IndexDiffFilter: handle path prefixes correctly

When comparing git directory paths to check whether one is a prefix
of another, one must add a slash to avoid false prefix matches when
one directory name is a prefix of another. The path "audio" is not
a prefix of the path "audio-new", but would be a prefix of a path
"audio/new".

Bug: 566799
Change-Id: I6f671ca043c7c2c6044eb05a71dc8cca8d0ee040
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

2 files changed, 27 insertions, 5 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/StatusCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/StatusCommandTest.java
index 7e0de82d82..5311edb0eb 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/StatusCommandTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/StatusCommandTest.java
@@ -160,4 +160,25 @@ public class StatusCommandTest extends RepositoryTestCase {
 			assertTrue("Expected no differences", status.isClean());
 		}
 	}
+
+	@Test
+	public void testFolderPrefix() throws Exception {
+		// "audio" is a prefix of "audio-new" and "audio.new".
+		try (Git git = new Git(db)) {
+			// Order here is the git order, but that doesn't really matter.
+			// They are processed by StatusCommand in this order even if written
+			// in a different order. Bug 566799 would, when having processed
+			// audio/foo, remove previously recorded untracked folders that have
+			// "audio" as a prefix: audio-new and audio.new.
+			writeTrashFile("audi", "foo", "foo");
+			writeTrashFile("audio-new", "foo", "foo");
+			writeTrashFile("audio.new", "foo", "foo");
+			writeTrashFile("audio", "foo", "foo");
+			writeTrashFile("audio_new", "foo", "foo");
+			Status stat = git.status().call();
+			assertEquals(Sets.of("audi", "audio-new", "audio.new", "audio",
+					"audio_new"), stat.getUntrackedFolders());
+		}
+	}
+
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/treewalk/filter/IndexDiffFilter.java b/org.eclipse.jgit/src/org/eclipse/jgit/treewalk/filter/IndexDiffFilter.java
index 19cda42485..4731f345bc 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/treewalk/filter/IndexDiffFilter.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/treewalk/filter/IndexDiffFilter.java
@@ -217,14 +217,15 @@ public class IndexDiffFilter extends TreeFilter {
 	 */
 	private void copyUntrackedFolders(String currentPath) {
 		String pathToBeSaved = null;
-		while (!untrackedParentFolders.isEmpty()
-				&& !currentPath.startsWith(untrackedParentFolders.getFirst()
-						+ "/")) //$NON-NLS-1$
+		while (!untrackedParentFolders.isEmpty() && !currentPath
+				.startsWith(untrackedParentFolders.getFirst() + '/')) {
 			pathToBeSaved = untrackedParentFolders.removeFirst();
+		}
 		if (pathToBeSaved != null) {
-			while (!untrackedFolders.isEmpty()
-					&& untrackedFolders.getLast().startsWith(pathToBeSaved))
+			while (!untrackedFolders.isEmpty() && untrackedFolders.getLast()
+					.startsWith(pathToBeSaved + '/')) {
 				untrackedFolders.removeLast();
+			}
 			untrackedFolders.addLast(pathToBeSaved);
 		}
 	}