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, 58 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/DirCacheCheckoutTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/DirCacheCheckoutTest.java
index fbe7dd0417..bb553a444e 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/DirCacheCheckoutTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/DirCacheCheckoutTest.java
@@ -1614,6 +1614,64 @@ public class DirCacheCheckoutTest extends RepositoryTestCase {
 		assertNotNull(git.checkout().setName(Constants.MASTER).call());
 	}
 
+	@Test(expected = CheckoutConflictException.class)
+	public void testFolderFileConflict() throws Exception {
+		RevCommit headCommit = commitFile("f/a", "initial content", "master");
+		RevCommit checkoutCommit = commitFile("f/a", "side content", "side");
+		FileUtils.delete(new File(db.getWorkTree(), "f"), FileUtils.RECURSIVE);
+		writeTrashFile("f", "file instead of folder");
+		new DirCacheCheckout(db, headCommit.getTree(), db.lockDirCache(),
+				checkoutCommit.getTree()).checkout();
+	}
+
+	@Test
+	public void testMultipleContentConflicts() throws Exception {
+		commitFile("a", "initial content", "master");
+		RevCommit headCommit = commitFile("b", "initial content", "master");
+		commitFile("a", "side content", "side");
+		RevCommit checkoutCommit = commitFile("b", "side content", "side");
+		writeTrashFile("a", "changed content");
+		writeTrashFile("b", "changed content");
+
+		try {
+			new DirCacheCheckout(db, headCommit.getTree(), db.lockDirCache(),
+					checkoutCommit.getTree()).checkout();
+			fail();
+		} catch (CheckoutConflictException expected) {
+			assertEquals(2, expected.getConflictingFiles().length);
+			assertTrue(Arrays.asList(expected.getConflictingFiles())
+					.contains("a"));
+			assertTrue(Arrays.asList(expected.getConflictingFiles())
+					.contains("b"));
+			assertEquals("changed content", read("a"));
+			assertEquals("changed content", read("b"));
+		}
+	}
+
+	@Test
+	public void testFolderFileAndContentConflicts() throws Exception {
+		RevCommit headCommit = commitFile("f/a", "initial content", "master");
+		commitFile("b", "side content", "side");
+		RevCommit checkoutCommit = commitFile("f/a", "side content", "side");
+		FileUtils.delete(new File(db.getWorkTree(), "f"), FileUtils.RECURSIVE);
+		writeTrashFile("f", "file instead of a folder");
+		writeTrashFile("b", "changed content");
+
+		try {
+			new DirCacheCheckout(db, headCommit.getTree(), db.lockDirCache(),
+					checkoutCommit.getTree()).checkout();
+			fail();
+		} catch (CheckoutConflictException expected) {
+			assertEquals(2, expected.getConflictingFiles().length);
+			assertTrue(Arrays.asList(expected.getConflictingFiles())
+					.contains("b"));
+			assertTrue(Arrays.asList(expected.getConflictingFiles())
+					.contains("f"));
+			assertEquals("file instead of a folder", read("f"));
+			assertEquals("changed content", read("b"));
+		}
+	}
+
 	public void assertWorkDir(Map<String, String> i)
 			throws CorruptObjectException,
 			IOException {