Fetch: Introduce negative refspecs.

Implement negative refspecs in JGit fetch, following C Git. Git
supports negative refspecs in source only while this change supports
them in both source and destination.

If one branch is equal to any branch or matches any pattern in the
negative refspecs collection, the branch will not be fetched even if
it's in the toFetch collection.

With this feature, users can express more complex patterns during fetch.

Change-Id: Iaa1cd4de5c08c273e198b72e12e3dadae7be709f
Sign-off-by: Yunjie Li<yunjieli@google.com>

2 files changed, 95 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/FetchCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/FetchCommandTest.java
index 6479d157eb..0884d72235 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/FetchCommandTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/FetchCommandTest.java
@@ -96,6 +96,53 @@ public class FetchCommandTest extends RepositoryTestCase {
 	}
 
 	@Test
+	public void testFetchSimpleNegativeRefSpec() throws Exception {
+		remoteGit.commit().setMessage("commit").call();
+
+		FetchResult res = git.fetch().setRemote("test")
+				.setRefSpecs("refs/heads/master:refs/heads/test",
+						"^:refs/heads/test")
+				.call();
+		assertNull(res.getTrackingRefUpdate("refs/heads/test"));
+
+		res = git.fetch().setRemote("test")
+				.setRefSpecs("refs/heads/master:refs/heads/test",
+						"^refs/heads/master")
+				.call();
+		assertNull(res.getTrackingRefUpdate("refs/heads/test"));
+	}
+
+	@Test
+	public void negativeRefSpecFilterBySource() throws Exception {
+		remoteGit.commit().setMessage("commit").call();
+		remoteGit.branchCreate().setName("test").call();
+		remoteGit.commit().setMessage("commit1").call();
+		remoteGit.branchCreate().setName("dev").call();
+
+		FetchResult res = git.fetch().setRemote("test")
+				.setRefSpecs("refs/*:refs/origins/*", "^refs/*/test")
+				.call();
+		assertNotNull(res.getTrackingRefUpdate("refs/origins/heads/master"));
+		assertNull(res.getTrackingRefUpdate("refs/origins/heads/test"));
+		assertNotNull(res.getTrackingRefUpdate("refs/origins/heads/dev"));
+	}
+
+	@Test
+	public void negativeRefSpecFilterByDestination() throws Exception {
+		remoteGit.commit().setMessage("commit").call();
+		remoteGit.branchCreate().setName("meta").call();
+		remoteGit.commit().setMessage("commit1").call();
+		remoteGit.branchCreate().setName("data").call();
+
+		FetchResult res = git.fetch().setRemote("test")
+				.setRefSpecs("refs/*:refs/secret/*", "^:refs/secret/*/meta")
+				.call();
+		assertNotNull(res.getTrackingRefUpdate("refs/secret/heads/master"));
+		assertNull(res.getTrackingRefUpdate("refs/secret/heads/meta"));
+		assertNotNull(res.getTrackingRefUpdate("refs/secret/heads/data"));
+	}
+
+	@Test
 	public void fetchAddsBranches() throws Exception {
 		final String branch1 = "b1";
 		final String branch2 = "b2";
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/RefSpecTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/RefSpecTest.java
index b56308cb72..ef0817adb8 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/RefSpecTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/RefSpecTest.java
@@ -443,6 +443,26 @@ public class RefSpecTest {
 		a.setDestination("refs/remotes/origin/*/*");
 	}
 
+	@Test(expected = IllegalArgumentException.class)
+	public void invalidNegativeAndForce() {
+		assertNotNull(new RefSpec("^+refs/heads/master"));
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void invalidForceAndNegative() {
+		assertNotNull(new RefSpec("+^refs/heads/master"));
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void invalidNegativeNoSrcDest() {
+		assertNotNull(new RefSpec("^"));
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void invalidNegativeBothSrcDest() {
+		assertNotNull(new RefSpec("^refs/heads/*:refs/heads/*"));
+	}
+
 	@Test
 	public void sourceOnlywithWildcard() {
 		RefSpec a = new RefSpec("refs/heads/*",
@@ -480,4 +500,32 @@ public class RefSpecTest {
 		assertTrue(a.isMatching());
 		assertTrue(a.isForceUpdate());
 	}
+
+	@Test
+	public void negativeRefSpecWithDest() {
+		RefSpec a = new RefSpec("^:refs/readonly/*");
+		assertTrue(a.isNegative());
+		assertNull(a.getSource());
+		assertEquals(a.getDestination(), "refs/readonly/*");
+	}
+
+	// Because of some of the API's existing behavior, without a colon at the
+	// end of the refspec, dest will be null.
+	@Test
+	public void negativeRefSpecWithSrcAndNullDest() {
+		RefSpec a = new RefSpec("^refs/testdata/*");
+		assertTrue(a.isNegative());
+		assertNull(a.getDestination());
+		assertEquals(a.getSource(), "refs/testdata/*");
+	}
+
+	// Because of some of the API's existing behavior, with a colon at the end
+	// of the refspec, dest will be empty.
+	@Test
+	public void negativeRefSpecWithSrcAndEmptyDest() {
+		RefSpec a = new RefSpec("^refs/testdata/*:");
+		assertTrue(a.isNegative());
+		assertTrue(a.getDestination().isEmpty());
+		assertEquals(a.getSource(), "refs/testdata/*");
+	}
 }