Repository: Introduce exactRef and findRef, deprecate getRef

The Repository class provides only one method to look up a ref by
name, getRef.  If I request refs/heads/master and that ref does not
exist, getRef will look further in the search path:

 ref/refs/heads/master
 refs/heads/refs/heads/master
 refs/remotes/refs/heads/master

This behavior is counterintuitive, needlessly inexpensive, and usually
not what the caller expects.

Allow callers to specify whether to use the search path by providing
two separate methods:

- exactRef, which looks up a ref when its exact name is known
- findRef, which looks for a ref along the search path

For backward compatibility, keep getRef as a deprecated synonym for
findRef.

This change introduces findRef and exactRef but does not update
callers outside tests to use them yet.

Change-Id: I35375d942baeb3ded15520388f8ebb9c0cc86f8c
Signed-off-by: Jonathan Nieder <jrn@google.com>

3 files changed, 9 insertions, 7 deletions

diff --git a/org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/CheckoutTest.java b/org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/CheckoutTest.java
index 7bf4c26c38..939a9f6fdd 100644
--- a/org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/CheckoutTest.java
+++ b/org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/CheckoutTest.java
@@ -198,7 +198,8 @@ public class CheckoutTest extends CLIRepositoryTestCase {
 
 		assertStringArrayEquals("Switched to a new branch 'new_branch'",
 				execute("git checkout --orphan new_branch"));
-		assertEquals("refs/heads/new_branch", db.getRef("HEAD").getTarget().getName());
+		assertEquals("refs/heads/new_branch",
+				db.exactRef("HEAD").getTarget().getName());
 		RevCommit commit = git.commit().setMessage("orphan commit").call();
 		assertEquals(0, commit.getParentCount());
 	}
diff --git a/org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/ResetTest.java b/org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/ResetTest.java
index 0785c5c5ff..dae477928b 100644
--- a/org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/ResetTest.java
+++ b/org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/ResetTest.java
@@ -67,7 +67,7 @@ public class ResetTest extends CLIRepositoryTestCase {
 		assertStringArrayEquals("",
 				execute("git reset --hard " + commit.getId().name()));
 		assertEquals(commit.getId(),
-				git.getRepository().getRef("HEAD").getObjectId());
+				git.getRepository().exactRef("HEAD").getObjectId());
 	}
 
 	@Test
@@ -77,7 +77,7 @@ public class ResetTest extends CLIRepositoryTestCase {
 		assertStringArrayEquals("",
 				execute("git reset --hard " + commit.getId().name()));
 		assertEquals(commit.getId(),
-				git.getRepository().getRef("HEAD").getObjectId());
+				git.getRepository().exactRef("HEAD").getObjectId());
 	}
 
 	@Test
@@ -86,7 +86,7 @@ public class ResetTest extends CLIRepositoryTestCase {
 		assertStringArrayEquals("",
 				execute("git reset --hard " + commit.getId().name() + " --"));
 		assertEquals(commit.getId(),
-				git.getRepository().getRef("HEAD").getObjectId());
+				git.getRepository().exactRef("HEAD").getObjectId());
 	}
 
 	@Test
@@ -119,7 +119,7 @@ public class ResetTest extends CLIRepositoryTestCase {
 				(useDoubleDash) ? " --" : "");
 		assertStringArrayEquals("", execute(cmd));
 		assertEquals(commit.getId(),
-				git.getRepository().getRef("HEAD").getObjectId());
+				git.getRepository().exactRef("HEAD").getObjectId());
 
 		org.eclipse.jgit.api.Status status = git.status().call();
 		// assert that file a is unstaged
diff --git a/org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/StatusTest.java b/org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/StatusTest.java
index 793fc7daf6..854c52d88b 100644
--- a/org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/StatusTest.java
+++ b/org.eclipse.jgit.pgm.test/tst/org/eclipse/jgit/pgm/StatusTest.java
@@ -42,13 +42,14 @@
  */
 package org.eclipse.jgit.pgm;
 
+import static org.eclipse.jgit.lib.Constants.MASTER;
+import static org.eclipse.jgit.lib.Constants.R_HEADS;
 
 import java.io.IOException;
 
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.lib.CLIRepositoryTestCase;
-import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.junit.Test;
 
@@ -254,7 +255,7 @@ public class StatusTest extends CLIRepositoryTestCase {
 	}
 
 	private void detachHead(Git git) throws IOException, GitAPIException {
-		String commitId = db.getRef(Constants.MASTER).getObjectId().name();
+		String commitId = db.exactRef(R_HEADS + MASTER).getObjectId().name();
 		git.checkout().setName(commitId).call();
 	}