks.
 	 */
@@ -258,7 +260,7 @@ public class CommitCommand extends GitCommand<RevCommit> {
 				RevCommit revCommit = rw.parseCommit(commitId);
 				RefUpdate ru = repo.updateRef(Constants.HEAD);
 				ru.setNewObjectId(commitId);
-				if (reflogComment != null) {
+				if (!useDefaultReflogMessage) {
 					ru.setRefLogMessage(reflogComment, false);
 				} else {
 					String prefix = amend ? "commit (amend): " //$NON-NLS-1$
@@ -790,10 +792,13 @@ public class CommitCommand extends GitCommand<RevCommit> {
 	 * Override the message written to the reflog
 	 *
 	 * @param reflogComment
+	 *            the comment to be written into the reflog or <code>null</code>
+	 *            to specify that no reflog should be written
 	 * @return {@code this}
 	 */
 	public CommitCommand setReflogComment(String reflogComment) {
 		this.reflogComment = reflogComment;
+		useDefaultReflogMessage = false;
 		return this;
 	}