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 * 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
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package org.eclipse.jgit.revwalk;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;

import org.eclipse.jgit.revwalk.filter.MessageRevFilter;
import org.eclipse.jgit.revwalk.filter.RevFilter;
import org.junit.Test;

public class FirstParentRevWalkTest extends RevWalkTestCase {
	@Test
	public void testStringOfPearls() throws Exception {
		RevCommit a = commit();
		RevCommit b = commit(a);
		RevCommit c = commit(b);

		rw.reset();
		rw.setFirstParent(true);
		markStart(c);
		assertCommit(c, rw.next());
		assertCommit(b, rw.next());
		assertCommit(a, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testSideBranch() throws Exception {
		RevCommit a = commit();
		RevCommit b1 = commit(a);
		RevCommit b2 = commit(a);
		RevCommit c1 = commit(b1);
		RevCommit c2 = commit(b2);
		RevCommit d = commit(c1, c2);

		rw.reset();
		rw.setFirstParent(true);
		markStart(d);
		assertCommit(d, rw.next());
		assertCommit(c1, rw.next());
		assertCommit(b1, rw.next());
		assertCommit(a, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testSecondParentAncestorOfFirstParent() throws Exception {
		RevCommit a = commit();
		RevCommit b = commit(a);
		RevCommit c = commit(b, a);

		rw.reset();
		rw.setFirstParent(true);
		markStart(c);
		assertCommit(c, rw.next());
		assertCommit(b, rw.next());
		assertCommit(a, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testFirstParentMultipleOccurrences() throws Exception {
		RevCommit a = commit();
		RevCommit b = commit(a);
		RevCommit c = commit(b);
		RevCommit d = commit(b);

		rw.reset();
		rw.setFirstParent(true);
		markStart(c);
		markStart(d);
		assertCommit(d, rw.next());
		assertCommit(c, rw.next());
		assertCommit(b, rw.next());
		assertCommit(a, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testReachableAlongFirstAndLaterParents() throws Exception {
		RevCommit a = commit();
		RevCommit b1 = commit(a);
		RevCommit b2 = commit(a);
		RevCommit b3 = commit(a);
		RevCommit c = commit(b1, b2);
		RevCommit d = commit(b2, b3);

		rw.reset();
		rw.setFirstParent(true);
		markStart(c);
		markStart(d);
		assertCommit(d, rw.next());
		assertCommit(c, rw.next());
		// b3 is only reachable from c's second parent.
		// b2 is reachable from c's second parent but d's first parent.
		assertCommit(b2, rw.next());
		assertCommit(b1, rw.next());
		assertCommit(a, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testStartCommitReachableOnlyFromLaterParents()
			throws Exception {
		RevCommit a = commit();
		RevCommit b1 = commit(a);
		RevCommit b2 = commit(a);
		RevCommit c = commit(b1, b2);

		rw.reset();
		rw.setFirstParent(true);
		markStart(c);
		markStart(b2);
		assertCommit(c, rw.next());
		// b2 is only reachable from second parent, but is itself a start
		// commit.
		assertCommit(b2, rw.next());
		assertCommit(b1, rw.next());
		assertCommit(a, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testRevFilter() throws Exception {
		RevCommit a = commit();
		RevCommit b1 = commitBuilder().parent(a).message("commit b1").create();
		RevCommit b2 = commitBuilder().parent(a).message("commit b2").create();
		RevCommit c = commit(b1, b2);

		rw.reset();
		rw.setFirstParent(true);
		rw.setRevFilter(MessageRevFilter.create("commit b"));
		rw.markStart(c);
		assertCommit(b1, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testTopoSort() throws Exception {
		RevCommit a = commit();
		RevCommit b1 = commit(a);
		RevCommit b2 = commit(a);
		RevCommit c = commit(b1, b2);

		rw.reset();
		rw.sort(RevSort.TOPO);
		rw.setFirstParent(true);
		markStart(c);
		assertCommit(c, rw.next());
		assertCommit(b1, rw.next());
		assertCommit(a, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testCommitTimeSort() throws Exception {
		RevCommit a = commit();
		RevCommit b1 = commit(a);
		RevCommit b2 = commit(a);
		RevCommit c = commit(b1, b2);

		rw.reset();
		rw.sort(RevSort.COMMIT_TIME_DESC);
		rw.setFirstParent(true);
		markStart(c);
		assertCommit(c, rw.next());
		assertCommit(b1, rw.next());
		assertCommit(a, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testReverseSort() throws Exception {
		RevCommit a = commit();
		RevCommit b1 = commit(a);
		RevCommit b2 = commit(a);
		RevCommit c = commit(b1, b2);

		rw.reset();
		rw.sort(RevSort.REVERSE);
		rw.setFirstParent(true);
		markStart(c);
		assertCommit(a, rw.next());
		assertCommit(b1, rw.next());
		assertCommit(c, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testBoundarySort() throws Exception {
		RevCommit a = commit();
		RevCommit b = commit(a);
		RevCommit c1 = commit(b);
		RevCommit c2 = commit(b);
		RevCommit d = commit(c1, c2);

		rw.reset();
		rw.sort(RevSort.BOUNDARY);
		rw.setFirstParent(true);
		markStart(d);
		markUninteresting(a);
		assertCommit(d, rw.next());
		assertCommit(c1, rw.next());
		assertCommit(b, rw.next());
		assertCommit(a, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testFirstParentOfFirstParentMarkedUninteresting()
			throws Exception {
		RevCommit a = commit();
		RevCommit b1 = commit(a);
		RevCommit b2 = commit(a);
		RevCommit c1 = commit(b1);
		RevCommit c2 = commit(b2);
		RevCommit d = commit(c1, c2);

		rw.reset();
		rw.setFirstParent(true);
		markStart(d);
		markUninteresting(b1);
		assertCommit(d, rw.next());
		assertCommit(c1, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testFirstParentMarkedUninteresting() throws Exception {
		RevCommit a = commit();
		RevCommit b1 = commit(a);
		RevCommit b2 = commit(a);
		RevCommit c = commit(b1, b2);

		rw.reset();
		rw.setFirstParent(true);
		markStart(c);
		markUninteresting(b1);
		assertCommit(c, rw.next());
		assertNull(rw.next());
	}

	@Test
	public void testDepthWalk() throws Exception {
		RevCommit a = commit();
		RevCommit b1 = commit(a);
		RevCommit b2 = commit(a);
		RevCommit c = commit(b1, b2);

		try (DepthWalk.RevWalk dw = new DepthWalk.RevWalk(db, 1)) {
			dw.setFirstParent(true);
			dw.markRoot(dw.parseCommit(c));
			dw.markStart(dw.parseCommit(c));
			assertEquals(c, dw.next());
			assertEquals(b1, dw.next());
			assertNull(dw.next());
		}
	}

	@Test
	public void testDoNotRewriteParents() throws Exception {
		RevCommit a = commit();
		RevCommit b1 = commit(a);
		RevCommit b2 = commit(a);
		RevCommit c = commit(b1, b2);

		rw.reset();
		rw.setFirstParent(true);
		rw.setRewriteParents(false);
		markStart(c);
		assertCommit(c, rw.next());
		assertCommit(b1, rw.next());
		assertCommit(a, rw.next());
		assertNull(rw.next());
	}

	@Test(expected = IllegalStateException.class)
	public void testMarkStartBeforeSetFirstParent() throws Exception {
		RevCommit a = commit();

		rw.reset();
		markStart(a);
		rw.setFirstParent(true);
	}

	@Test(expected = IllegalStateException.class)
	public void testMergeBaseWithFirstParentNotAllowed() throws Exception {
		RevCommit a = commit();

		rw.reset();
		rw.setFirstParent(true);
		rw.setRevFilter(RevFilter.MERGE_BASE);
		markStart(a);
		assertNull(rw.next());
	}
}