Fix bug regarding handling of non-versioned files during merge

There was a bug introduced by commit 0e815fe. For non-versioned files
the merge algorithm detected an incoming deletion from THEIRS.
Consequently such files were deleted. That's a severe bug which was
fixed by more precisely detecting incoming deletions.

Change-Id: I4385d3c990db11d62e371a385dc8ee89841db84a
Signed-off-by: Christian Halstrick <christian.halstrick@sap.com>
Signed-off-by: Philipp Thun <philipp.thun@sap.com>
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java

@@ -197,6 +197,56 @@ public class MergeCommandTest extends RepositoryTestCase {
 		assertEquals(RepositoryState.MERGING, db.getRepositoryState());
 	}
 
+	public void testMergeNonVersionedPaths() throws Exception {
+		Git git = new Git(db);
+
+		writeTrashFile("a", "1\na\n3\n");
+		writeTrashFile("b", "1\nb\n3\n");
+		writeTrashFile("c/c/c", "1\nc\n3\n");
+		git.add().addFilepattern("a").addFilepattern("b")
+				.addFilepattern("c/c/c").call();
+		RevCommit initialCommit = git.commit().setMessage("initial").call();
+
+		createBranch(initialCommit, "refs/heads/side");
+		checkoutBranch("refs/heads/side");
+
+		writeTrashFile("a", "1\na(side)\n3\n");
+		writeTrashFile("b", "1\nb(side)\n3\n");
+		git.add().addFilepattern("a").addFilepattern("b").call();
+		RevCommit secondCommit = git.commit().setMessage("side").call();
+
+		assertEquals("1\nb(side)\n3\n", read(new File(db.getWorkTree(), "b")));
+		checkoutBranch("refs/heads/master");
+		assertEquals("1\nb\n3\n", read(new File(db.getWorkTree(), "b")));
+
+		writeTrashFile("a", "1\na(main)\n3\n");
+		writeTrashFile("c/c/c", "1\nc(main)\n3\n");
+		git.add().addFilepattern("a").addFilepattern("c/c/c").call();
+		git.commit().setMessage("main").call();
+
+		writeTrashFile("d", "1\nd\n3\n");
+		assertTrue(new File(db.getWorkTree(), "e").mkdir());
+
+		MergeResult result = git.merge().include(secondCommit.getId())
+				.setStrategy(MergeStrategy.RESOLVE).call();
+		assertEquals(MergeStatus.CONFLICTING, result.getMergeStatus());
+
+		assertEquals(
+				"1\n<<<<<<< HEAD\na(main)\n=======\na(side)\n>>>>>>> 86503e7e397465588cc267b65d778538bffccb83\n3\n",
+				read(new File(db.getWorkTree(), "a")));
+		assertEquals("1\nb(side)\n3\n", read(new File(db.getWorkTree(), "b")));
+		assertEquals("1\nc(main)\n3\n",
+				read(new File(db.getWorkTree(), "c/c/c")));
+		assertEquals("1\nd\n3\n", read(new File(db.getWorkTree(), "d")));
+		File dir = new File(db.getWorkTree(), "e");
+		assertTrue(dir.isDirectory());
+
+		assertEquals(1, result.getConflicts().size());
+		assertEquals(3, result.getConflicts().get("a")[0].length);
+
+		assertEquals(RepositoryState.MERGING, db.getRepositoryState());
+	}
+
 	public void testSuccessfulContentMerge() throws Exception {
 		Git git = new Git(db);
 

org.eclipse.jgit/src/org/eclipse/jgit/merge/ResolveMerger.java

@@ -390,7 +390,7 @@ public class ResolveMerger extends ThreeWayMerger {
 				if (e != null)
 					toBeCheckedOut.put(tw.getPathString(), e);
 				return true;
-			} else if (modeT == 0) {
+			} else if ((modeT == 0) && (modeB != 0)) {
 				// we want THEIRS ... but THEIRS contains the deletion of the
 				// file
 				toBeCheckedOut.put(tw.getPathString(), null);