RevWalk support for shallow clones

StartGenerator now processes .git/shallow to have the
RevWalk stop for shallow commits.

See RevWalkShallowTest for tests.

Bug: 394543
CQ: 6908
Change-Id: Ia5af1dab3fe9c7888f44eeecab1e1bcf2e8e48fe
Signed-off-by: Chris Aniszczyk <zx@twitter.com>

2 files changed, 216 insertions, 21 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/FooterLineTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/FooterLineTest.java
index 7f440df22a..1720b26bbc 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/FooterLineTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/FooterLineTest.java
@@ -48,7 +48,7 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
-
+import java.io.IOException;
 import java.util.List;
 
 import org.eclipse.jgit.lib.Constants;
@@ -58,7 +58,7 @@ import org.junit.Test;
 
 public class FooterLineTest extends RepositoryTestCase {
 	@Test
-	public void testNoFooters_EmptyBody() {
+	public void testNoFooters_EmptyBody() throws IOException {
 		final RevCommit commit = parse("");
 		final List<FooterLine> footers = commit.getFooterLines();
 		assertNotNull(footers);
@@ -66,7 +66,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testNoFooters_NewlineOnlyBody1() {
+	public void testNoFooters_NewlineOnlyBody1() throws IOException {
 		final RevCommit commit = parse("\n");
 		final List<FooterLine> footers = commit.getFooterLines();
 		assertNotNull(footers);
@@ -74,7 +74,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testNoFooters_NewlineOnlyBody5() {
+	public void testNoFooters_NewlineOnlyBody5() throws IOException {
 		final RevCommit commit = parse("\n\n\n\n\n");
 		final List<FooterLine> footers = commit.getFooterLines();
 		assertNotNull(footers);
@@ -82,7 +82,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testNoFooters_OneLineBodyNoLF() {
+	public void testNoFooters_OneLineBodyNoLF() throws IOException {
 		final RevCommit commit = parse("this is a commit");
 		final List<FooterLine> footers = commit.getFooterLines();
 		assertNotNull(footers);
@@ -90,7 +90,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testNoFooters_OneLineBodyWithLF() {
+	public void testNoFooters_OneLineBodyWithLF() throws IOException {
 		final RevCommit commit = parse("this is a commit\n");
 		final List<FooterLine> footers = commit.getFooterLines();
 		assertNotNull(footers);
@@ -98,7 +98,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testNoFooters_ShortBodyNoLF() {
+	public void testNoFooters_ShortBodyNoLF() throws IOException {
 		final RevCommit commit = parse("subject\n\nbody of commit");
 		final List<FooterLine> footers = commit.getFooterLines();
 		assertNotNull(footers);
@@ -106,7 +106,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testNoFooters_ShortBodyWithLF() {
+	public void testNoFooters_ShortBodyWithLF() throws IOException {
 		final RevCommit commit = parse("subject\n\nbody of commit\n");
 		final List<FooterLine> footers = commit.getFooterLines();
 		assertNotNull(footers);
@@ -114,7 +114,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testSignedOffBy_OneUserNoLF() {
+	public void testSignedOffBy_OneUserNoLF() throws IOException {
 		final RevCommit commit = parse("subject\n\nbody of commit\n" + "\n"
 				+ "Signed-off-by: A. U. Thor <a@example.com>");
 		final List<FooterLine> footers = commit.getFooterLines();
@@ -130,7 +130,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testSignedOffBy_OneUserWithLF() {
+	public void testSignedOffBy_OneUserWithLF() throws IOException {
 		final RevCommit commit = parse("subject\n\nbody of commit\n" + "\n"
 				+ "Signed-off-by: A. U. Thor <a@example.com>\n");
 		final List<FooterLine> footers = commit.getFooterLines();
@@ -146,7 +146,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testSignedOffBy_IgnoreWhitespace() {
+	public void testSignedOffBy_IgnoreWhitespace() throws IOException {
 		// We only ignore leading whitespace on the value, trailing
 		// is assumed part of the value.
 		//
@@ -165,7 +165,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testEmptyValueNoLF() {
+	public void testEmptyValueNoLF() throws IOException {
 		final RevCommit commit = parse("subject\n\nbody of commit\n" + "\n"
 				+ "Signed-off-by:");
 		final List<FooterLine> footers = commit.getFooterLines();
@@ -181,7 +181,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testEmptyValueWithLF() {
+	public void testEmptyValueWithLF() throws IOException {
 		final RevCommit commit = parse("subject\n\nbody of commit\n" + "\n"
 				+ "Signed-off-by:\n");
 		final List<FooterLine> footers = commit.getFooterLines();
@@ -197,7 +197,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testShortKey() {
+	public void testShortKey() throws IOException {
 		final RevCommit commit = parse("subject\n\nbody of commit\n" + "\n"
 				+ "K:V\n");
 		final List<FooterLine> footers = commit.getFooterLines();
@@ -213,7 +213,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testNonDelimtedEmail() {
+	public void testNonDelimtedEmail() throws IOException {
 		final RevCommit commit = parse("subject\n\nbody of commit\n" + "\n"
 				+ "Acked-by: re@example.com\n");
 		final List<FooterLine> footers = commit.getFooterLines();
@@ -229,7 +229,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testNotEmail() {
+	public void testNotEmail() throws IOException {
 		final RevCommit commit = parse("subject\n\nbody of commit\n" + "\n"
 				+ "Acked-by: Main Tain Er\n");
 		final List<FooterLine> footers = commit.getFooterLines();
@@ -245,7 +245,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testSignedOffBy_ManyUsers() {
+	public void testSignedOffBy_ManyUsers() throws IOException {
 		final RevCommit commit = parse("subject\n\nbody of commit\n"
 				+ "Not-A-Footer-Line: this line must not be read as a footer\n"
 				+ "\n" // paragraph break, now footers appear in final block
@@ -281,7 +281,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testSignedOffBy_SkipNonFooter() {
+	public void testSignedOffBy_SkipNonFooter() throws IOException {
 		final RevCommit commit = parse("subject\n\nbody of commit\n"
 				+ "Not-A-Footer-Line: this line must not be read as a footer\n"
 				+ "\n" // paragraph break, now footers appear in final block
@@ -314,7 +314,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testFilterFootersIgnoreCase() {
+	public void testFilterFootersIgnoreCase() throws IOException {
 		final RevCommit commit = parse("subject\n\nbody of commit\n"
 				+ "Not-A-Footer-Line: this line must not be read as a footer\n"
 				+ "\n" // paragraph break, now footers appear in final block
@@ -332,7 +332,7 @@ public class FooterLineTest extends RepositoryTestCase {
 	}
 
 	@Test
-	public void testMatchesBugId() {
+	public void testMatchesBugId() throws IOException {
 		final RevCommit commit = parse("this is a commit subject for test\n"
 				+ "\n" // paragraph break, now footers appear in final block
 				+ "Simple-Bug-Id: 42\n");
@@ -352,7 +352,7 @@ public class FooterLineTest extends RepositoryTestCase {
 		assertFalse("not CC", line.matches(FooterKey.CC));
 	}
 
-	private RevCommit parse(final String msg) {
+	private RevCommit parse(final String msg) throws IOException {
 		final StringBuilder buf = new StringBuilder();
 		buf.append("tree " + ObjectId.zeroId().name() + "\n");
 		buf.append("author A. U. Thor <a@example.com> 1 +0000\n");
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/RevWalkShallowTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/RevWalkShallowTest.java
new file mode 100644
index 0000000000..479d9d304a
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/RevWalkShallowTest.java
@@ -0,0 +1,195 @@
+/*
+ * Copyright (C) 2012, Marc Strapetz <marc.strapetz@syntevo.com>
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.eclipse.jgit.revwalk;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.eclipse.jgit.junit.JGitTestUtil;
+import org.eclipse.jgit.lib.*;
+import org.junit.*;
+
+import static org.junit.Assert.*;
+
+public class RevWalkShallowTest extends RevWalkTestCase {
+
+	// Accessing ==============================================================
+
+	@Test
+	public void testDepth1() throws Exception {
+		final RevCommit a = commit();
+		final RevCommit b = commit(a);
+		final RevCommit c = commit(b);
+		final RevCommit d = commit(c);
+
+		createShallowFile(d);
+
+		rw.reset();
+		markStart(d);
+		assertCommit(d, rw.next());
+		assertNull(rw.next());
+	}
+
+	@Test
+	public void testDepth2() throws Exception {
+		final RevCommit a = commit();
+		final RevCommit b = commit(a);
+		final RevCommit c = commit(b);
+		final RevCommit d = commit(c);
+
+		createShallowFile(c);
+
+		rw.reset();
+		markStart(d);
+		assertCommit(d, rw.next());
+		assertCommit(c, rw.next());
+		assertNull(rw.next());
+	}
+
+	@Test
+	public void testDepth3() throws Exception {
+		final RevCommit a = commit();
+		final RevCommit b = commit(a);
+		final RevCommit c = commit(b);
+		final RevCommit d = commit(c);
+
+		createShallowFile(b);
+
+		rw.reset();
+		markStart(d);
+		assertCommit(d, rw.next());
+		assertCommit(c, rw.next());
+		assertCommit(b, rw.next());
+		assertNull(rw.next());
+	}
+
+	@Test
+	public void testMergeCommitOneParentShallow() throws Exception {
+		final RevCommit a = commit();
+		final RevCommit b = commit(a);
+		final RevCommit c = commit(b);
+		final RevCommit d = commit(b);
+		final RevCommit e = commit(d);
+		final RevCommit merge = commit(c, e);
+
+		createShallowFile(e);
+
+		rw.reset();
+		markStart(merge);
+		assertCommit(merge, rw.next());
+		assertCommit(e, rw.next());
+		assertCommit(c, rw.next());
+		assertCommit(b, rw.next());
+		assertCommit(a, rw.next());
+		assertNull(rw.next());
+	}
+
+	@Test
+	public void testMergeCommitEntirelyShallow() throws Exception {
+		final RevCommit a = commit();
+		final RevCommit b = commit(a);
+		final RevCommit c = commit(b);
+		final RevCommit d = commit(b);
+		final RevCommit e = commit(d);
+		final RevCommit merge = commit(c, e);
+
+		createShallowFile(c, e);
+
+		rw.reset();
+		markStart(merge);
+		assertCommit(merge, rw.next());
+		assertCommit(e, rw.next());
+		assertCommit(c, rw.next());
+		assertNull(rw.next());
+	}
+
+	@Test
+	public void testObjectDirectorySnapshot() throws Exception {
+		RevCommit a = commit();
+		RevCommit b = commit(a);
+		RevCommit c = commit(b);
+		RevCommit d = commit(c);
+
+		createShallowFile(d);
+
+		rw.reset();
+		markStart(d);
+		assertCommit(d, rw.next());
+		assertNull(rw.next());
+
+		rw = createRevWalk();
+		a = rw.lookupCommit(a);
+		b = rw.lookupCommit(b);
+		c = rw.lookupCommit(c);
+		d = rw.lookupCommit(d);
+
+		rw.reset();
+		markStart(d);
+		assertCommit(d, rw.next());
+		assertNull(rw.next());
+
+		createShallowFile(c);
+
+		rw = createRevWalk();
+		a = rw.lookupCommit(a);
+		b = rw.lookupCommit(b);
+		c = rw.lookupCommit(c);
+		d = rw.lookupCommit(d);
+
+		rw.reset();
+		markStart(d);
+		assertCommit(d, rw.next());
+		assertCommit(c, rw.next());
+		assertNull(rw.next());
+	}
+
+	private void createShallowFile(ObjectId... shallowCommits)
+			throws IOException {
+		final StringBuilder builder = new StringBuilder();
+		for (ObjectId commit : shallowCommits)
+			builder.append(commit.getName() + "\n");
+		JGitTestUtil.write(new File(rw.repository.getDirectory(), "shallow"),
+				builder.toString());
+	}
+}