Fix DirCacheCheckout to return CheckoutConflictException

Problem occurs when the checkout wants to create a file 'd/f' but
the workingtree contains a dirty file 'd'. In order to create d/f the
file 'd' would have to be deleted and since the file is dirty that
content would be lost. This should lead to a CheckoutConflictException
for d/f when failOnConflict was set to true.

This fix also changes jgit checkout semantics to be more like native
gits checkout semantics. If during a checkout jgit wants to delete a
folder but finds that the working tree contains a dirty file at this
path then JGit will now throw an exception instead of silently keeping
the dirty file. Like in this example:

	git init
	touch b
	git add b
	git commit -m addB
	mkdir a
	touch a/c
	git add a/c
	git commit -m addAC
	rm -fr a
	touch a
	git checkout HEAD~

Change-Id: I9089123179e09dd565285d50b0caa308d290cccd
Signed-off-by: Rüdiger Herrmann <ruediger.herrmann@gmx.de>
Also-by: Rüdiger Herrmann <ruediger.herrmann@gmx.de>

1 files changed, 12 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 e690ad6964..3651542fc6 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
@@ -47,6 +47,7 @@ import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 import java.io.File;
 import java.nio.file.Files;
@@ -236,8 +237,8 @@ public class CheckoutTest extends CLIRepositoryTestCase {
 	 * <li>Checkout branch '1'
 	 * </ol>
 	 * <p>
-	 * The working tree should contain 'a' with FileMode.REGULAR_FILE after the
-	 * checkout.
+	 * The checkout has to delete folder but the workingtree contains a dirty
+	 * file at this path. The checkout should fail like in native git.
 	 *
 	 * @throws Exception
 	 */
@@ -266,11 +267,15 @@ public class CheckoutTest extends CLIRepositoryTestCase {
 					db.getFS());
 			assertEquals(FileMode.REGULAR_FILE, entry.getMode());
 
-			git.checkout().setName(branch_1.getName()).call();
-
-			entry = new FileTreeIterator.FileEntry(new File(db.getWorkTree(), "a"),
-					db.getFS());
-			assertEquals(FileMode.REGULAR_FILE, entry.getMode());
+			try {
+				git.checkout().setName(branch_1.getName()).call();
+				fail("Don't get the expected conflict");
+			} catch (CheckoutConflictException e) {
+				assertEquals("[a]", e.getConflictingPaths().toString());
+				entry = new FileTreeIterator.FileEntry(
+						new File(db.getWorkTree(), "a"), db.getFS());
+				assertEquals(FileMode.REGULAR_FILE, entry.getMode());
+			}
 		}
 	}