TestRepository: Add methods to amend commits or refs

Change-Id: I47082416f6e281262b160ba15272258f9109abd1

org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/TestRepository.java

@@ -435,6 +435,72 @@ public class TestRepository<R extends Repository> {
 		return update(ref, to.create());
 	}
 
+	/**
+	 * Amend an existing ref.
+	 *
+	 * @param ref
+	 *            the name of the reference to amend, which must already exist.
+	 *            If {@code ref} does not start with {@code refs/} and is not the
+	 *            magic names {@code HEAD} {@code FETCH_HEAD} or {@code
+	 *            MERGE_HEAD}, then {@code refs/heads/} will be prefixed in front
+	 *            of the given name, thereby assuming it is a branch.
+	 * @return commit builder that amends the branch on commit.
+	 * @throws Exception
+	 */
+	public CommitBuilder amendRef(String ref) throws Exception {
+		String name = normalizeRef(ref);
+		Ref r = db.getRef(name);
+		if (r == null)
+			throw new IOException("Not a ref: " + ref);
+		return amend(pool.parseCommit(r.getObjectId()), branch(name).commit());
+	}
+
+	/**
+	 * Amend an existing commit.
+	 *
+	 * @param id
+	 *            the id of the commit to amend.
+	 * @return commit builder.
+	 * @throws Exception
+	 */
+	public CommitBuilder amend(AnyObjectId id) throws Exception {
+		return amend(pool.parseCommit(id), commit());
+	}
+
+	private CommitBuilder amend(RevCommit old, CommitBuilder b) throws Exception {
+		pool.parseBody(old);
+		b.author(old.getAuthorIdent());
+		b.committer(old.getCommitterIdent());
+		b.message(old.getFullMessage());
+		// Use the committer name from the old commit, but update it after ticking
+		// the clock in CommitBuilder#create().
+		b.updateCommitterTime = true;
+
+		// Reset parents to original parents.
+		b.noParents();
+		for (int i = 0; i < old.getParentCount(); i++)
+			b.parent(old.getParent(i));
+
+		// Reset tree to original tree; resetting parents reset tree contents to the
+		// first parent.
+		b.tree.clear();
+		try (TreeWalk tw = new TreeWalk(db)) {
+			tw.reset(old.getTree());
+			tw.setRecursive(true);
+			while (tw.next()) {
+				b.edit(new PathEdit(tw.getPathString()) {
+					@Override
+					public void apply(DirCacheEntry ent) {
+						ent.setFileMode(tw.getFileMode(0));
+						ent.setObjectId(tw.getObjectId(0));
+					}
+				});
+			}
+		}
+
+		return b;
+	}
+
 	/**
 	 * Update a reference to point to an object.
 	 *
@@ -452,17 +518,7 @@ public class TestRepository<R extends Repository> {
 	 * @throws Exception
 	 */
 	public <T extends AnyObjectId> T update(String ref, T obj) throws Exception {
-		if (Constants.HEAD.equals(ref)) {
+		ref = normalizeRef(ref);
-			// nothing
-		} else if ("FETCH_HEAD".equals(ref)) {
-			// nothing
-		} else if ("MERGE_HEAD".equals(ref)) {
-			// nothing
-		} else if (ref.startsWith(Constants.R_REFS)) {
-			// nothing
-		} else
-			ref = Constants.R_HEADS + ref;
-
 		RefUpdate u = db.updateRef(ref);
 		u.setNewObjectId(obj);
 		switch (u.forceUpdate()) {
@@ -478,6 +534,20 @@ public class TestRepository<R extends Repository> {
 		}
 	}
 
+	private static String normalizeRef(String ref) {
+		if (Constants.HEAD.equals(ref)) {
+			// nothing
+		} else if ("FETCH_HEAD".equals(ref)) {
+			// nothing
+		} else if ("MERGE_HEAD".equals(ref)) {
+			// nothing
+		} else if (ref.startsWith(Constants.R_REFS)) {
+			// nothing
+		} else
+			ref = Constants.R_HEADS + ref;
+		return ref;
+	}
+
 	/**
 	 * Soft-reset HEAD to a detached state.
 	 * <p>
@@ -807,6 +877,8 @@ public class TestRepository<R extends Repository> {
 
 		private boolean insertChangeId;
 
+		private boolean updateCommitterTime;
+
 		CommitBuilder() {
 			branch = null;
 		}
@@ -930,8 +1002,11 @@ public class TestRepository<R extends Repository> {
 				setAuthorAndCommitter(c);
 				if (author != null)
 					c.setAuthor(author);
-				if (committer != null)
+				if (committer != null) {
+					if (updateCommitterTime)
+						committer = new PersonIdent(committer, new Date(now));
 					c.setCommitter(committer);
+				}
 
 				ObjectId commitId;
 				try (ObjectInserter ins = inserter) {

org.eclipse.jgit.test/tst/org/eclipse/jgit/junit/TestRepositoryTest.java

@@ -43,19 +43,29 @@
 
 package org.eclipse.jgit.junit;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
 
+import java.util.Date;
 import java.util.regex.Pattern;
 
 import org.eclipse.jgit.internal.storage.dfs.DfsRepositoryDescription;
 import org.eclipse.jgit.internal.storage.dfs.InMemoryRepository;
 import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.AnyObjectId;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.ObjectLoader;
+import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.revwalk.RevBlob;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevObject;
 import org.eclipse.jgit.revwalk.RevWalk;
+import org.eclipse.jgit.treewalk.TreeWalk;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -76,7 +86,7 @@ public class TestRepositoryTest {
 	@After
 	public void tearDown() {
 		rw.close();
-		tr.getRepository().close();
+		repo.close();
 	}
 
 	@Test
@@ -168,4 +178,98 @@ public class TestRepositoryTest {
 		assertEquals(detached, head.getObjectId());
 		assertFalse(head.isSymbolic());
 	}
+
+	@Test
+	public void amendRef() throws Exception {
+		RevCommit root = tr.commit()
+				.add("todelete", "to be deleted")
+				.create();
+		RevCommit orig = tr.commit().parent(root)
+				.rm("todelete")
+				.add("foo", "foo contents")
+				.add("bar", "bar contents")
+				.add("dir/baz", "baz contents")
+				.create();
+		rw.parseBody(orig);
+		tr.branch("master").update(orig);
+		assertEquals("foo contents", blobAsString(orig, "foo"));
+		assertEquals("bar contents", blobAsString(orig, "bar"));
+		assertEquals("baz contents", blobAsString(orig, "dir/baz"));
+
+		RevCommit amended = tr.amendRef("master")
+				.tick(3)
+				.add("bar", "fixed bar contents")
+				.create();
+		assertEquals(amended, repo.getRef("refs/heads/master").getObjectId());
+		rw.parseBody(amended);
+
+		assertEquals(1, amended.getParentCount());
+		assertEquals(root, amended.getParent(0));
+		assertEquals(orig.getFullMessage(), amended.getFullMessage());
+		assertEquals(orig.getAuthorIdent(), amended.getAuthorIdent());
+
+		// Committer name/email is the same, but time was incremented.
+		assertEquals(new PersonIdent(orig.getCommitterIdent(), new Date(0)),
+				new PersonIdent(amended.getCommitterIdent(), new Date(0)));
+		assertTrue(orig.getCommitTime() < amended.getCommitTime());
+
+		assertEquals("foo contents", blobAsString(amended, "foo"));
+		assertEquals("fixed bar contents", blobAsString(amended, "bar"));
+		assertEquals("baz contents", blobAsString(amended, "dir/baz"));
+		assertNull(TreeWalk.forPath(repo, "todelete", amended.getTree()));
+	}
+
+	@Test
+	public void amendHead() throws Exception {
+		repo.updateRef("HEAD").link("refs/heads/master");
+		RevCommit root = tr.commit()
+				.add("foo", "foo contents")
+				.create();
+		RevCommit orig = tr.commit().parent(root)
+				.message("original message")
+				.add("bar", "bar contents")
+				.create();
+		tr.branch("master").update(orig);
+
+		RevCommit amended = tr.amendRef("HEAD")
+				.add("foo", "fixed foo contents")
+				.create();
+
+		Ref head = repo.getRef(Constants.HEAD);
+		assertEquals(amended, head.getObjectId());
+		assertTrue(head.isSymbolic());
+		assertEquals("refs/heads/master", head.getTarget().getName());
+
+		rw.parseBody(amended);
+		assertEquals("original message", amended.getFullMessage());
+		assertEquals("fixed foo contents", blobAsString(amended, "foo"));
+		assertEquals("bar contents", blobAsString(amended, "bar"));
+	}
+
+	@Test
+	public void amendCommit() throws Exception {
+		RevCommit root = tr.commit()
+				.add("foo", "foo contents")
+				.create();
+		RevCommit orig = tr.commit().parent(root)
+				.message("original message")
+				.add("bar", "bar contents")
+				.create();
+		RevCommit amended = tr.amend(orig.copy())
+				.add("foo", "fixed foo contents")
+				.create();
+
+		rw.parseBody(amended);
+		assertEquals("original message", amended.getFullMessage());
+		assertEquals("fixed foo contents", blobAsString(amended, "foo"));
+		assertEquals("bar contents", blobAsString(amended, "bar"));
+	}
+
+	private String blobAsString(AnyObjectId treeish, String path)
+			throws Exception {
+		RevObject obj = tr.get(rw.parseTree(treeish), path);
+		assertSame(RevBlob.class, obj.getClass());
+		ObjectLoader loader = rw.getObjectReader().open(obj);
+		return new String(loader.getCachedBytes(), UTF_8);
+	}
 }