reftable: resolve symbolic references

resolve(Ref) helps callers recursively chase symbolic references and
is a useful function when wrapping a Reftable inside a RefDatabase, as
RefCursor does not resolve symbolic references during iteration.

Change-Id: I1ba143f403773497972e225dc92c35ecb989e154

1 files changed, 37 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/reftable/ReftableTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/reftable/ReftableTest.java
index b53853b2e5..6809d7b2b2 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/reftable/ReftableTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/reftable/ReftableTest.java
@@ -52,6 +52,7 @@ import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
@@ -240,6 +241,42 @@ public class ReftableTest {
 	}
 
 	@Test
+	public void resolveSymbolicRef() throws IOException {
+		Reftable t = read(write(
+				sym(HEAD, "refs/heads/tmp"),
+				sym("refs/heads/tmp", MASTER),
+				ref(MASTER, 1)));
+
+		Ref head = t.exactRef(HEAD);
+		assertNull(head.getObjectId());
+		assertEquals("refs/heads/tmp", head.getTarget().getName());
+
+		head = t.resolve(head);
+		assertNotNull(head);
+		assertEquals(id(1), head.getObjectId());
+
+		Ref master = t.exactRef(MASTER);
+		assertNotNull(master);
+		assertSame(master, t.resolve(master));
+	}
+
+	@Test
+	public void failDeepChainOfSymbolicRef() throws IOException {
+		Reftable t = read(write(
+				sym(HEAD, "refs/heads/1"),
+				sym("refs/heads/1", "refs/heads/2"),
+				sym("refs/heads/2", "refs/heads/3"),
+				sym("refs/heads/3", "refs/heads/4"),
+				sym("refs/heads/4", "refs/heads/5"),
+				sym("refs/heads/5", MASTER),
+				ref(MASTER, 1)));
+
+		Ref head = t.exactRef(HEAD);
+		assertNull(head.getObjectId());
+		assertNull(t.resolve(head));
+	}
+
+	@Test
 	public void oneDeletedRef() throws IOException {
 		String name = "refs/heads/gone";
 		Ref exp = newRef(name);