Revert 4678f4b and provide another solution for bug 467631

Making gitlinks and folders match in a tree walk was the wrong
approach to fix bug 467631. The problem is that in such a conflict
the tree walk may then not descend into the folder.

Revert the changes to Paths.java and PathsTest.java from commit
4678f4b. Instead test for the problem case from bug 467631 explicitly
in IndexDiff. Add Daniel's test case from bug 545162, and add yet
another test case for DiffEntry.scan() that covers the problem
originally reported in bug 545162.

Bug: 545162
Change-Id: Ie2214c5d5ee32ac6596b621f0f1c7b86d38fa9b7
Also-by: Daniel Veihelmann <daniel.veihelmann@gmail.com>
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

2 files changed, 42 insertions, 16 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/IndexDiff.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/IndexDiff.java
index 94b9ddc188..f37c310752 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/IndexDiff.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/IndexDiff.java
@@ -47,7 +47,11 @@
 
 package org.eclipse.jgit.lib;
 
+import java.io.File;
 import java.io.IOException;
+import java.nio.file.DirectoryIteratorException;
+import java.nio.file.DirectoryStream;
+import java.nio.file.Files;
 import java.text.MessageFormat;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -261,6 +265,8 @@ public class IndexDiff {
 
 	private Set<String> missing = new HashSet<>();
 
+	private Set<String> missingSubmodules = new HashSet<>();
+
 	private Set<String> modified = new HashSet<>();
 
 	private Set<String> untracked = new HashSet<>();
@@ -501,9 +507,15 @@ public class IndexDiff {
 				if (dirCacheIterator != null) {
 					if (workingTreeIterator == null) {
 						// in index, not in workdir => missing
-						if (!isEntryGitLink(dirCacheIterator)
-								|| ignoreSubmoduleMode != IgnoreSubmoduleMode.ALL)
-							missing.add(treeWalk.getPathString());
+						boolean isGitLink = isEntryGitLink(dirCacheIterator);
+						if (!isGitLink
+								|| ignoreSubmoduleMode != IgnoreSubmoduleMode.ALL) {
+							String path = treeWalk.getPathString();
+							missing.add(path);
+							if (isGitLink) {
+								missingSubmodules.add(path);
+							}
+						}
 					} else {
 						if (workingTreeIterator.isModified(
 								dirCacheIterator.getDirCacheEntry(), true,
@@ -543,8 +555,8 @@ public class IndexDiff {
 							smw.getPath()), e);
 				}
 				try (Repository subRepo = smw.getRepository()) {
+					String subRepoPath = smw.getPath();
 					if (subRepo != null) {
-						String subRepoPath = smw.getPath();
 						ObjectId subHead = subRepo.resolve("HEAD"); //$NON-NLS-1$
 						if (subHead != null
 								&& !subHead.equals(smw.getObjectId())) {
@@ -573,6 +585,21 @@ public class IndexDiff {
 								recordFileMode(subRepoPath, FileMode.GITLINK);
 							}
 						}
+					} else if (missingSubmodules.remove(subRepoPath)) {
+						// If the directory is there and empty but the submodule
+						// repository in .git/modules doesn't exist yet it isn't
+						// "missing".
+						File gitDir = new File(
+								new File(repository.getDirectory(),
+										Constants.MODULES),
+								subRepoPath);
+						if (!gitDir.isDirectory()) {
+							File dir = SubmoduleWalk.getSubmoduleDirectory(
+									repository, subRepoPath);
+							if (dir.isDirectory() && !hasFiles(dir)) {
+								missing.remove(subRepoPath);
+							}
+						}
 					}
 				}
 			}
@@ -592,6 +619,15 @@ public class IndexDiff {
 			return true;
 	}
 
+	private boolean hasFiles(File directory) {
+		try (DirectoryStream<java.nio.file.Path> dir = Files
+				.newDirectoryStream(directory.toPath())) {
+			return dir.iterator().hasNext();
+		} catch (DirectoryIteratorException | IOException e) {
+			return false;
+		}
+	}
+
 	private void recordFileMode(String path, FileMode mode) {
 		Set<String> values = fileModes.get(mode);
 		if (path != null) {
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/Paths.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/Paths.java
index be1b95e0d4..6be7ddbe12 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/Paths.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/Paths.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2016, 2018 Google Inc.
+ * Copyright (C) 2016, Google Inc.
  * and other copyright owners as documented in the project's IP log.
  *
  * This program and the accompanying materials are made available
@@ -43,7 +43,6 @@
 
 package org.eclipse.jgit.util;
 
-import static org.eclipse.jgit.lib.FileMode.TYPE_GITLINK;
 import static org.eclipse.jgit.lib.FileMode.TYPE_MASK;
 import static org.eclipse.jgit.lib.FileMode.TYPE_TREE;
 
@@ -107,7 +106,7 @@ public class Paths {
 				aPath, aPos, aEnd, aMode,
 				bPath, bPos, bEnd, bMode);
 		if (cmp == 0) {
-			cmp = modeCompare(aMode, bMode);
+			cmp = lastPathChar(aMode) - lastPathChar(bMode);
 		}
 		return cmp;
 	}
@@ -184,15 +183,6 @@ public class Paths {
 		return 0;
 	}
 
-	private static int modeCompare(int aMode, int bMode) {
-		if ((aMode & TYPE_MASK) == TYPE_GITLINK
-				|| (bMode & TYPE_MASK) == TYPE_GITLINK) {
-			// Git links can be equal to files or folders
-			return 0;
-		}
-		return lastPathChar(aMode) - lastPathChar(bMode);
-	}
-
 	private Paths() {
 	}
 }