Use a new RevWalk for validating not advertised wants

Shadow commits in the RevWalk in the UploadPack object may cause the
UNINTERESTING flag not being carried over to their parents commits since
they were marked NO_PARENTS during the assumeShallow or
initializeShallowCommits call.

A new RevWalk needs to be created for this reason, but instead of
creating a new RevWalk from Repository, we can reuse the ObjectReader in
the RevWalk of UploadPack to load objects.

Change-Id: Ic3fee0512d35b4f555c60e696a880f8b192e4439
Signed-off-by: Zhen Chen <czhen@google.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/UploadPackTest.java

@@ -0,0 +1,90 @@
+package org.eclipse.jgit.transport;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Collections;
+import org.eclipse.jgit.internal.storage.dfs.DfsRepositoryDescription;
+import org.eclipse.jgit.internal.storage.dfs.InMemoryRepository;
+import org.eclipse.jgit.junit.TestRepository;
+import org.eclipse.jgit.lib.NullProgressMonitor;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.transport.UploadPack.RequestPolicy;
+import org.eclipse.jgit.transport.resolver.ServiceNotAuthorizedException;
+import org.eclipse.jgit.transport.resolver.ServiceNotEnabledException;
+import org.eclipse.jgit.transport.resolver.UploadPackFactory;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Tests for server upload-pack utilities.
+ */
+public class UploadPackTest {
+	private URIish uri;
+
+	private TestProtocol<Object> testProtocol;
+
+	private Object ctx = new Object();
+
+	private InMemoryRepository server;
+
+	private InMemoryRepository client;
+
+	private RevCommit commit0;
+
+	private RevCommit commit1;
+
+	private RevCommit tip;
+
+	@Before
+	public void setUp() throws Exception {
+		server = newRepo("server");
+		client = newRepo("client");
+
+		TestRepository<InMemoryRepository> remote =
+				new TestRepository<>(server);
+		commit0 = remote.commit().message("0").create();
+		commit1 = remote.commit().message("1").parent(commit0).create();
+		tip = remote.commit().message("2").parent(commit1).create();
+		remote.update("master", tip);
+	}
+
+	@After
+	public void tearDown() {
+		Transport.unregister(testProtocol);
+	}
+
+	private static InMemoryRepository newRepo(String name) {
+		return new InMemoryRepository(new DfsRepositoryDescription(name));
+	}
+
+	@Test
+	public void testFetchParentOfShallowCommit() throws Exception {
+		testProtocol = new TestProtocol<>(
+				new UploadPackFactory<Object>() {
+					@Override
+					public UploadPack create(Object req, Repository db)
+							throws ServiceNotEnabledException,
+							ServiceNotAuthorizedException {
+						UploadPack up = new UploadPack(db);
+						up.setRequestPolicy(RequestPolicy.REACHABLE_COMMIT);
+						// assume client has a shallow commit
+						up.getRevWalk().assumeShallow(
+								Collections.singleton(commit1.getId()));
+						return up;
+					}
+				}, null);
+		uri = testProtocol.register(ctx, server);
+
+		assertFalse(client.hasObject(commit0.toObjectId()));
+
+		// Fetch of the parent of the shallow commit
+		try (Transport tn = testProtocol.open(uri, client, "server")) {
+			tn.fetch(NullProgressMonitor.INSTANCE,
+					Collections.singletonList(new RefSpec(commit0.name())));
+			assertTrue(client.hasObject(commit0.toObjectId()));
+		}
+	}
+}

org.eclipse.jgit/src/org/eclipse/jgit/transport/UploadPack.java

@@ -71,7 +71,6 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
-
 import org.eclipse.jgit.errors.CorruptObjectException;
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
 import org.eclipse.jgit.errors.MissingObjectException;
@@ -1261,7 +1260,7 @@ public class UploadPack {
 		@Override
 		public void checkWants(UploadPack up, List<ObjectId> wants)
 				throws PackProtocolException, IOException {
-			checkNotAdvertisedWants(up.getRevWalk(), wants,
+			checkNotAdvertisedWants(up, wants,
 					refIdSet(up.getAdvertisedRefs().values()));
 		}
 	}
@@ -1298,7 +1297,7 @@ public class UploadPack {
 		@Override
 		public void checkWants(UploadPack up, List<ObjectId> wants)
 				throws PackProtocolException, IOException {
-			checkNotAdvertisedWants(up.getRevWalk(), wants,
+			checkNotAdvertisedWants(up, wants,
 					refIdSet(up.getRepository().getRefDatabase().getRefs(ALL).values()));
 		}
 	}
@@ -1316,7 +1315,7 @@ public class UploadPack {
 		}
 	}
 
-	private static void checkNotAdvertisedWants(RevWalk walk,
+	private static void checkNotAdvertisedWants(UploadPack up,
 			List<ObjectId> notAdvertisedWants, Set<ObjectId> reachableFrom)
 			throws MissingObjectException, IncorrectObjectTypeException, IOException {
 		// Walk the requested commits back to the provided set of commits. If any
@@ -1325,32 +1324,34 @@ public class UploadPack {
 		// into an advertised branch it will be marked UNINTERESTING and no commits
 		// return.
 
-		AsyncRevObjectQueue q = walk.parseAny(notAdvertisedWants, true);
-		try {
-			RevObject obj;
-			while ((obj = q.next()) != null) {
-				if (!(obj instanceof RevCommit))
-					throw new WantNotValidException(obj);
-				walk.markStart((RevCommit) obj);
-			}
-		} catch (MissingObjectException notFound) {
-			throw new WantNotValidException(notFound.getObjectId(), notFound);
-		} finally {
-			q.release();
-		}
-		for (ObjectId id : reachableFrom) {
+		try (RevWalk walk = new RevWalk(up.getRevWalk().getObjectReader())) {
+			AsyncRevObjectQueue q = walk.parseAny(notAdvertisedWants, true);
 			try {
-				walk.markUninteresting(walk.parseCommit(id));
-			} catch (IncorrectObjectTypeException notCommit) {
-				continue;
+				RevObject obj;
+				while ((obj = q.next()) != null) {
+					if (!(obj instanceof RevCommit))
+						throw new WantNotValidException(obj);
+					walk.markStart((RevCommit) obj);
+				}
+			} catch (MissingObjectException notFound) {
+				throw new WantNotValidException(notFound.getObjectId(),
+						notFound);
+			} finally {
+				q.release();
+			}
+			for (ObjectId id : reachableFrom) {
+				try {
+					walk.markUninteresting(walk.parseCommit(id));
+				} catch (IncorrectObjectTypeException notCommit) {
+					continue;
+				}
 			}
-		}
 
-		RevCommit bad = walk.next();
-		if (bad != null) {
-			throw new WantNotValidException(bad);
+			RevCommit bad = walk.next();
+			if (bad != null) {
+				throw new WantNotValidException(bad);
+			}
 		}
-		walk.reset();
 	}
 
 	private void addCommonBase(final RevObject o) {