Fix false positives in hashing used by PathFilterGroup

The ByteArraySet failed to check the length of the entry correctly leading
to matches where no match should be.

Bug: 401249
Change-Id: I925bc48d9cafcdf13e1a797bb09fc2555eb270c5
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/treewalk/filter/PathFilterGroupTest.java

@@ -134,6 +134,19 @@ public class PathFilterGroupTest {
 		assertTrue(filter.include(fakeWalk("d/e/f/g/h")));
 	}
 
+	@Test
+	public void testLongPaths() throws MissingObjectException,
+			IncorrectObjectTypeException, IOException {
+		TreeFilter longPathFilter = PathFilterGroup
+				.createFromStrings(
+						"tst/org/eclipse/jgit/treewalk/filter/PathFilterGroupTest.java",
+						"tst/org/eclipse/jgit/treewalk/filter/PathFilterGroupTest2.java");
+		assertFalse(longPathFilter
+				.include(fakeWalk("tst/org/eclipse/jgit/treewalk/FileTreeIteratorTest.java")));
+		assertFalse(longPathFilter.include(fakeWalk("tst/a-other-in-same")));
+		assertFalse(longPathFilter.include(fakeWalk("a-nothing-in-common")));
+	}
+
 	@Test
 	public void testStopWalk() throws MissingObjectException,
 			IncorrectObjectTypeException, IOException {

org.eclipse.jgit/src/org/eclipse/jgit/treewalk/filter/ByteArraySet.java

@@ -88,7 +88,7 @@ class ByteArraySet {
 	}
 
 	private static boolean equals(byte[] a, byte[] b, int length) {
-		if (a.length < length || b.length < length)
+		if (a.length != length || b.length < length)
 			return false;
 		for (int i = 0; i < length; ++i) {
 			if (a[i] != b[i])